Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: p2pAmps on October 11, 2015, 06:59:35 am
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For those interested 5E3s here is Doug's rendition of the infamous 5E3 Tweed Deluxe. I am almost done with her as I am still waiting on my Belton tube sockets (I thought I had enough)... The cab will be here from Mather in mid Nov. I haven't made my mind up yet on a speaker so.....
(http://www.emike.net/td/1.jpg)
(http://www.emike.net/td/2.jpg)
(http://www.emike.net/td/3.jpg)
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Nice!
I've been daydreaming about a modified 5E3 but think building one dead stock first makes good sense. I'll save your pics if I decide to use one of Doug's boards.
Chip
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You shoulda been a dentist or a surgeon!
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Opinion question: Do you think I should substitute the unused ground switch for a standby?
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Opinion question: Do you think I should substitute the unused ground switch for a standby?
Read this before making your decision or implementing:
http://www.valvewizard.co.uk/standby.html (http://www.valvewizard.co.uk/standby.html)
It's a great spot for another fuse.
Really nice work on everything you've posted.
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Opinion question: Do you think I should substitute the unused ground switch for a standby?
Read this before making your decision or implementing:
http://www.valvewizard.co.uk/standby.html (http://www.valvewizard.co.uk/standby.html)
It's a great spot for another fuse.
Really nice work on everything you've posted.
That was an interesting read, thank you, and thanks for the nice comment
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I'd keep it original. Just get a Class Y cap. The amp does look nice.
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Wow! Neat and colorful--I like it. A 5E3 is just plain fun :happy1:
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Note that the Hoffman 5E3 layout doesn't include 100Ω resistors for a virtual center-tap on the board, and it looks like your chosen PT doesn't have a heater center-tap.
When I built a Hoffman 5E3, I noticed this after finishing assembly; I added the 100Ω resistors at the input tube. I had a resistor each for 4/5 & 9, joined the free ends together in a ring terminal, crimped/soldered, and then secured the ring terminal under a mounting bolt for the input tube socket.
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Why stick with only carbon comp resistors?
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Note that the Hoffman 5E3 layout doesn't include 100Ω resistors for a virtual center-tap on the board, and it looks like your chosen PT doesn't have a heater center-tap.
When I built a Hoffman 5E3, I noticed this after finishing assembly; I added the 100Ω resistors at the input tube. I had a resistor each for 4/5 & 9, joined the free ends together in a ring terminal, crimped/soldered, and then secured the ring terminal under a mounting bolt for the input tube socket.
Hi, yeah those 2 100Ω are there, just hard to see in the current pics. Look real close under the pilot light... I tucked the green/yellow wire inside the PT...
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Why stick with only carbon comp resistors?
Well, I guess I don't have a solid answer other than so far everything I have built with CC sound great and I have not had any issues (so far)...
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Hi, yeah those 2 100Ω are there, just hard to see in the current pics. Look real close under the pilot light... I tucked the green/yellow wire inside the PT...
Gotcha! I see those 100Ω's now.
It's probably personal preference, but I'd have used the PT's center-tap given it was available. Separately, unless you're trying to replicate the 5E3, I've found soldering to the pilot-light assembly is needlessly-hard. Those resistors work the same wherever you place them along the heater string.
That said, nice, neat installation!!
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Opinion question: Do you think I should substitute the unused ground switch for a standby?
How do your voltages compare with "true" vintage voltages? Given the physical location of the Ground switch, adding some form of sag switch might be in order? Don't know whether you want to add resistance between the supply cap and the screen alone, add a sag resistor between the rectifier and the reservoir (plate node cap) dropping voltage on entire power rail, or increase the resistance between the plate and screen grids from 4.7K to drop screen and preamp voltages.
Or you could try Geezer's cathode bypass attenuator switch as shown on Sluckey's website: http://home.comcast.net/~seluckey/amps/misc/Amp_Scrapbook.pdf (http://home.comcast.net/~seluckey/amps/misc/Amp_Scrapbook.pdf)
My first thought was a master volume in place of the 1 meg grid leak for the PI stage, but I think that switch is just a bad spot for that due to high voltage all around.
Chip
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Opinion question: Do you think I should substitute the unused ground switch for a standby?
How do your voltages compare with "true" vintage voltages? Given the physical ocation of the Ground switch, adding some form of sag switch might be in order? Don't know whether you want to add resistance between the supply cap and the screen alone, add a sag resistor between the rectifier and the reservoir (plate node cap) dropping voltage on entire power rail, or increase the resistance between the plate and screen grids from 4.7K to drop screen and preamp voltages.
Chip
I wish I knew what you were talking about LOL... Dude, I am a total rookie but I have fun just the same
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Opinion question: Do you think I should substitute the unused ground switch for a standby?
I have read many times about not needing a standby and I must say I always keep mine in the operate position. I built a replica of a 63 Vibroverb for a fellow player and used the standby for a dwell. Well the guy had a squealing worm extrude from his rear end. I put him a standby switch in and left the dwell a 1 meg resistor.
So I usually waste a nice Carling Switch so someone can flip on their DC.
On my 5E3 I have a couple of extras like a switch to change the first Bypass to a 4.7 and reduced the bypass cap values to get headroom since they distort so quickly. BTW, in the schematic library there is a schematic of the reissue that has the voltages.
Nice work. BTW, I have been on your youtube site and I believe you have a tad more knowledge than you claim.
Here are a few images for mods on the 5e3. The gain switch is nice.
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Incredible build and I cant believe you dressed each component leg :worthy1: . I read that same article on standby swtiches some time back and thought the same thing about a waste of a switch.
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Very nice build. I miss my 5E3. Your looks great!
The only thing I didn't like about it was the fact that it didn't seem to have much in the way of volume control. Anything past about 2 or 3 seemed to be almost full volume.
Steve
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Very nice build. I miss my 5E3. Your looks great!
The only thing I didn't like about it was the fact that it didn't seem to have much in the way of volume control. Anything past about 2 or 3 seemed to be almost full volume.
Steve
Yeah Steve I get what you are saying. What I am looking forward to is playing with the circuit and some different mods. There is so much info out there it will be neat to try some different things. Ed Chambley has a lot of great info on 5e3s as do many other guys here on the forum.
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:worthy1:
So, for the 1st preamp gain stage, I made up a couple of brackets from some parts I had laying around to mount a couple of rotary switches. They both are movable so I can use them on other gain stages too. I did test and mark the outside foil on the CC's. (They don't look real pretty but they work fine.)
I saw how to that with the caps but can't remember anymore, could you explain please
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Ummmm, how did you get my quote from a different thread in this thread? :dontknow:
I mean, I know how but why?
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:laugh: I did cross threads, sorry. But I'm still interested in knowing how to find the positive end of a cap
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The positive end of the cap? :dontknow:
Is this what your looking for?
http://el34world.com/Forum/index.php?topic=11427.0 (http://el34world.com/Forum/index.php?topic=11427.0)
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That's exactly what I was looking for, thanks.
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:icon_biggrin:
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Since this is a Tweed build have you thought about a speaker yet? I stuck the WGS 12" in my 5G9 just to test and it sounds great but to clean at higher volumes. I assuming this is because it's a 60 watt speaker. I did bid on a 50's era(53to be exact) Jensen P12R alnico to get me in the correct period. It's from a reputable source and has been tested, for the same price as a new one
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Ok, so I finally fired this guy up an hour ago and OMG! It sounds amazing! Seriously. Now, once i get the cab and speaker I will re-evaluate but if it sounds the same or better I will be one happy dude...
Deluxe Reverb next on the list :icon_biggrin:
(http://p2pamps.com/td/4.jpg)
(http://p2pamps.com/td/5.jpg)
(http://p2pamps.com/td/6.jpg)
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So what did you end up going with, stock circuit, any mods?
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Sluckys Tweed Deluxe Reverb would be a great project.
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So what did you end up going with, stock circuit, any mods?
Well, no mods yet... I am waiting to get the cab and speaker first then re-look at things
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Sluckys Tweed Deluxe would be a great project.
I would be very interested in seeing Steve's build and changes... Sluckey?
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Sluckeys Tweed Deluxe Reverb:
http://home.comcast.net/~seluckey/amps/tdr/tdr.htm (http://home.comcast.net/~seluckey/amps/tdr/tdr.htm)
Note that it's an AB763 circuit with a single channel which has reverb. No tremolo. The "Tweed" aspect is the chassis and cab, not really the circuit if I understand correctly. It's a really neat project - a Blackface in Tweed clothing. What's so cool about the project is physically fitting the Blackface AB763 circuit into that chassis...
:worthy1:
Doug has a complete project for a single-channel Deluxe Reverb with tremolo:
http://el34world.com/Hoffman/files/Hoffman_AB763_1.pdf (http://el34world.com/Hoffman/files/Hoffman_AB763_1.pdf)
An interesting question would be "Can you fit this board into a Princeton Reverb chassis?" Take out the tremolo since it uses a 12AX7 you don't have space for. If the board fits, you could use it "as is", but all of the circuitry for the tremolo and V4 (that tube you don't have space for) is together. Maybe you could cut that section out of the board, leaving you with two boards and shorter combined length. Control pots: Volume, Treble, Middle, Bass, Dwell and Reverb. That would be a wolf in sheep's clothing too although many would prefer a 12" speaker. I've read about guys stuffing a 12" into a PR cab though...
Chip
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She is all but finished now. I have a few small changes to do while I tweak it in. Fun amp and sound pretty cool with my PR in stereo!
(http://p2pamps.com/td/8.jpg)
(http://p2pamps.com/td/9.jpg)
(http://p2pamps.com/td/10.jpg)
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Your work is always top notch!
I appreciate your attention to every little detail. Like how you made sure to give your speaker jacks some clearance from the AC heater wires.
Many would just run those in tight to the chassis, practically on top of those jacks, and then wonder why they have hum.
Like Ed, I also think you have far more experience than you admit to.
:worthy1:
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Your work is always top notch!
I appreciate your attention to every little detail. Like how you made sure to give your speaker jacks some clearance from the AC heater wires.
Many would just run those in tight to the chassis, practically on top of those jacks, and then wonder why they have hum.
Like Ed, I also think you have far more experience than you admit to.
:worthy1:
Thank you so much but guess what? I do have some hum :( I need to go through this thing from top to bottom. I have already checked all the obvious stuff. Next I will go through the ground routing which I will make perfect if its not. This is a side project while I work on a PR and a Twin Reverb frame off resto. Oh yeah, I have a day job too LOL
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I do have some hum
I don't see a real center tap for the filament winding. Nor do I see an artificial center tap ( 2 x 100Ω resistors). The whole purpose of referencing the filament circuit to ground through use of a center tap is to reduce hum.
Look at page 2 of this pdf to see how Doug connected the artificial ceter tap resistors...
http://el34world.com/Hoffman/files/Hoffman_5E3.pdf (http://el34world.com/Hoffman/files/Hoffman_5E3.pdf)
Yeah Steve, the 2 100Ω CT are hung off the pilot, hard to see in my pics but they are there. I'm going to tear all the grounds out tonight and re-solder them all to one PT bolt on the power side.
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Ah. I found them.
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Ah. I found them.
I think I may have my grounds separated too much. Sooooo, I brought the CT off the pilot, the AC ground, the cap ground, and the red/yellow off the OT all the the same lug on the PT. That may have helped a little but I still hear a hum. This amp is grounded exact to Doug's layout. Yes, I did swap tubes for known good ones, no change so far
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Mike - I'd add a separate grounding bolt close to the power tubes and not use a PT bolt. Just my approach.
Can you use vertical separation to get heater wires farther away from preamp caps, etc?
You might try tacking the virtual center tap to one of the power tube sockets and "grounding" at top of shared cathode resistor. More typical to elevate the heater ground in a single-ended amp or one with a cathode follower, but it might help here.
Cab looks great BTW!
Chip
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Mike - I'd add a separate grounding bolt close to the power tunes and not use a PT bolt. Just my approach.
Can you use vertical separation to get heater wires farther away from preamp caps, etc?
You might try tacking the virtual center tap to one of the power tube sockets and "grounding" at top of shared cathode resistor. More typical to elevate the heater ground in a single-ended amp or one with a cathode follower, but it might help here.
Cab looks great BTW!
Chip
"Mike - I'd add a separate grounding bolt close to the power tunes and not use a PT bolt. Just my approach. "
I usually do that on Bassmans and most BF/SF Fenders
Can you use vertical separation to get heater wires farther away from preamp caps, etc?
Well I did pull the heater wires away from the caps while running with my chop stick, no change in hum at all.
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I think I may experiment around a little and try this ground scheme to see what happens...
(http://p2pamps.com/ground.jpg)
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Maybe ground the first two E caps to the PT bolt and the Pre-amp E cap to the input jack ground or near it ...? Separate the HT grounds from the Pre-amp grounds.
As far as a stock 5E3 most think too much mud and bassy, most change the coupling caps from .1 to .047 in the pre-amp. Maybe change the cathode caps on the first stage from 22uf to around 5uf. This will tight'n up the amp, take away the mud at higher volumes.
Very clean build,
al
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Maybe ground the first two E caps to the PT bolt and the Pre-amp E cap to the input jack ground or near it ...? Separate the HT grounds from the Pre-amp grounds.
As far as a stock 5E3 most think too much mud and bassy, most change the coupling caps from .1 to .047 in the pre-amp. Maybe change the cathode caps on the first stage from 22uf to around 5uf. This will tight'n up the amp, take away the mud at higher volumes.
Very clean build,
al
Hi and thanks. I already change the 1st bypass cap to a 4.7uF and all the .1s to .022. Tone is great just have to track down the hum issue
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HBP has talked about Fenders reasoning in how they dressed the heater wires in the tweed amps and the brown/black face amps.
In the tweed amps they tucked the heater wires up in the chassis fold to get distance from the the eyelet boards sensitive part leads. The black/brown face amps the chassis is laid out differently so they were able to leave the heater wires up in the air above the tube sockets and still have them away from the eyelet board.
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What is the green wire that the green arrow is pointing to?
And I can't see where the B+ CT, red arrow, is connected to the 1st B+ filter caps ground?
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What is the green wire that the green arrow is pointing to?
And I can't see where the B+ CT, red arrow, is connected to the 1st B+ filter caps ground?
Ok, so right now the heaters are as in the pictures which I may change.
The CT from the pilot is on a ground lug on the PT
The AC ground, same lug
The PT, same lug, and the board, same lug
On the preamp side I have it grounded exactly like Doug's layout... Using the brass plate, all pots are bussed together and connected to inputs
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Ok, so your 1st filter cap ground from the eyelet board is the black wire that runs from the board under the fuse and to that PT ground lug with the heater faux CT?
I'd try moving the PT B+ CT from where you have it now over to the black wire and heater faux CT.
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I do have some hum :( I need to go through this thing from top to bottom. I have already checked all the obvious stuff.
Does hum change or go away when you pull preamp tubes? Do you have any high-value (like 100uF+) cathode bypass caps laying around?
Overall, I have confidence in your work that solder joints and ground connections are good. You also noted chopsticking heater wires didn't help hum, so I'd tentatively eliminate that (yes, I've talked before about how Fender tucked the heater wiring into the chassis lip on tweed models, but if moving what you have doesn't give noticeable improvement I'm doubtful about rerouting the wiring).
My overall hunch is tube heater-to-cathode leakage. Freshstart's suggestion to "ground" the 100Ω resistors to the cathode-side of the output tube cathode resistor would help alleviate this, as would a massive (100-330uF) cathode bypass cap on the input tube (if that tube has leakage). I've convinced myself that Fender put the 250uF bypass on the Bassman not to get gain to very low frequencies, but as insurance against preamp tube leakage.
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I do have some hum :( I need to go through this thing from top to bottom. I have already checked all the obvious stuff.
Does hum change or go away when you pull preamp tubes? Do you have any high-value (like 100uF+) cathode bypass caps laying around?
Pulling the V1 tube does not change the hum
Overall, I have confidence in your work that solder joints and ground connections are good. You also noted chopsticking heater wires didn't help hum, so I'd tentatively eliminate that (yes, I've talked before about how Fender tucked the heater wiring into the chassis lip on tweed models, but if moving what you have doesn't give noticeable improvement I'm doubtful about rerouting the wiring).
My overall hunch is tube heater-to-cathode leakage. Freshstart's suggestion to "ground" the 100Ω resistors to the cathode-side of the output tube cathode resistor would help alleviate this, as would a massive (100-330uF) cathode bypass cap on the input tube (if that tube has leakage). I've convinced myself that Fender put the 250uF bypass on the Bassman not to get gain to very low frequencies, but as insurance against preamp tube leakage.
I'm going to give grounding the 100Ω resistors to the cathode-side of the output tube cathode resistor is whirl and see what happens. I have a 300Ω 10watt cathode resistor in place now as I thought she was running a little hot. I was out of 330Ω so I used a 300 for now.
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Got it, how about V2?
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> try this ground scheme
Your input jacks are full-metal, right? So the green wire at the input jacks IS tied to chassis.
Then you have that green wire running off as "Y" and tying it to chassis *again* at/near the PT.
Usually two paths between two chassis points invites trouble (though trouble does not always result).
If your HIGH current grounds around the power and OUTput stage are tied to PT chassis, then it "can" work to have the first stages tied to ground *only* at the input jacks. While this means combined power and signal in chassis from preamp to power section, the preamp power is small and clean, so may not induce hum.
That's what I did on my Champish project. With test gear, the output hum with Volume at zero was nearly zero (determined to be reasonable for the power filtering I had). As the volume came up, hum rose, but it seemed to me to be entirely reasonable for an open chassis under large fluorescent lamps; I'd expect less with a bottom plate and a less hostile place.
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> try this ground scheme
Your input jacks are full-metal, right? So the green wire at the input jacks IS tied to chassis.
Then you have that green wire running off as "Y" and tying it to chassis *again* at/near the PT.
Usually two paths between two chassis points invites trouble (though trouble does not always result).
If your HIGH current grounds around the power and OUTput stage are tied to PT chassis, then it "can" work to have the first stages tied to ground *only* at the input jacks. While this means combined power and signal in chassis from preamp to power section, the preamp power is small and clean, so may not induce hum.
That's what I did on my Champish project. With test gear, the output hum with Volume at zero was nearly zero (determined to be reasonable for the power filtering I had). As the volume came up, hum rose, but it seemed to me to be entirely reasonable for an open chassis under large fluorescent lamps; I'd expect less with a bottom plate and a less hostile place.
PBR, you lost me with the green wire on the input jacks???? The grounds on my inputs are white... The only green wires are at the speaker jacks and the filament wires...
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I think he's looking at the layout drawing you posted in reply #40.
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I think he's looking at the layout drawing you posted in reply #40.
LOL, I'm a Dumba$$
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Maybe ground the first two E caps to the PT bolt and the Pre-amp E cap to the input jack ground or near it ...? Separate the HT grounds from the Pre-amp grounds.
As far as a stock 5E3 most think too much mud and bassy, most change the coupling caps from .1 to .047 in the pre-amp. Maybe change the cathode caps on the first stage from 22uf to around 5uf. This will tight'n up the amp, take away the mud at higher volumes.
Very clean build,
al
Hi and thanks. I already change the 1st bypass cap to a 4.7uF and all the .1s to .022. Tone is great just have to track down the hum issue
Makes the amp really guitar friendly. All types of pups, doesn't it. It also gives a tad more headroom. When you get the hum issue fixed, I have a alternative way of wiring the Volumes and a Dual Pot on the tone control which completely separates the volumes completely. It is simply the same as the 6G3 Deluxe. I had it set up this way to use for live adding a Celestion Blue. I also added a side chain compressor and the trick switch. It also had the paul C mod (ampeg) and raised the voltage on the PI by lowering the rail resistor. Not much mind you.
The Paul C mod or the Ampeg mod, I ended up with a 3m7 Resistor and it is almost like a mini 5f4 with a 2. 10.
I also have another which is almost stock except for the changing the high pass and creating a frequency cutoff with a low pass filter. I added a cut control to this one and this with the standard tone control and adjustable NFB I can still get a good bit of headroom. This one has a verb too.
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try a new / different 5y3
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I was stumped by the hum you described about three years ago, never thought about the rectifier tube.. that's what solved it... even tore the board out , chasing the hum.
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I was stumped by the hum you described about three years ago, never thought about the rectifier tube.. that's what solved it... even tore the board out , chasing the hum.
Yeah, been there already. I have new and NOS 5Ys... same with all tubes. I don't think this is a tube issue.
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Not reading all the threads.. is this your first 5E3 ?
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You've tried to parallel all E- caps ?
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Too see if one is Faulty Towers ?
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Not reading all the threads.. is this your first 5E3 ?
Hi Floyd, yes this is my first 5e3 build but I have built many other Fender amps. I just need some time to sit down and go through this thing step by step and solve the hum issue. Between work, two other money builds, and TG coming up I haven't been able to devote a lot of time. Soon I hope
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Well guys, I have been through this this pretty carefully and still have a slight hum. Any hum at all is just not acceptable to me as I certainly can't record an amp with noise. I am starting to wonder if the OT is giving me grief or is this something I have done (probably me)... Not to sure where to go from here. I am considering tearing the board out and starting over with a traditional layout.
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When I suggested pulling tubes, I intended (but didn't say) you should pull V1, see if you have hum, then replace it and pull V2. You repeat this process working from input to output to try to localize which stages have/influence the hum. Believe it or not, I once fixed an amp where the hum was only eliminated by pulling the output tubes; the fault was a failed bias filter cap which was injecting 60Hz straight into the output tube grids.
If you think there is hum from PT to OT, you could try placing a steel sheet between them to see if it blocks the hum (one site on the web shows a guy using a piece of galvanized duct sheeting).
Some variation of Doug's Listening Amp (http://el34world.com/Hoffman/tools.htm) is probably a good tool to localize the hum source.
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Don't rip out the Hoffman board.. I sent you a PM.. try that
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You have the + of the main filter caps running under the pots ? ? Why would the Hoffman board do that . or did YOU change the orientation ?
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You have the + of the main filter caps running under the pots ? ? Why would the Hoffman board do that . or did YOU change the orientation ?
Floyd was 1000% right. I swapped the 2 16uF caps around that were near the pots and she is dead silent now! I am grateful Floyd caught that, thank you so much bro... Here is a new pic of the changes. I would guess others might see this issue too till they flip those caps. Again, big thanks to Floyd, I am always learning new things...
(http://p2pamps.com/fix.jpg)
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Wow, nice catch!!
I built a 5E3 with the standard Hoffman arrangement and had zero hum problems. However, this just goes to show something which may be a problem could also not manifest that problem but in a few instances.
Doug may need to consider re-doing the layout; the problem was likely the wire from rectifier to 1st filter cap right under the pots.
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It sure is busy under the speaker jacks, but that was a great observation.
+1 on some layout detail being fine in 98% of builds but occasionally being a problem.
Thanks guys,
Chip
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It sure is busy under the speaker jacks, but that was a great observation.
+1 on some layout detail being fine in 98% of builds but occasionally being a problem.
Thanks guys,
Chip
Indeed. I plan to go back and clean up the wiring under the jacks best I can. I always like very clean wiring and mine is sort of a mess right now after half tearing the board out.
Flyod makes a very good point that we all should already know, keep that B+ away from anything preamp, pots for instance. When you look at the original layout the + on the filter caps is oriented away from the pots too. All makes since now...
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keep that B+ away from anything preamp, pots for instance.
More specifically, KEEP THE FIRST FILTER CAP B+ AWAY FROM PREAMP. There is usually 5 to 10VAC ripple on the B+ at that first cap. I like to keep the screen node cap B+ away from sensitive stuff too, even though the ripple AC is much reduced.
But by the time the B+ reaches the third filter cap the ripple is reduced so much that there is no problem running a B+ wire next to the preamp. Third node B+ should be about as clean as chassis ground.
You left the third filter cap oriented like the original layout, right? And it's right under the input jacks.
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keep that B+ away from anything preamp, pots for instance.
More specifically, KEEP THE FIRST FILTER CAP B+ AWAY FROM PREAMP. There is usually 5 to 10VAC ripple on the B+ at that first cap. I like to keep the screen node cap B+ away from sensitive stuff too, even though the ripple AC is much reduced.
But by the time the B+ reaches the third filter cap the ripple is reduced so much that there is no problem running a B+ wire next to the preamp. Third node B+ should be about as clean as chassis ground.
You left the third filter cap oriented like the original layout, right? And it's right under the input jacks.
Steve, I did leave that 3rd cap in place as I wanted to see the results before I tore it down even more. The amp is dead dead quite now so I figured I would leave well enough alone. Sounds like you would flip that 3rd cap too????
My only surprise is I am sure there have been many who have followed the turret layout and had good results, maybe not, but who knows. One thing is for sure at least on my build, flipping cap 1 and 2 around did the trick in this case...
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Sounds like you would flip that 3rd cap too????
No! That's not what I meant. I meant that by the time the B+ gets to that third cap the ripple is reduced to practically nothing and is NOT a problem having B+ near sensitive preamp circuit.
Then I used the fact that you did not flip your third cap as an example to reinforce that statement. The overall point being, power amp B+ and grounds are dirty. Keep both away from preamp circuits. Preamp B+ and grounds are clean and will not induce hum into sensitive circuits.
My only surprise is I am sure there have been many who have followed the turret layout and had good results, maybe not, but who knows.
Not all of those 5E3s were put into a tweed style chassis. If that board were installed in a chassis similar to a Princeton Reverb, the cap orientation would likely be a non-issue. I would likely have lost a lot of hair before finding that solution. Lifting a board in a tweed style chassis is a lot bigger job that it would seem when just talking about it.
I think you should pm Doug and point him to this thread. That mod would be painless to do while the board is still naked. It makes a lot of sense to me to make that a permanent change.
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I have sold probably sold over 100 of the 5E3 boards over the years, never heard of a hum issue regarding cap orientation
Also, many of my boards have the + end of the caps facing toward the pots, never heard of an issue
I have built a bunch of amps including bassmans with the caps oriented like that, no problems
If you look at my builds on the library page you can see the exact same cap orientation.
Most likely it's a ground issue somewhere
Check out these pics of some builds
http://el34world.com/Hoffman/images/Dscn0294.jpg (http://el34world.com/Hoffman/images/Dscn0294.jpg)
http://el34world.com/Hoffman/images/Img_8786.jpg (http://el34world.com/Hoffman/images/Img_8786.jpg)
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Another example of this phenomena is when I built a Super Reverb and had problems with the tremolo circuit injecting its signal elsewhere in the amp. I'd done my own layout closely following Doug's older design. Drove me crazy until I broke out the listening amp and discovered that it showed up on the first phase inverter grid. Running leads from Speed and Intensity pot 1/2" or more above the board and having them drop straight down to their connection points fixed it.
On the older Hoffman AB763 you'll see that there's a little extra space between the tremolo circuit and the phase inverter. Not much, but I'm guessing it was there for a reason. I'd packed it tighter.
http://el34world.com/Hoffman/images/AB763OldTwoChannel.gif (http://Older AB763 Layout)
If you read Kevin O'Connor, Merlin, and other experts, you begin to think "Gee, Leo Fender sure cut corners in his layouts to save costs." Yes, he did. But they worked. So do Doug Hoffman's.
DON'T BOZO THE LAYOUT!
Regards,
Bozo
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Another example of this phenomena is when I built a Super Reverb and had problems with the tremolo circuit injecting its signal elsewhere in the amp. I'd done my own layout closely following Doug's older design. Drove me crazy until I broke out the listening amp and discovered that it showed up on the first phase inverter grid. Running leads from Speed and Intensity pot 1/2" or more above the board and having them drop straight down to their connection points fixed it.
On the older Hoffman AB763 you'll see that there's a little extra space between the tremolo circuit and the phase inverter. Not much, but I'm guessing it was there for a reason. I'd packed it tighter.
http://el34world.com/Hoffman/images/AB763OldTwoChannel.gif (http://Older AB763 Layout)
If you read Kevin O'Connor, Merlin, and other experts, you begin to think "Gee, Leo Fender sure cut corners in his layouts to save costs." Yes, he did. But they worked. So do Doug Hoffman's.
DON'T BOZO THE LAYOUT!
Regards,
Bozo
I did not BOZO the layout at all, I followed it to the T. I merely flipped the + side of the first two filter caps and my hum disappeared.
Believe me, I am not here to talk down to anything or any layout, I am hear to learn and post what I have personally experienced, thats it...
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If it works for you and amp is quiet, that's all that matters
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Mike - Sorry!
My "Don't bozo the layout" message was NOT intended for you! You faithfully followed Doug's layout.
I was just trying to emphasize how important little things in the layout may be important for reasons we may not see right off. I sure didn't "get it" for my first couple of builds.
You fixed the problem in your build and shared that fix with the rest of us. Thanks!
Chip
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Mike - Sorry!
My "Don't bozo the layout" message was NOT intended for you! You faithfully followed Doug's layout.
I was just trying to emphasize how important little things in the layout may be important for reasons we may not see right off. I sure didn't "get it" for my first couple of builds.
You fixed the problem in your build and shared that fix with the rest of us. Thanks!
Chip
Thanks Chip
:icon_biggrin: :icon_biggrin: :icon_biggrin:
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Hard to say why your build had hum
As long as you got it down to a level that you like, that's all that matters
I was looking at your pics
Hard to see some things in detail, but just some random notes
The Main CT (red/yellow), Heater CT (from 100 ohms) and the main black ground wire from the 16uf caps should all go to the same chassis ground point.
The red wire coming from the tube rectifier should not be anywhere near the pots
It's DC but not smooth DC
In the pic below, it's right up against a pot
If possible, keep the input jack tips as far away from any parts on the board
I always try and mount the board as close to the tube sockets as I can and have as much space as you can get on the pot side of the board
It's more difficult building inside Tweed chassis because they are not very tall
I am not too fond of building inside tweed chassis
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Hard to say why your build had hum
As long as you got it down to a level that you like, that's all that matters
I was looking at your pics
Hard to see some things in detail, but just some random notes
The Main CT (red/yellow), Heater CT (from 100 ohms) and the main black ground wire from the 16uf caps should all go to the same chassis ground point.
The red wire coming from the tube rectifier should not be anywhere near the pots
It's DC but not smooth DC
In the pic below, it's right up against a pot
If possible, keep the input jack tips as far away from any parts on the board
I always try and mount the board as close to the tube sockets as I can and have as much space as you can get on the pot side of the board
It's more difficult building inside Tweed chassis because they are not very tall
I am not too fond of building inside tweed chassis
Thanks Doug for the notes. So, I had already moved the CT to the same ground lug before changing the caps around which had no effect but I did it anyway. As far as the red rectifier wire, you're right that it was to close to the pot. In hind sight it would have been more scientific if I would have move that wire first and noted the results.
Mounting the board closer to the tube sockets is another good idea. I kinda centered mine.
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Looking at Doug's posted layouts (with the + side E caps near the pots and no mum), I do see that Mike's E caps were slightly closer to the pots, maybe much closer than Doug's.....?
If that's all Mike did to rid the hum, seems like that was the culprit.
I don't think there is anything wrong with Doug's posted layouts, just that they have "more" space than Mike's.
Moral of the story "watch that distance", close is "no problem (like Doug's), real close "might" be.
Good learning thread.
al
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Hard to exactly why it hummed
We would have had a bunch of threads like this here if every tweed chassis type build since the 1990's resulted in hum
I'd say the 5F6A and 5E3 were the first two turret boards I started making back in the mid to late 90's some time
There's a zillion of them out there in the wild
I have a tons of builds where the filter caps are along the back of the pots even closer than what Mike had in his build
So there's high voltage DC less that 3/8th's of an inch from several pots in a bunch of my builds
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> The Main CT (red/yellow), Heater CT (from 100 ohms) and the main black ground wire from the 16uf caps should all go to the same chassis ground point.
The rectifier return (here red/yellow) and the first-cap MUST come together in one point.
In many classic layouts this is a Chassis point.
It is possible to wire an amp so this is not chassis, but that's a very different plan.
The Heater CT return is not at all critical (if it is, you have a bad heater).
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Sound clip of two Hoffman amps... PR and 5E3
Recorded on my iPhone so use your imagination on the in person sound....
! No longer available (http://www.youtube.com/watch?v=RuxkodyG-bQ&feature=youtu.be#)
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Sounds good from here!
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Sounds good from here!
Thank you Doug... Now if I could learn to play better I might be on to something :)
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Sounds good from here!
Thank you Doug... Now if I could learn to play better I might be on to something :)
You play well enough! :icon_biggrin:
You just build better!!! :l2:
This is not meant to diss your playing in any way, just to say IMO you are a virtuoso builder.
Your attention to detail and craftsmanship is rare. IMO, You are a Master builder! :icon_biggrin:
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Very impressive playing and I loved the tone of both amps! Very nice. THANKS for sharing it!
With respect, Tubenit
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Man, now that's a lot of sound from 2 little amps! :icon_biggrin:
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Sweet! :m8
If that's what they sound like through an iPhone mic, I wanna hear 'em properly mic'd...
Cheers,
Chip
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Sweet! :m8
If that's what they sound like through an iPhone mic, I wanna hear 'em properly mic'd...
Cheers,
Chip
Agreed Chip. I should be using it real soon on a few sessions if the tunes call for that sound. You never know till you get to the studio sometimes what amp you will use...
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Playing 2000 seats tonight and this is all I need!!
(http://p2pamps.com/td.jpg)
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:laugh: Yeah you and Neil Young with a 5E3 miced up in a big room.
Have a great gig Mike! :icon_biggrin:
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I've built a you know what load of the Hoffman 5E3 amps. It is my favorite amplifier ever. Attached is the layout I have used for everyone.
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On the preamp side I have it grounded exactly like Doug's layout... Using the brass plate, all pots are bussed together and connected to inputs
That is old school and criticized. No offense but that layout is not recommended by a number of "ampologists" like Aiken, Merlin, Weber, to name a few. It works at times like anything but Fender's in general are known to be prone to hum issues, also steel chassis, tranny placements, cap cans, Switchcraft jacks, lead dress, etc. besides grounding all could be much improved upon.
Here's my tweaked tweedy...ppimv next to Tone, switched Presence in Tone placement, post tone stack Vol in 1st Vol slot, Treb & Bass in two inputs with small knobs, and Gain control in other input after 1st stage. Quiet as a church mouse and I use the Standby as we could go 1/2 hour between sets and I use it for garage runs to make other circuit tweeks to other equipment when testing or making a fresh beer run.
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On the preamp side I have it grounded exactly like Doug's layout... Using the brass plate, all pots are bussed together and connected to inputs
That is old school and criticized. No offense but that layout is not recommended by a number of "ampologists" like Aiken, Merlin, Weber, to name a few. It works at times like anything but Fender's in general are known to be prone to hum issues, also steel chassis, tranny placements, cap cans, Switchcraft jacks, lead dress, etc. besides grounding all could be much improved upon.
Here's my tweaked tweedy...ppimv next to Tone, switched Presence in Tone placement, post tone stack Vol in 1st Vol slot, Treb & Bass in two inputs with small knobs, and Gain control in other input after 1st stage. Quiet as a church mouse and I use the Standby as we could go 1/2 hour between sets and I use it for garage runs to make other circuit tweeks to other equipment when testing or making a fresh beer run.
Jojo, my hum issue turned out to be the first 2 filter caps B+ side way to close to the pots. I re-orientated those caps and the hum vanished...
I know there are many mods to the 5e3 but I honestly love mine exactly the way it is... Call me weird :)
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It's not any sort of fact that Fenders have hum issues
I have built a ton of Fender circuit without hum
Barry just stated up above that he has built the same layout a S***load of times
I doubt either one of us would continue building the same way if there were issues
Who knows why Mikes amp hummed
All that matters is he has it working like he wants
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It's not any sort of fact that Fenders have hum issues
I have built a ton of Fender circuit without hum
Barry just stated up above that he has built the same layout a S***load of times
I doubt either one of us would continue building the same way if there were issues
Who knows why Mikes amp hummed
All that matters is he has it working like he wants
I do have to say guys I could not be happier with my 5e3. I played a 2K seater last night and the amp sounded amazing! I had 3 different guys come to me after the show I never met before telling me my tone was outstanding. I think it's great we can all try different stuff and in the end make it work!
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Who knows why Mikes amp hummed
All that matters is he has it working like he wants
Exactly right. Wasn't trying to do anything to upset anyone just point out some of Fender's weaknesses. And they had many at various points along the way. But in the end overall they made some of if not the best sounding amplifiers OAT. But just because someone built something a bunch of times doesn't make it right, correct, or the best. It could mean that mistakes are simply being repeated. Good, bad, or indifferent. You and Barry don't do or use things exactly the way Fender did at every point along the way back in the day also, correct? Case in point - you use a three prong grounded Vac plug, don't use the cheesey old fiber eyelet boards, twist up the heater wires w/ artificial CT ground resistors instead of grounding one side of the string, employ better filtered power supply strings, install grid stop resistors mounted directly to the tube sockets as they are supposed to be, etc... There are good reasons for doing things a certain way when it's been proven to be an improvement over another. Those who resist change are often left behind or simply stuck in old ways. Again - I'm not saying you or Barry are like this...only objective viewpoints. You guys are held in high esteem 'round here.
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I am not one of those guys that does everything exactly like Fender did
You can tell that by looking at my layout compared to fenders
Mt turret board layout is way different
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The Hoffman layout 5E3 with the changes from the original Fender (layout, grounding, choke added etc) is in my opinion one of the greatest sounding amplifiers with a tele or strat one can find anywhere. I get feedback all the time on the Hoffman 5E3 amps I built years ago as they change hands (either from G.A.S. or at estate sales) from the new owners saying in essence "Wow!" or "Holy Crap!" "This thing sounds awesome." Some of them are in recording studios and others are being gigged with in the Hollywood world on soundtracks for video games and movies. Every time I plug my ash telecaster into my personal Hoffman 5E3 it just makes me smile. Incredible tone to be sure. The Hoffman BFPR and BFDR with the bias vary tremolos are also incredible. I'm really looking forward to finally building and hearing the Sluckey AC15 amp. I'm figuring it will be the next holy grail amp with which I have a tonal love affair. Prior to finding Doug's website years ago, I was trying to play blues and rock through a Roland JC120 solid state amp. Then I built a Hoffman 5E3 on my kitchen table in Corona and my musical life was forever changed. The Roland went on eBay almost immediately and I've never missed it. It's tube amps for me till death now.
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It's tube amps for me till death now.
Barry, glad to see you around again my friend.
I am not one of those guys that does everything exactly like Fender did
You can tell that by looking at my layout compared to fenders
Mt turret board layout is way different
Doug thank you for confirming what I earlier said. Fender amps were not the picture of perfection in their layouts, lead dress, and materials used.
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The Hoffman layout 5E3 with the changes from the original Fender (layout, grounding, choke added etc) is in my opinion one of the greatest sounding amplifiers with a tele or strat one can find anywhere. I get feedback all the time on the Hoffman 5E3 amps I built years ago as they change hands (either from G.A.S. or at estate sales) from the new owners saying in essence "Wow!" or "Holy Crap!" "This thing sounds awesome." Some of them are in recording studios and others are being gigged with in the Hollywood world on soundtracks for video games and movies. Every time I plug my ash telecaster into my personal Hoffman 5E3 it just makes me smile. Incredible tone to be sure. The Hoffman BFPR and BFDR with the bias vary tremolos are also incredible. I'm really looking forward to finally building and hearing the Sluckey AC15 amp. I'm figuring it will be the next holy grail amp with which I have a tonal love affair. Prior to finding Doug's website years ago, I was trying to play blues and rock through a Roland JC120 solid state amp. Then I built a Hoffman 5E3 on my kitchen table in Corona and my musical life was forever changed. The Roland went on eBay almost immediately and I've never missed it. It's tube amps for me till death now.
Barry, I will say the honeymoon with the AC15 is way over and is still my number 1 small watt. I think you will really like this build and it is cool that Tele and Les Paul's both sound great and I cannot leave out my Suhr Strat. I built it in a head and use a 1, 12 Celestion Blue. Sluckey got an Avatar cab and a blue himself and told me he really likes the combination.
I have been on a amp selling binge and finally got back down to the point where I feel it is ok to build some more and am actually considering another Vox and maybe use 4 little bottles for the AC30 route, but I just do not prefer the top boost model. It is really cool to watch someone check out one of your builds and not know you built it. I put mine in a local music store to sell and they usually sell fairly fast cause I price them just to get my money back. I have to say the owner of the store wants me to build a lot of the AC15, but I have only built 2. One he has and mine which I don't think will ever tire of.
There is something to the cap switching as opposed to a tone stack. I did knock up a test which sounded really good and I may add it in as a switchable feature.
I tried a EF86 to 12Ax7 PI and 3, EL84's into a JTM45 Output Tranny what I had on hand. Just as a test I inserted a Brownface tonestack and it was really cool. Like the 6G9 Tremolux that used 2 EL84. I prefer it without the tonestack, but I must admit it was a different sounding amp and would make a great addition to a studio.
Good to see you around.
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Ed,
You can have your tone stack and put in a switched push-pull pot to defeat it and then still switch in various bass shelving caps at will and have the best of both worlds? Something to consider? Also, have you tried using the Gain control I showed you for the '86? I won't build a pentode amp with it now. And I also feel the triode option is a must have too. Between the two controls and the stack options, I feel like I can get any tone and gain level I want on any given day.
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Here are a couple of sound bites. It's the 5e3 and a 68 Deluxe I did a gut job on.
Too much verb on the video but what the hell, I'm having fun anyway... :icon_biggrin:
66 335 here
! No longer available (http://www.youtube.com/watch?v=_z3l6E0IK7Y#)
66 Guild Starfire VI
https://www.youtube.com/watch?v=KWF0gqszz0o (https://www.youtube.com/watch?v=KWF0gqszz0o)
67 335 here
! No longer available (http://www.youtube.com/watch?v=yH5y3Lpi6Qo#)
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What I am hearing sounds great! Is this both amps at the same time in each video? I'm not sure what I am listening to even though I like it quite a bit.
with respect, Tubenit
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What I am hearing sounds great! Is this both amps at the same time in each video? I'm not sure what I am listening to even though I like it quite a bit.
with respect, Tubenit
Yeah man, both amps running. recorded with the iphone LOL
You know what they used before Protools? Pros...
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The '67 335 sounds massively different than the '66. I suspect some of that is knob settings, but it sounds like a much "singier" guitar. I've owned several 335s over the years...I am kind of stuck on 25.5" guitars and feel crowded with my fat hands on most Gibsons. There are people who manage to get a lot better tone from their 335s than I ever found with mine. Great playing guitars, though.
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The '67 335 sounds massively different than the '66. I suspect some of that is knob settings, but it sounds like a much "singier" guitar. I've owned several 335s over the years...I am kind of stuck on 25.5" guitars and feel crowded with my fat hands on most Gibsons. There are people who manage to get a lot better tone from their 335s than I ever found with mine. Great playing guitars, though.
The 66 has the orig Pat Stickers in it. The 67 does not. The 67 is too hot for a 335 IMHO. The pickups in that guitar would be great in a LesPaul but a 335 is suppose to sound more woody. In person the 66 clearly shines over the two. Now the Guild is a wonderful guitar and just has that "thing" about it. It also records super good and sits in the track very nicely. Of course I love Teles, Strats, LPs, SGs, and old gibbys.
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Yeah man, both amps running. recorded with the iphone LOL
Sounds very nice Mike but maybe look into a Zoom iQ5, they're a definite step in the right direction for reasonable $$$. At the end he quickly demo's with an acoustic. https://www.youtube.com/watch?v=5Bh9rZhhz0w (https://www.youtube.com/watch?v=5Bh9rZhhz0w)
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Yeah man, both amps running. recorded with the iphone LOL
Sounds very nice Mike but maybe look into a Zoom iQ5, they're a definite step in the right direction for reasonable $$$. At the end he quickly demo's with an acoustic. http://www.youtube.com/watch?v=5Bh9rZhhz0w (http://www.youtube.com/watch?v=5Bh9rZhhz0w)
Ha! Look at that thing...
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Wifey got me one for like $70 no tax or shipping but can't play with it for another 5 days ;)
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Wifey got me one for like $70 no tax or shipping but can't play with it for another 5 days ;)
Very good... I think I'm getting socks LOL... You can laugh but thats what I wanted
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I'm not laughing. There is nothing quite like the feel of new socks!
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Very good... I think I'm getting socks LOL... You can laugh but thats what I wanted.
I'm not laughing. There is nothing quite like the feel of new socks!
Same here, new socks, new underwear and I'm very happy.
My how life/age changes our comfort zone. :wink:
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I've listened a few times now and all I got to say is....... :blob8:
How bout a pic of the Guild Starfire?
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I've listened a few times now and all I got to say is....... :blob8:
How bout a pic of the Guild Starfire?
1966 and the cleanest one I have ever seen. I feel lucky
(http://p2pamps.com/guild/1.jpg)
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Thanks. :icon_biggrin: Good looking style of a guitar.
I really like the tone you get with it. :occasion14:
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Thanks. :icon_biggrin: Good looking style of a guitar.
I really like the tone you get with it. :occasion14:
There is a real "cool" factor to this old guitar. Hard to explain, it just has so much mojo and sits in a track really well. It has definitely exceeded my expectations.
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Guild has always been a bit of a sleeper company and mostly known for good acoustics. I have a terrific all black 12-string and a buddy has the 6-string version, totally coincidental. They play and sound as good as anything out there. I can only imagine that this same high quality is in their hollowbodies too? Wish I had the chance to find out. 😍
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Here's a 1956 Guild I bought as a wreck and paid way too much to refin, which I don't like to do, but I wanted a blond fatback. L-5 type binding, Grovers, refin blond, refin back of neck SG red (because....I can)
(http://i172.photobucket.com/albums/w32/ttm4/GUILD%20X-175%201956/GUILD006.jpg) (http://s172.photobucket.com/user/ttm4/media/GUILD%20X-175%201956/GUILD006.jpg.html)
(http://i172.photobucket.com/albums/w32/ttm4/GUILD%20X-175%201956/GUILD007.jpg) (http://s172.photobucket.com/user/ttm4/media/GUILD%20X-175%201956/GUILD007.jpg.html)
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Holy crap that is one beautiful blonde!
:bravo1:
Chip
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Thanks, it's pretty cool. I also had the neck reshaped from 1/2 baseball bat to '64 Strat. :icon_biggrin:
I really need to get a great tapped (splittable) HB pickup in for the neck. That's a junkbox hotrod pu which is completely inappropriate. Overall, it's definitely not bad for a plywood guitar.
(http://i172.photobucket.com/albums/w32/ttm4/GUILD%20X-175%201956/GUILD004.jpg) (http://s172.photobucket.com/user/ttm4/media/GUILD%20X-175%201956/GUILD004.jpg.html)
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Overall, it's definitely not bad for a plywood guitar.
They use plywood for good reason on elect hollow bodies and 12-string guitars also. On electrics it reduces & better controls feedback and on 12-strings it handles the extra pressures better while also still sounding & projecting as good if not better than solid wood tops.
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Both of those Guild guitars are really remarkable! Thanks for sharing the photos.
With respect, Tubenit