Yet Another Tweed Deluxe Build

[PRR]

> 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.

[p2pAmps]

> 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...

[Willabe]

I think he's looking at the layout drawing you posted in reply #40.

[p2pAmps]

I think he's looking at the layout drawing you posted in reply #40.

LOL, I'm a Dumba$$

[Ed_Chambley]

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.

[floyd]

try a new / different 5y3

[floyd]

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.

[p2pAmps]

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. 

[floyd]

Not reading all the threads.. is this your first 5E3 ?

[floyd]

You've tried to parallel all E- caps ?

[floyd]

Too see if one is Faulty Towers ?

[p2pAmps]

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

[p2pAmps]

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.

[HotBluePlates]

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 is probably a good tool to localize the hum source.

[floyd]

Don't rip out the Hoffman board.. I sent you a PM.. try that

[floyd]

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 ?

[p2pAmps]

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...

[HotBluePlates]

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.

[Fresh_Start]

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

[p2pAmps]

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...

[sluckey]

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.

[p2pAmps]

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...

[sluckey]

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.

[EL34]

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/Img_8786.jpg

[Fresh_Start]

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

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

[p2pAmps]

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

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...

[EL34]

If it works for you and amp is quiet, that's all that matters

[Fresh_Start]

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

[p2pAmps]

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
 

[EL34]

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

[p2pAmps]

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. 

[dude]

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

[EL34]

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

[PRR]

> 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).

[p2pAmps]

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

[EL34]

Sounds good from here!

[p2pAmps]

Sounds good from here!

Thank you Doug...  Now if I could learn to play better I might be on to something :)

[Paul1453]

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! 

You just build better!!! 

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!   

[tubenit]

Very impressive playing and I loved the tone of both amps!  Very nice.  THANKS for sharing it!

With respect, Tubenit

[Willabe]

Man, now that's a lot of sound from 2 little amps! 

[Fresh_Start]

Sweet!   

If that's what they sound like through an iPhone mic, I wanna hear 'em properly mic'd...

Cheers,

Chip

[p2pAmps]

Sweet!   

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...

[p2pAmps]

Playing 2000 seats tonight and this is all I need!!

[Willabe]

     Yeah you and Neil Young with a 5E3 miced up in a big room.

Have a great gig Mike!   

[bnwitt]

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.

[jojokeo]

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.

[p2pAmps]

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 :)

[EL34]

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

[p2pAmps]

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! 

[jojokeo]

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.