It's raining here.......

[SILVERGUN]

Thanks for taking care of lego's question guys.....I was away from the computer.

I actually have a cap like the one Willabe describes, in this amp...
It's between stages and I believe it helps to shunt some highs.

[lego4040]

I do get it now, thank you. I down loaded Jack Darr's book but I also bought one. I wasn't printing all that out and I like having books to read

[Tone Junkie]

Sorry guys I meant to post a schematic so we could see it. I couldn't find one last night exept for Merlins book and I didn't think it would be proper to post the page. and then I got sidetracked.
Thanks SG that's exactly like I was talking about except on V1a right after the 68K. Both of them same function different spots.
Bill

[SILVERGUN]

I'm using Doug's relay board and PS board, and haven't nailed down the location of the power supply board....I have plenty of available heater current.
It could go at either end of the chassis depending upon where I should tap the filament run for power. (will mount on the inside of either end-cap)
Is there a more preferred spot so as to minimize potential noise?
Should I tap it right where the 6.3 comes into the chassis or at the other end of the filament run ,,,after the first preamp tube?
I imagine if I put it after the first preamp tube that I run the risk of hearing it. 

Is there any known associated noise problem at either location?

[SILVERGUN]

OK, now it's on.....Flyers are out, and I can concentrate on getting D-O-N-E

Is it OK to tap the filament string as a parallel branch to run one relay PS board, or should it be in series?

[sluckey]

It must be parallel just as shown in your schematic. I'd tap into the string at pins 2 and 7 of that first brown socket and put the power supply on the left end of the chassis (as seen in the photo). I'd also try to mount the relay board near the circuit that it will actually be switching in order to avoid long runs of signal wires. In fact, if this will be a turret board construction, I'd just put the relay socket and diode directly on the main turret board. I understand this may be a challenge in that long skinny box! 

[lego4040]

Your lose my gain, now its Penguin hunting time. This Relay stuff is interesting, never knew they were in amps

[SILVERGUN]

silvergun,
In the diagram, where you show caps on the cathodes, It is my understanding that the fully bypassed cathode helps the gain on the tube.  Gurus let me know if I am wrong.

That is correct Dr., but I'm no guru.
The gain through the stage is frequency dependent on the value of those caps...
I see the 4.7uf on V1a as "mostly" bypassed, and the .47uf on V2a to be only partially bypassed which will help serve as a treble boost for that stage by shifting the response up in frequency.

Fully bypassed stages in high gain amps can make for "woofy", loose, sloppy, bass response....
One of my ah-ha moments on the breadboard was when I realized how to "shape" the signal by using different value caps in conjunction with different value cathode resistors to create desired boost points throughout the signal path.

Merlin has a great description of this function (along with a chart that opened my eyes) on page 26 of this chapter in his preamp book that you can download for free here: http://www.valvewizard.co.uk/Common_Gain_Stage.pdf

[smackoj]

Sgun; nice work. your builds are starting to shine like a diamond in goats ass. keep up the good work.   

[SILVERGUN]

Sgun; nice work. your builds are starting to shine like a diamond in goats ass. keep up the good work.

Well smack-o,,,that's the nicest thing anyone has said to me in a while 

Maybe I'll name it Diago?      short for - Diamond In A Goats Opening

Ooops,,,nope,,,somebody beat me to it:
http://www.diago.co.uk/guitar-amps/little-smasher.html

 

[Tone Junkie]

Sgun; nice work. your builds are starting to shine like a diamond in goats ass. keep up the good work.

Well smack-o,,,that's the nicest thing anyone has said to me in a while 

Maybe I'll name it Diago?      short for - Diamond In A Goats Opening

Ooops,,,nope,,,somebody beat me to it:
http://www.diago.co.uk/guitar-amps/little-smasher.html
.

 

Ok now thats funny. Diaga sounds better anyway ,everyone would ask what it meant.
Bill   
Guess I found the name for my new amp line.

[SILVERGUN]

T.J.,,,(or anyone else for that matter)
I know you're a bit of a tube roller...
Any suggestions on a good choice for current production EL34's to "try" in this ultra high gain setup?

I've been using Winged C's on the bench and would probably just put them in the amp, unless something stands out as a better choice.
I'm just over 500volts on the plates and in the 490's on the screens, so I appreciate the Winged C's 500 volt screen rating. (they held up on the breadboard)
OT primary is 3.6K for 2 EL34's
The player is looking for a soup'd up "old school metal" tone, and I don't have a lot of experience with different power tube types.....or a lot of spare cash to throw around.

I was also considering adding a dropping resistor in series with the 5Hy choke to try to make sure the screens stay in check.

[smackoj]

Let me be the first to congratulate Tone Junkie on his new Goat's Ass amp lineup. Simply marvelous stuff!

Sgun; I don't know a lot about current prod. 84's but I love the Sovtek WXT6L6 tubes. Mucho power and great tone.  Here is a link to their EL84 tubes. I also hear most guys using the JJs but that may be for price point .... don't know fo sho.

 

https://www.tubedepot.com/products/sovtek-el84-power-vacuum-tube

[SILVERGUN]

Sgun; I don't know a lot about current prod. 84's but I love the Sovtek WXT6L6 tubes. Mucho power and great tone.  Here is a link to their EL84 tubes. I also hear most guys using the JJs but that may be for price point .... don't know fo sho.

34's smack-o.....please quit laughing about the goat's ass long enough to pay attention 

https://www.tubedepot.com/products/sovtek-el84-power-vacuum-tube

Let's get rid of that link....I try to avoid linking to Doug's competition as much as possible....I know where to find them, just looking for opinions.....and thanks for the bit about the WXT6L6's ...I'll hang onto that 

 

[SILVERGUN]

I decided to mount the OT inside the cabinet by bolting it through the front baffle.

Do I have to ground the frame of the OT to the aluminum chassis?

[Tone Junkie]

SG Im not really knowledgable about differant EL34 applications in the 490 range. last amp I made with the voltages that high, I put in 6550 out of worry. I had 2 pair of the winged C and wanted to keep them and that was one of the only ones people were saying would take that kind of voltage. but I havnt checked concensus lately.
 
smackoj Do you think my buisness plan will work. put out one diamond in a goats ass every 2 or 3 month,s maybe get market saturation 20 or 30 yrs. (LOL) brand recognition maybe 50  .
Bill

[sluckey]

I fear you now have a "wheel in the ditch".

[Ed_Chambley]

If you really are serious, I have some that EL34's that will work just fine.  The 6550 is a good selection, but I have ran servicemaster internationals at higher voltages and would in a minute in a headbanger amp.  Problem is, where are you going to keep getting them?  People swear by JJ's but I have toasted many nearing this voltage.  Fact is even the old =C= I would not trust.  I got some of the old ones to get you running for a while, but therein is the problem.  Where to get new ones?

I would try 6550, which I use for this application.  You will not lose and forcefulness in the mids and if Heavy Metal is what you are going for, how can something with more bottom be wrong.   They certainly are not going to be a cleaner sounding tube.  If you don't care for the 6550, just buy a lot of EH as they have a good tone.

[SILVERGUN]

I fear you now have a "wheel in the ditch".

UH-OH!

WhattdidIDOOOO?

[SILVERGUN]

If you really are serious, I have some that EL34's that will work just fine.  The 6550 is a good selection, but I have ran servicemaster internationals at higher voltages and would in a minute in a headbanger amp.  Problem is, where are you going to keep getting them?  People swear by JJ's but I have toasted many nearing this voltage.  Fact is even the old =C= I would not trust.  I got some of the old ones to get you running for a while, but therein is the problem.  Where to get new ones?

I would try 6550, which I use for this application.  You will not lose and forcefulness in the mids and if Heavy Metal is what you are going for, how can something with more bottom be wrong.   They certainly are not going to be a cleaner sounding tube.  If you don't care for the 6550, just buy a lot of EH as they have a good tone.

I'm not against permanently mounting a bucking xfmr in this thing if I have to drop some V's
Truth is, I built the amp on the board with 350VAC feeding the rectifier, and now that I have the PT in there the voltages I'm seeing are higher,,,but with no load...
I'll have to see how far it drops when everything's up and running...
Problem is I got a big 'ole PT and I'm afraid it aint gonna budge a whole lot 

Wont know til it's fired up.

[Willabe]

I fear you now have a "wheel in the ditch".

UH-OH!

WhattdidIDOOOO?

I decided to mount the OT inside the cabinet by bolting it through the front baffle. Do I have to ground the frame of the OT to the aluminum chassis?

I think he's saying you might have problems with the OT wiring now being too long.

That's what I'd be concerned about.


                   Brad     

[SILVERGUN]

I think he's saying you might have problems with the OT wiring now being too long.

That's what I'd be concerned about.

OK,,,I'm a big boy.....I can take it 

I've wasted more time on this project trying to adapt to a non-standard layout,,,, that another couple hours won't kill me.

The suspense might....

Willabe, could you ask sluckey what he's seein?   

[sluckey]

I'm seeing a part-part here, a part-part there, here a part, there a part, EVERYWHERE a part-part....

I think you have figured out how to stuff your breadboard in a combo cab!     Not sayin' it ain't gonna work, but if it doesn't, it's gonna be a beetch to troubleshoot.

The engineers at Sears would be proud.

[SILVERGUN]

I think you have figured out how to stuff your breadboard in a combo cab! 

That's exactly what I started to think to myself the other day.....maybe MY line of amps is just a line of breadboards 

I just hated the idea of hanging anything heavy off of that flimsy chassis....and I let that dictate some of my choices...
It has cost me more TIME than I would ever have imagined to build this way.....this is my one big mistake that will make me stronger and smarter for the future.....everybody gets one big one, right?

If it works, then I knew it all along and there was never a doubt 

What do you think about grounding the frame of the OT?....I was just curious as to whether it is a must for electrical safety or noise suppression or both.

[sluckey]

everybody gets one big one, right?

Oh no. We all get ONE AT A TIME. Repeat as necessary. 

What do you think about grounding the frame of the OT?....

I don't think there will be any benefit, but I'd probably do it. What did you do with your PT?

[Ed_Chambley]

If you really are serious, I have some that EL34's that will work just fine.  The 6550 is a good selection, but I have ran servicemaster internationals at higher voltages and would in a minute in a headbanger amp.  Problem is, where are you going to keep getting them?  People swear by JJ's but I have toasted many nearing this voltage.  Fact is even the old =C= I would not trust.  I got some of the old ones to get you running for a while, but therein is the problem.  Where to get new ones?

I would try 6550, which I use for this application.  You will not lose and forcefulness in the mids and if Heavy Metal is what you are going for, how can something with more bottom be wrong.   They certainly are not going to be a cleaner sounding tube.  If you don't care for the 6550, just buy a lot of EH as they have a good tone.

I'm not against permanently mounting a bucking xfmr in this thing if I have to drop some V's
Truth is, I built the amp on the board with 350VAC feeding the rectifier, and now that I have the PT in there the voltages I'm seeing are higher,,,but with no load...
I'll have to see how far it drops when everything's up and running...
Problem is I got a big 'ole PT and I'm afraid it aint gonna budge a whole lot 

Wont know til it's fired up.

Well you don't want it to budge much.  My 1 metal amp is stiff and needs to be.  It too is running el34's and I did have to bring down the voltages as I was toasting tubes, but not any good ones.  I did not really know what the topic had steered to.  I understand what the deal is not, what I do not understand is why you used that chassis?  Not throwing stones, just dirt clods.  I mean you are building an amp that should standup.  It is not a wedding band amp, correct?


Are you not a big wheel at a welding machine shop?  Certainly someone there can weld. 


Oh well, you raise them to act right then they go and do stuff like this.


I will go back in my hole now, but not before I say I prefer in new production EH El34's.  The highs are similar to old mullards, they just do not have the beef.

[SILVERGUN]

What did you do with your PT?

Grounded the frame by bolting through that alum. angle where the power connector is. Power connector is grounded at that same point.

I did follow all usual grounding procedures, and have the first 2 filter caps there as well as the 6.3v CT and negative connection off of the bridge rectifier.

The last step will be to ground the chassis box to that same angle by bolting through and using a short length of braided ground wire.

[SILVERGUN]

why you used that chassis?  Not throwing stones, just dirt clods.  I mean you are building an amp that should standup.  It is not a wedding band amp, correct?

It's for a GIRL  ....and she rocks 

She asked me for a 2x12 combo, and we talked about weight and size, and this was MY bright idea....

After reading all the horror stories of all of you guys.....I took it upon myself to swim upstream...

All I do now is walk around shaking my head and muttering "nevvver again"

It will work....failure is not an option. period. (that's what I tell myself as I'm crying myself to sleep)


And next,,, I'm gonna order a Champ kit 

[SILVERGUN]

Here's an update pic...

The relay power supply squoze nicely into that corner, and you can see where the entrance connectors come into the chassis for the OT connections, and attach right to pin(s)#3 with a little buss wire...

Sluckey was right about me not being able to reach the chassis mount screw hole that I had predrilled.....(I mean ventilation holes that I meant to put there )

[Ritchie200]

Hey SG,

Since you are doing all this wonderful "tone shaping" on the preamp side, do you really want to color it with EL34's limping along in the small joints or crunching when she turns it up for an outdoor gig?  You might get good results - but then again...

Like Ed, I am not a fan of 6550's.  Why not use some KT88's in the power section?  Typically a nice bold response that really does not change unless you nail them to the wall.  They would live a long life at those voltages and faithfully reproduce all the cool things you are doing in the preamp.  Just a thought.

Also, it's a good thing you mounted that output tranny next to the speakers.  Those short speaker runs are perfect.  Line loss would be terrible had you mounted it on the chassis.  Cant let anything get in the way of that smooth funk/jazz you keep telling me about.....

Jim

[SILVERGUN]

Since you are doing all this wonderful "tone shaping" on the preamp side, do you really want to color it with EL34's limping along in the small joints or crunching when she turns it up for an outdoor gig?  You might get good results - but then again...

Like Ed, I am not a fan of 6550's.  Why not use some KT88's in the power section?  Typically a nice bold response that really does not change unless you nail them to the wall.  They would live a long life at those voltages and faithfully reproduce all the cool things you are doing in the preamp.  Just a thought.

Well,,,I went 2-EL34 probably mostly because of a lack of vision.....call me a sheep. I honestly didn't realize that these voltages would create this much of a problem. Got the 50 watt JCM800 OT @ 3.6K and didn't even think twice about it. 

Plus they're all I've got here....being new into tubes comes with some unfortunate downsides......I haven't been collecting tubes for the last 20 years    , so my cupboard is pretty bare.
And I wanted to give her the option of being able to pick up a spare set at Banjo World in a pinch.

Got the 100 watt PT because I don't believe in running PT's warm/hot (comes from welding machines where I've seen the effect of insulation breakdown), and didn't realize how high the V's would be with no load. duh.. I'm used to 500 AMP loads so milliamps don't add up in my head yet.

I'll see how it goes when it's all fired up, and where my voltages are under load...
I did voice the amp around the ELs, so there's something there I like,,,,I never realized that the screen ratings were so low until I started shopping around for the "right" pair.....the Winged C's never lit up once, and I bang'd em around pretty hard soooo 

The KT88s might be in MY future....I hear they pull off a nice smoothjazzsoftsoulfunk lead tone like no other.

In a pinch, there's plenty of room in the base of the cabinet for a bucking xfmr.....I just feel kinda silly putting one there when I just spec'd out the PT for this thing......dummy

Maybe some day I'll grow up and stop putting all of the focus on the preamp, and payafukintention to the other important details.

You don't know what you don't know until you know you don't know. 
This is how we learn.


 

[Ritchie200]

Methinks you are too hard on yerself!  There are certainly many sonic ways to skin this cat.  I was just thinking about a tube that can live a long full life at those voltages.

What? No reply on the short speaker leads?  I'm disappointed!

Jim

[SILVERGUN]

What? No reply on the short speaker leads?  I'm disappointed!

I thought I picked up on some sarcasm there?.......but somewhere around post #70 I think I may have lost some of my sense of humor, and didn't get the joke. 
That's right about the time I figured out this wasn't such a "brilliant" idea. 

- Funny thing is, when sluckey made the "wheel in the ditch" comment and Willabe followed up with his thought about the OT wires possibly being too long,,,,I wanted to punch myself in the face for taking something from another thread out of context and making it into an instant "rule of thumb"
..Over on the AC15 thread, Ed had asked sluckey if there was any reason to keep the OT wires short,,,and sluckey replied "no, just keep them away from the preamp circuit"
.....so in my really big, empty head, that registered as 'there is never any reason to worry about the length of the OT wires' 
....AND, so that's how I came to the conclusion that I didn't have to pay any attention to the placement of the OT, or the length of the wires.

I can't wait to fire this thing up just so the troubleshooting can begin. 

LC

[Willabe]

I was just taking a guess about what Sluckey meant.    

You are spreading things out but I don't know how long you OT wires will end up being.

I think Sluckey hit it on the head thou, about figuring out how to put a bread board in a combo speaker cabinet.

Hey it's an idea, you tried it, maybe it'll work, maybe not. Not the end of the world if it doesn't. Not the 1st time that has happened here and wont be the last.

Hit 3 out of 10 plate appearances and your a star and make millions, but that's 7 failed attempts.


           Get your peanuts here, Red hot's, get your Red hot's here.         


                Brad     

[SILVERGUN]

I was just taking a guess about what Sluckey meant.

I know...and I always appreciate the help...

This one's all me.... 
After this I will never try to reinvent the wheel again.....I promise. 

I won't be able to blame anyone but me if this doesn't fly....and that's the way I like it.

Hit 3 out of 10 plate appearances and your a star and make millions, but that's 7 failed attempts.

OK....I like my odds on that!
Maybe I can be a superstar!? 

[Willabe]

OK....I like my odds on that!
Maybe I can be a superstar!? 

Sure can!      


                                       Beer here, get your ice cold beer here!


           Brad                    

[Ritchie200]

3 out of 10 may make you a superstar in Chi-town.  We have higher expectations here in a REAL baseball town....

Jim

[Willabe]

Yeah, yeah, 

I told you not long ago, "It's gonna be a LONG summer in Chgo".

 And the home plate ump says,                        Play Ball


                   Cracker Jacks, get your Cracker Jacks here!

(Yadiar Molina! Boooooo!!!!!, best catcher AND 1 of the best hitters in the Majors! I tip my blue Cubs hat, he's the real deal!)


                  Brad     
 


                     

[HotBluePlates]

Well,,,I went 2-EL34 probably mostly because of a lack of vision.....call me a sheep. I honestly didn't realize that these voltages would create this much of a problem.

Just finish the amp. It worked on the breadboard, will probably work in the amp.

If it doesn't, you will have learned something and can adjust-fire from there.

[Ritchie200]

Yeah, what he said!!!!

You must remember that those of us with time/schedule/family/financial/ability/etc./etc.... constraints are living vicariously through you!  And unlike Chicago and Philly, we don't boo our players, we cheer them on!  Well, yeah, we do give them crap from time to time to keep them honest....

Jim

[sluckey]

You're gonna need a standby switch on that amp. In keeping with the general theme, may I suggest something like this? Mount it on top of the cab and it can double as a tote handle...   

[HotBluePlates]

You're gonna need a standby switch on that amp.

He's got one... in the ash-tray on top! Handy place to put your cigarette, too! And if the amp catches on fire, you've got a ready place to pour the beer...

Actually, I think the location and embodiment of the standby switch could be a cool feature. It's no on the back where it might be hard to reach on stage, and it's recessed so it won't get sheared off when the combo gets thrown into the van. It's not in the way if you pech other things on top of the cabinet.

Perfection might be the sealed switches intended for marine (or military) use, but those are probably more $$$$$$ than they're worth in this application.

[SILVERGUN]

You're gonna need a standby switch on that amp. In keeping with the general theme, may I suggest something like this? Mount it on top of the cab and it can double as a tote handle... 

You're killin' me.... sorry I didn't think of that first....It'd go right along with the theme.

He's got one... in the ash-tray on top! Handy place to put your cigarette, too! And if the amp catches on fire, you've got a ready place to pour the beer...

Actually, I think the location and embodiment of the standby switch could be a cool feature. It's no on the back where it might be hard to reach on stage, and it's recessed so it won't get sheared off when the combo gets thrown into the van. It's not in the way if you pech other things on top of the cabinet.

Good catch HBP,,,,I'm glad to see someone's paying attention.
I did actually think it through and found those same positive attributes.....
That was one of my crowning achievements, when I decided that this thing was going to be unapologetically different...
Getting past the idea of running a hole saw down through the top of my beautiful new cabinet was like ripping off a Band-Aid.....
I measured 6 times and drilled once, because that's what all good hack carpenters do. 

Here's a shot of the "ash tray"...it's a Cole Hersee truck part, and unfortunately the chrome isn't as nice as I would've wanted...doesn't really match the corners, and looks more like galvanized than chrome........character,,,that's what I tell myself. 

[SILVERGUN]

Alright.....I realize I have one major personality flaw...
I only like to disclose things that go well and when something goes wrong I clam up and work through it.....

Well, I had a near death incident the other night when I found out I wasn't getting filament V to one of my power tubes.....
I almost shoved my 800 degree soldering iron up through my nasal cavity and straight into my brain to stop the pain of what I found....

Even though I WAS getting 6.3vac on the inside of the chassis at the socket,,,,when I removed the tube and shoved my meter leads into the holes for pins 2 and 7 ....NOTHING 
So I shut off the power and started poking around and the #7 pin connection just broke right off as soon as I touched it with a pair of needlenose.

SO I must now replace both sockets because I bent the pins back the same on each one..............

The good news was that right before this brick wall showed up, I had perfect voltages everywhere else and was ready to hear it roar...
Only problem was that one EL34 was much darker than the other,,, and I had 0mv cathode current reading there.........you can't beat 'em if you don't heat 'em.

So here's my rant...
Are you kidding me???
I used Belton octal tube sockets because I had them here and they looked pretty heavy duty......except for the part I couldn't see which is the TINY little pin that connects the inside socket terminal to the outer solder tab (pictured).....why does that tab taper down to 1mm (so it can break?)
I had attached the filament wires and then bent the tabs back to get them out of the way.......REALLY BAD IDEA, because it snapped right at the bend!

I don't have this kind of time in my life....

[sluckey]

Bet all the recent heater discussion really paid off. Ain't you glad you didn't use the Soldano wiring method? 

[Ed_Chambley]

Bet all the recent heater discussion really paid off. Ain't you glad you didn't use the Soldano wiring method? 

I will tell you what.  You really give it you all.  It would be no problem for me to change it out, cannot see why it would be for someone of your caliber.

Not slippin since retirement are you?

[SILVERGUN]

Bet all the recent heater discussion really paid off. Ain't you glad you didn't use the Soldano wiring method? 

Yes....that stuff is just for looks anyway,,,, and I'm not wasting my time on such trivial pursuits anymore...
I've got amps to build.

It would be no problem for me to change it out

Yeah, me either, except I didn't have anymore here.... I do have about 6 of the ceramic ones that Doug sells and obviously should've just used those in the first place.......
So that's twice burnt now....
-Once with the conductive black board that I didn't get from Doug
-And now this...

This just goes to show.....get everything from Doug or the amp gods will rain terror down upon you. 

[sluckey]

You've obviously never been inside THAT chassis. I've been inside three of them. I know what I'm speaking about.

[Ed_Chambley]

You've obviously never been inside THAT chassis. I've been inside three of them. I know what I'm speaking about.

Yes, I just about made that mistake, remember?  I built one of those AB763 in a deluxe cab and you told me about how thin the thing is and how tight it is.  I did listened didn't I?

OTOH, I did forget you are just regurgitating what you mentor Gerald Weber taught you.
Now that's funny!

[SILVERGUN]

You've obviously never been inside THAT chassis.

UGHhh.....seriously painful.....like trying to cook a turkey in a toaster oven....just dumb


So I switched gears and made a backer board for the grill cloth....
I'm really enjoying using a router with a circle cutting guide to do holes.....thinking about opening a side business using the cutouts and selling stools