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Oh Mike....I was just at that site today, talking with the guy who built my custom electric guitar.

We were discussing ordering parts and doing a tandem build.  We figured, though neither of us knows diddley about electronics...we'd be smart enough to get through it if we did it together....learning as we go.

I look forward to this thread!  Thanks for the photos and all!

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> Do you not need the phase inverter with a single output tube  
With tubes phase inversion is never a problem, you can always invert simply swappin the terminals of a transformer winding.
 
> Where is the tone stack plumbed in? Is it simply passive and the 12ax7 is 2 gain stages?
 
I'd need to see the schematic, but the tone control can be implemented either passive or in the feedback loop without requiring any additional tubes.
 
> I designed a fender/supro hybrid   
Then you should know the answer to your previous questions. Or maybe if your design worked is a proof of that miracles happen ;)
 

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I hope this pushes you over the hump Skull!

I have to take back what I said... soldering should be the easy part... but my eyes just keep getting middle age worse... I'm using my special super power glasses... but the reflections on the solder just leave me thinking I'm blind sometimes. So I am second guessing myself and spending extra time with it. I always wondered why I wanted to work quicker than my mentors... they were the age I am now when I was 25 and could see like an eagle. :-)

Anyways, it's a pleasure to have laid out the power input and the speaker hookups last night. It's really fun for me to touch the wires and see the schematic in my mind. It's easier with these simple amps.

I kinda started backwards.... most folks do the board stuffing first... but I wanted to get the leads from the transformers all squared away early on.

I am about to wire up the heaters.

When ever you do a one-off DIY you are left to decide if you know the best place for the wires. It's best to keep wires as short as possible.... but later you may wish to move one to reduce noise bleed.... so I am sorta choosing to stay just short of medium length. :-)

All that wire was PVC coated and I have a sorta new nifty wire stripper for that stuff. I am about to begin using my old style cloth covered wire for the remainder of the project. The wire stripper I am using is so nice... I think I may go all PVC insulation next time.

Here's a work in progress photo:





best regards,
mike

Mike, I think you left out a nine pin socket; where are you going to put the EL-84?

Ron, I would stay with the 5Y3 on the rectifer (Mike that's what the octal is for). Also, I see one BIG PROBLEM in your specs. Those 50v coupling caps aren't gonna cut it. Go 450v at least; I always use 600v. As far as your filter cap, I would put the 20uf on the B+ and use the 40uf on the screen, that to my ear at least, will tighten up the amp.
Good luck to you both.

Tom

I guess I should say I'm an EL-84 guy, the 6v6 leaves me cold, just me... But I've always preferred the Vox and Marshall 20 sound over the Fenders.

Mike,
Looks like it will be a VERY "clean" build, of course having seen some of your other work you have posted I would expect nothing less.

I was refering to Ron's schematic on the 50v couplers, I would hate to see someone run with that and have a problem.

I have a friend (David Wellman) who insists that anything over 8uf on the pre stages is a waste, and creates tonal issues, he builds a great amp so its hard to disagree. I'm usually at 20uf in the first couple of stages. On the 5Y3 I try to stay with 20uf, GZ-34 I use 40uf, but in my 100's (SS rect) I'll load it up. I do think that the need for a super stable supply on the screens is often overlooked. I put a diode in the string to prevent the B+ from sucking the life from the rest of the amp; but I like a little (lot maybe) "sag". Another reason I always use the valve rect on anything under 100 watts. Just my ear and style.

Keep the posts coming.
Your in the quest for tone...
Tom

Mike,
I always run a ground buss from the input jack through the lug of each pot that needs grounding terminating at a lug on the power tranny. Now that's not the best for what you want to do, changing out parts. I have run one (buss wire) along the edge of the turret board as you described.

I hope this illustrates what I mean.


I always assemble the board first, then put it in the amp.



I like the turrets, but what you're doing will work well, maybe the best compromise between Leo's method (never liked the cards) and the "British" method (meaning the turrets). I'm sure the eyelets speed assembly.

Tom

Mike,
I'm reviewing your layout drawing, and I have a question.
Surely you're NOT going to tie pin 8 (cathode) to pin 7 (heater string)?
Maybe I should review the AX site, but that can't be right...

I must say that holding the suppressor (pin 1) negative relative to the cathode IS a good idea. I always tie the suppressor to my raw bias supply with the EL-34.

   Ron Vogel "I am on the fence if I like the tone stack where it is in the circuit"
Ron, the tone stack is in exactly the right spot. The Western Electric circuit (think '59 Bassman, Plexi Marshall here) is the ONLY way to go. Always place the tone stack last.
That is the "problem" with the Blackface Fenders. You can't get the pre-amp to drive. The tone stack sucks the life out of the signal before it gets to stage 2.
In the Western circuit you turn up the volume and push the second stage out of its linear region. That's when the "magic" starts. (remember that WE spec'ed a 12y7 here, less gain)
Now the white Twins and blonde Bassmans, that still had the Presence control, will get "busy", but when the Verb amps come on the scene and the Presence control is gone, no drive.
I will say the Blackface amps do EXACTLY what they are designed to do; they play LOUD and CLEAN. But why do you think the Marshalls caused such in stir here in '67. Baby they played LOUD and DIRTY!
Of all the Fenders I owned/played I had one Bassman in the day, it sat on two small Fender 2x12 cabs loaded with pre-Rola Celestions, that you could "drive". THAT amp rocked, ALMOST as good as my Plexi full stack! (I think Dave Edmunds' "The Stumble" and Hendrix's "Voodoo Child" are a Bassman on 4x12 Marshall)
Just my .02, but I love the EL-84 so take what I say with a grain of salt.

Yours in the quest,

Tom