SingleCut's DIY Amp Build

[hipofutura]

I returned from last Saturday's N.E. MLP meet with an old busted-ass amp of SingleCut's. No cab, no speaker, and no sound. I'm going to morph it into something very cool (I hope) and send it back to him.

It's a 6V6 PP with an octal 6SJ7 preamp tube and octal 6N7 P/I. The amp is very well constructed and has gone through at least two modifications and some repairs. I found a couple broke connections which would explain why it didn't work. My guess is that it was built in the 60's. It appears to be part of a larger assembly and was then modified for recording use. Was probably in a studio at one point.

The Stancor trannys are very nice. The unloaded HV is 785 VAC. Right off the dial! The chassis is way under-spec and has sagged from the weight of the trannys, but it will work fine for the new build. The Sprague Atom filter caps are very nice, but also very old.

I'm going to rebuild to the power supply and power amp back to the original design, but with new components (for the most part). I already have the preamp and P/I designed. Going to use conventional 9 pin 12AX7 tubes. I'll build an eyelet board and re-arrange the tubes to make everything fit.

First order of business is to clean up everything and fresh paint.

The following pics show the starting points.

I'll post updates and pics as it starts going back together.

[Case24]

Was this the dumpster find amp? Can't see the pics, Hip.

[rocknhorse1]

Yeah, this was Single's dumpster score. Very cool Don Can't wait to see this take shape. This one will actually get to leave the house too!!

[singlecut]

i'm very happy don offered to work on my project. i had the extreme pleasure to see and play his amps and gotta say, very impressed.
g-man beat me to one or it would have been mine.
don tells me he can turn this into something and i believe him after seeing and hearing his work.
i'm really excited and honored to have him accept the challenge.
i've also asked him to build me one of his killer aged tweed cabs. that is depending on his decision that the final result desrves one.
anyway, thank you don, i will follow this very closely and i PROMISE not to be a pain in the ass. when it's ready , then it's ready. untill then, THANK YOU!!!!

[hipofutura]

Case, must be some web/browser filtering at your end. I can see the pics.

Originally Posted by rocknhorse1

This one will actually get to leave the house too!!

Don't tell SC, but once this things running it's going on ebay. I'll just tell him it detonated so I used it for parts.

[aneas fool]

Originally Posted by hipofutura

Case, must be some web/browser filtering at your end. I can see the pics.



Don't tell SC, but once this things running it's going on ebay. I'll just tell him it detonated so I used it for parts.

Don your cruel ...scamming SC so you can flog when its done...LOL ... I think its a great jester doing this project for SC ...your one cool guy............JIM

[hipofutura]

Thanks Jim. Very kind of you to say.

I really do believe in Karma. I've been blessed beyond measure, and many people have done generous and wonderful things for me. Only fitting, I do the same. But if CS's wife throws him out for dragging another amp home, he's not moving in with me!

[rocknhorse1]

Don, I cant see the pictures either.

[hipofutura]

Originally Posted by rocknhorse1

Don, I cant see the pictures either.

I just reloaded the pictures. Is it any better?

[Tuya Customs]

Hey Rosco, if you're not going to use those octals can I buy them off of you? The phaez bassman randy is building is going to use octals.

[singlecut]

if don dosen't need them you can haVE them. just pay don for shipping.
or what ever he needs to take the time to ship them to ya
i'm out of it. don is doing what he thinks is right. so if he's says they are not for this amp. please enjoy

[singlecut]

Originally Posted by hipofutura

Thanks Jim. Very kind of you to say.

I really do believe in Karma. I've been blessed beyond measure, and may people have done generous and wonderful things for me. Only fitting, I do the same. But if CS's wife throws him out for dragging another amp home, he's not moving in with me!

i just checked with my better half,all she said was " as long as your happy baby"
i'm a lucky S.O.B.

[singlecut]

Originally Posted by hipofutura

i returned from last saturday's n.e. Mlp meet with an old busted-ass amp of singlecut's. No cab, no speaker, and no sound. I'm going to morph it into something very cool (i hope) and send it back to him.

It's a 6v6 pp with an octal 6sj7 preamp tube and octal 6n7 p/i. The amp is very well constructed and has gone through at least two modifications and some repairs. I found a couple broke connections which would explain why it didn't work. My guess is that it was built in the 60's. It appears to be part of a larger assembly and was then modified for recording use. Was probably in a studio at one point.

The stancor trannys are very nice. The unloaded hv is 785 vac. Right off the dial! The chassis is way under-spec and has sagged from the weight of the trannys, but it will work fine for the new build. The sprague atom filter caps are very nice, but also very old.

I'm going to rebuild to the power supply and power amp back to the original design, but with new components (for the most part). I already have the preamp and p/i designed. Going to use conventional 9 pin 12ax7 tubes. I'll build an eyelet board and re-arrange the tubes to make everything fit.

First order of business is to clean up everything and fresh paint.

The following pics show the starting points.

I'll post updates and pics as it starts going back together.

this is so cool. I'm a bit taken back. Don you are the man

[hipofutura]

Originally Posted by Tuya Customs

Hey Rosco, if you're not going to use those octals can I buy them off of you? The phaez bassman randy is building is going to use octals.

Tuya, PM me your address and I'll send them down.

[G Man]

Very sweet Don. Now I don't feel so bad about beating SC out of the tweed homebrew as it looks like he will have his own of sorts. Looking forward to watching your progress on this one.

[BillB1960]

Originally Posted by hipofutura

The Stancor trannys are very nice. The unloaded HV is 785 VAC. Right off the dial! The chassis is way under-spec and has sagged from the weight of the trannys, but it will work fine for the new build. The Sprague Atom filter caps are very nice, but also very old.

Good lord! Is it just me or is that some serious iron?!

I'm thinking you could run a locomotive with those trannys.

[hipofutura]

Originally Posted by BillB1960

Good lord! Is it just me or is that some serious iron?!

I'm thinking you could run a locomotive with those trannys.

You are right, Bill. It's the biggest PT I've worked with, other than hifi iron. I don't know what's up with that choke! Never seen anything like it. Ain't no DC going to get past that thing. I'm curious to see what it does to the B+ voltage.

[Tuya Customs]

Originally Posted by singlecut

if don dosen't need them you can haVE them. just pay don for shipping.
or what ever he needs to take the time to ship them to ya
i'm out of it. don is doing what he thinks is right. so if he's says they are not for this amp. please enjoy

Wow thanks you thats really cool of you

[rocknhorse1]

I didn't know those were for sale??!! I would have given cash on the spot for the "Soul Tramp"!!!! Damn, you are a lucky bastard Gman.
I can see the pics now Don, thanks.

[hipofutura]

Originally Posted by rocknhorse1

I didn't know those were for sale??!! I would have given cash on the spot for the "Soul Tramp"!!!! Damn, you are a lucky bastard Gman.

I didn't either! Just kind of happened. Both G-man and SingleCut asked about buying the amp, and all I could do was babble.

I may sell the other two tweed Champs I had there. That would make room for more builds. I still have several others (without cabs) in a closet.

"Soul Tramp"..... What a great name!

I really really don't want to sell the Stephens alnico, but it's such an integral part of the amps tone. They rarely show up on ebay and they're $200 when they do. I may pick up another, when available.

[Cygnus X1]

I remember this!
Very cool Don.
What circuit are you going to use?
Looks like it might have been a 5C3 at one time?

[FF_Pedals]

Maybe I should start going to the dump .

Now this is a pile of garbage I'd love to find :

[aneas fool]

Originally Posted by FF_Pedals

Maybe I should start going to the dump .

Now this is a pile of garbage I'd love to find :

One mans junk is another mans treasure...start diving for those treasures

[hipofutura]

Tonight I built the eyelet board and populated it. I've drilled the chassis for the new tone stack. I'm missing about six components so I placed an order with Mojo. A couple toggles, a couple caps, and a couple resistors. I didn't realize I'd run out of some basic components. Time to stock up.

Tomorrow I hope to paint the chassis and trannys. I have this image in my mind as to how I want it to look. If I'm right it's going to look VERY cool! Once the paint dries I can start bolting everything back together. It's also time to make the faceplate.

SC, this is going to be a new amp! The only original parts I'm using are the trannys and chassis. And a couple big power resistors. I decided to install new ceramic tube sockets. The originals looked OK, but small cracks in them can cause hard to diagnose intermittent problems.

Here's the eyelet board. Nice SOZO coupling caps and Richey filter caps. It's missing a couple caps and a resistor. I was going to use a cap can for the filter caps, but there just wasn't any room on the chassis.

[jiveturkey1]

This is going to be fun!

[FF_Pedals]

^ Nice board!

[LPV]

Don are you going to be able to draw enough current to get that b+ down a bit ? Whats the plan there, how much will the 6v6's see on the plates?

[hipofutura]

Originally Posted by LPV

Don are you going to be able to draw enough current to get that b+ down a bit ? Whats the plan there, how much will the 6v6's see on the plates?

LPV, part of the problem is that this amp was designed when AC power was 110 volts, and it's now 120. The original amp had a series of four high wattage wire-wound power resistor and the monster choke that dropped the voltage. I'm going to rebuild that circuit and then see where it leaves me. I'm guessing it's going to be just about where I want it. I'll make adjustments as required. I'll post a pick of the power supply once I build it.

At this point I don't know what the plate voltages will be, but it's coming soon!


FF, thanks! I love being able to punch my own eyelet boards. So much cheaper and provides ultimate flexibility.

[randelli]

Looks really clean!

Do you like eyelet boards more than turret boards? Is it a personal preference or do you get a better build? Just curious

[hipofutura]

Originally Posted by randelli

Looks really clean!

Do you like eyelet boards more than turret boards? Is it a personal preference or do you get a better build? Just curious

Randelli, it's probably a "Ford vs Chevy" sort of thing. I started out with eyelet boards and have yet to move away from them. Turret boards are definitely prettier. Some will argue a rigid turret board will last longer than an eyelet board, but there's plenty of 50 - 60 year old amps around with eyelet boards. That's good enough for me.