Parts Salvage Question

[HJW]

The preamp chassis is about 12" W x 2 3/4"D x 2" H. Caps look nasty.







The all the wiring between the preamp and power amp is sticky, as is the wiring to the turntable. Is that common ?

[Enzo]

Probably from wax cooked off all those wax capacitors in there. They all need to go away.

[HJW]

Probably from wax cooked off all those wax capacitors in there. They all need to go away.

Yes, they are done for sure. Would the wax be an issue on the pots and other components ? I tried alcohol on the wiring harness and it didn't help much.

I kind of hate robbing such a gorgeous piece of Americana, but I'm gassing for a second tube amp for guitar. If I could trade it for a point to point amp, I would, or sell it to fund one.

Here are the eye candy shots. The legs are not on it in the pic, but I have them. It's on a dolly.

[tedmich]

Yes, they are done for sure. Would the wax be an issue on the pots and other components ? I tried alcohol on the wiring harness and it didn't help much.

I kind of hate robbing such a gorgeous piece of Americana, but I'm gassing for a second tube amp for guitar. If I could trade it for a point to point amp, I would, or sell it to fund one.

Well to make an omelet you have to break some eggs. Its an old (sticky) egg currently, I'd build an 18watt clone, like this:


with the tubes and PT/OT from this unit for ~$50 of new parts; you'll love it!

[HJW]

Well to make an omelet you have to break some eggs. Its an old (sticky) egg currently, I'd build an 18watt clone.....
......with the tubes and PT/OT from this unit for ~$50 of new parts; you'll love it!

Thanks Ted. That's what I want, a simple amp. Just a couple of questions I have:
- Are you are saying 50 bucks worth of parts + the cost of the Hammond transformers and the 4 tubes ?

- Is that a class A design ?

What I really want is point to point lower watt amp, which that design is, and one that isn't forgiving. One that is very responsive and will reveal any nuances gone wrong. Like when I butcher a Mark Knopfler lick lol.

If that minimalist design will work for what I'm shooting for, I'll try it.

btw, I lucked into another one. It's a VC 22 single chassis. Same year,'59. I haven't pulled the chassis out yet.







Would the design you offered above work with that chassis, and possibly add those bass and treble pots into the mix ? Perhaps replace the balance pot with a mids ? Sure would be cool to preserve the pull on, push off/volume control, along with the face and other control knobs.

[tedmich]

Thanks Ted. That's what I want, a simple amp. Just a couple of questions I have:
- Are you are saying 50 bucks worth of parts + the cost of the Hammond transformers and the 4 tubes ?

- Is that a class A design ?

What I really want is point to point lower watt amp, which that design is, and one that isn't forgiving. One that is very responsive and will reveal any nuances gone wrong. Like when I butcher a Mark Knopfler lick lol.

If that minimalist design will work for what I'm shooting for, I'll try it.

btw, I lucked into another one. It's a VC 22 single chassis. Same year,'59. I haven't pulled the chassis out yet.

Would the design you offered above work with that chassis, and possibly add those bass and treble pots into the mix ? Perhaps replace the balance pot with a mids ? Sure would be cool to preserve the pull on, push off/volume control, along with the face and other control knobs.

the minimalist is just that: the simplest Marshall 18watt, but others are more loved (=more made?) like the Lite IIB.
http://mhuss.com/18watt/schematics/18wattLite2b.gif


The $50 was for the resistors/caps and you have the tubes/sockets/PT/OT right? Build it up if the voltages are ok on the PT, and if its as godlike as they say THEN drop the bucks on a primo PT/OT.

To paraphrase Gen. George Patton, an amp made now is better than a perfect amp planned to be made sometime in the future.

(Once made it can be perfected!)

oh and on the class A stuff, its complicated (search here) most good guitar amps are not ever run as class A. Audiophiles love class A, SE, ultralinear, no NFB etc (not necessarily all at once!) but guitar people use what works.

[Steve Conner]

What am I missing here? You're talking about buying transformers, but you have about a half dozen right there. I don't see why you shouldn't be able to make an 18 watt clone (or two) with a PT and OT from those old consoles.

They may not be exactly the same as the recommended Hammond parts, but I'll bet the Hammond parts aren't the same as what Marshall used in the original 18 watter. That's the beauty of tube amps, things just need to be in the ball park, they don't need to be exact.

The VC22 chassis should work fine if you get some 12AX7s for the 6CG7 slots. You could reuse the existing controls, if they're of suitable values and tapers, and aren't too scratchy. I wouldn't try reusing any resistors or capacitors.

Tedmich: I like the "General Patton" quote

[HJW]

the minimalist is just that: the simplest Marshall 18watt, but others are more loved (=more made?) like the Lite IIB.
http://mhuss.com/18watt/schematics/18wattLite2b.gif


The $50 was for the resistors/caps and you have the tubes/sockets/PT/OT right? Build it up if the voltages are ok on the PT, and if its as godlike as they say THEN drop the bucks on a primo PT/OT.

To paraphrase Gen. George Patton, an amp made now is better than a perfect amp planned to be made sometime in the future.

(Once made it can be perfected!)

oh and on the class A stuff, its complicated (search here) most good guitar amps are not ever run as class A. Audiophiles love class A, SE, ultralinear, no NFB etc (not necessarily all at once!) but guitar people use what works.

Right, I have the original transformers. I'm spending a lot of time reading up on everything. Especially safety related stuff. I just have to determine what I can do myself, and what I can't, I'll let a tech do it. Cleaning it, getting the old caps out, etc. Whatever will save me labor charges.

Thanks for the second version schematic. Perhaps I can do both since I have 2 chassis. I'll read up on the class a thing

[HJW]

What am I missing here? You're talking about buying transformers, but you have about a half dozen right there. I don't see why you shouldn't be able to make an 18 watt clone (or two) with a PT and OT from those old consoles.

They may not be exactly the same as the recommended Hammond parts, but I'll bet the Hammond parts aren't the same as what Marshall used in the original 18 watter. That's the beauty of tube amps, things just need to be in the ball park, they don't need to be exact.

The VC22 chassis should work fine if you get some 12AX7s for the 6CG7 slots. You could reuse the existing controls, if they're of suitable values and tapers, and aren't too scratchy. I wouldn't try reusing any resistors or capacitors.

Tedmich: I like the "General Patton" quote

Hi Steve, no if the transformers are healthy I don't intend on replacing them. I just haven't determined if they are.

I'd love to use the VC 22 chassis instead. Hopefully the controls will work.