Stickman builds his first tube amp

Update!

I've been doing a bit of fab work for this thing.

Updates: fuck it, I'm gonna put it in a pre-made cab.

Why? Cause I want to get this one done faster, and my router table needs some attention before I'm gonna be ready to make a cabinet. So, whatevs.

But, I have made a little progress.

Toroid mounting:

Originally I thought "eh, fuck it, I'll just make a little adapter plate that has recesses in it to route the wires through".

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V1 wasn't so great. Not enough clearance underneath, would have squished the wires. No bueno.

1000059093.jpg

So, trimmed the fat. Made it a diagonal piece. Much better now.

1000059094.jpg

Then, I cut up the turret board. Easy nuff. I'm using the hoffman layout in lieu of the original setup.

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Got my caps in place & a couple of the higher current resistors.

Now, wait for the rest of my parts to come in.

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And it's gonna have a name.

The Stickman Chump* (all rights reserved).

Ya know. Like a champ. But really, like a chump (eyyyyyy).

More to come.
 
Little note:

The toroid is an atypical design choice. I did it because I don't know any better, and I'm trying to do this relatively economically.

In truth: EI transformers are far more economical on a large scale manufacturing basis, but they're also *extremely specialized* when we're talking about tube amps.

You know. Secondary voltages in excess of 250vac, maybe with a 50v tap. Add to that a separate 6.3 or 12.6vac winding, and if you really wanna get esoteric: a 5v winding for a rectifier tube.

Step up transformers exist, but in industry you're typically stepping up to specific (common) voltages. You know: 115 to 277. 230 to 460. They're far less common than step down transformers, though.

So, folks make fewer of them. And those economics of scale filter down to us, where the boutique options are basically all that remain.

So, yeah. There are some fantastic, vintage-spec, extremely well made power transformers out there made by folks like mercury magnetics, or edcor, or whomever. But they have a price tag to match.

For folks who aren't interested in adhering to old-skool vintage accurate builds, there are alternatives, but the market is pretty sparse.

Antek makes a variety of Toroids that are affordable and come in the secondary voltages that we want. They don't fit traditional chassis', but those can be modified to accept them. Toroids have some advantages to them: they're slightly lighter weight at the same VA rating, and they don't quite experience the same voltage sag under load as EIs.

That could be a problem for a vintage builder. That sag is part of what makes a vintage amp a vintage amp.

There are other options. Pacific Audio Magnetics makes a relatively affordable blackface deluxe reverb transformer:

Products

Pacific Audio Magnetics
pacificaudiomagnetics.com pacificaudiomagnetics.com

I've also recently picked up a little bit of an experiment...

Aliexpress sellers offer a switchmode power supply that provides 300vdc@600ma, and 6.3 or 12.6vdc at 4 amps.

That's a lot of juice. I wouldn't necessarily recommend this thing, nor would I recommend using it at those current draws...but I bought one.

Why? I'm curious. I don't know enough about switching power supplies, but I wanted to see A) whats the noise floor like if I use this thing to power a tube amp and B) how well did these folks do with controlling EMI?

Its probably not cleared by any regulatory agency regarding interference. I'll likely end up looking out for an isolation transformer to use upstream of it before I start experimenting with it, but it was 50 bucks and weighs about a pound.

And I think to myself: fuck it would be cool to run a 20 watt JCM800 head with this little thing. I could make that thing soooo goddamned light.

But, I won't get ahead of my skis here. That's on the backburner.
 
Last edited:
Stickman393 said:
Little note:

The toroid is an atypical design choice. I did it because I don't know any better, and I'm trying to do this relatively economically.

In truth: EI transformers are far more economical on a large scale manufacturing basis, but they're also *extremely specialized* when we're talking about tube amps.

You know. Secondary voltages in excess of 250vac, maybe with a 50v tap. Add to that a separate 6.3 or 12.6vac winding, and if you really wanna get esoteric: a 5v winding for a rectifier tube.

Step up transformers exist, but in industry you're typically stepping up to specific (common) voltages. You know: 115 to 277. 230 to 460. They're far less common than step down transformers, though.

So, folks make fewer of them. And those economics of scale filter down to us, where the boutique options are basically all that remain.

So, yeah. There are some fantastic, vintage-spec, extremely well made power transformers out there made by folks like mercury magnetics, or edcor, or whomever. But they have a price tag to match.

For folks who aren't interested in adhering to old-skool vintage accurate builds, there are alternatives, but the market is pretty sparse.

Antek makes a variety of Toroids that are affordable and come in the secondary voltages that we want. They don't fit traditional chassis', but those can be modified to accept them. Toroids have some advantages to them: they're slightly lighter weight at the same VA rating, and they don't quite experience the same voltage sag under load as EIs.

That could be a problem for a vintage builder. That sag is part of what makes a vintage amp a vintage amp.

There are other options. Pacific Audio Magnetics makes a relatively affordable blackface deluxe reverb transformer:

Products

Pacific Audio Magnetics
pacificaudiomagnetics.com pacificaudiomagnetics.com

I've also recently picked up a little bit of an experiment...

Aliexpress sellers offer a switchmode power supply that provides 300vdc@600ma, and 6.3 or 12.6vdc at 4 amps.

That's a lot of juice. I wouldn't necessarily recommend this thing, nor would I recommend using it at those current draws...but I bought one.

Why? I'm curious. I don't know enough about switching power supplies, but I wanted to see A) whats the noise floor like if I use this thing to power a tube amp and B) how well did these folks do with controlling EMI?

Its probably not cleared by any regulatory agency regarding interference. I'll likely end up looking out for an isolation transformer to use upstream of it before I start experimenting with it, but it was 50 bucks and weighs about a pound.

And I think to myself: fuck it would be cool to run a 20 watt JCM800 head with this little thing. I could make that thing soooo goddamned light.

But, I won't get ahead of my skis here. That's on the backburner.
Click to expand...
Do you have a link to the 300vdc inverter you were talking about?
 
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