• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

jaymanaa / Urizen's Amp Project

Status
Not open for further replies.
jaymanaa

jaymanaa

RIP 1961-2018
Hi All, while awaiting parts for the big chrome Conns of Terry's, I'm going to do some preliminary work on Ken's newest amp. It appears to be a homebrew of remarkable quality. Someone really knew their stuff when they whittled this one out. It uses EL34s in PP, with a 12AY7 splitter, and AX7 drivers. The exciting thing is the iron. The PT is absolutely huge (and sheilded), with a 4 inch :yikes: stack. The OPTs are Thordarson Ultra linear jobs (22S39). So far I have tested all the TXs and they look fine.:banana: I'm planning all new lytics, new silver wire, fancy smansy coupling caps, etc.... Cosmetically I'm planning on a first rate paint job, with some custom (by hand) pin stripping. I have a feeling this thing will be like a ST70 on steroids. Thanks for letting me operate Ken, I'll try to do her proud.:thmbsp:
 
Last edited:
Register to hide this ad
Fifty dollars worth indeed! I can make you feel even better though. I tested the Seimans EL 34s that were in it, and they test as new and matched.:jawdrop: They're just like the ones I been running in my 70, and I love their sound (very accurate and un-colored), at least in that circuit. The power supply on this thing is exactly what I would have tried to do too. It's got SS rectification (which will get some fancy Cree diodes) into a big low DCR choke 33 ohms, and lots-o-capacitance. I seriously think this amp will be all you will ever need, even with difficult loads. With the size of this PT, I don't doubt that we will be able to wring out 50 or 60 per channel (realistically).:yes: Time will tell.
 
jaymanaa said:
I tested the Seimans EL 34s that were in it, and they test as new and matched.
Click to expand...

I'll be. I thought they would be trashed. More great news! FWIR, the seller told me that it was in working condition, and was indeed a homebrew. He had small kids and didn't want it available to prying fingers. He replaced it with first rate SAE system, and was a nice fella to boot. He joined AK, but I've not seen him post again.

I take it your going to replicate the circuit that's there, or have you got some tricks up yer sleeves?
 
Urizen said:
I'll be. I thought they would be trashed. More great news! FWIR, the seller told me that it was in working condition, and was indeed a homebrew. He had small kids and didn't want it available to prying fingers. He replaced it with first rate SAE system, and was a nice fella to boot. He joined AK, but I've not seen him post again.

I take it your going to replicate the circuit that's there, or do have you got some tricks up yer sleeves?
Click to expand...

I'm tracing the circuit now and drawing a schematic, and from what I see so far, I like it a lot.:yes:
 
jaymanaa said:
I'm tracing the circuit now and drawing a schematic, and from what I see so far, I like it a lot.:yes:
Click to expand...

Whoever built it did a good looking job dressing the wiring, esp. around the tube sockets. Your pic is the first time I've seen it's underbelly.
 
:lurk: monster iron! The wildest I have(operational) is the potted iron on my Ampeg.This is good lookin' start,Urizen! Heck, it's probably great now!
 
Urizen said:
FWIR, the seller... had small kids and didn't want it available to prying fingers.
Click to expand...

Sorry he had to let it go. Some kids can be taught - tubes are hot, they burn, they'll kill you and you will die. After the lesson, they won't go within six feet of the amplifier. I guess there is always the chance of the accident. Better safe than sorry. His loss, your gain.

That's quite a stack of iron in the power transformer, isn't it?
 
Urizen said:
Whoever built it did a good looking job dressing the wiring, esp. around the tube sockets. Your pic is the first time I've seen it's underbelly.
Click to expand...

He did a really good job with the lead dress.:yes: The only thing I found so far that I didn't like, was the fact that he used solid aluminum wire for all the ground busses. I bet it was built when aluminum wire was hitting the scene in construction (and was supposedly the best thing since bread). He also used mica caps in all the pf spots, which is something you don't see often. I'm going to have to replace the leads on that big ol' power TX. The insulation is toast, but at least it's fine on the potted outputs. It would suck to have to unpot them.
 
OK Ken, I found the bad part! We need one of these, so start looking down there, and I'll look up here.:D
 
Last edited:
Are those the same socket tubes as a 7591? There are some VERY nice socket tubes that a place on Ebay sells. Machined and gold plated pin sockets. Not the poor quality stock style crimped ones. I have a spare 500c that I planned on having redone with a bunch of cool parts like this.

3221854334_41b7769e03_o.jpg
 
DENNYDOG said:
Are those the same socket tubes as a 7591? There are some VERY nice socket tubes that a place on Ebay sells. Machined and gold plated pin sockets. Not the poor quality stock style crimped ones. I have a spare 500c that I planned on having redone with a bunch of cool parts like this.

3221854334_41b7769e03_o.jpg
Click to expand...

Denny those are very nice looking, I like but probly a little to steep for my pocket lol.
 
They are $18/pc including the shipping. Search CMC gold pins on Ebay if you are interested. They come from a guy in Taiwan.
 
Status
Not open for further replies.
Back
Top Bottom