mike stehr
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Posts posted by mike stehr
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On 11/4/2022 at 9:25 AM, captainbeefheart said:
Here is the Delon full wave doubler circuit, I'm sure you have seen it before.
The Lafayette Stereo 250A uses this very circuit, except the cap values are 250uF.
It runs a quad of EL86, which (I think) draw a bit more current than EL84.
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Another bump
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repriced bump
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On 10/13/2022 at 10:15 AM, gigantic said:
I want the added color of tubes to drive my Heresies, while using my AVR to drive my subwoofer and second pair of front speakers for 2 channel audio and occasionally, 5 or 7 channel.
Some sort of tube buffer, maybe?
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Considering the obnoxious frustration password I set-up for PP, I consider them rather nice letting that password slide....
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Howdy,
Schiit Loki Mini high fidelity tone control.
Excellent condition. Low hours of use...maybe 15 hours.
Comes with manual and wall wart power supply.
Packed well and shipped to lower 48.
Sold
Thanks!
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Knob.
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There is a slight nick on the faceplate...
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Rear panel.
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SOLD
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3 hours ago, henry4841 said:
As far as square, it is a rectangle but getting close to being a square.
My bad...I meant squared corners.
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Are you leaving the base square this time around?
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5 minutes ago, Schu said:
there's no hope for Humanity...
You will own a cheap AVR, eat bugs and be happy...
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28 minutes ago, Curious_George said:
The name of the section(s) have changed too. It is no longer Technical/Modifications, it is Technical/Restorations.
What's technical about restoration? Just call it that...
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1 hour ago, seti said:
That is really cool. I need a few of those!! I have some HP Power Supplies awaiting restoration but I don't think they are as flexible. I've also had my eye on some Lambda Supplies.
I have a Lambda C-281M. 325 volts at 200ma maximum operating voltage. The Hewlett Packard 712A would be nice to have...
A retired EE friend had a tube power supply he picked up when he was an employee at Magnavox...it was older looking unit that uses 6550 for pass tubes.
600 volts at 200ma. I'd always tried to talk him out of it to no avail.
I also have a Lambda LA-100-03BM. Switchable up to 35 volts at 10 amps. An 80–90-pound tank...
1 hour ago, henry4841 said:I make my share. The getter on those tubes look really good. Good indication the tubes are still good without having a tester.
It was really a case of paying too much attention to the images I took to reference for rebuilding, and not enough attention to the schematic.
I wouldn't be surprised if these are the original tubes that came with the unit.
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The Heathkit DC tube supplies seem to be a little over-price these days, and it has been mentioned that one could build a high voltage/current B+ supply using transistors for series pass duty, with op-amps or what not for control. Purchase some filament transformers to use for heating the tubes.
It's just a cool old school Heathkit built on 04/17/1963.
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Recapping, etc was rather simple. But of course, I didn't pay enough attention to the schematic and re-oriented the larger diodes backwards.
After blowing some fuses I corrected that. Then wondering why, the voltage was wonky, I put a cap on the wrong pin for the control tube.
After correcting that, the power supply works as it should. Schematic blunders on my part...
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Pictures of your Tube Amplifiers
in Talkin' Tubes
Posted
heh
It's the static display version.
A guy ditched on me at an audio meet and greet.
It used a couple of filament transformers to light up the heaters to the tubes for display.
Then it had a plastic hammond case inside mounted on the front, with a Velleman LED control PCB inside, and a couple 9-volt batteries. (with 2004 date codes)
There was a little switch on the back for the LED display.
The knobs on the front are fake...like cabinet knobs screwed in with Allen bolts.
The switches are real, but not connected to anything.
If anything, I scored two dozen fresh input jacks, and ten good tube sockets.
The wood chassis is actually solid Bubinga.
I'm pondering the idea of using the aluminum chassis plate and Bubinga base for an amplifier project.
But maybe shorten the plate and base for a smaller profile.
Interesting piece for the Poverty Audio scrapyard...