kevin gilmore

You want a denon, onkyo, the new sherwood newcastle thing, or the new sony all of which definitely do audio over hdmi. Including native sacd.

No chance He can't afford me... Neil's amp rebuilt right is probably 30 to 40 hours of labor. Plus a bunch of parts. I don't even have the time to build my new stuff

If your build 2 of my schematics as in 2 filament supplies and 2 of the high voltage supplies tweeked for 400 volts (and one of them grounded upside down to make -400) plus a bias supply you would have one kickass power supply. And a small C- sully. Sort of like that 12 tube thing mikhail built except mine would be built with the right parts and actually work instead of blowing up. (yes one of those has died recently too, looks even worse on the inside) So here is a story. Out of college 34 years ago i went to work for zenith radio and learned lots from the true tube masters that worked there. Most of which were at least 30 years older than i was at the time. So recently i've contacted a couple of them, as most have already passed into that great DHT heaven in the sky, and i found one of them who was willing to work on the SP stuff after i told him of people' woes. That is until i showed him pictures of the stuff. At that point he said no fucking way, it would be easier to strip it to the bare chassis and start over wiring things correctly. The 3 pictures i showed him was this SDS mess, neil's amp, and spritzers amp. So i'm back to trying to find someone who will work on this stuff. If i do find someone, it ain't gonna be cheap. Unless i find a high-school kid that wants to learn. For neil's amp, the 4 pots on the front panel HAVE TO CHANGE. Plus they have to be wired differently. Schematics of the modifications have indeed been tested and work fine. But spritzer needs to test his way on his amp.

blu-ray burner absolutely required. And pretty cheap. Since you are going to use a tv as your display device make sure that your video card has a hdmi output.

depends on whether the fet is in a fully isolated case or not. In any case thermal grease or a silicon grease washer is a real good idea to keep the board from burning up.

this is the correct way to do this. Lock-in amplifier - Wikipedia, the free encyclopedia I have a recent vintage SRS amp, now i just need some time to set the thing up. Does not really measure impedance as such, but is real good at measuring phase. I think that increasingly stereophile is more and more full of shit. What you can do is put a 300 ohm pot in series with the headphones and turn it up and down, simulating a low impedance and high impedance amplifier. Sound is hugely different. Grado's and hd600's don't exhibit the same kind of behaviour. If stereophile would do the same thing with different damping factors, things would come out very different.

actual measured voltages with quickly built hacked together power supply with 0a3 (75) output voltage range 123-216 0b3 (90) output voltage range 140-257 0c3 (105) output voltage range 159-298 Looks like 150ma no problem. 520 volts at the plate of the regulator tube.

Switching with the power on is a gigantically bad idea. Maybe next time i go in there i will add a couple of extra resistors to make sure the switch does not temporarily disconnect all the feedback.

I have a switch that allows me to change between the two. So the answer depends on the day and on the music... And the phase of the moon and the temperature outside And how much booze... Some people really like amplifiers without global feedback. Especially when female voices are involved. (no, not the B&C)

complete with all the glorious fuckups... http://gilmore.chem.northwestern.edu/singlehourextreme.jpg

updated schematic with correct 6au6 pinout http://gilmore.chem.northwestern.edu/sdsgaspsfix.jpg

There are lots of ways to do this, i think this is the best. Some notes. voltron really liked the sound of 2 x 75 volt tubes... i.e. 150 volts for the power supply. The WCF amplifier he has is AC coupled between first and second stages so you can definitely have 2 different voltages if you want to. The design as introduced works with just about all gas tubes and has a intentionally limited voltage range. With a 75 volt gas tube the output is about 90 to 150 with a 90 volt gas tube the output is about 110 to 180 ... with a 150 volt gas tube the output is about 170 to 300 And yes you can adjust the voltages with the amp on. You would want to turn the output section voltage up and down slowly otherwise you will get a slight bass thump.

OK, i have something that i really like. It is completely in the spirit of the original power supply, fixes absolutely everything, can't burn up as there is no sand in the high voltage section, no dangerous anything, nothing out of spec... Best part, no modification of the chassis. Well almost, need 9 pin to 8 pin adapters for the 6au6's. Keeps all the iron. Otherwise adapter plates for the 6au6's. Uses only one gas tube per channel, 1 socket is for the 6au6 and the other is for the 6l6. http://gilmore.chem.northwestern.edu/sdsgaspsfix.jpg unfortunately, still sand in the filament supply, but absolutely nothing can be done about that. WARNING: pinouts of the 6au6 completely wrong. And the picture of the 6l6 is not correct either, but the pinouts are right. Cute part 2. The switch that was the voltage selector is now the voltage pot. It can be a dual section in which case both supplies adjust at the same time, or if you do it as 2 seperate knobs on the same shaft, you can adjust the front end gain power supply seperate from the output power supply. Now all you need is an ultra trendy analog meter to stick into the front panel. (ok, now you have to do some chassis work) do it eddie current style and it will look real cool.

That also works for me. Sounds sooooooooo nice with hd800's... Wish someone would allow me to buy connectors so that i could go balanced. (hint hint)

I'm using different fets on the prototype, but if you make the bias pot 100k you should be able to get down to 250ma.

That is up to neil. But if you ask him real nice i'm absolutely sure he will send them to you... Major fail with capacitors just hanging there from stickem cable ties that long since let loose... Send the amp to me... But really you will never get it back...

I wonder what would happen if you went to jack at woo audio and told him you wanted him to build an extreme his way. It sure would be pretty and it would work forever. Offer to supply the schematic and have him make the necessary changes to make it reliable. He already knows how to do dc filament supplies, and high voltage supplies for that kind of thing, should be easy.

I would really need high resolution pictures of the amp pointed to the neutrik connectors from a couple of different angles to determine which wire is which. As far as i can tell, 2 of the 5 wires total are filament, one is ground, one is front end B+ and the other is output tube B+ A simple harness to the heathkit is all that would be necessary. Ironbut should clearly be able to figure out which wire is which and to make up a fast harness. There is literally thousands of really outstanding surplus power supplies out there. The heathkit is nice because it has both supplies that you need. But anything that meets the following specs should work. something that makes 6.3 VDC or 6.3 VAC at up to 10 amps. something that makes around 150 VDC at about 150ma. (best guess at total high voltage current) So anything in the 0 to 300 volt range with 250ma or more is perfect. Certainly not as pretty as your current supply. But will likely give you 20 years of trouble free power. The black gate output caps are your limiting factor given the WCF design, so absolutely no more than 350 volts max. Now as to how to fix that current mess and still have the gas tubes light is another story entirely. Unless you want the gas tubes to be a night light but otherwise electrically not part of the circuit. Mikhail was all about show anyway. Not the least of which is that unproperly filtered gas tubes are noisy anyway. Filament transformer will have to be replaced at some point in the future anyway. Neil found someone good to fix his amp (although its going to be expensive, lots of man hours of work there) maybe you can contact that guy and show him my current best guess on the power supply schematic and then show him pictures of the thing. If he doesn't run away screaming, you might be able to get him to fix the thing, at least temporarily. I've been playing with a few different ideas using the transformers and other parts in there i can salvage. Currently i don't like what i've come up with. Its kind of stupid if what you thought you were getting really was an all tube power supply. Lots of solid state all over that thing, none of the caps across the diodes needed to shut them up... There is another version of this power supply out there that actually has 6l6 pass tubes, that would be a better idea, but now we are talking about more holes in the top chassis, no reasonable way to wire the mess...

The rules on surplus stuff i send to people is that i never ever want it back. Not a lot of room left in that sds supply to add a bigger transformer. OH hell, just tie the wires in, and cram it in there somewhere. Use hammer to make sure it fits.

There is absolutely no reason to touch the amplifier chassis in any way. Replace the power supply chassis with a couple of power supplies in the meantime while you decide the ultimate fate of the old power supply. Won't change the sound in the slightest. You can go back to the old supply later. Or just change out the fet and diode and use it till the filament transformer finally burns up completely.

OK, perfect for the filaments LAMBDA LQ-530 0-10V, 0-14A DIGITAL DC POWER SUPPLY - eBay (item 320264048971 end time Jul-10-09 19:32:45 PDT) Great for the high voltage. Still overkill. I have more than a dozen of these, various voltages and currents. They can't be killed. SORENSEN [email protected] REGULATED VARIABLE DC POWER SUPPLY:eBay Motors (item 350188032602 end time Jul-06-09 12:50:09 PDT)

OK, this is a joke. Well it's not a joke, but if you buy this i will have to fly out there and take it away from you before you hurt yourself. But really this beast plus a large filament supply and you can run the world. HP 6479C 0-300 Volt, 0-35 Amp, 11KW, DC Power Supply - eBay (item 150353372151 end time Jun-30-09 12:37:17 PDT) Zero to 300 volts... absolutely perfect Zero to 35 amperes... A little bit of overkill 208 3 phase with neutral and ground absolutely required. Your electric company will love you. Trying to find a perfect and reasonable match for a pair of power supplies now.

Oops then he really is making 1100 volts with 900 and 700 volt parts. The green/yellow is the center tap and is clearly not connected, so the 2 greens go directly to the diode bridge. OK, so here is what i would do NOW. Go on ebay and look for a heathkit IP17. These things are workhorse units which got me thru a number of years at zenith in the plasma panel research department. Very hard to kill. And tubes! Its a slight bit light on the filament current, but i pushed one to 6 amps regularly. Completely adjustable. Here is a brand new one which is way overpriced NIB HEATHKIT 400VDC POWER SUPPLY 4 TUBE AUDIO AMPLIFIER - eBay (item 270406989290 end time Jul-11-09 10:00:21 PDT) here is one that is beat to shit for a lot cheaper. Heathkit Ip-17 Tube 6L6 H.V. Power Supply ip17 Buy Now - eBay (item 390060230006 end time Jul-18-09 17:59:25 PDT) buy some new neutrik connectors, and wire the thing up to the amp chassis. DONE... Then decide what you are going to do with the boat anchor.

I'm now wondering if mikhail did not do a reverse of what he did on that extreme. Wire the one transformer as a 220 vac input and run it on 110 vac. That way the output would be down to 400 vac, about 560 vdc into the caps... Very hard to see how the primaries are wired. If he did this, then it would be no wonder that the tubes don't light all the time. As you need about 2.7 times the starting voltage to get the tubes to kick in. So 3 tubes would need about 600 volts to start.

It will have a very different sound signature however. Some would probably like that even more. Mikhail did build a couple of balanced platinum extremes and found a way to shove them into a supra chassis... Bet those are going to be real fun to fix when they go boom. You would need about 16 real amperes of filament juice to light one of those up. Plus about 75 watts of high voltage.