Sounds familiar. I remember seeing a 6DZ7 based amp in that magazine, which added the 6DZ7 to my hamfest list. The 6DZ7 has two output pentodes in a common octal bottle. One tube per channel, so only 2 would have been needed for a stereo amp. I have seen two different versions of 6DZ7's, one looked like a pair of 6BQ5's stuffed into the same bottle. The other looked like a single pentode but the grids and plates were split and seperated.
When things were good in the plant where I work there were several thousand people working there. (tic tic tic) There was a computer club, ham radio club, and an audio club.(tic tic tic) I was a member of all 3. (tic tic tic) Around 1980 one of the members aranged for a group buy of the newly released Carver M-400. (tic tic tic) I bought one and the club presidents used Phase Linear 4000 preamp. (tic tic tic) 10 to 12 M-400's were sold. (tic tic tic) Despite Carvers warnings I played my guitar through it and 2 4 X 12 cabinets, loud, very loud. (tic tic tic) Just when the neighbors were about to call the cops the protection circuits would shut down the fun. (tic tic tic) When I finally returned from about 15 years on the dark side (SS amps) My Carver was still working. (tic tic tic) Everyone elses had blown up. (tic tic tic) The pair is still stashed around here somewhere, but hasn't been powered up in at least 10 years. (tic tic tic) Was the Carver a great sounding amp? Actually I preferred the sound of the 1970 vintage 40 watt Voxson receiver that I replaced with the Carver, but the loud crowd convinced me otherwise. Was the Carver a deal for the price? Yes, if you could get past the tic tic tic tic tic........ Anyone who ever had a M-400 knows about tic tic tic.....
The M-400 had a very undersized power supply and virtually no heat sinks. It ran class G with 3 different supply rails and 3 pairs of output transistors per channel. The power supply used a triac that pulsed line power to the filter caps through an isolation transformer. Pulses were few at low volumes but drew power in short bursts of 5 to 10 amp current slugs. Those pulses found their way into everything, especially the phono section, resulting in tic tic tic at low volumes or in between record tracks.
Just trying to work out what the "DC restorer" is led to an experiment. I soldered some 1N4148 in series with 5V1 zeners (cathode to cathode) from ground to the coupling caps feeding the grid stoppers on a 6L6GT (6P3S) PP amp with cathode bias (680 ohm resistors, 30mA current, 370V B+). The intention was to clamp the lower half of the sine wave at -5.6V or so. The initial listening result is that it is definitely no worse and seems to sound better if anything. Would like to experiment further.
Ian
Ian
Grid current causes "blocking distortion" increasing negative bias (charging coupling cap). Clamping to an opposite side "restores" DC. I used it for solo guitar amps. Musicians call it "Farting distortions". Decreasing capacitance of coupling caps works better, but it affects bass response. So this technique may be used for amps owner of which like to listen to the music on clipping levels. But source followers for such case would serve better (or cathode followers like in Ampeg SVT amps, made for bass guitars).
bjut how many carver amps like the one pictured do you own?
knob is machined aliminum billet,,ask the man that owns a pair.
Amazing. How do you suppose he gets that round coil onto the bobbin shown in the "output transformer that is huge" picture? And, we will have to try out that new mukluk winding glove scheme. I have long thought that the need to control wire with bare fingers was far over rated. I mean look at him. He's winding a perfectly round coil without any side supports at all, and then he gets it to fit onto that vastly oblong bobbin used in the OPT shown, that has square corners. The guy is just amazing! A Marvel!
And then, he has found the only remaining producer of Adamantine Steel core, the only core material made from alum and oxygen and it has a Moh's of nine. No one else has ever been able to stamp lamination from the stuff, much less roll it flat into a sheet first! A true Marvel! And then he says modern commercial core is way better than this metal of the God's. I mean, just check out Greek mythology, no other material could be used to make a castration knife to be used on a God. Just think how long a plough share beaten from this material would last, having first had it's metal tempered in the testicular blood from a God!.
The final picture says it all though. There is Bob, with his gloves still on and winding. But, do you see any wire? He must be winding pure diamond wire onto that coil we cannot see. I am just certain this is what he is doing, only diamond wire could produce those startling colors and those staunch transients. Pure genius!
Bud
And then, he has found the only remaining producer of Adamantine Steel core, the only core material made from alum and oxygen and it has a Moh's of nine. No one else has ever been able to stamp lamination from the stuff, much less roll it flat into a sheet first! A true Marvel! And then he says modern commercial core is way better than this metal of the God's. I mean, just check out Greek mythology, no other material could be used to make a castration knife to be used on a God. Just think how long a plough share beaten from this material would last, having first had it's metal tempered in the testicular blood from a God!.
The final picture says it all though. There is Bob, with his gloves still on and winding. But, do you see any wire? He must be winding pure diamond wire onto that coil we cannot see. I am just certain this is what he is doing, only diamond wire could produce those startling colors and those staunch transients. Pure genius!
Bud
The one in the picture is a Radio Shack part.
I can't speak for what you have and who said it has to be the same part?
Are you sure? I'm convinced that he does not use any diamond. He uses pure Akasha.
So much fun but he built it and now he's selling it. Productive. Silly comments are not productive and I'm still waiting to see something that big built around these parts. This is the place where everybody runs away at the mere thought of a 100W OT.
Try winding one that sounds any good. BTW, is he doing the Jaws joke?
Try winding one that sounds any good. BTW, is he doing the Jaws joke?
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Bob is certainly fond in exaggerated marketing. What is for sure unit for sale is real, not fake or mock-up. Visual design and appearance IMHO is crude, but many audiophile megabuck equipment looks even uglier and filled with boutique crap anyway. I must admit warranty terms are best I ever heard.
I took a closer look at pictures attached to the auction. What looked like round bobbin with copper wire is not a bobbin at all, it is blocking bush on axis holding bobbin, which is made with impregnated paper spread on wooden block. Since bobbins at these dimensions and stack thickness are not available, I think Bob made them with off the shelf materials (paper tube impregnated with epoxy or whatever else + 2 side panels). On the last photo mentioned he simply wears off gloves.
As for Adamantine steel this is another sweet marketing candy. Or may be steel produced with the equipment from Adamant Technologies SA, or is processed with Adamantane (hydrocarbon) chemistry somehow, who knows
Or even better, re-factored stuff attached on the picture
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I have no doubt the amp is real. Bob does actually cause other people to provide him with designs and is also quite capable of getting still more people to make a product for him. There are a number of disgruntled designers in the pacific north west who will attest to the truth of this.
Bob's brother is the individual who has always done the winding. A number of years ago I showed him how to wind coils directly on Nomex paper, without a former tube and without the coil collapsing it's ID into the core volume. Not so hard to do once you know how. Hopefully he remembered how and it is allowing him to provide Bob with safe, effective, OPT's.
As for making OPT's that sound good, not a problem. All the way out to 500 watts if need be. Ask Vic Tiscareno or Byron Collett or Dennis Had or Rene' Jaeger or Gary Koh or Andy Marshall or Mike Soldano or Bill Sundt or Don Anderson or Jack Anderson or Rick Chinn or Dan Deirdorf or any of the 200 or so DIY folks who have purchased audio reproduction amplifier OPT's. Or the unknown number who play guitar amplifiers with O-Netics OPT's in them. And then there are Lundahl, Electraprint, Magnequest, Hashimoto, Silk, Sowter, Intact Audio and Tribute, if O-Netics is not to your taste. Not hard to get a very good sounding OPT, just so long as the manufacturer realizes they are not making power transformers and so might require a different train of thought.
I certainly have no problem with Bob doing what he does best, but if he is going to do silly things with a silly grin on his face and post the pictures I have no problem with teasing about it either. After all, I too have a long list of very unusual products trailing along behind me, EnABL, Ground Control, dreaded cables and, of course, audio transformers.
Bud
Bob's brother is the individual who has always done the winding. A number of years ago I showed him how to wind coils directly on Nomex paper, without a former tube and without the coil collapsing it's ID into the core volume. Not so hard to do once you know how. Hopefully he remembered how and it is allowing him to provide Bob with safe, effective, OPT's.
As for making OPT's that sound good, not a problem. All the way out to 500 watts if need be. Ask Vic Tiscareno or Byron Collett or Dennis Had or Rene' Jaeger or Gary Koh or Andy Marshall or Mike Soldano or Bill Sundt or Don Anderson or Jack Anderson or Rick Chinn or Dan Deirdorf or any of the 200 or so DIY folks who have purchased audio reproduction amplifier OPT's. Or the unknown number who play guitar amplifiers with O-Netics OPT's in them. And then there are Lundahl, Electraprint, Magnequest, Hashimoto, Silk, Sowter, Intact Audio and Tribute, if O-Netics is not to your taste. Not hard to get a very good sounding OPT, just so long as the manufacturer realizes they are not making power transformers and so might require a different train of thought.
I certainly have no problem with Bob doing what he does best, but if he is going to do silly things with a silly grin on his face and post the pictures I have no problem with teasing about it either. After all, I too have a long list of very unusual products trailing along behind me, EnABL, Ground Control, dreaded cables and, of course, audio transformers.
Bud
Jacco,
That is definitely a hand guided winding machine. The device on the end is a winding arbor. No doubt, Bob did sit in front of the correct piece of equipment. I don't for a moment think that the end of what Bob has in his glove is actually attached to anything. I do think it is probably wire, and of a rather heavy gauge, likely AWG 9 or so and the color does look like a typical insulation for the larger gauges of wire.
Links,
I won't dispute the use of the round coil of wire, but it is a round coil of wire. Almost certainly a polybutadine coated wire, so it has glued itself together while being wound. If you look closely in the head on pic you can see a step in the surface of the round puck, with a wire end curling from it. The arbor does not appear to be a collapsible device and with no obvious side supports for wire, as would be found in a free form winding arbor. I suspect a bobbin is used in the actual OPT winding. The pic of the alleged OPT does show a bobbin having been used and it is a relatively easy process to cut up bobbins and then weld them together with a large (100 watt) soldering iron. Not trivial, but possible. You can even meet CE 6500 specs, by using 3 pieces of appropriately wide electrical grade tape across the joints.
Too bad we can't somehow twist this thread into another cable argument thread, and then sit back with popcorn and beer to watch the opposing sides suck each other in. I miss that daily entertainment so!
Bud
That is definitely a hand guided winding machine. The device on the end is a winding arbor. No doubt, Bob did sit in front of the correct piece of equipment. I don't for a moment think that the end of what Bob has in his glove is actually attached to anything. I do think it is probably wire, and of a rather heavy gauge, likely AWG 9 or so and the color does look like a typical insulation for the larger gauges of wire.
Links,
I won't dispute the use of the round coil of wire, but it is a round coil of wire. Almost certainly a polybutadine coated wire, so it has glued itself together while being wound. If you look closely in the head on pic you can see a step in the surface of the round puck, with a wire end curling from it. The arbor does not appear to be a collapsible device and with no obvious side supports for wire, as would be found in a free form winding arbor. I suspect a bobbin is used in the actual OPT winding. The pic of the alleged OPT does show a bobbin having been used and it is a relatively easy process to cut up bobbins and then weld them together with a large (100 watt) soldering iron. Not trivial, but possible. You can even meet CE 6500 specs, by using 3 pieces of appropriately wide electrical grade tape across the joints.
Too bad we can't somehow twist this thread into another cable argument thread, and then sit back with popcorn and beer to watch the opposing sides suck each other in. I miss that daily entertainment so!
Bud
That's cause I learned all of this stuff from RPE's and thus became one myself. The other stuff I go on about is my inventions I try to tell others about. Completely different sorts of things. One is the sane teaching the mad, the other is the mad teaching the compassionate.
As for cables, LCR, with C being triumphant, nothing else needed. Except for the show n the popcorn and a beer to help understanding.... most definitely interested to see what the new cable thread mushrooms into. Already has some quivering bits laying about.
Bud
"
Every vacuum tube amp in the world suffers from shifting DC operating points, and this unfortunately has remained a functional limitation and maddening sore point for amplifier designers ever since the very beginning of vacuum tubes. Consequently I had to invent a DC restorer circuit using a 6AL5 / 5726 tube; it eliminated every last vestige of DC shift, while simultaneously reducing distortion three-fold and vacuum tube idle power by the same amount. As Tim would say, "Nothing new under the sun", just the same, it's never been done before, and it works flawlessly.
"
Sorry Bob,
My Audio Cyclopedia dated 1959 , on page 547, has shown that the Altec Lansing 436B compressor amplifier also used the same "a DC restorer" circuit that you have claimed invented, what a coincidence, used the same 6AL5 tube. Care to clear-out the smoke? Attached is the schematic.
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