Reminder:
Without proper care, 833A amplifiers can have Shocking results.
Safety First!
Prevent "The Surviving Spouse Syndrome".
I have an 833A with one half of the filament broken, so the other side of the filament takes 10V at 5 Amps.
I use it at Christmas Time, just the lit filament, no B+.
Without proper care, 833A amplifiers can have Shocking results.
Safety First!
Prevent "The Surviving Spouse Syndrome".
I have an 833A with one half of the filament broken, so the other side of the filament takes 10V at 5 Amps.
I use it at Christmas Time, just the lit filament, no B+.
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That is very true of anything that uses the unforgiving 1000 or more Volts. 300 to 400, depending on whether you use cathode resistance and direct coupling of the lower anode adjusting the circuit to the lower grid voltage of a 300B, a 2A3, or a 45 is not likely to be deadly but it will shock. Always cover with insulating collars caps to plates. So folks, read what 6A3sUMMER tells us and keep things safe.
Hello, Magz. Your speakers are also big and 4 Ohms, like mine. So we had to solve common problems. And I believe that you have come to an excellent sound. Also the system looks beautifully.
If I am right, Wavac amps also operate at 1000 V and zero grid bias. But maybe you also have come to relatively high output resistance, as Wavac. It would not be good with my speakers.
For $350,000 do you even get polypropylene filter capacitors in the high Voltage power supplies? Using the best parts money can buy you pay under $2000 for parts to build an amplifier at least as good as the WAVAC. I don't have the know how to perform the psychological manipulation it takes to get anyone to pay me $348,000 for a week or two of the labor it takes to build that kind of an amplifier and it would not surprise me if most people could build one faster than I can, but getting so conspicuously overpaid would not be honest or fair to any customer so I would not do it even if I could.
I have found interesting info at radio amateurs forum, at the below following post #20, about GU-48 tubes
????????? ?? ??-48 - ???????? 2
"Actually, the attractiveness of the GU-48 tubes arose immediately, as soon as the expensive Wavac SH-833 amplifier was manufactured in Japan. It is noteworthy, that in the Wavac SH-833 there is not the original 833A, but our GU-48 of the "Polyaron" plant, although the Japanese also had the original 833A on tests, and not one.
There are 2 options - 833A with metal anode, and 833C with graphite anode. Actually, our GU-48 is a complete analogue of the 833A. OJSC "Svetlana" is selling to the west the GU-48 of the "Polyaron" plant, simply by repainting them in 833A.
It is the fact that this tube was not originally developed in the USSR. Apparently, it is not widespreaded in audio amplifiers due to the fact, that we have a GU-81M with a lower internal resistance. Analogues of the GU-81M have not been made and are not being made in the USA. Only in Europe were there similar examples - Telefunken RS 384.
I can say with confidence, comparing both tubes live, that our GU-48 was clearly done after studying the errors and shortcomings of the 833A. The disadvantages of 833A are that the anode and grid-cathode block hold independently of each other (cathode and grids - by the filament horns, the anode - by one of the upper pins) and there have been cases when, during the operation of the tube, that relative position of the tube electrodes has been changed with the corresponding "swim" of the I - V characteristic. "
I would add from myself, that now interest to graphite anode GU-81M goes to almost zero, since GU-48 is better soundwise.
????????? ?? ??-48 - ???????? 2
"Actually, the attractiveness of the GU-48 tubes arose immediately, as soon as the expensive Wavac SH-833 amplifier was manufactured in Japan. It is noteworthy, that in the Wavac SH-833 there is not the original 833A, but our GU-48 of the "Polyaron" plant, although the Japanese also had the original 833A on tests, and not one.
There are 2 options - 833A with metal anode, and 833C with graphite anode. Actually, our GU-48 is a complete analogue of the 833A. OJSC "Svetlana" is selling to the west the GU-48 of the "Polyaron" plant, simply by repainting them in 833A.
It is the fact that this tube was not originally developed in the USSR. Apparently, it is not widespreaded in audio amplifiers due to the fact, that we have a GU-81M with a lower internal resistance. Analogues of the GU-81M have not been made and are not being made in the USA. Only in Europe were there similar examples - Telefunken RS 384.
I can say with confidence, comparing both tubes live, that our GU-48 was clearly done after studying the errors and shortcomings of the 833A. The disadvantages of 833A are that the anode and grid-cathode block hold independently of each other (cathode and grids - by the filament horns, the anode - by one of the upper pins) and there have been cases when, during the operation of the tube, that relative position of the tube electrodes has been changed with the corresponding "swim" of the I - V characteristic. "
I would add from myself, that now interest to graphite anode GU-81M goes to almost zero, since GU-48 is better soundwise.
There is very interesting powerful European pentode with metal plate - 5C/450A, but rare
I never heard about such an issue with GU-48 tubes. And, I am sure from my personal experience, metal anode is always better sound wise. Although, mechanical design is also important.
There is no doubt in your words. The only point, sound details are shown also by many transistor amps. Metal anode refers more to "cleaned" or "purified" sound details.
Graphite anodes, hot anodes, metal, nickel, etc.
I've never see better looks than mesh and holed
I like mesh rectifier tubes, and run an EML 274B rectifier in my UX-201A preamp/DAC.
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Oh, this tube is really good, both technically and visually. And you Roman (Kruzhka) seems to be a happy owner of such tubes, since you sell themThere is very interesting powerful European pentode with metal plate - 5C/450A, but rare
5C/450A STC 4212E Tube Valve Audio DHT Pentode Triode Blue Print Tested! | eBay
But the price I could not afford. For one such tube I could have 7pcs of good old NOS (1974 with zirconium plated thick metal anode) and even matched GU-48. And who knows, about final sound result, if to compare these tubes. Also a spare pair of tubes is needed, if to invest in such a huge project.
Among old metal anode tetrodes, that were manufactured in Tashkent in years 1950s, I would mention GKE-100 tube. It is still more affordable than metal anode GM-70. Its maximum plate dissipation is 80W, plus 16W dissipated by the second grid if triode connected, so we come to near 100W dissipation power. Triode curves have been measured by one colleage from Ukraine.
I also heated them up, and was surprised by their stable behaviour. After 70 years of storage, anode current came to stable point after few seconds of operation.
I also heated them up, and was surprised by their stable behaviour. After 70 years of storage, anode current came to stable point after few seconds of operation.
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