1000VCT 6.3V 400VA Toroidal Power Tube Amp Transformer, with a 10H+ 300ma+ (if stereo) choke input should give a supply in the range your looking for with SS or hybrid bridge rectification.
A few 80 MFD 500 VAC 50/60 hz Eyuda International Oil Filled Motor Run Capacitors for B+.
A separate, likely DC, filament supply will be needed.
Budget OPTs for amps of this sort are another can of worms entirely.
Probably no such thing as a budget opt for this project, but talk to Jack Elliano over at Electra-Print about it. His prices are extremely reasonable compared to most of the crowd, and his transformers work very well. (I'm a satisfied customer, the custom ones he made for my 500mW headphone amplifier are very, very, good indeed.)
Heyboer might be another possibility.
In this case parafeed might be another option to consider as it would simplify the HV power supply filtering requirements. Removing the dc from the core in high impedance applications usually results in a transformer with better overall performance at the frequency extremes.
Heyboer might be another possibility.
In this case parafeed might be another option to consider as it would simplify the HV power supply filtering requirements. Removing the dc from the core in high impedance applications usually results in a transformer with better overall performance at the frequency extremes.
hi,
I had this tube amp in my side & recently I broken for it & need to know why its so expensive & after i use over two months I feel it was quite good with Horn speakers. sound was detail & very fast. dynamic.
this is AN Kondo Ongaku push TAD horn speakers.
I also was OEM some OPT for Japan audio company. production some Superadio metal OPT & nano amorphous. I had a question that can I made same level OPT or probably better than it. than I Broken for it & test all seperate data. clone for it & comapre for original performance.
I will one by one post in here for this several month plan.
thx
thomas
I had this tube amp in my side & recently I broken for it & need to know why its so expensive & after i use over two months I feel it was quite good with Horn speakers. sound was detail & very fast. dynamic.
this is AN Kondo Ongaku push TAD horn speakers.
I also was OEM some OPT for Japan audio company. production some Superadio metal OPT & nano amorphous. I had a question that can I made same level OPT or probably better than it. than I Broken for it & test all seperate data. clone for it & comapre for original performance.
I will one by one post in here for this several month plan.
thx
thomas
Istep by step open for the tube amp & test data.
thx
thomashttp://i65.photobucket.com/albums/h214/tubediyer/IMG_4138.jpg?t=1193948071
thx
thomashttp://i65.photobucket.com/albums/h214/tubediyer/IMG_4138.jpg?t=1193948071
At the time I thought it was, and I would still build another one if I didn't already have one. The amp sounds great, but it is large (2 chassis), heavy, and pumps about 400 watts worth of heat into the air. For these reasons, it doesn't get much use now.
The whole thing got started when I got a pair of "10K ohm 211 or 845 SE" transformers from an Ebay auction. I started out building a "Poor mans Ongaku" clone (published in Sound Practices magazine), but I was unhappy with the sound. This led to the development of PowerDrive and the design of my 845SE amp. When I first put the design on my web site, my email box was bombed with all sorts of debate about what was, or wasn't an Ongaku, 211's 845's and the contamination of tube amplifiers with sand, especially a well revered design. There was all sorts of opinion about the "proper" operating point for a 211. The most popular responses were 650 volts, EXACTLY 960 volts (the Sound Practices circuit), and 1100 volts.
My amp has enough drive and bias adjustment range to allow the use of 211's or 845's. I have used both tubes in NOS and new Chinese flavors. I prefer the sound of the 845. I have also used 3 different power supply voltages. The first amp used an Audio Note power transformer and the power supply design from the magazine. I got anywhere from 890 to 950 volts depending on bias current. The second, and current power supply produces 1050 volts at the "normal" bias current of 70 mA per tube. I have run the Chinese tubes as hot as 110 mA dropping the supply to 1030 volts. To my ears this was far more dynamic than the lower supply voltage. When I was experimenting with the 833A amp, I got the idea to connect the 845 amp up to the 1500 volt 1/2 amp power supply. I removed the input cap so that I was getting about 1300 volts. The 845 positively rocked on 1300 volts at about 70 mA.
The OPT's that I have came from a supplier that turned into a first rate con artist who stole most everyones money. Too bad, because his early transformers sounded good.
I got a pair of Eastern Audio 600 ohm SE OPT's from a fellow forum poster. They work well for my intended application, and for the price that I paid for them. As with many Chinese components the specs are highly inflated. These are called "50 watt" transformers. That is probably true at 1KHz. The guy who sold them to me said that they were good for 10 watts. That seems about right. They are smaller than other 10 to 15 watt SE OPT's. I have not had the time to perform any testing on them yet. A 10K ohm transformer is a lot harder to make than a 600 ohm transformer.
As others have pointed out these tubes need a fairly high load impedance. You may get by with a lower load impedance if you choose a lower supply voltage and a higher bias current.
Yes, they were. I have been using this pair as delivered for a few years. I have not had them apart. The response is posted somewhere on my web site. I got another pair of 300B transformers from him about a year later, and they were junk. I never could get them to work right. The air gap was just that, an air gap that was only set by the screws holding the end bells on, so they were "adjusted" in shipment. Most transformers use a shim of some sort. I just use several layers of Kapton tape.
I also got a pair of 60 watt P-P transformers from him. I don't know how you screw up a pair of transformers as much as these, so I will eventually take them apart to find out. I plan to reuse the cores and end bells for a 600 ohm SE transformer.
Found the transformer response curve. It is down in the middle of the page. This is the whole 845SE amp at 10 watts.
http://www.tubelab.com/845SE.htm
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