Push Pull Stereo 807 Amp

[lego4040]

Output transformers first, Check. I haven’t seen a 400ma ever but the Triad R-24A has 300. I have been contemplating a 807 mono block as well. This is a long process I go through and in no Rush, I still have a Blaceface Princeton Reverb to finish here. I do like keeping myself going and learning, I still don’t have a dedicated schematic but that will happen once I get the OT’s. When looking at the 807 data sheet at Duncan I see 8,9,10k primary for the higher wattage amps.

 

[lego4040]

I would look into Heyboer transformers as well. I've used both Edcor and Heyboer, and have had better success with Heyboer. I've got a 1625 quad amp with Heyboer, and the HF is outstanding from them.

I didn’t realize Heyboer made fidelity OT’s or is it that their transformers are good enough. I have used them in some guitar amps. Which model did you use

 

[Freo-1]

I've actuality have two sets out audio output transformers made by Heyboer, and both of them are excellent performers. In fact, the other output transformers I had made were rated for 120 watts at 6.6K. I use them with a pair of 6883B/8552 output tubes (around 90 watts from a pair), and the amp sounds outstanding. Heyboer will make whatever you ask them to regarding wattage, output taps, impedance, etc.

The 6883B/8552 tube is a real sleeper of a tube. It makes for an excellent output tube, great sonic character, available as NOS for a very good price. To me, it sounds somewhat better than the current production 6550 tubes, and as long as its configured as a pentode, paying attention to screen grid voltages, it's a long lasting tube as well.

 

[zackthedog]

I've now got my Heyboer Peerless S-265-Q clones up and running. Pretty much a stock triode Williamson circuit with 807s. Absolutely lovely, and apparently quite stable. I left off the screen taps so they were $425 for the pair with shipping. Screen taps add about $40.

 

[Freo-1]

Congrats! Happy to hear you have a successful outcome with your project. Heyboer provides very good value.

 

[zackthedog]

Thanks, I'm really very pleased with them. They sound "right"--clear and even-handed. My last temptation is Sowter's "Williamson" tranny, but I imagine they're pretty expensive. They don't give a price. Maybe I'll inquire sometime. ;-)