Power Supply - 6SN7 KT88 PP Amp 50W

[e_fortier]

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[e_fortier]

KT88 stereo 50W PP power transformer..?

Hi,

If I may, I'd like some recommandation since my need are very similar as the OP.

I'd like to build a STEREO (single chassis) KT88 PP 50W, UL, cathode bias using 6K6 OPT, and would simply want to verify if a single power transformer rated 800Vct (400-0-400), 535mA (Hammond 278cx) would be sufficient (not struggle) to power a stereo KT88 50W amp as shown in the attached typical KT88 spec. I would be using SS diodes

Looks like I would need to supply 500Vdc at 400mADC + a little bit more for the pre-amp section.

I plan to use the Full wave capacitor input set-up, see config supply pdf attached.

Thanks a lot,
Eric

 

[kodabmx]

Hi,

If I may, I'd like some recommandation since my need are very similar as the OP.

I'd like to build a STEREO (single chassis) KT88 PP 50W, UL, cathode bias using 6K6 OPT, and would simply want to verify if a single power transformer rated 800Vct (400-0-400), 535mA (Hammond 278cx) would be sufficient (not struggle) to power a stereo KT88 50W amp as shown in the attached typical KT88 spec. I would be using SS diodes

Looks like I would need to supply 500Vdc at 400mADC + a little bit more for the pre-amp section.

I plan to use the Full wave capacitor input set-up, see config supply pdf attached.

Thanks a lot,
Eric

I use this transformer (HV winding only) for a PPP 6P3S (8 tubes, 420V, 60ma/tube plus driver and phase) without issue. It hums, though (mechanical noise from endcaps). I wrote Hammond and asked them if it was normal and if it was normal to run 85+c at it's rated output. They did some tests, reversed a previous engineering change and send me an engineering sample free of charge. Quality company if you ask me. Also I've used those Triad C14-C chokes with great success. Can't go wrong for the money, either.

You might want to consider the 378CX instead for it's better quality and the added bonus of a bias tap.
http://www.a1parts.ca/transformers/Hammond 300 Series Plate & Filament Power.htm
I can't find Hammond anything cheaper than at A1 Parts.

 

[e_fortier]

Thanks a lot for the heads up regarding the hum + xtrm running hot, whenever I design something my temp. limit is usually 45C max. I'll forget about the 278CX.

I never had any issue with Antek transformer so I wonder if their model would work OK in my application ; AS-4T400 - 400VA 400V Transformer - AnTek Products Corp

p.s. Nice hint about A1 Parts, they do have great price for Hammond xtrm.

Thanks,
Eric