Mikael SET KT88 Amp

[sorenj07]

Got contracted to build one of these for someone. He's sending over some Transcendar 5K 10W OPT's, and I'm ordering/building the rest. It should be fun because I get to build it according to MY style, which is a beastly 400V 465mA PT and 10H 300mA mostly-choke-input filter. Fun!

I'll sketch out the PSU at some point, but it's a cLC followed by a channel split and another LC for B+ followed by yet another LC for the 6N1P. Solid state rectification, and I simulate 401V on the dot. All chokes for B+ allow at least 150mA per channel, which should accommodate each KT88's max current draw of 140mA nicely.

Signal schematic:

http://diyaudioprojects.com/Tubes/KT88/index.htm

Instead of an Auricap I'll be using some of the K40-Y types that everyone (especially at AA) seems to be raving about. Cathode bypass caps will probably be 105 degree Nichicons bypassed by metal film types. Input potentiometer will probably be the reasonably priced dual 100K Noble pot offered at PCX.

With the client's permission I'll post some pics of how construction is going. Strictly point-to-point of course, with teflon wiring as much as possible :)

[jduffy]

Man, I just love the idea of this amp. I've read about it in other forums.

I'll look forward to your pics and comments. Sounds like you're going to be building a sweet rig. Yellow_Light_Colorz_PDT_11

Some day I hope to build one as well.

[Brik]

Sounds like an exciting project!

Regarding the power supply, the stereo KT88/6550 PP (45W/ch, 65mA idle current per tube) amp I am building right now
has the Hammond 278CX (400-0-400, 465mA, 6.3V@6A) with cLC supply to achieve ~410V B+ voltage.

I hope the Trancesdar 5K 10W Opts are happy with the hefty current draw. :o

/b in Taiwan

[sorenj07]

I'll be pushing them to 8-9W each, time to see what they're made of :) I'm keeping the signal schematic for the Mikael amp the same except for fixed bias operation in combination with triode mode only. The Transcendars don't have UL taps. SE Amp CAD has been my friend with the redesign process :)

[TomMcNally]

I wonder how an EL34 version with Edcor 5K 15 watt transformers would sound for a low-budg amp. Might be fun.