Zen Variations 3

Hello everybody! I'm glad to introduce my hybrid version of the ZenV3 power amplifier. I build it in the 19" case from rack-mounted UPS, and you can see a front view on the 1st picture. The chassis is in 1.5mm anodized steel, while the frontal panel is 4mm aluminum On the 2nd - there is a back view. You see 4 output connectors, mains connector, fuse socket (russian military), 2 input gold plated RCA connectors and 2 volume controls. Why I've put volume pots to the back side? Because I think to use the power amplifier with the separate pre-amplifier/input selector, that have a volume regulator with the remote control. Pots at the power amp. are intended only to set the desired level for what 9-pin RS232 connector? At this time - for nothing. It was a hole on the back side, and I simply close it with the connector. But maybe in a future I'll use it for something (for remote switching ON/OF, for example) The difference between my amplifier ant the original ones (ZenV3 and ZenV4) - is that I use a tube front stage on ECC88 (russian 6N23P) in SRPP topology and decrease a little bit the gain of the output stage. On 3rd and 5th pictures you see the top views on the amplifier: main PSU on the left side, small transformer and PCB at the bottom - PSU for tube stage, which located on the right bottom corner, and Zen3 output stage in the center. Both amplifier's PCS located at the heatsinks, which covered with the plastic (the piece of the old unused PCB). Two sets of heatsinks (L & R), plastic cover and bottom plate of the case - this is the air channel. For better view - see 4th picture, without the heatsinks are 3 130*80*35mm on each channel, 12 fins. The worst case point temperature is 90C with 200v 110mm cooler, working from 110v - at this condition, I not hear anything at 0.5m from the amplifier! The main transformer is 350W E-core, with 2* 38V*4A and 2* 24V*0.2A, the filtering cap. Are (for one channel) one 50V 8900uf from MERCO/ELECTRA and one 50V 10000uF from Mallory (picture 6 and 7). The mosfets are IRFP150N from International Rectifier. The regulated voltage for the tube stage - 6.3V for filament and 180V for plate made with LM317 and IRF640 mosfet. The sound is very nice. Very wide, deep and detail soundstage, very deep bass. Not very big power of the amplifier - is not a problem, I've test this amplifier with many loudspeakers from my friend, and with 90-91dB speakers we never use it more then 5-6W -it was enough! Thanks to ALL, Alexander Torres, .(JavaScript must be enabled to view this email address)