I was encouraged by this tube when I swapped those with the stock tubes in my Sakua-AV200 hybrid amp, so now i decided to build a preamp out of it. configuration is cascaded common cathode-common anode using one bottle per channel....
I borrowed an Alexan HC961 plastic casing from my son to house this preamp, i then proceeded to cut out holes for the tube sockets and other parts and started mounting them....
after assembling the power supply, I checked the raw dc voltage, the power traffo i built was intended for another project, but a lightbulb flashed in my head yesterday and off i go to building this amp...
I decided on a plate load of 4.7k, I felt that it was just about right for the B+ available:
looking at the curves, at a plate of about 40 volts, grid bias needed is about 0.56 volts, now a silicon diode like a 1N4007 surely fits the bill.... so then consruction can be completed.
this is the schematic of the completed amp:
I would like to mention that the power supply uses a common mode choke to filter both sides of the plus and minus sides of the psu isolating the from end of the psu stage to the rest of the amp.
set-up and listening test:
I put aside my 7N7 pre-amp and hooked up this pre-amp:
so how was the sound?
like always, i liked the "hotel california" on this pre-amp, i can hear the bass guitar and kick drums, not so loud but distinct.......like the other amps i built, this amp is very quiet, no hum, no hiss no extra noise inspite of its being housed in a platic case.....