Tony's 6H32 pre-amp

[Tony]

Hi All,


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 build ths 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.

more pics,





completed amp:


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 front end of the psu stage with 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.....

[analog_sa]

May be good to correct the tube type as many will get confused.

[Tony]

ok, 6N32, which is also 6922, 6dj8....

[analog_sa]

Or maybe rather 6H23?

[kevinkr]

Originally Posted by analog_sa

Or maybe rather 6H23?

I'd say so based on the shown data sheet..

[Wavebourn]

6Н23П (Русский) = 6N23P (Latin)

[MrCurwen]

I really don't mean to be rude, but why would you run a nice, linear triode like 6N23P with that kind of a loadline?

[Wavebourn]

Originally Posted by MrCurwen

I really don't mean to be rude, but why would you run a nice, linear triode like 6N23P with that kind of a loadline?

Because everyone has his/her right on trials and errors when learning.

[Cassiel]

Yeah, but learning it's not for everyone. Be proud of your failures then and keep in mind that success sometimes leaves you cold.

BTW, Wavebourn you'll be a good father.

[Wavebourn]

Originally Posted by stalker

Yeah, but learning it's not for everyone. Be proud of your failures then and keep in mind that success sometimes leaves you cold.

BTW, Wavebourn you'll be a good father.

Thank you Stalker; I have 2 grand-daughters.

By the way, the first my amplifier schematic I drew when I was a kid did not contain anode load resistors: I did not understand then why they are needed. The first my transistor radio receiver did not have bias: I did not know why it was needed. Also, it did not have AGC.