With Sylvania VT-107A I measured 0.05% THD+N at 1VRMS for the G3X which is 66dB SINAD. That was with a simple capacitance multiplier Zener stabilized PSU so it may be even better with your 21st Century Maida. Say 70dB of SINAD. Most of it would be THD. Pure buffer version exceeded 80dB SINAD. But no voltage gain in a buffer. 80-70=10. Here's your 10dB push of gain lifting the noise. Thus no extra noise sources from G3X just the gain.
Its a power tube with gain and it owes to produce some background stuff but not annoying. Certainly traceable by the ear when investigating. Including microphonic ding if you will disturb the chassis or the glass. Possibly less on aviation grade Bendix than when on a civilian grade 6V6.
Its a power tube with gain and it owes to produce some background stuff but not annoying. Certainly traceable by the ear when investigating. Including microphonic ding if you will disturb the chassis or the glass. Possibly less on aviation grade Bendix than when on a civilian grade 6V6.
Don't think I coud reliably hear the difference between ground and ground lift for the - of the heater. But I did feel after I first switched to ground...noisier. Anyway now it is grounded to the heater lift just on the node where the two 100ohm resistors are joined (because that is for ac really to create an artificial null point) I can barely hear the faint hum. So I'm happy since it is quieter than the first one I built.
Bottlehead's moreplay 6v6 preamplifier does just that:
"this preamp, the level control is moved to the plate (output) of the circuit, which results in a lower noise floor and a consistent sonic signature when used with highly sensitive amplifiers and/or speakers."
https://bottlehead.com/product/moreplay-preamplifier-kit/
What I've seen with bottlehead's names.....I'm sure it is no accident the year on that tube is 69.
That dude also added a grid, its a power tetrode, but anyway.
BTW the Bottlehead kit as I see it is a way to circumvent SNR problems by suppressing input and dividing output when missing regulated PSUs. Operating point looks relaxed from the size of resistors. IMHO no performance priorities to what they did there other than practical benefits like controlling costs and difficulty level.
BTW the Bottlehead kit as I see it is a way to circumvent SNR problems by suppressing input and dividing output when missing regulated PSUs. Operating point looks relaxed from the size of resistors. IMHO no performance priorities to what they did there other than practical benefits like controlling costs and difficulty level.
Listening tonight to a live performance of a Baroque orchestra playing Biber, Fux, Bach, etc. Just lovely. Switching back to the Aikido, it's also lovely, very relaxed and "big" and musical, but also---what?---a bit more romantic. This preamp has a more immediate and punchy sound. Not a trace of sonic fatigue or strain.
Listen to them again make sure you don't like them and they will go fast when listed on ebay. Very tightly structured special tubes can come across subjectively dry for audio fun sometimes.