I think I confirmed 6L6 's answer. I didn't like the sound with the caps on the amp boards. There is more 'depth' as standard.
Just shows again.... Mr Pass does really know what he is doing
Thanks for your how to thread 6L6 it helped me a great deal and I have to commend you on your listening impression you posted at the start of this thread. You have it spot on!
Just shows again.... Mr Pass does really know what he is doing
Thanks for your how to thread 6L6 it helped me a great deal and I have to commend you on your listening impression you posted at the start of this thread. You have it spot on!
Last edited:
What do you suggest as 'big' ?
15,000uF or whatever you have on the PSU board as a single cap.
will post soon!That sounds like an ideal driver! Do you have a schematic?
R 14 is a negative feedback resistor I do believe. 12au7s are not on my list of usable tubes. Regardsits not actually that much gain, about 26dB. The positive feedback resistor R14 takes care of that. The design is very quiet and very low distortion and drives the F4 well with some headroom.
The 2nd order distortion can actually be adjusted by changing the value of R14.
6sn7 or 12sn7 is more linear than 12au7 . As for 9pins I like 5755 close to a 5751 in gain different pin out and very linear. If you have a good sounding at7 try it . for that mater all 6dj8s .
I also like the 5755
generally yes , if you connect it floating (that demands separate complete PSU)
read this :
http://www.diyaudio.com/forums/pass-labs/28336-aleph-x-builders-thread-122.html#post3915715
read this :
http://www.diyaudio.com/forums/pass-labs/28336-aleph-x-builders-thread-122.html#post3915715
Finished my F4... Thanks to those who offered their assistance along the way. Is using Antek 500VA transformer, soft start, and speaker protection boards. So far so good running behind my 300B SET monoblocks. Surprised at how long this thing takes to warm up
not much listening time in yet, but what I can say is that nothing struck meas being markedly different...until I turned things up... then yeah... there was a difference there
cheers,
bryan
not much listening time in yet, but what I can say is that nothing struck meas being markedly different...until I turned things up... then yeah... there was a difference there
cheers,
bryan
Attachments
Not much listening time in yet, but what I can say is that nothing struck meas being markedly different...until I turned things up... then yeah... there was a difference there
Yep, that's the F4 - invisible. It sounds like the device driving it. So if you ever wanted to find out what a 300B amp would sound like with 50WPC/4ohm and an output impedance pf 0.02ohm, now you know.
Love the power switch BTW, complete overkill is always awesome. I bet it has a great solid klank when engaged.
- Home
- Amplifiers
- Pass Labs
- A guide to building the Pass F4 amplifier