Yes, I can see that.......on schematic.....so we need a way to control bias without "degeneration".....
Then there should also be a good "sonic" reason to avoid degeneration.....like lower distortion, lower output impedance....larger class A envelope.....etc....
I have a general question about the XA25. Are the two negative terminals both connected to circuit ground? As in, could you connect the two negatives as a common ground for a single ended TRS output?
yes, common PSU, common negatives on back
when you buy one, confirm with ohmmeter, for your convenience
🙂
what is TRS?
when you buy one, confirm with ohmmeter, for your convenience
🙂
what is TRS?
I have a multimeter, but I'm asking for a friend that owns the XA25. He wanted to use a 1/4" headphone jack adapter with the amp for very low efficiency planar headphones. I assumed the negatives were connected since it's single ended input only. Thank you!
Biasing the output stage by using current sensing from Drain pins via Opto should work here as well.
I have a simple aplifier circuit using this technic and it work just fine.
🙂
I have a simple aplifier circuit using this technic and it work just fine.
🙂
Pretty sure.ChatGPT wouldn’t be able to distinguish between an XA25 and a two foot section of RR rail. Let’s leave the discussion to humans.
I noticed that too. Maybe a quad in series per phase with leveling resistors? What is the rail voltage of this thing? I assume it's ... high-ish? (due to the pucks)
capacitors sometimes can be used in other purposes, not just smoothing da rails
Ha!
to help a little - Pa pulled some century old tricks from bag
nothing wrong with using collective wisdom......
to help a little - Pa pulled some century old tricks from bag
nothing wrong with using collective wisdom......
After reading some of the threads on First Watt and Pass Labs designs, as well as the square law paper, this is my guess of the XA-25 front end, maybe it could be close… ? I have no clued how could be the output stage, optocoupler biased with runaway control, and DC coupled!
I'm gradually coming back to audio electronics, which I haven't worked on it for maybe 10 years, Since the Blowtorch threads and Charles Hansen designs. I lost a lot of electronics knowledge in the meantime, knowing that my job was more artistic as a sound engineer. When I retired I rather did amateur music as bass player with friends.
What are your thoughts, let’s go ;-)
I'm gradually coming back to audio electronics, which I haven't worked on it for maybe 10 years, Since the Blowtorch threads and Charles Hansen designs. I lost a lot of electronics knowledge in the meantime, knowing that my job was more artistic as a sound engineer. When I retired I rather did amateur music as bass player with friends.
What are your thoughts, let’s go ;-)