Hello.. I have a few questions for Mr. Alex Cavalli:
1.) The description says the 6922 triode stages are cap coupled.. What cap type did you use? Not just the dielectric material but the manufacturer too if possible pls? Is the value widely available?
2.) If it the triode sections are cathode biased, do they use electrolytic cathode bypass caps? Or are they left unbypassed (some local feedback - apart from the global one?)
3.) Is the solid state output capacitively coupled too? Do they use electrolytics as output coupling caps?
4.) Is the SMPS wallwart an off the shelf item? Or are they custom designed for the amp? What is done to filter out and decouple any HF hash that the SMPS may impart to the signal?
Thank you very much....
Hi,
Maybe we'll get some partial answers - in the months to come, if not from Mr. Cavalli himself, maybe from those who have beta tested them.
Anyway, I just checked a thread from Superbestaudiofriends, and I saw a photo of the innards (from an earlier iteration I think.) From what I can see, it seems like it uses Wima coupling caps. Just a best guess.. If they stick with that, hopefully it's the FKP line, and not the MKP which sounds a bit rough up top IMO. The electrolytics for the B+ etc are harder to see what types, but hopefully they are low esr/esl types. For cathode bypass and output coupling (if they are present) maybe I could have it changed to Elna Silmic II's (which aren't super boutique.) It would void the warranty, but for a relatively affordable $250 it might be worth modding.
I can also see that there has been some effort at filtering and decoupling via chokes and smd film caps for the incoming DC supply. Which hopefully is enough.
1.) The description says the 6922 triode stages are cap coupled.. What cap type did you use? Not just the dielectric material but the manufacturer too if possible pls? Is the value widely available?
Wima, polypropylene film. Widely available.
2.) If it the triode sections are cathode biased, do they use electrolytic cathode bypass caps? Or are they left unbypassed (some local feedback - apart from the global one?)
Bypassed with electrolytics.
3.) Is the solid state output capacitively coupled too? Do they use electrolytics as output coupling caps?
No. The SS buffer is directly (DC) coupled to the headphones.
4.) Is the SMPS wallwart an off the shelf item? Or are they custom designed for the amp? What is done to filter out and decouple any HF hash that the SMPS may impart to the signal?
It is not off the shelf. There is a simple filter circuit at the DC input jack.
Hi Mr. Alex Cavalli,
Thank you for the answers. It is very much appreciated...
Thanks for confirming the Wimas, they are already good quality. Anyway, I now know the first things to be 'rolled' if I ever get the upgrade bug, and they are not the coupling caps.
Kind regards....
Oh. One more thing. The electronic components are not "cheap Chinese junk." They are all spec'd from manufacturers such as Panasonic, Nichicon, Vishay, OnSemi, Fairchild, Bourns, etc.
Thanks for the reassurance.. I just want to make clear though that it was 'RaidBoss3d' who stated and implied that "cheap Sino parts" are used.. Not me.
1.) The description says the 6922 triode stages are cap coupled.. What cap type did you use? Not just the dielectric material but the manufacturer too if possible pls? Is the value widely available?
2.) If it the triode sections are cathode biased, do they use electrolytic cathode bypass caps? Or are they left unbypassed (some local feedback - apart from the global one?)
3.) Is the solid state output capacitively coupled too? Do they use electrolytics as output coupling caps?
4.) Is the SMPS wallwart an off the shelf item? Or are they custom designed for the amp? What is done to filter out and decouple any HF hash that the SMPS may impart to the signal?
Thank you very much....