Pars

Thanks Michael! This has some differences from the BOM I was putting together and from trying to follow the thread. No 15K resistors (guess they're 5K now) 20K resistor 22pf cap I take it the 2x50K resistors in the schematic are now 1 100K? Same with the 2x34K resistors are the single 68K? I can't find the schematic mentioned in the thread (cfp2f.jpg), 2nd page of thread around April 1, 2015.

Oh boy... Got an email from these guys today describing their new DAC. I recall them being quite the tube hacks back in the (HF) days. http://www.doge.audio/products/tube-dac/doge-7-tube-dac/ I would presume that they haven't changed much... Sent from my iPhone using Tapatalk

You need a fugly set of cable pants for your Y split. I keed I keed.... nice job! Sent from my iPhone using Tapatalk

I believe it is simple physics... smaller = more heat Sent from my iPhone using Tapatalk

I would guess it is because everything is in a smaller area and enclosure, thus less ability to dissipate heat.

I also saved it and did find it (if it is the one Kevin was thinking of)...

If you have the THAT socketed, you can just plug the JFETs in there, assuming they are thru-hole TO92 packages (that is what I did on my SS Dynalo). Make sure they are good machined pin sockets though (Mill-Max, etc.) and not those crap leaf sprung ones.

Happy Birthday Marc! Sent from my iPhone using Tapatalk

Appears to be back up again

Thanks Michael... yes, I rather like that one. As for the Dynafet, yes it uses obsolete parts, some of which you could work around: 2SJ109/2SK389 dual (sub linear systems LSJ74/LSK170 x2) 2SA1349/2SC3381 dual (sub 2SA970/2SC2240 if you can find them; not sure what else would be a good sub) 2SA1145/2SC2705 (possible sub 2SA1370/2SC3467). Don't know if the SS thru-hole transistors would be a good replacement, and would have to check pinout And the FETs. These were designed to use the Renesas 2SJ76-79 and 2SK213-216 (mine uses 2SJ77/2SK214). You can still get the J79/K216 I think, but they need to be matched (closer the better). The FETs that Amb uses for the Sigma22 will work (pinout needs checking) and apparently are much less cranky than the Renesas parts. In the Dynafet thread, I had also posted some links to threads on diyaudio listing possible replacements as well. This might not be something you would want to play with, as you probably saw all the mods I had to do to get mine to work. This has been the only amp of mine that I have been listening to though. I might be interested in your pair of CFA (CFP?) boards anyway, so shoot me a pm if you want to part with them.

Don't quite understand your question? At any rate, the ground lug from the TRS jack should go straight to PSU ground (sigma22?)

I'd go for that Michael, but took a look and don't have any more blanks. I do have a built-up one with Roederstein resistors, all devices socketed with Mill-Max pin sockets. That one has some sentimental value to me The original transistors that I had (have) weren't that bad between N and P. I do have a pair of original Dynahi boards, as well as around 5 of the original Dynahi PSUs. Also, a couple of cetoole discrete I/V boards, some amb and KG protection boards (with my mods), etc. Oh, and a pair of DynaFET boards To vortaku: I would recommend using the modern SS layout, using current parts. Many of the parts for the original are somewhat unobtanium (Toshiba 2SJ74 2SK170 JFETs). You can get equivalent parts from Linear Systems, but the original transistors (2SA1015 / 2SC1815) aren't easily obtained.

I worked withDan Gardner quite a bit on this around this time, doing edits for the build guide, etc. I've never seen board files or gerbers for these, and I am pretty sure that Kevin doesn't have them either. Dan hasn't been active on these forums for a long time. Either we could contact him or I could possibly do a layout. I may still have a couple of boards but would need to look. Sent from my iPhone using Tapatalk

Hmmm. I would probably start by swapping the input wiring (pot to boards). If the noise moves then it has something to do with that. Otherwise go over the board (components and location correct? Solder joints?) Sent from my iPhone using Tapatalk

Happy Birthday! Sent from my iPhone using Tapatalk

Interested in building a single-ended CFA2 (or is that CFP2)? Can't find the schematic matching the cfp2gmt board files on the archive... I have the cfa2.pdf schematic, but it doesn't match the board file. Maybe I'm not looking for the right name here... Also, what is the board size on these? I'll have to admit I am having a hard time following this thread and all the loops and progressions from se to balanced to power amps...

RIP Gord Sent from my iPhone using Tapatalk

Door stops can be expensive... Sent from my iPhone using Tapatalk

Happy Birthday! Sent from my iPhone using Tapatalk

Happy Birthday! Sent from my iPhone using Tapatalk

Happy Birthday! Sent from my iPhone using Tapatalk

Only the input - channel should be tied to ground, NEVER the output - channels. In effect you would be shorting the output devices to ground which probably wouldn't make them very happy:) For SE output only the + signals and signal ground should be used. That said, on my SS Dynalo Mk2, I have both RCAs and XLR inputs, with a toggle switch to tie the - inputs to ground for SE input via the RCAs. I don't hear a difference when using SE input and unshorting the - inputs via the switch. Maybe I need to listen more closely? Sent from my iPhone using Tapatalk

Well sure he "sacrificed" Birgir... a lot of people's money. Sent from my iPhone using Tapatalk

Hmmm... "once I had been able to establish a robust company with excellent products." Guess that never happened... Sent from my iPhone using Tapatalk

For both Jose and penmarker: if you are only using an ss dynahi in SE mode, why even populate the - channels? All they are doing is burning power... Even then, the - inputs would be tied to ground, as done in the original dynahi /dynalo. Sent from my iPhone using Tapatalk