JoaMat

Still too early say anything about stability. Yesterday I built another board. One side worked as supposed but the other side’s bais was stuck at zero whatever I did. When I touched a few places on the board with a test pin the PSU’s current raised so the current limiter kicked in. This happened even with an unconnected test pin. I can build very odd things… that I don't understand. Bottom line: JoaMat should build himself a Headphone Protector.

Here is result of today’s work. The board was milled yesterday. Schematically it’s similar to CFA3. Two of the triple Darlingtons transistors are to-126. All other transistors are sot-23 and sot-26. To early to say how stable this thing is…

tta/ttc and kca1220/ksc2690 are, in my opinion, reliable. I've used them for years as substitute for j79/k216. Next step is the 37 vias. Board, 0.5mm wire and tools. Anyone prepared to pay a fortune for handmade printed circuit board?

That panel looks good. Is it for an original DIY T2 or a Modified DIY T2? Me to have done some milling. 0.38 mm end mill, 18000 rpm and 300 mm/min. Two sides, 121 holes (5 diameters) and cutout took a little less than 2 hours.

Thank you, wilco (will comply).

Thanks, then I’ll give it a try.

Seems to work in LTspice. Too simple to be true?

Thanks Kevin! Working on an all heatsink version. Left side is almost ready...

Only the four output transistors need to be on heat sink. The rest are 1/4W or less. It’s certainly an advantage to have all transistors in triple Darlington on heat sink (I think), but my intention is to only put the four outputs on heat sink and see how that works.

Welcome to HeadCase. You are obviously on the right track. It’s a rainy today so I had the time to finish this. Milling of the first board is scheduled at Monday 13:30 local time.

Yep, smaller seems doable. Lm339 in so14 package and smd relay. Should be able to cnc mill board myself.

I found a backplate for Neutrik NC4FAV at oshpark.com. But I think I also need some protection for the dynamic headphones… …schematically same as Kevin’s protect3. Board size 2.75in x 1.95in. With a little creativity the board can probably be made a bit smaller.

It’s an awfully warm summer here in southern Sweden and it’s too hot to sleep… did this last night… Video_22-08-19_09-57-37.mp4 An attempt to make a smd version of CFA3. Same board size as the smd version of Dynahi I built some months ago. Lots of more work… doubt I’m capable to get this to work though.

and this

Lovely – smds on breadboard. Excited to see lt8365 on a similar board.

Happy Birthday!!!

Thanks for the suggestens. It turned out to be this… Two unsoldered pads inside amplifier to the right. The amplifier has been working all right for a couple of months, until now. Luckily, I noticed the two missing pads. No bad apple, just a poor soldering guy.

By coincident I saw Jazz Piano Player Roberto Fonseca on Mezzo TV Montreal Jazz Festival something, playing solo piano. Thereafter I grabber a bottle of wine and found/enjoyed

Not built today, This combo works realy good but this combo is not good. Where is the bad apple?

Found this https://youtu.be/0kMh4r2Bkdc. Thank you!

https://static.qobuz.com/goodies/47/000128674.pdf https://static.qobuz.com/goodies/21/000150312.pdf

Happy Birthday, José!