StrawHat

I don't know if it can help but one thing I never do is run the wires from the psu to the amp boards in series, I always use separate power wiring for each amp board and join them at the power supply. You seem to know what you're doing so it's just my humble 2 cents. I can't remember why I do this but I think I had some problems with that kind of wiring in the past with two Beta22 boards and I have been avoiding it ever since. Maybe it's just builder's superstition I think that if you changed the stock gain you also need to change the compensation capacitors.

Seems like a great project! Do the input board and the attenuator work with the TI PCF8574 or only the NXP will do like the AMB version? NXP discontinued the PDIP-16 version some time ago...

I'm Portuguese but USA should have won the game...the way our team is playing is embarrassing

I'm looking for another set of KGSSHV boards, if someone has an extra set that don't need please contact me. Thank you

Money sent...can't wait!

@Kerry Are those connectors on the right 0.2" pitch? May I ask you the part number please? I'm trying to find an alternative to the Phoenix terminal blocks

Payment sent! Thank you

Would it be possible to add the Dynalo mk2 to the list?

I finally quit my job! After 3 years working in a casino I was sick of degenerate gamblers and greedy unscrupulous bosses. That is one disgusting world I hope I'll never be a part of again. I'm really excited right now I hope I'll be happier or at least sleep better.

Yeah those are awesome too

Is anybody into martial arts here? I've had my first sword lesson today and it was awesome! I've been doing kung fu for the last two years and can only recommend it to everybody, it completely changed my way of living. It's amazing how physical discipline and spiritual meditation can change your point of view about every other thing!

Janis Joplin - I Got Dem Ol' Kozmic Blues Again Mama!

I'm sorry I didn't want to say something stupid. I don't fully understand complex circuits like this. Thank you very much for all your work.

And what about a tube input stage? Would it work with the dynahi design?

Actually I think it's better because you don't have to touch the body of the device so no risk of heating it you just put it on your desk and grab the leads.

I tested all the transistors before stuffing the boards but I did it with one of those DMM hfe testers I think my testing is not very reliable. I have already ordered a new set of boards from Lil'Knight so I will definitely continue this project but before continuing I need to buy a good DMM and one of those transistor testers. I was thinking of buying this one: http://www.peakelec.co.uk/acatalog/dca75-dca-pro.html Anybody has any experience with it? Seems a little better than the DY294.

I checked and rechecked every part I'm pretty sure I populated everything correctly. I'm starting to suspect I may have some fake transistors. I bought all the transistors form reichelt.de except the matched jfets which I bought from here: http://stores.ebay.it/Himmels-Rohren-Shop?_trksid=p4340.l2563 They all seem to be real though.

I tried with the inputs shorted to ground with 1k resistors after reading an old post from Ti Kan on the original HF dynahi thread but it didn't help

So I wanted to ask some advice to help me set my dynahi I can't set the offset to 0 it's just to unstable. On startup without any adjustments to the trimpots the offset is on the volts scale (1~5). With the servo connected or disconnected it's the same I can adjust it with lots of patience to some milivolts (10~30) but then out of nowhere it just jumps up to 5v again. I replaced the 500R resistors with 1k to be able to adjust the bias current. The only different parts on the amp are the 2pf caps because I could find only 2.2pf that could fit the holes. BTW to anyone using the spreadsheet BOM those 2pf caps have the leads too big for the board they need to be changed. Same problem with the opamp sockets. The only matched transistors I have are the input jfets and the ccs 2sa1145/2sc2705. Thank you for any help you can provide.

I'm using a single 160VA 2x30V transformer to power both boards and have now two full working psu's. I didn't populate the lower voltage sections for now as I won't be using them and still haven't applied the current limiting transistors fix Anyway both psu's are rock solid at +/- 30V for now but I'm having lots of problems biasing and correcting the DC offset on the amp boards. I think that's what I get for not doing any matching

Thank you! May I ask you what transformer will you be using? I still have to decide VA rating and secondary voltage.

I've just started building this amp and wanted to share with everyone since this thread hasn't seen much activity. I decided to start populating the pcb's while I wait for the transistors for the amp boards. Power supplies are almost finished but I wanted to ask Dr. Gilmore if we should still leave Q9,Q10,Q24,Q14,Q15,Q26 unpopulated or the fix suggested on post #25 solves this issues.