Quite a LONG thread. I really have lots to catch up on.

Thanks Tangent, your website is always a pleasure to read. I put the trafo, psu and the PPA in the same case, so there will only be a IEC receptacle. I did ground the OG to the case because I didn't have a isoloated jack(isolated jacks arrive tomorrow) at hand, but the case is only grounded to...

IMHO, It is a decent bulid.

I hope this time isn't some stupid mistakes again. My PPA is completely fine working on the bench. But when I place them in my case(tie the rca jacks to the case I think), the Q3 isolation jfets just blow away as I power up. I checked the PSU and it wasn't shorted to any ground. Desoldering...

Quote: Originally Posted by linuxworks well, not to insult, but I've zapped a few caps when I forgot to discharge them. so its easy for people to forget I did, more than once! as a matter of course, I simply replace all MOSFETS and .47ohm r's. I don't even bother checking the...

Problem solved. Stupid mistake, I installed two TLE2426 in the PPA. Removed one, Okay. Now work on the chasis.

Something is wrong with my ppav2 left channel. It is using OPA627X3, gain=5. The opamp and buffers are a little warm but not hot. I adjusted buffer bias to 30ma in all three channels. But there is no voltage drop across R10 in my left channel and the dc offset is ~330ma(OL to OG). My right...

Quote: Originally Posted by linuxworks when you worked on your power supply, DID YOU DISCHARGE THE CAPS, first? very important.... Yes, I think I am aware of that. Today I swapped the zener diodes, and I used another DMM to check again, no good. Uh, I am completely lost...

Uh, I think something is wrong with my Sigma22s. Today I decided to reflow all the joints in my Beta22 and Sigma22 because I think there are some cold joints compromising the performance(I am so lame..). When I carefully finished reflowing my four Sigma22s, I checked the output voltage, two of...

Beautiful amp!! Congratulations, fault151.

Hi, myk7000 I am quite happy with my Beta22 and HD800, can't give any comment on the rest of the amps though. I just want to remind you that HD800 is very source depend, a good amp can't really guarantee anything.

Arrrrh, SMD parts give me headache.

I reflowed all the joints and the problem is solved now, or at least seems to be solved. Thanks AMB.

Thank you very much for the quick response. I'll do it later and report back.

Umm..... another situation is here. One channel(R-) of my beta22 has some problem. When I turn on the amp, the beta22 capacitors begin to charge, or at least it sounds like, I can hear music from it. After fully charged, like few seconds, it is dead silent! I tested the output pad and it is 0...

Quote: Originally Posted by amb Start measuring the MOSFETs for shorts. Thanks, Ti. I've just replaced 4 MOSFETs on the board and now my Beta22 sings again. Still some hiss/hum noise with my earbuds but as long as I can't hear them with my K701, I will leave it as it is. Will...

Today I've just fix most noise problems, but unfortunately one of my boards may blow some mosfets. I turn up the amp, then I found two output resistors on my R+ channel start glowing like a bulb, I turn off the amp ASAP. After some inspection I found the output pad shorted to V-. So I think I...

Quote: Originally Posted by FallenAngel With minimal setup, yes, that's correct. Of course there are a lot of "kits" on the TPA site, so read what's a kit and what's completed. I'm assuming this is one of your first projects - you'll soon realize casework takes more time than any board...

I start my first build with B22. I am pretty sure you wouldn't want to do the same. B22 is a great project and quite fun, but if you build something else before this and gather some experience, the B22 will be a lot easier.

Hello, I've done some research on the Buffalo32s, but I still want to make sure. I see those Buffalo32s on the TPA page says: "Assembled and Tested", so I guess I can just purchase the Buffalo32s DAC module and hook it up to my PSUs to make a functional DAC? Surely with case and connectors...

No update recently, but actually my case was finished a week ago. No LUCK though. I've been fighting the hum noise/hiss for several days due to my lame wiring, and one of my step attenuators broke down. I have to ship the attenuator back to the seller and they may ship a new one for me. Oh...

I found my B22 sound a little richer and smoother after, I guess, 100hrs. Anyway you can build one and test it yourself.

Very interested.

Quote: Originally Posted by cobaltmute Now that Headwize is back for browsing, there is info here: HeadWize: DIY Workshop > β22: A discrete, cascoded, fully complementary, pure class A amplifier (part 3) and the part 1 and 2 threads before that. Great news! I have never had a...

Quote: Originally Posted by fsrick just want to clarify one thing, I think DACT is serial type, not ladder. And you really need bigger heatsink to drive your speakers. Yup, thanks for the clarification, I am actually aware of that, but I speak broken English. IMHO the serial...