Kerry

I've developed some software to use with the Arduino Uno board. I can post that in the next day or so with some simple instructions. Kevin is working on an all-in-one device (display, process, interface) separately.

I just looked at the circuit and it looks like it will draw around 52mA or so (Kevin - please chime in if I'm wrong here) for both channels. Doubling is not a bad rule of thumb, so 100mA should be OK, but 150mA would give a bit more headroom. The power supply is pretty efficient. It consumes about 5mA for the pre-reg stuff, about 1.2mA for the bleed-off resistors around the caps, and an additional 3mA on the positve rail for the bias. Edit: I was looking at the current sinks on the output stage to guess the current draw.

I've tried to cut things too tight on my first couple of transformers and ended up under voltage when the full load was applied. You also have to consider that there could be as much as a 10% variance in what's coming out of the wall. If you're looking to save on heat, then you're better off using the doubler circuit for the bias. Because of the current regulator and two RC filters, it is incredibly clean. If you want simpler, then don't use use the doubler, but make sure you've got enough volts under load. Richard at SumR is pretty good if you tell him what the load is (I usually multiply by 2.5 of the actual required current) and what your required AC voltage is under load.

Thanks. That really helps

I've got all of the board only orders shipped now I've got a lot of testing to go still, so the assembly orders will take a bit longer.

I was just looking at the BOM for the KGSSHV power supply. The bridge diodes you have listed in the BOM (511-STTH1512W) look like they are too big. I looked up the part number on Mouser. I think you need TO-220, not TO-247. I haven't gone in great detail yet, but I just happened to notice this. Thanks for pulling this all together.

That looks beautiful

Nice job! The wire work aways seems bad, but it moves pretty quickly.

Very nice and simple to build

The power supply pass FETs will give off quite a bit of heat. Also the current sources feeding the zener strings and battery will give off a bit heat. The active battery and resistors will generate a small amount of heat as well. Basically you need to make sure there is venting above the PS especially the pass FETs. I've found that having additional venting in the top panel (not just over the hottest parts) will help as well. As far as the bottom goes, it is a good idea to make sure there is enough venting to allow for good air flow. I'm not sure from your description above, but it sounds like you could use some more. I don't remember which version of the amp you are building and was curious what the 4 large rectangular cut-outs are.

Very nice upgrade. Thank you I also wanted to echo Deepak's concern on the Search within a topic. It simply shows the Topic header as the only result, but not the posts.

Yeah. That sums up how I feel too!

I just did a listening test and the first three boards all work great! Volume switching is nice and quiet (electrically not physically). Lots of steps so there are no jumps either.

I have a couple of extra boards if you need. Let me know.

Wow... That's a lot of boards Initial visual inspection looks pretty good. I'm going to say a prayer that they all work. I've got some extra parts if not. I'll have a chance to test some later this evening. I'll post some results as well.

Got home too late from work to pick up the package. They are in and I will pick it up tomorrow AM.

I did scope the outputs and I'm seeing random noise on the scope. Because of the feedback, I'm guessing it will carry its way throughout the circuit. If there is noise on the bias line, it would not affect the outputs on the scope. You are right and I will check the all of the power supply outputs on the scope, though I'm not expecting that to be the issue since I'm scoping each output with reference to ground I'd likely see any oscillations in the outputs. Also, the noise is not in sync between the left and right channel. Same type of noise, but different and in stereo The pins do have some oxidation so I was going to try cleaning. Not sure of the best method yet. Recommendations welcome. I appreciate your two cents

I've checked a bunch of differnt voltages and everything seems fine. I also put the amp up on the oscilloscope to check for any oscillations, but only see what looks like random noise. I'm starting to suppect the input tubes and Kevin felt that that could be the issue. I'm going to try and get some cheap input tubes to confirm the diagnosis.

Great news. The boards / assemblies have been shipped and I expect to have them tomorrow.

Double checked everything and fired up one channel at a time. I was able to adjust both batteries to 740V without any issues. My outputs are all sitting around +18V (seems close), but I'm getting some noise. A bit of crackling and buffeting (shifting white noise). Not too loud, but very present. Interesting it is pretty much the same on both channels. I'm going to start checking some more voltages. Any thoughts? EDIT: Both channels play music. When I connected a source to the right channel (SE) it seems to have stopped the noise (I need to double check this). Left channel still has noise, but plays music. EDIT 2: I've got both channels up now at the same time (finished the other umbilical). The right channel is identical to the left channel with respect to noise. I mistakenly thought there was no noise on the right channel because I plugged the headphones into the jack without bias power (since I only had one side powered). Both channels now play music, but the noise is still there. As I turn the volume up, it seems to diminish a bit but is still present. I can already tell that this going to sound remarkable.

OK. I've got one umbilical cord ready and I'm going to go through a final check before powering this puppy up. Any last thoughts from the group?

Good luck with the HV differential probe. Definitely can come in handy.

Got the Amp and PS done, just working on the umbilical cords. I'm going to make them 30" which allows for both side x side or stacked configurations. Amp... PS...

I just found this thread. Late to the party again. I've got some stuff to post here, but I just got back from a business trip and still need to catch up with life.

Lil'knight took care of me Thanks for the offers!