Kerry

Mine looks right. I'd like to get the most recent rev of the boards. Also,I would be interested in the golden reference LV version if there are enough others.

Congrats

Nice I like the idea of decoupling.

I'll do one set of amp boards and one dual power supply.

The FQFP8N80C part should work fine, though the SiC part is desirable. I'm interested in the results. Let us know.

I love those boards! Thanks

Congrats! Enjoy while you figure out how to box it up

Very nice build!

That's exactly my kind of insanity

Glad to hear you sorted out the issue. As a general rule is important to lift the resistors off the board. This had caused all kind of mischief on these HV builds. Enjoy

I was also thinking it might be nice to have more room (larger diameter) for the C4. If we go with a higher value for D1. Maybe slide Q8/9 over to the right a bit. Also, the labels for AC In are set to AC360. This would work good for a 450VDC supply. I think we could use AC325 for the 400VDC supply. Antec makes some nice ones that are inexpensive.

Seems true on both of those. From the schematic R1 could go higher to 4K (reduces heat from Q6), R6 could go to 50K, C7 should be as low as possible (5pF) provided it doesn't oscillate. Also, D1 could go higher (100V - 200V). It reduces the noise floor a bit. We might need to add a protection diode across Q6 if you raise D1 to protect on Q6 power off.

Cool. I want to build this version.

Nice John

Nice John

I've been playing between the KGST and BH (I have 007 Mk I). For me, the BH has more balls especially when you use it with good tubes (XF2 for instance). I truly enjoy both and quite often choose the KGST, but if I wanted to show off for someone, I'd use the BH. I also have the KGSSHV. There is nothing wrong with it, but I don't enjoy it as much. I'm going to give the Carbon a go and I have some very high expectations there. It's all very subjective though.

I just saw the schematic for this - It's official - I've shat I love the visual from Laowei

Thanks Jim. I read and forget so much. It's nice to get these refreshers.

Nice build Wachara! It is a wonderful sounding amp. Nice oaky body.

That's Purdy

That looks like a great idea. I've had concerns about feeding the reference. I've minimized it down to 180uA, but love the idea of removing it and using ground as the reference. I'll model that later. Might want to drop raise the current a bit for the error amp. Thanks for pushing this. Awesome work

Congrats! Really glad to hear that. Looks like this will go onto my list.

Nice read Jim. Thanks.

You should definitely bring the zener string voltage down by about 25V. You're basically removing the value of the pre-regulator and passing a bunch of ripple voltage into the error amp. It will still work, but degrades the performance of the regulator. There tends to be a 10V - 20V variance from cold to warm on the zener strings. If you bring the zener string down to 450 when warm they will likely be around 430V or so cold. You'll need 10V - 20V or so above the 400V regulated out so things are getting very close and I wouldn't recommend raising the regulated voltage. Note that when spec'ing the transformers you should leave about 10% headroom to account for voltage fluctuations in line voltage, so optimally you'd look for 495V or so (also accounts for about 3V-4V of ripple). That's why Kevin suggests 500V unregulated and setting the zener string to 450V. All these extra tolerances are there because actual electronics are different from what we calculate. I've been playing with some ways to lower the drop out voltage a bit. They model well, but complicate things a bit. EDIT: I wouldn't worry too much about your unregulated voltage of 477/479V.

Looks nice. You might want to switch the output connectors to the back side of the board. If I understand it correctly, the inputs and switch face the back side of the amp and the outputs would face inside the amp.