GeorgeP

I organized a DIY T2 chassis group buy a couple years ago, and I've had a couple people inquiring as to whether I could do another. So putting this out there to see whether there is sufficient interest in doing it again. I would need at least 5-6 participants for it to be viable. Last time the cost of the chassis was $1500 ish, with anodizing, holes tapped, brackets are laser etched faceplates. Before I place any order, in the event there are enough participants, I would need a $200 up front commitment as the machine shop needs 50% at commencement and 50% on completion and I can't have people changing their minds later on. So reply here or PM me.

awesome as usual, Joachim! are you running it at 500v?

I prefer buying Belden spc Teflon coated hook-up wire. It's roughly the same cost (but you have to buy 50 or 100ft lengths), and it is properly labeled and you can check the specs, whereas with the resellers and surplus sellers, it's difficult/impossible to verify. That said, I have only had good experiences with navships and bulkwire.com.

only if brain damage or death are among your goals....

Good going - enjoy! By the way, what switch are you using?

Amen.

Your case looks like a 2U? If so, those sinks should be very warm to hot after 2 hours. Apart from the bracket width issue, what did you use to mate your brackets to the heatsinks?

umm, you might want to rethink doing this...

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yes, carry on.

At least one piece of advice - do NOT turn the amp on without the tubes. Also, not sure about the reference to me describing the transistors "turning black" - I don't always remember everything I write, but that certainly doesn't sound like something I wrote. As Craig pointed out there are a number of different issues that could be the cause of your symptom(s). Having a DMM will probably be necessary to sort out your issue. Did you try swapping the umbilicals? Also, check the wiring block in the amp section (by removing the bottom plate) to make sure none of the wires loosened in transit.

if you are building it for 15v you can't just follow the board silk.

16-0-16 should work fine. Did you try it and then got lower voltages?

Awesome work, Michael! But you might want to swap the power connectors on the psu to female ones for safety reasons in case it ends up in someone else's hands. And it looks like you might have both servos engaged?

in that case 60% then. also wondering what the heatsinks are for. Doesn't seem like anything is connected to them.

I think those are 450v chem-con caps - no boutique stuff here. guessing the chassis accounts for about 95% of the cost based on what can be seen here.

I bought one. Seems to work well. Curve tracing feature is pretty nice too. Don't know how it stacks up against more established testing devices though. If you have any questions about it, I can try to answer them.

Nice! Stealth black.

RIP Cohen.

I think it could be either based on the designation. Not sure why TKD does this. In terms of the noticeable differences though, wouldn't one of them be that the attenuator has 19 or 20 distinct dB steps (without clicks, unless the s version), while the pot doesn't have any steps?

jh13?

20mA and ~100deg on psu side and ~114deg on amp side - that is after about 4hours. The 450v version I built previously was closer to 130deg on the amp side. I do find the servo to not be necessary though (even though it is populated here) - the amp is just that good at getting to the proper balance and offsets fairly quickly. With the servo, maybe it shaves a few minutes off the warm-up time.

Just adding yet another carbon build to the thread (crappy phone pics). 400v supplies rather than 450v allowed the caps to be board mounted in my chassis (though I am having some of Kevin's off-board PCBs made for a possible future 450v version). 400v also has the added benefit of running (slightly) cooler than the 450v version. Added the GRLV supplies but don't have a non-GRLV version to compare. But this amp is a true winner. Every time I listen to it I am awe struck at how good it is, particularly when compared to the T2 - they both have that ability to fool you into not realizing how loud you have cranked up the volume.

Nice work! What did you use for the etching? And do you have a link to the case?

just use a resistor in line. No reason to try seeing if and when it will burn out.