starcat

What are the differences between those gerbers and which one is the latest balanced version, 42? What does flipground7 mean? Mucho thanks!

Any plans for a group buy?

That's the proper way of doing it in fully balanced equipment, chassis is separated from circuit ground and for shielding purposes only. Chassis goes then centrally to the star earth grounding (mostly in the PSU), where also circuit ground centrally may or may not go to (through a 10R resistor). 99% of the time Rane is not fully balanced but SE equipment using only balanced for I/O.

I am using silver plated stranded copper wire, PTFE insulation rated for 600VAC, mil-spec, wall thickness .25mm, temperature rating up to 200°C (392°F). Probably good enough for both wires against each other.

I am using this 15mm polyester sleeve from HellermannTyton for the cable above and considering using it for the T2 umbilicals as well. I don't have any additional sleeving inside the outer sleeve for special wires. I have twisted the 6.3V AC heater wires inside. Anything else I should take care for? This sleeve is very nice and is available in 25mm and 35mm as well.

Yeah, they take a long time but are fun to make 🙂 I just completed the umbilical for the BHSE I am building (with original HeadAmp boards) and it took long as well despite using an AMP connector with crimp type pins. To be honest, I liked that connector much more than the Amphenol we use for the T2. It is like cutting wires, crimp pins on both sides and insert into the connector housing and voila. The pins are automatically isolated within the connector housing as well, so no fiddling with shrink tubing or soldering into the connector and the pins are available for different AWG sizes as well.

Phew, completed the wiring. Thinking about wrapping the wires or leave them as is for better cooling.

Btw, to you connect in the PSU the circuit ground to chassis ground? And if yes, directly or through an inrush current limiter with 10R or just via a 10R resistor? I would opt for an inrush current limiter with 10R, question is how many Amps would be best for the T2 PSU and what fuses are you using? I have read somewhere Craig isn't using a fuse at all 🙂 in his rhodium plated inlet.

Swapped a ref102 from the positive rail PSU while turning it off. Now measuring -259.27 for the -260V rail and confirming the problem was a malfunctioning ref102, so the PSU is now fully operational. Will let it run for several hours. Any procedure for load testing it? Kerry, JoaMat, James, Craig - thank you very much! Now off to making the umbilicals and finishing the amp 🙂 soldering the LEDs next - anything special about testing and matching them?

Measured at pin6 again: -531.7 No spare atm but I could take one off the working PSUs (and turn that one off).

Inserted above Q15 voltages referenced to ground. I did a diode test with both when PSU was off and they both measured the same. Will post asap.

Ok, measured some voltages Q15/C3675 B -500.79 C -227.5 E -501.31 Q20/C3675 B -562.1 C -120.74 E -562.4 Q19/FPQ G -126.27 D -132.84 S -137.05 Q16/IXYS G -132.19 A -132.03 K -132.49 Q17/IXYS G -132.35 A -132.11 K -132.12 Q18/IXYS G -531.1 A -131.92 K -528.00 ref102 pin2/v+ -531.2 pin6/vout -531.9/-532 op27 pin2/-in -539.6 pin3/+in -540.2 pin4/-v -562.4 pin6/out -561.5 pin7/+v -531.1 across D12 zener 31V right of R45 -531.1 R44 -130.27 R43 -130.67 D10 -136.51 R48 400

Tested with the Peak DCA With the Peak DCA75 measured without desoldering, Q18 show as unrecognized more often than not. Changing the pins and it shows up. It measures like Q16, Q17 however (when it gets recognized). FQPF8N80C Q19 gets recognized the same way as Q14. BR3 must be ok as the -560V is output correctly and stable as well.

Hmm, diode testing Q16-Q19 doesn't show anything suspicious, they measure like Q11-Q14. Going further...

Thanks, James! Checked 1. Is 2 and 3 a possibility when I am getting stable -560V out of the same PSU? It is the -260 that is flaky, pointing to the 300V as Kerry suggested.