JoaMat

Happy Birthday, Kerry!

New T2 - great @s_r Remote diagnosis is not easy… but the dark LED in red circle – is it dead or wrong orientation? Diode test might give some answer.

They do sell as spare parts. You just have to dig deep enough. Click this link and scroll down till you find side panels 1/2/3/4 U and lengths of 170/230/280/350 mm.

Seems you have built yourself a good amplifier – Congratulations! To get rid of those annoying offsets – build KGOOS.

like this? - "Stax original"

Interesting item. I use Pomona model 6341. On my third pair now – after some use it seems that the wire break at the handle edge - else I like them. Probe Master looks good so I ordered a pair. Can be bought in EU at https://eleshop.eu/probe-master-8150-spring-loaded-micro-tip-test-lead-kit.html and/or https://www.welectron.com/Probe-Master-8150-Spring-Loaded-Micro-Tip-Test-Lead-Kit_1 .

Happy Birthday!

Happy Birthday!

Yes, Kevin’s design. Just added one 6922 and two resistors. I have a lot of 6922 doing nothing.

Inspired by Satyrnine's project and an attempt to recover from my Tube input CFA3smd failure some time ago I’ve been busy with this today. I call it Cascode Tube Input Something - intended for my CFA3smd something. +220/+15/-15V and filament needed. Based on ubaltoblatubeschem2, thank you Kevin.

Happy Birthday, Chris!

Now I think I’ve a 300B filament power unit I like. All smd on bottom side and common (through hole) trimmers and LEDs, and the Tracos of course on top side. With trimmers voltage at tube pins is easily set to 5.00 +/-0,05V. There is voltage drop cross wires and solid-state relays. Cover with ventilation slots. The Tracos produce some heat.

Yep, it seems to work. So far so good. No heat problems. Current set to 1.5A and when filament voltage reaches 3.7V solid state relay closes.

Happy Birthday!

Take a look in the balanced headphone protector thread. Just a few pages and I think you might find something useful there.

Soft start would be nice... …if it works. Not sure it will, but I know a way to find out. Above is based and inspired by this:

Never underestimate good old designs.

I 3D printed a cover to my filament power supply today. Just four Traco TPP 15-105-D and some tblocks. I don’t think my tubes need slow start – and if they do – they are not my tubes.

In the wake of Sir Ahmad Roon Radio continued with...

DIY T2 amplifier with 300B tubes. Amplifier is built on Kevin’s board. Only modification is decreased high voltages, +/-400V instead of +/-500V. Homemade 300B to EL34 adapters connected to four Traco 5V switched PS for filament power. I only replaced the EL34 with 300B along with the filament power supply. No other adjustments. It works – I’m in no harry to change back to EL34.

Wish you a very happy day.

Yes, they were new. Thanks for feedback.

Hum/noise disappeared after an hour. I’m a bit surprised but I can’t hear it any longer.