Keeping paperwork updated can be a major PITA. Especially projects strung between separate people.

Thanks for clearing it up, and making your mini T2 available to us DIYers, Joachim! 

11 minutes ago, JoaMat said:

(I hope, crossing fingers).

Oops. Schematic posted above uses 2sa1486 in the current tunnel – my first boards had the 2sa1486.

Schematic in the link uses twin ksa1156 in the tunnel and the boards have the twin ksa1156. The boards Micheal and Jose have had made are created from the linked schematic.

All mini T2 boards I have are spoken for. Thanks!

OK, time to bring this thread up on the first page. I think this is one of the most interesting threads after “The ultimate DIY? A Stax SRM-T2!“ (alright, there are lots of interesting things on HeadCase). Here Kevin introduces GG, sandwich, DHT, T8000DR etc., etc..

On 9/27/2018 at 11:44 AM, JoaMat said:

Have been listen to the new amplifier with EML 20B v4 tubes for a couple of days. Since 20B pinout  and heater voltage differs from EL34 I use adapters. Maybe it’s about time to make a board dedicated for the Emission Labs tubes. The tubes looks amazing and have printing on the glass. In this early stage layout the printing and the front of the tubes are facing the listener.

I found the big tube 3D model (300b) at grabcad.com, done by Andrew Whitham, United Kingdom.

Slow progress, but finally I have something. mini T2 with Emission Labs tubes.

It passed all tests in Proteus so it should work. If it blows up,   . That must not happen.

mini T2 with Emission Labs Directly Heated Triodes.

It didn’t blow up. Left channel offset servo didn’t work so I replaced its ksc2690 with a 1K trimmer.

 GLAD PÅSK! written on the copper clad is Swedish for Happy Easter!

Very nice and GLAD PÅSK! 

Happy Easter folks!

Three months ago I bought a pair of Russian 300B. Intention was to try them in an electrostatic amplifier.

Eventually I’ve put them in my DHT mini T2.

Only mono version but it works. There is some unwanted hum/noise. Maybe because 5VAC for filament. I’ve DC alternatives, so future will tell if that might solve the issue.

Anyhow, I’m enjoying the music (only left ear) and I still have some good stuff left.

Edited April 9, 20233 yr by JoaMat

Think I prefer stereo. Moved the 300B to a T2.

Left channel has EL61 with adapters from China and right side has 300B with homemade adapters. Works all right.

8 hours ago, JoaMat said:

There is some unwanted hum/noise.

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

If these were new tubes, then that can happen. 

Yes, they were new. Thanks for feedback.