If dual tube input. One tube as upper device and the other as lower like T2 or one tube each side?

I wanted to compare the dual input tubes (like in the T2) against the single. I'd build the dual first first though.

one comment about the tubes, have tried many tubes on testbench, 12au7,12ax7,12at7,7308 etc

you need a mu of at least 33 and a transconductance of at least 12500

 

Anyone about to build this, Megatron, etc and don't want to use a dropping resistor, I might have some spare power supply boards for tube front ends soon.  Works up to 250V no problem, 300V is possible if you find caps that fit and heatsink appropriate parts properly.

How come T8000 fires is slowly fading away ? We need more fuels ?

Where  was the fire?

29 minutes ago, mwl168 said:

Where  was the fire?

+1

Sounds like the consensus was t-POS...


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56 minutes ago, Pars said:

Sounds like the consensus was t-POS...


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What ? T-Perfected-Over-Standard ? JK, but that is sad....we need Stax to be serious again

Edited October 4, 20178 yr by Whitigir

i'm mostly just waiting for the version with ss output and tube ccs

Sounds crazy, we could do it...   

On ‎2017‎-‎07‎-‎06 at 7:26 PM, kevin gilmore said:

power jumper block cleaned of all the epoxy

j1,j3,j4 for 100v remove all others

j2 j3 j5 for 120v remove all others

j5,j6 for 240v remove all others

and servo board pictures, unnecessarily complex

tube rollers are going to have a lot of trouble with this, the servo has a pretty limited range, and the Russian similar's definitely will not work

 

How to make the servo less complex?

servo attaches directly to the plate of the tube. similar to T2. no way to make less complex.

Moving the servo to the cathode would that be a good idea?

 

better idea would be to use the servo from the kgsshv-carbon

but does not compensate for the tube drifting section to section

 

Draft of dual 6922 input (similar to T2 input), with current tunnel (as Carbon etc.)

Voltage cross 2sa1486 580V and 700mW of heat.

Trying to use the above draft in a board layout. The print out is roughly a quarter of the original DIY T2 board in size. Output section reminds of T2 less unnecessary parts.   This is progressing very slowly and I’m thinking it might go into trash can before it gets to the CNC router. Hmm..  probably trash can.

More paper work. Width incl. heat sinks 9.5in and length 7.9in. No angel brackets sands mounted direct on heat sinks, saves 1.6in.

    

 

I like it, you are going in the other direction from the original T2, small amp chassis and a huge PSU. 

Very nice Joachim!

With the micro golden reference HV power supplies (which do work very nicely) and lower voltage (less caps) you could get the power supply size down a bit as well  

Thanks.

Yep, your micro power supplies are very interesting. My idea is to make a PSU with +/-15V, +220V, +400V and -460V.

Shooting from the hip - how about producing 580V (BIAS) by GRHV? 

All components are now on the right channel board. More work is to be done but so far it has gone quite nice.

By the way, I think I've learned netlisting and I love it - tells me when I'm out of track.

Netlisting is even better if we were ever to bother with schematics...which we never do. 

Wooooaaaaa this is looking wesome, I am loving it !

 

29 minutes ago, spritzer said:

Netlisting is even better if we were ever to bother with schematics...which we never do. 

You guys have it in you - the schematic in your heads. I’ve no head and therefor I use schematic which I derive from your layouts    hihihihi

Edited August 27, 20188 yr by JoaMat