M125 individual tube bias

Hi. I have a pair of M125's to build and am wondering if there is an official mod out there to individually bias the power tubes. I have VTA M125 CCS driver boards.

I found this post on another forum:

http://audiokarma.org/forums/index.php?threads/vta-m125-from-bob-latino.714532/#post-9611772

I'm wondering if that looks feasible.

Thx Bob. I'm sure it would never end with addons!!

I'd be using four output tubes. Does the CCS take care of keeping the tubes equally biased as they age and drift apart.

Tom

Yes, but a few hundred hours in there is no guarantee the tubes will still be matched. I already have bought the tubes from Pcx.

Back to the original post. I'm wondering if the add to the driver board circuit looks feasible. I'm not an electrical engineer but have no trouble following a schematic. There's lots of room under the chassis to fit the extra parts. I have the skills and equipment to mod the st st chassis as necessary for extra pin jacks and pots. It may not affect the sound, but I would like to be able to monitor the tubes as they age and be able compensate as necessary.

Thank you for the responses so far. I don't expect VTA to modify there product offerings for every request that comes across. These amps are an excellent value and the unselfish support is much appreciated!

Tom

Look at my Post No 33 at the following location https://dynacotubeaudio.forumotion.com/t3199p25-dumb-question-on-setting-bias

That is my solution to your requirement "to be able to monitor the tubes as they age..."

My configuration is for MKIII Dynacos and I can watch them from across the room as I listen to my music. The only distraction is wanting to get up and and tweak the bias if it is slightly off. In time this itch will disappear.

Since you are using all 4 tubes on your M125 you will be biasing pairs so your settings will be doubled. I am sure that this reading is covered in the instructions.   My setup uses the chassis mounted sockets to plug into the bias points so hardwiring is not required. There is no under the chassis work required.  

Have fun!