Tube Change/Biasing a Stax 006t II

[lupoal]

Done All fine.

BTW. @lupoal what trimpots did you use? I'm thinking of making similar change myself, those original pots are awful...

I've used Bourns 3339 - 1/2W, 4 turns --> 339P-1-202-LF
but next time I would choose a 10 turns rectangular shape (it is necessary to little bend pins in any case), 4 turns are better than the horrible single-turn from factory but still not the best in term of adjustment comfort

 

[TYATYA]

Thank you Ardilla for the re-posting of the instruction and pictures. I think it‘s similar for the 007tII and one just has to identify the trimpots for Balance and offset. They are not as nicely labled as in the 006.

You take all your risk!
I done for my 007tA.
I did below steps.
+Check TP1 TP2 voltage then adjust it to close to zero as you could using nearby TVR (3 and 4)
Mine, BF 0.015V, AF 0.002V (this is quite easy!!)
+ Check L+ L- voltage then adjuts to close to zero using TVR1
Mine, BF 4.6V, AF 0.3V
+ Check L+ to GND voltage then adjust to close to zero.
Mine, BF3.6V, AF0.3V

Note, R-CH and L-CH printed on the boad is correct, dont be confuse.

Do the same for R channel.

 

[Marcin Gomulkiewicz]

Sorry to derail the thread a little bit, but it is partially connected:

On a closer inspection I noticed that 4 220uF/400V Elna LAH caps may need replacing - their top is not ideally flat. According to Elna spec sheet those are 1.508 ESR/0.87A ripple current. When choosing a replacements, should I look for those values (uF/V/ESR/rc), or should I add some more restrictions to my search?

And after replacing those, will I need to rebias the amp again? (those damn pots are so sensitive that it hurts me to even think about it...)