tamu
100+ Head-Fier
- Joined
- Nov 6, 2008
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ok. I'll have a look. thanks
here is regal's current mod..
Here's how to get the most of your tubes on the SOHA II. The issue I was hearing on some of the 12AU7s and 6DJ8's was a slight weakness or thinness. So here is how you can safely get more current thru the tube:
1. Set B+ to 85V
2. Add another 18k ohm resistor on top (parallel) of R4L&R (makes it 9k ohm)
3. Add another 200 ohm resistor on top (parallel) of R6L&R (makes it 100 ohm)
Adjust P1L&R to give .550 V across R6L&R
Check to make sure you have at least a 19V drop across the top CCS (adjust P1 until you do)
This gives 2.75 mA thru each tube section.
also I am using the heatsinks in the excel bom, but they are fricken hot too.. but if they are enough then I guess I'll just heatsink HV and be done..
I am currently running 80V, I'll try 75 or so. I am unfamiliar with alex's guidelines..I am using the 1" tall heatsinks. will this be ok? or should I grab some 1.5"s or something?
right now the soha has no cover or anything and there is a fan right next to me. here are some pics it will be in this box for a while until I case it up..
I have taped up some caps to test which ones I like best. FT-3 teflon (big ones), sprague vitaminQ, and obbligato premiums. getting ready to put in a good listening session this weekend..
I am starting to think my alps pot is hurting my sound so I'm switching it up with this stepped atten from ebay.. we'll see how it works i'm about to solder it up after this post
well did a little building and listening this weekend, but now I have a problem.. I am paying the price for having an open top box sitting all on the same project table..
apparently a clipped lead managed to get into the soha between the pin 4 and C1 lead on the right side of the board.
I started to see smoke coming from the tb+r area (looed like it was coming from the caps, but not sure) the right side now doesn't work. I coudln't see any visible burn or char on the boards so i'm not sure what component is damaged.
the tpr measures 80V which is my Hv setting. so what have I blown? lol. just when I was ordering a case for it and all too!