Cary Audio CAD-280SA V12R

bradluke0154 posts03-31-2020 6:56pmIts 35 ma per tube . 2 tubes per side = 70 ma. 4 tubes per side =140ma . 6 tubes per side = 210 ma . The manual is wrong , if you go to 275 ma with 6 tubes per side you will pop the fuse.


No fuse pops so far...But it sure sound good at 240ma total on the bias, I mean, there is quit a difference in SQ. I went as high as 260 from 240 with no SQ change, then backed off until it sounded REALLY good, not pretty good..REALLY GOOD. I'll rebias in a few days to 35 per an see if the SQ is as good...Could be a settling thing, my ears, or remember to take the cotton out of my ears this time...DUNO.. ;-)

I thought I was having a stroke... kept reading the same thing.. 210 210 210 total LOL.

So it's 35ma x every valve in pairs, per side. Wow hee hee. People say I ask too many questions.. Maybe.. but that's the old mechanic in me..I try to stay out of trouble, not GET OUT OF TROUBLE.

So:

1.  turn the unit OFF
 
2. turn both bias adj screws counterclockwise.

3. install or remove tubes in pairs per side, starting front to rear or rear to front. Not every other one, BUT in pairs per side in matched positions on the other side.

4. Hook up the bias meter, analog or digital..Digital is better (self diag and calibration)

5. With speakers hooked up (or dummy load), POWER UP turn the volume down on the preamp, and let the amp(s) warm up.

6. Adj the bias per rail @ 35ma for every valve in pairs. 70 (2),140 (4), 210 (6) are the prefered bias numbers, by turning the adj screw clockwise SLOWLY. recheck, recheck, recheck then recheck.
do the same on the OTHER rail. New valves, recheck in 6-10 hours rebias, as needed.

NOW

7. Don't worry be HAPPY. (You know like the song.. LOL) and turn the music...UP....:-}  <  happy Galic face, start doing the Irish Jig...

I'm so happy....

Thank you, Thank you, Thank you very much...

NOW, next problem... can you help me turn lead into GOLD...???

Just askin'..LOL

Regards

One thing I forgot to mention... This amp and neo 8 planars, no running out of gas, I've yet to crank it, BUT, at 49% volume, on the led, the Rabbit, the dog, and the hummingbirds start looking for shelter. No power issues, no distortion issues (the rabbit can't take it...)  :-)

Regards...

decooney226 posts03-31-2020 12:30amIt's just 210 div by 6, per "rail" as you noted.  If you are handy, pull lower cover, look and see if it has those four of the thin silver'ish Audio 1 coupling caps.

Yes it does, took pictures. Few other spendey little caps too. I saw the sokeys (sp) fast recover. Clean as could be..looks easy to work on.
Has a logic board in the back, front? Everything is point to point.
Wire to the speaker terminals was the only thing I didn't like.
I don't think it was #20, very small. that's gotta go. I have some really good pure silver # 12, 16, 18 wire. 16 will work, twice as big as what's in there..There was a bit of resin, around, alcohol will take care of it..

Regards

Please do yourself a favor , don't start screwing around inside the amp . Play with the 4 or 8 ohm taps for the speakers , play with the bias , roll the tubes , use 2 , 4 or 6 per channel and try different power cords . But please don't put silver wire in there , if you must mess around use copper and make sure the wire you put in is both facing the same way . Wire in different directions sound different . Don't make me come over there with a baseball bat …..lol . 

If you are looking to keep a softer more veiled over sound the Audio1 caps are okay, not bad caps, just not great ones. If you want a little more texture, clarity, and musicality, many other caps sound better.  Did not realize the true benefit of front' end EL84 or 12BZ7/6922 vintage tube changes until after swapping out the little silverfish Audio1s.  Heard that amp with four different sets of caps between myself and three friends who owned V12i and V12Rs, all much prefer higher quality coupling caps in that amp. Be safe, it can hurt if you touch the wrong stuff in there!