Cary Audio CAD-280SA V12R

Hexfreds, like a schottky.  I think I know what your talking about, at least what they look like.  Is it for a power supply upgrade? fast acting quick recovery diode. I think this unit has it, but that would be strange that the silver fish audio 1 would still be there.  I took a few pics, the audio 1 are a good cap.  I call it "The Marantz sound", they were famous for those things..
Sound good actually, not sloppy, but VERY tubie..

So which caps did you use in your V12?

Need someone that has had it done AND knows what it looked like before and after, I'll find a pic or two.. Keep lookin' someones bound to chime in..

There is a guy named Mike Samra, one smart cookie, red sock, green sock guy.  Look up the name, big Mac guy..He might know about it and will talk your ear off once you get hold of him..Walk you right through it..

I'll see if I can find him..


Regards

A couple of the posters above had mentioned they had the Hexfred upgrade done so I was hoping one of them could shed some light.
I replaced all the electrolytic caps with generics of same values and replaced all the non-electrolytics with Mundorf MCAP ZN 630VDC caps of same values.
I have always biased each side at 210ma. Below 210ma the sound degrades but above I don’t hear any improvement. Above 250ma and you will start blowing fuses.

You MUST get a digital multi-meter that measures milliamps as that analogue looking dial meter Cary sells is not precise. You have to wire one of those larger headphone type jacks to plug into your amp and connect to your multimeter. Cary advises that you disconnect everything from amp before biasing, even the speakers. You will not damage CARY amps running them without a speaker load connected.
Also, the 3A Filament Fuse should be a 4A slow blow. Cary printed the wrong value on the back of the unit. In the schematic for the V12R is confirms it should be a 4A slow blow.

Also, the 3A Filament Fuse should be a 4A slow blow. Cary printed the wrong value on the back of the unit. In the schematic for the V12R is confirms it should be a 4A slow blow.

The fuse is a 4 amp SB, now, had a 5 amp in it, I pulled all the fuses and replaced them.  I've bias with a mono 1/4" male splitter with 2 RCAs hook one lead to the outside RCA and the other to the inside via a probe.  That's when I learned 210ma sounds ok but 230-240 at lower volume is just as sweet as they come.  I'm really liking 6L6 cheapo valves Solvex.  Only valve that going from single to UL sounds better.  I like the sound better for certain music, especially old country western, or big band stuff. Haven't  heard anything that sounds bad other than a bad recording, got a few of those..

At 100.00 + an hour at Cary, I can do a little work myself.. Suppose to be almost bulletproof, amp, I need it..

I'd like to see the upgrades too, there are some clusters of diodes two sets of three that look to be hexfred, at least when I looked them up.

Is it a power supply upgrade? I had Samra do a C20 with Schottkys, PIOs, and a few Teflons.  Quietest point to point, I've ever had.. and the most musical. Just no remote...  I like a remote.

Regards

aren't you exceeding max plate voltage running 6V6s in the V-12?seem to recall max plate voltage of 285tks

johnss352 posts04-13-2020 10:42amaren't you exceeding max plate voltage running 6V6s in the V-12?seem to recall max plate voltage of 285tks

Not sure, to tell the truth. I can tell you this, they sound pretty darn good.
No failures, no red plating, no fuse blowing. Run cool as a be. AND a cool looking valve too.  Dropped 30 degrees from using KT88, 20 from EL34 and 6L6. I ran them 24 hours checked the bias via led twice, held the bias. I left them in for over 48 hours.. never an issue.. Sound was little thin, low mids and HF not quite as controlled.  The real pleaser was the 6L6s, cheapo valves maybe 100.00 or so..Under 200.00 for both sets one of 12 6V6s and 16 6L6s.

I have two more caps swaps in mind, The supreme EVO silver/gold and  supreme EVO silver/gold oils. Never used them, I want to try them. Other than that. One neat amp.. Very well made

Regards