Cary Audio CAD-280SA V12R

re: Heat, my local tech-friend (40yr Mcintosh tech, Repair/Modifier guy) was adamant I did not need to run the bias up to spec, had me running it as low as 200ma per side. Felt it was a waste of energy and extra heat for no reason.  I tried it at lower bias and it actually sounded great, ran cooler for sure. Extends tube life too!  

You know there is a a lot of talk on bias, cool leans out the sound thin, quack quack , to hot shortens tube life and runs hot . I've found that there is a sweet spot for biasing valves. It actually SOUNDS better. Again not just a little.  I use these from 300hz UP, no bass duty at all.

A Mac TEC, usually doesn't bias stuff after it's set up. Set it and forget it, its one of the good things about a Mac,  BUT I have a 240 you can.  AB (push pull amps) not so critical, Class A, it makes a BIG difference, AB too, if you really listen, just not as dramatic.....

So The R has the better transformer and the 12XXX. 

What about the monoblocks? same. Ver 1.2.3 ? Kinda rare for sure.

@oldhvymech
He was a Mac tech for his daily job, but did mods and built amps all kinds of crazy rebuilds and such on his own.  Retired now.  Built all his own amps, that kinda guy. I helped him on design and build of three pairs of large horn Altec/Onken copy  speakers, so she shared a little over the years. Was fun to listen to little updated 2A3 and 300B amps he modded.  He helped me to make my former V12R sing, was really nice.

Yes, "R" larger trans and "Bz7" TV tube, funny.  

Monos:
I'm not as up on the V12 mono blocks. Slightly different layouts.

Since KT150s came out I went a completely different direction, never pursued it any further with Cary monos after. 

I don't even run the 12BZ7s, maybe some like um, sure a lot better tube to choose from, I have some chinese 12ax7 that blow the doors off them
less than 5 bucks a valve...same cheap valve Mac uses in their new stuff.

I just received a 12 pack of 6V6s and 2 8 packs of 6L6 under 200 for the whole lot.

Installed the little 6V6s, hour or so of playing... Just wonderful, transformer is running cool a could be. Whole unit dropped 30 degrees.
looks like there is a good summertime combo after all. Although the 4 Volvo el34s were pretty impressive.  A dozen ways to go...Seems like there all pretty good..

Regards..

I have a V12R I've owned for a number of years and would like to do the Hexfred Rectifier installs.  I already replaced the coupling caps but wasn't sure about where the Hexfreds go so I left it alone. Could someone shed some light on which of the existing parts should be replaced with the Hexfreds and how many? Do you happen to have a pic of the Hexfreds after they were installed? Thanks.