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!  

Yes. It’s actually "I" to "R" upgrade. I owned a stock V12R for a while and sold it a year ago to try other-brand Monoblocks to test different amps with my custom designed speakers. The lucky new owner loves it and has compared it to other high $ amps. With further upgrades to the V12R, it truly holds its own.

The V12"I" to V12"R" conversion involved upgrading the main output transformer to the "Big Blue Wire" transformer, among other things - and was a notable difference for those who went from I too R.

The stock Ruby EL34 tubes are actually Shuguang EL34-BSTR tubes and they sound fantastic after removing the stock Audio1 caps and replacing with much better coupling capacitors and added Hexfred diodes. Yes, the stock V12R can be upgraded again to bring it to any entirely different level compared to the stock version of itself.

I rarely ran my V12R in 100wpc Ultralinear mode. It always sounded more engaging in the 50wpc strapped Triode mode, particularly after the 2nd round of extended upgrades were completed. It was a fun and unique path in the tube amp journey.

If I may suggest to those with V12Rs,

Output Tubes:
Don’t be so quick to yank/replace/chuck those Ruby’s for others, some were the actual Shuguang EL34-BSTR tube version which sounded really good in that amp 1) if it’s biased right and 2) if you have really good vintage EL84s and 6922 or 12BZ7 tubes up front 3) have the right preamp/tubes in front of the V12R.

Bias/LEDs/Meter:
My local tech was a retired 40-year McIntosh tech, helped me to upgrade my V12R. He noted it’s not necessary to crank up bias to the recommended 285ma in the original owners manual (old / false / was never updated online). We called the prior designer at Cary together and noted having to drop it down to quite a bit or risk blowing the 4amp fuse periodically. Ended up with 5amp fuses, later. BUT, no longer an issue or need when we dropped it down under 220ma. Yes, as I recall, 35ma (per tube) and 210ma (per side/channel) was about right, sounded good too. Helps the output tubes to last longer too, don’t forget that part! No need to light those LEDs up, use a good meter, and those LEDs are not all that accurate or in sync with each other.

Input/Driver tubes:
The "R" version allowed for 12BZ7 (TV tubes), and IF you get a good vintage matched pair RCA or Sylvania, it does add interesting tone, rasp, and texture to the music - something Dennis Had came up with in the R. In a brief conversation via email, Dennis mentioned he still owns one, or diid a few years ago.

UL/Triode switch:
While the Triode/Ultralinear switch was cool in the V12R, i never felt UL was at the same level of sound as a regular non-switchable Pentode Push Pull sound like my Quicksilver 120 Monoblocks paired now paired with my Cary SLP-98 preamp.

Preamp Matters! 
A really good preamp and the 6SN7s in my Cary SLP-98 along with the choice of interconnects used between the preamp-to-amp and source to preamp really helped dictate the final result for the V12R as well.

Once you put really good coupling caps and Hexfred Diodes in that amp, it jumps to a whole new level once again. Enjoy the V12R, it’s a fun piece. Sure liked mine. New owner loves it.

It'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. 

Nope, just 210ma per side, total.  If you get the fancy Cary meter to plug in, you'll likely check bias more, or a simple headphone 1/4" TRS type jack plug with wires and voltmeter.  Let amp warm up good, keep volume down or preamp off, set bias screw at 210-220ma per side (total), you can watch the LEDs (and start backing off) of course to get it close but watch the meter. One 1/4" old style headphone jack per side.  Nothing else to share or over-think there.  Or, just do as manual says, light up LEDS and back off, and then use the meter to fine tune side/channel down at tad till you get to 210-220ma per side.  Message me if you get stuck, will explain over the phone.  

Fancy one from Cary for $100:

Pic https://caryaudio.com/wp-content/uploads/2013/04/MA-300_front.png
Page, accessories
https://www.caryaudio.com/vacuum-tubes-and-accessories/

or, 1/4" headphone jack with loose wires to voltmeter.  




 

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!  

@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. 

@oldhvymech
"I did have Mundorf .22uf 1000v Supreme Silver gold oils. for the audio 1 cap swap, I also had .22uf 1400v Supreme aluminum caps."

Not following ya. Where "did" the Mundorfs go?

The ones to get are the non-oils for fuller sound and detail with Ruby EL34s, specially these  >> Mundorf Capacitor 0.22uF 1000Vdc MCap® Supreme EVO SilverGold Black SESG <<

The stock Ruby EL34 (Shuguang EL34-BSTR) sounded the smoothest with the Mundorf SESG Evo (non-oil) Supreme caps in my V12R amp, and I was using vintage RCA EL84s and Siemens 12BZ7s or RCA 6922s on the front end (50w Triode) mode.

With that said, my Cary SLP-98 preamp did have Jensen Oiler caps in it with vintage 6SN7s. On that amp I did use all OFC copper neutral interconnects and OFC copper bi-wire speaker cables. No silver. The combo was really nice, smooth, holographic.

Really good coupling caps  do influence the outcome. After I did mine on my former V12R and now current Mono Tube amps, I could THEN truly hear the differences with input/output tube changes -and- interconnect changes too.

Yes. Three versions.   Early V12, then V12i for 'Inspired",  & V12R for "Race".  Most "R" models were Red chassis.  The "R" had the larger "Blue Wire" transformer and the change on input tubes, the 6922 to 12BZ7 in particular. Some people sent in the "I" models to be upgraded and converted to the R version.  Upgrading the R further was even better.   

They all pop up for sale periodically, particularly during summer time and function even better over the winter season. 

With twelve power tubes and four input/driver tubes, the collective sixteen tubes in a V12R also functions well as a great room heater. 

The Hexfreds just added a little faster/tighter bass in my former V12R.  I felt having the right coupling caps and interconnects was most rewarding. Overall, the stock EL34 Ruby (Shuguang made EL34BSTR) tubes were great.  If you change too many things at once you'll never know. As for the manual, the last version was never updated for fuses.