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MC275MkV as Monobloc Amps

Yamaha B-2

Yamaha B-2

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OK......first off, is anyone else running a pair of MC275MkV (or MKIVs) as monobloc amps?

Here are my observations:
- Ran-in the amps as full-range stereo amps for about two-weeks with a matched quad of Tung-sol 6550 reissues (thank you, Doug's Tubes) in each. A far better sound than the stock KT-88s, to my ears.
- Ran each amp in mono-mode with balanced input, supplying a full-range signal to each speaker. Very nice, but nothing to knock ones socks off. Listened for about two-weeks in this configuration.
- Just reconfigured each amp to supply a stereo signal to the speakers. Doing the high-low bi-amp thing with one amp supplying the low/mid-drivers and the other amp supplying the tweeters. Two sets of speaker cables supplying the two pairs of terminals on the speakers with the speakers' passive internal crossover performing the frequency splitting duties. Much better sound. I've found that the 2-way speakers I've owned (Mission, Paradigm, Solioquy and Krell) have responded well to either a bi-amp or bi-wire configuration.

Eventually will try the external active crossover in this configuration. Will be quite interesting to hear what, if any difference that might add.

My biggest problem is that my preamp has only one pair of balanced outputs and one pair of single-ended. I may go so far as to ask the BAT folks to modify to have two pairs of balanced and one pair of single-ended. Their facility is just across the river, so is easy to drop off and pick up.

My final word is that the sound is cleaned up quite nicely with this configuration of one amp running the low end and one the top. I will add that I am using matched sets of flat, 12ga silver-coated woven copper cables.

Would be interested in anyone else's experiences.
 
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Hi Yamaha B,

I did have the experience of running mono 275's but they are like the 3rd version .... so cant really give any indication to yours. However, as to one set of "balanced" output, you dont need to modify your BAT ... as you can use a splitter to same effect. But this will apply only for 2 mono sets of MC275's (4 pieces).

Since you have one pair, its not necessary to do so as your BAT pre should do the job ... unless you are bi-amping them as Stereo!

To me, its always better to use a splitter than to mod a pre, unless its from the same people who makes the pre-amp.

Thats my $0.02 worth of story.

Cheers.
 
I'm currently running both of my MC275Vs as monoblocks driving Magnepan 3.6Rs with great success. If I recall correctly, RonC has indicated before that Mc tube amps operate better when they see the full frequency range as opposed to one channel driving the mid/tweets and the other channel driving the lows, unless one is using an external active crossover.

Harry
 
Wish I had the room in my current listening space for a pair of 3.6Rs. Awesome speaker. Lucky me, we will be moving back into our condo some time in the next 2-3 years and my listening space there will allow same.

OK....back on topic. Have your tried bi-amping hi-low with the 3.6Rs? That is, running one MC275 to supply the low end of the 3.6Rs and the other amp to run the high end? Both amps would be running full-range and the 3.6R crossover would take care of splitting the signal. Am running mine that way and to my ears the sound is better than running each amp in straped mode.

When running in straped mono mode there are two tubes on each push-pull side of the amp. When running in stereo mode there is only one pair, so no imbalance between tubes. Am thinking that this may be the source of the improvement. YMMV.
 
Yamaha, I agree w/ your hookup suggestion, but about the:
When running in straped mono mode there are two tubes on each push-pull side of the amp. When running in stereo mode there is only one pair, so no imbalance between tubes. Am thinking that this may be the source of the improvement.
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Doesn't the 275 running in mono mode still keep its two channels/circuits separate ('parallel', as opposed to bridged or 'strapped')?
 
One amp, one channel, 4-output tubes......doesn't matter the configuration, still have to have 2-tubes on each side of the push-pull arrangement. The very best sounding solid-state amps (other than VFET), at least to my ears, are those with only a pair of output devices per channel. Bryston 2B-LP and Sony TA-N86B, for instance. Same thinking. Not having to match the output devices, be they tube or solid-state, seems to make a difference. YMMV.
 
When you mono the MC275 the signal to noise ratio goes up or improves by 3 db. No need to match tubes as long as they are not defective. The unity coupled design takes care of this.

thanks,
Ron-C
 
Guess my next configuration will be monobloc MC275s with bi-wiring. So many configurations.......so little listening time. Go Rockies!
 
WhiteSE said:
Yammie..how many hernias are you planning on?..-)
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Yeah.......I know. But, I'm thinking of only moving the speaker cables around this time, rather than the amps. :D

Have settled on the monobloc configuration with bi-wiring to the speakers. Here is what the amp end of things looks like with the Kubala-Sosna Fascination IC and the flat 12ga silver coated woven copper speaker cables I make up.

DSCN0379.jpg
 
After another month of listening, I can state definitively, that to my ears, the best way to listen to an MC275 in my rig is as a stereo amp and not as a monobloc.
 
After another month of listening, I can state definitively, that to my ears, the best way to listen to an MC275 in my rig is as a stereo amp and not as a monobloc
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I've heard that before although I don't have first hand knowledge in this.
 
ron-c said:
Did that speaker cable sound bright or emphasize the high frequencies? Thanks, Ron-C
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Not that I noticed. The difference is that the level of detail in the single, stereo mode is better. Also just a bit better on the sound-stage depth. But mostly a detail thing. And I am a detail sort of listener rather than a 'big picture' listener. Driving a pair of monitors in the near-field. About 75% of my listening is jazz, where the emphasis is on the individual players as opposed to the group.

MC2102 arrives at the door in about an hour, so will start the listening A/B to determine which is better. Tough choice. Will the one pair of outputs per channel in the MC275 provide the better sound or will the quad outputs of the MC2102? In the end, do I keep the MC275 or the MC2102? What great fun! :thmbsp: Decisions, decisions............
 
Yamaha B-2 said:
After another month of listening, I can state definitively, that to my ears, the best way to listen to an MC275 in my rig is as a stereo amp and not as a monobloc.
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I agree, I liked the MC275 as a stereo amp better than as monos. MC2102s a different story though.
 
Got the MC2102 installed and running. To insure the test is fair, I pulled the tubes from the MC275s and put in the MC2102 - Tung-sol 6550 reissues, RCA 'black-plate' 12AT7s and Mullard 12AX7s. A considerably larger difference than I would have guessed. The bottom-end and lower mid on the MC2102 is MUCH bigger. But, everything needs ~100 hours of running to make heads or tails of it all. More later.
 
I heard 2x275's in a 16x20 room playing at volume 65 on a c220 amp, and that was easily one of the best experiences I have had in audio. There was such a fullness and realness that it was so easy to get lost in the music. I haven't heard that setup so I can't compare, but man even after RMAF 2x275's are still very high up on my wish list.
 
Yamaha B-2 said:
Got the MC2102 installed and running. To insure the test is fair, I pulled the tubes from the MC275s and put in the MC2102 - Tung-sol 6550 reissues, RCA 'black-plate' 12AT7s and Mullard 12AX7s. A considerably larger difference than I would have guessed. The bottom-end and lower mid on the MC2102 is MUCH bigger. But, everything needs ~100 hours of running to make heads or tails of it all. More later.
Click to expand...

Now all you need is another 2102 :D
 
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