I've been told that if you run a pair of MC275 V in Mono, the effect is such that there is a noticeable slowness to the sound as opposed to running in stereo...makes sense?

Been recommended to use 2 X MC275 for Biamping instead although I would not get the extra power which I think I need but am not sure (I play fairly loud at times with all types of music)

can someone shed some light on this as well as tell me if a single (or biamped) MC275 will be able to nicely drive the B&W 802D?

It might change the damping facter To speakers.. but I dought the slowness is a term that is even measurable.

Slow? Nonsense. The MC275 was designed from the get go to be run as a mono amp. It will work well with the 802D and you should run it in the 4 ohm mode.

Thanks,
Ron-C

can someone shed some light on this as well as tell me if a single (or biamped) MC275 will be able to nicely drive the B&W 802D?The 802D is a rather difficult speaker to drive well. It has been called an "amplifier ball buster". I've seen and heard the 402 faulter at driving it well, the 501s being slightly better at it and the 1201s probably being perfect for the job. A single 275? Yes, it will play music but it will not have control over the speaker if that makes sense to you.

The MC402 will not faulter when driving the 802D. The sound you hear as an overload in the bass, is the woffer in distress. This is a function of low bass and power. A good test is the heart beat on Dark Side of the Moon. Gets ugly past 150 watts.

Thanks,
Ron-C

To me the term "slow" has always meant that the amplifier does not have control. It takes massive current to start and stop the woofer "on the dime" as they say, when the amp doesn't have control over the woofer, the bass will get sloppy and the overall effect is the "slow" you hear and percieve. No one has ever called Bryston, Krell, McIntosh SS or Boulder "slow" but other less capable amps may come across that way.

The MC402 will not faulter when driving the 802D. The sound you hear as an overload in the bass, is the woffer in distress. This is a function of low bass and power. A good test is the heart beat on Dark Side of the Moon. Gets ugly past 150 watts.A woofer in distress at 150w for a speaker rated up to 500w for recommended power? Hardly. Lack of current is the "woofer distress". Hook up the MC1201s or the typical B&W show partners, the Classe CA-M400 monoblocks to them and give it another listen. :yes:
Take a look at this impedance plot for the 802D and tell me this speaker will not torture just about any average amp.
http://www.stereophile.com/images/archivesart/1205802FIG1.jpg

I actually heard the 275's in parallel with a pair of 802D's at a local Mac dealer here in Phoenix. Wow! Amazing sound... a C220 and a CD player from Mac (don't remember the model) and Audioquest cables completed the system. The bass response was very deep and detailed. Cannot go wrong with the combo.

Were they playing them loud?



I actually heard the 275's in parallel with a pair of 802D's at a local Mac dealer here in Phoenix. Wow! Amazing sound... a C220 and a CD player from Mac (don't remember the model) and Audioquest cables completed the system. The bass response was very deep and detailed. Cannot go wrong with the combo.

To me the term "slow" has always meant that the amplifier does not have control. It takes massive current to start and stop the woofer "on the dime" as they say, when the amp doesn't have control over the woofer, the bass will get sloppy and the overall effect is the "slow" you hear and percieve. No one has ever called Bryston, Krell, McIntosh SS or Boulder "slow" but other less capable amps may come across that way.

Funny, I have heard of all these amps classified as slow when compared to PRAT champs like Naim and alike UK or Euro amps. All these amps have perceived difficulty in starting and stopping with the tempo of fast paced music.
Amps that don't control low bass output to generally tend to muddy the sound which can effect the upper bass and lower mids.

Slow, I heard 2x275 at my dealer hooked up to the big 800D series, all I know is that they were the ones with an 8 with a bunch of zero's-- each. The only reason I wanted to get a 2nd is that my Thiels dip down to 3 ohms at times. Oh we had put on Kill Bill, Battle without Honor at c220 volume level 65. :guitar:

The 275's to my ears didn't feel slow. After going back after having my Thiels for a bit. I don't think they were as quick as my Thiels with the mc275. I still can't get over how drums sound on my system so far.

I have heard a Naim amp and CD player. I was amazed how similar it was to the mc275 in the Dynamics and movement. I was listening to some Grieg, and I couldn't believe how fast some passages were, but I heard that's more a function of their CD players. Heck the Denon DVD player I have plays music at a faster tempo than my Cambridge.

just an onion.....:para:

Funny, I have heard of all these amps classified as slow when compared to PRAT champs like Naim and alike UK or Euro amps.Hmm, must be the "fit" European amps are faster as compared to the "fat" and "lazy" American amps... :rolleyes:

Yep, a single MC275 will drive 800Ds. Those are some nice speakers.

Tahnks,
Ron-C

I have to ask when the 275 originally came out, were speaker designs overall more efficient or less efficient as compared to todays speakers?

Which if they were less efficient it explains why the 275 feels more powerful because it was built to handle tough jobs...

Just a thought.

Speakers were more efficient when the MC275 came out in 1961. In 1961 MC275s were like MC1201s are now.

The MC275 may feel like more power because of it being a tube amp, most people who have used both will tell you that tube amps have more guts to handle the tough jobs.

Victor

Speakers were more efficient when the MC275 came out in 1961. In 1961 MC275s were like MC1201s are now.

The MC275 may feel like more power because of it being a tube amp, most people who have used both will tell you that tube amps have more guts to handle the tough jobs.

Victor

So as watts got cheaper, speaker designs got "worse"? Or did the designs tend to focus on other things without having to worry about efficiency, given more powerful amps. Thanks Victor that was kind of an eye opener.

Acoustic Research speakers were very popular as well as Bozak, JBL, Altec, Klipsch and KLH when the MC275 came out in the early 60s. These brands have similar sensitivities to what is available now, from low to high. Most of the speakers were 8 to 16 ohms with nothing in the 4 or 2 ohm range. The higher impedances matched better with the majority of tube amps and made speaker wire gage much less of an issue.

Thanks,
Ron-C

I have tried both the MC275 and the MC2102 in monos, neither of them showed any signs of "slowness" whatsoever. 2x 275 kick ass !
I doubt if anybody can find a better value than 2 x 275 on the market.

So as watts got cheaper, speaker designs got "worse"? Or did the designs tend to focus on other things without having to worry about efficiency, given more powerful amps. Thanks Victor that was kind of an eye opener.

My recollection is that the high-efficiency speakers of the 60s were horn loaded and / or required very large infinite baffle, transmission-line or base-reflex boxes to get decent base response. In general, they were large. Some also thought the horns added coloration to the sound.

In response, people like Henry Kloss and Peter Walker developed and /or produced other types of speakers like acoustic suspension and electrostatics. The acoustic suspension principle allowed very good low base response from much smaller boxes - bookshelf speakers became possible. They also did not use horns so as to reduce coloration. The down side was that these speakers became much less efficient and required bigger amplifiers. Electrostatics are also much less efficient than big boxes and horns.

Kind of a simplistic explanation, but that's what I remember.

I've been told that if you run a pair of MC275 V in Mono, the effect is such that there is a noticeable slowness to the sound as opposed to running in stereo...makes sense?

I was curious about this also. I have been in audio for a long time but not into McIntosh until very recently.

Seemed like no one has ever recommended bridging amplifiers. I have tried it myself, but only with early Brystons (2B and 3B) and Dynaco Stereo 70s. In those cases, the results were not good - the amps sounded much better in stereo.

But I keep hearing that bridging McIntosh works just fine. Interesting.

This works fine if the amp is engineered correctly. By the way the S/N ratio is 3 Db better in mono with the MC275.

Thanks,
Ron-C

Think of mono 275's as sounding 'the same, but better' than a single unit if that makes any sense to you i.e they certainly don't sound slow at all...and I know what UK 'fast' hi-fi sounds like since I live in the UK (but my kit is McIntosh and Audio Research).

My friend who owns a decent Naim system (and has never been keen on my previous valve or Quad solid state set ups) even approves wholeheartedly of my mono MC275's - and to get a timing and pace sensitive Naim disciple to like a tube set-up is really saying something !

Actually, as each of our systems have got better, they have started to sound more and more similar...so I would take that stuff about the mono 275's with a pinch of salt.

Incidentally, I have an interesting article here from the UK 'Practical Hi-Fi' in October 1978 when 5 valve amps then current were subjected to a battery of tests including a subjective 'maximum loudness' test - an interesting finding was very high subjective peak powers into higher impedances - for example the Radford 100watt unit was capable of transient peak powers upwards of 400 watts. This was remarked upon as warranting further investigation at the time, but I have never heard mention of it since.

I notice some very high peak impedances in midrange of the B and W speaker charts so the results might be interesting with the 275's.

Are you using an ARC preamp? Which model?


[QUOTE=wolfcub;1271144]Think of mono 275's as sounding 'the same, but better' than a single unit if that makes any sense to you i.e they certainly don't sound slow at all...and I know what UK 'fast' hi-fi sounds like since I live in the UK (but my kit is McIntosh and Audio Research).

Hi

Can someone take a look at attached picture and tell me whether that's the correct way to Mono a pair of MC275's for 4 ohm speakers?

Notice that both MC275 are hooked up exactly the same except that they go to different outputs in the PREAMP. The speakers go to the same LEFT binding posts

What would I use as jumper cables??

Do people agree that Mono'ing MC275's would be better than using 2 for biamping?

Hi



What would I use as jumper cables??



I always wondered that too. It didn't specifically say in the manual. I just assumed it was like a jumper cable like they used on the back of speakers.

Hi

Can someone take a look at attached picture and tell me whether that's the correct way to Mono a pair of MC275's for 4 ohm speakers?

Notice that both MC275 are hooked up exactly the same except that they go to different outputs in the PREAMP. The speakers go to the same LEFT binding posts

What would I use as jumper cables??

Do people agree that Mono'ing MC275's would be better than using 2 for biamping?


Yes that is the correct way to connect for 4 Ohm speakers although it doesn't matter which of the two banks of terminals you connect the speakers to - I use the left bank for the left speaker and vice versa so it is clear which amp is driving which speaker.

As to the jumpers, there doesn't seem to be anything specific to do the job, I use 2.5 sq mm solid core cable as used for house wiring (in the UK)- this costs next to nothing, has red and black cores, and is stiff enough to be bent very neatly to make the jumpers.

Re mono v's biamp - my opinion is that mono operation would be a much better option (than passive bi-amp) as you have more headroom due to the higher power output.

Thanks. To complicate things. I would like to biwire my speakers with the 2 mono 275's....8ohm to mid/highs, 4ohm to lows

How could I do that while mono'ing!?




Yes that is the correct way to connect for 4 Ohm speakers although it doesn't matter which of the two banks of terminals you connect the speakers to - I use the left bank for the left speaker and vice versa so it is clear which amp is driving which speaker.

As to the jumpers, there doesn't seem to be anything specific to do the job, I use 2.5 sq mm solid core cable as used for house wiring (in the UK)- this costs next to nothing, has red and black cores, and is stiff enough to be bent very neatly to make the jumpers.

Re mono v's biamp - my opinion is that mono operation would be a much better option (than passive bi-amp) as you have more headroom due to the higher power output.

Hi there, I am sure that couldn't be done with the mono 275's due to the need for the windings to be parallelled so only one tap could be utitlised at a time - I am also sure that it would be a 'Bad Idea' to try and do this with the stereo 275 -what reason would you have for running each driver from a different tap ?

So, based on this, I suppose it would be ok to biwire the mono's if I use the same 4ohm tap?

People tell me my speakers could be biwired from different taps for best results..that's all. But if that can be done with the 2 X MC275 mono's, then I can settle for biwiring using the same 4ohm tap

Hi there, I am sure that couldn't be done with the mono 275's due to the need for the windings to be parallelled so only one tap could be utitlised at a time - I am also sure that it would be a 'Bad Idea' to try and do this with the stereo 275 -what reason would you have for running each driver from a different tap ?

Not to beat a dead horse but you will need an electronic crossover for tube amps when used in passive bi-wiring. The only option with Mc tube amps is true bi-amping, if you want to actually improve the sound.

thanks,
Ron-C

Are you saying I will be unable to will be run two sets of loudspeaker cables from the MC275 4Ohm taps (in mono) to each of my speakers?

Apologies...but I don't quite understand what is "passive bi-wiring" with an electronic x-over in this context as I thought passive bi-wiring meant NO crossover


Not to beat a dead horse but you will need an electronic crossover for tube amps when used in passive bi-wiring. The only option with Mc tube amps is true bi-amping, if you want to actually improve the sound.

thanks,
Ron-C

Hi, I think there is some confusion here - if you want to bi-WIRE the speakers to the MC275 then that is fine as long as both speaker cables go to the same terminals on the 275 whether it is used in stereo or mono set up (i.e do not use the 8 Ohm tap for one driver and the 4 Ohm for the other but use the same tap for both drivers). If you want to bi-AMP the speakers, go with Ron's advice and use an active crossover - hope this helps.

And how r the MC275's rated running in mono driving Sonus Faber Cremona floor standers in stereo mode???? Ok? As that is my preferred option.

One of the systems I've ever heard was a Mac source with a C2200+MC275 and 802D's, and I'm far from being a unconditional 802D fan. Ok not ear bleading levels, only "eye-tears" beauty...

And how r the MC275's rated running in mono driving Sonus Faber Cremona floor standers in stereo mode???? Ok? As that is my preferred option.
I would also love to know about that, I hope to get those new Cremona M's some day... ;)

Bi-Wire is fine on the amps in Mono. The impedances must be the same though for both sets of wires.

thanks,
Ron-C

I would also love to know about that, I hope to get those new Cremona M's some day...Jim, the 275 in stereo should be fine as long as your room is medium size and you don't expect rock concert levels. The current Cremona is more efficient than the Cremona A's and the 275 for the most part keeps up with my Cremona A's as well as the 501s do in my 14x17 room. Yes, I have punched the 275 from time to time on some music, no problem getting to over 95dB in my room. :music: You can predict for yourself what will happen in your room with your speakers: http://www.myhometheater.homestead.com/splcalculator.html

PCH1

I am assuming you are referring to 1 X MC275 in stereo and not 2 in Mono? Am also wonder whether 95db is very loud..this is what I get from the calculator with just 1 MC275?



Jim, the 275 in stereo should be fine as long as your room is medium size and you don't expect rock concert levels. The current Cremona is more efficient than the Cremona A's and the 275 for the most part keeps up with my Cremona A's as well as the 501s do in my 14x17 room. Yes, I have punched the 275 from time to time on some music, no problem getting to over 95dB in my room. :music: You can predict for yourself what will happen in your room with your speakers: http://www.myhometheater.homestead.com/splcalculator.html

Jim

What is it about the 802D driven by C2200+MC275 that you don't like (unles I am reading your comments wrongly)?

One of the systems I've ever heard was a Mac source with a C2200+MC275 and 802D's, and I'm far from being a unconditional 802D fan. Ok not ear bleading levels, only "eye-tears" beauty...

I am assuming you are referring to 1 X MC275 in stereo and not 2 in Mono?Yes.
Am also wonder whether 95db is very loud..this is what I get from the calculator with just 1 MC275?It is for me. Again, different speakers may place a different demand on the amp so the calculator is just a rough guide. When a speaker wants lots of current, nothing but lots of current will do.

Good read on the topic of torturing amps. :thmbsp: http://stereophile.com/reference/707heavy/

What mono jumper cables do you use? What brand/where to buy?

Thx

Oh, 16 gage copper wire like the leads out of the output transformers would work well.

Thanks,
Ron-C

Ron

Thx but since I have never opened up an MC275, I may not know what comes out of the output transformers (I am talking about MC275 V)...is it like electrical wires they sell by custom length?

Could I use 16 or 14 gauge speaker wires instead..maybe terminated by spades?


Oh, 16 gage copper wire like the leads out of the output transformers would work well.

Thanks,
Ron-C

Could I use 16 or 14 gauge speaker wires instead..maybe terminated by spades?
http://zebracables.com/jumpers.html

so when you make the 275 mono, you just use speaker jumper cables? Would solid copper wire work also?

Yes solid copper would work but it is not a pliable as stranded wire.

Thanks,
Ron-C

at L&M Home Entertainment, who display at least two (or more) of everything McIntosh makes, including speakers! Mike Ware, one of the owners demoed many things for me and Kyle, including a pair of MartinLogan Summits, driven by a pair of monoblocked MC275 MkIV's -- they were definitely not slow!! For comparison, I drive a pair of ML CLS IIz's with one 275MKIV so I know what "fast" sounds like :yes:

Great feedback all.......much appreciated. Well looks like I will go with the Sonus Faber Cremona's and 2 x 275's in mono. Any suggestions re: pre-amp and transport??? Cheers all.

It would be a shame not to use the balanced inputs on the MC275's so ideally look for pre-amp and CD player with balanced outputs and that handle the signal as balanced throughout (i.e they do not simply run a balanced conversion at the output for a signal that is single-ended)....