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wrat

wrat

Active Member
Well i bit the bullet and picked up an MC275 MKV 2 days ago.
And while it seems to have enough power to drive my 'Logans
It also seems a bit soft on the top end.
Now this I expect from my modded Dynaco MK III,s BUT not the Mc any ideas. I am using the stock tubes as I am not about to spend $$ on tubes if this is just a Characteristic of the 275.
 
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wrat said:
Well i bit the bullet and picked up an MC275 MKV 2 days ago.
And while it seems to have enough power to drive my 'Logans
It also seems a bit soft on the top end.
Now this I expect from my modded Dynaco MK III,s BUT not the Mc any ideas. I am using the stock tubes as I am not about to spend $$ on tubes if this is just a Characteristic of the 275.
Click to expand...

I don't think the 275 likes the very low impedance dips that Logans can present up top.
 
PHC1 said:
I don't think the 275 likes the very low impedance dips that Logans can present up top.
Click to expand...

I was a little worried about that, I was assured by the dealer that it would not be a problem.
It is a brand new Gen V
 
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wrat.......I have owned the MC275 MkV amplifier. It is a wonderfully clean amplifier, far from a bit soft on the top end. It could be that what you were previously listening to was a bit bright. You might be experiencing a smooth, open, well defined top end for the first time in a long time. Since you do not have a signature line listing your equipment, it is a bit difficult to comment on what else might be adding or subtracting from what you hope to achieve. With a frequency response of +0 /-0.5dB from 20Hz to 20,000Hz, and +0/-3dB from 10Hz to 70,000Hz, the characteristic of the MC275 MkV is to faithfully reproduce and amplify the signal that is introduced to it. There is no soft top end here. A lot of things can influence the output of an amplifier. It all begins at the amplifier's input terminals. I would suspect your sources before I would doubt the MC275's output.
 
Yeah but 1 ohm impedance dips are not very friendly to even a well designed tube amp.
 
Did not realize Martin Logan speakers went to 1 ohm. There are few amplifiers that care to go there. Mighty close to a dead short.
 
jdandy said:
Did not realize Martin Logan speakers went to 1 ohm. There are few amplifiers that care to go there. Mighty close to a dead short.
Click to expand...

Yep it is a tough one BUT its at 20k and there is not a lot going on up there BUT again it is a contributing factor.

Sources are a Nottingham Interspace turntable and a Music server feeding an Audio Alchemy DDE 1.2
 
wrat said:
Yep it is a tough one BUT its at 20k and there is not a lot going on up there BUT again it is a contributing factor.

Sources are a Nottingham Interspace turntable and a Music server feeding an Audio Alchemy DDE 1.2
Click to expand...

May not seem significant but I've owned a pair of ML SL3s. At the time I tried a Rogue Audio and a Cary SLI-80 tube amps on them and both sounded soft up top. Still enjoyable but that sparkle was gone. Going back to a ss amp cured that right up. I've also tried both tube amps on a pair of Dynaudio and Proac speakers and they did not sound quite as soft. I guess even the 20Khz range matters in the overall airyness and sparkle up top of the system.
 
wrat said:
Yep it is a tough one BUT its at 20k and there is not a lot going on up there BUT again it is a contributing factor.

Sources are a Nottingham Interspace turntable and a Music server feeding an Audio Alchemy DDE 1.2
Click to expand...

When I heard my MC275/C220 thru Quad ESL-2805's with a Nottingham Dais (can't remember the cartridge) it was like both the bottom end and top end had this really gentle roll off. I even brought my cables with me along with my phono stage. ONCE I got back home, I got my high's back almost too much so. I even got to hear the MC275 thru an EAR 912, the worst I can say about that was that it sounded a little "hard" I put that on the Thiels, but not sure..but the voices were to die for, they sounded so real it was amazing Finally heard that "inner sound" that I hear so much about. I miss that pre-amp. The 275 will change with your sources. That is from my experience thus far.

I heard them thru the baby pair of ML and they had just this really nice touch of warmth to them. A pair of Maggie 3.6's were just as smooth as butter. So smooth, but beguiling. So far the Quads have been the best for them.

I had all Tele's in the mc275 when I played with the Nottingham.

oops almost forgot...CONGRATULATIONS!!:banana:

Mark
 
Enough with impedance dips, already!

Oh poppycock to all you naysayers!! The MC275 is a miracle with electrostats. Enough already with the "impedance dips. OY VAY!!

The MC275 (and all other Mac tube amps as far as I know) employ Frank McIntosh's famous Unity Coupled Circuit (now also balanced in the new models.) Why is this important for electrostats? Because the gain in the UCC is current controlled not voltage controlled as in most tube amps. The stat panel sees more CURRENT as the load impedance drops -- which is JUST WHAT A STAT WANTS! This is the reverse of what happens with most tube amps and VIRTUALLY ALL solid state amps; which is why folks who are crazy enough (IMO:yes:) to use ss amps w/ their stats, need to use REALLY BIG SS AMPS if they expect to have enough current (at 15Khz, 0.7 ohms) to enjoy any kind of a smooth high end! I've been there!

. . . . . . . end of rant Part 1 :D

OK, so for a long time, many people had disappointing results with tube amps and MartinLogan speakers. Why? Because they were using the amp to run the WHOLE SPEAKER; WHICH INCLUDED INEFFICIENT, SEALED ENCLOSURE, POWER-AND-DAMPING-HUNGRY WOOFERS!! C'mon folks . . . not fair!! You had to buy a humongous tube amp just to handle the woofers which would then be overkill for the panel. Woofers need the voltage control provided by a powerful ss amp. SO! guess what? MartinLogan hybrids now come with their own, built-in, class 'D' ss woofer amps. And if you do use a tube amp with the new models (and why wouldn't you?!:scratch2:) it will only have to drive the panel! And if you're saavy enough to research the best kind of tube amp (circuit) for driving an electrostatic panel, you'll keep coming back to McIntosh again and again; because nothing else interfaces with stats the way the Unity Coupled Circuit does.

. . . . . . . end of rant Part 2 :D

And BTW, you might want to know how Peter Walker drove the original QUAD ESL57's so successfully with nothing but a pair of 15W QUAD monoblock tube amps. Hint: The QUAD 57's impedance dips at around 160Hz. It is constant out to 15KHz.
 
sparkle?

PHC1 said:
May not seem significant but I've owned a pair of ML SL3s. At the time I tried a Rogue Audio and a Cary SLI-80 tube amps on them and both sounded soft up top. Still enjoyable but that sparkle was gone. Going back to a ss amp cured that right up. I've also tried both tube amps on a pair of Dynaudio and Proac speakers and they did not sound quite as soft. I guess even the 20Khz range matters in the overall airyness and sparkle up top of the system.
Click to expand...
Exactly what I would expect; but not for the reasons you suggest. Those inefficient SL3 woofers were sucking up all the voltage those particular amps could produce and nothing was left for the panels. Now if you'd had your Bryston 10B and biamped the SL3's (admittedly a pain) and stuck a moderately decent ss amp on the woofers, your sonic experience would have been quite a bit different, I guarantee. Unfortunately, most ML hybrid owners never took things that far, and like you, just bought a ss amp to run the whole speaker and hoped for the best. PS: My CLSIIz + MC275 'sparkles' like you wouldn't believe!
 
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