MC-2105's ear-bleeding highs and mids

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frp702003

New Member
I just purchased an MC-2105 to hook up with my Yamaha CX-1000 pre amp and Klipsch La Scala. I cannot stand the highs and mids, they are ear-bleeding. I previously had an Adcom GFA-585 at 250wpc and sounded so much better, why? This is my first Mc and I thought it would sound better (pure class A). I believe my connections are right, the negative to the "COM" connection in back of the amp and the positive to the 8ohms connection. I really need some feedback from anyone. I just can't think of anything
Regards,
Fernando
 
I've got an MC2105 as well.....but not knowing the LaScalas, I will say that Mc gear is very finicky about the speakers that it's used with. For example, I found that Infinity Qb's, which are normally very brilliant in the highs, sounded muddy on my amp. Right now I'm running it with ML-1Cs and the MQ101 EQ, and it sounds wonderful :) . Even sounded great on my A7s, so I don't think that the characteristics you're hearing are endemic to the amp, but rather the amp with those particular speakers.
 
The only La Scallas I have heard were of the 1990 vintage and it was being feed through a 2105. It was ear piercing to me ! Now Khorns through my 2205 were awesome but these were 1963 vintage. I don't know if it has something to do with the newer drivers and Xovers or maybe the La Scallas just don't like SS at all. My guess is Newer Klipsch and SS don't. My 2 cents.....

Grumpy
 
Hi frp702003, great talking to you earlier. Gotta love this forum, I've met more cool people and fellow audio enthusiast here.

This weekend will be great for doing some listening and a little trouble shooting of your system. I think you will find the MC240 with your LaScala's to your liking. I agree that matching Mac gear to speakers is not always a easy task. Just takes some time and patience to find nirvana.
 
I'm (wildly) guessing that (assuming that nothing is wrong with your mc) since my 2100 (same thing essentially) is nothing like bright.

1. your efficient lascala's are barely extracting a watt or so from the mcintosh. mcintosh amps are typically not known for the quality of their "first watt".

AND / OR

2. the output autoformers on the mcintosh isolate the power amp section from the speaker impedance variance, as opposed to a regular amp where a dip in speaker impedance (say at low frequency) causes more power to be deliverd (causing emphasis at that frequency point) and hence a more "bassy" sound.

try the mcintosh with other lower efficiency speakers to further isolate your problems.


cheers :uzi:
 
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Originally posted by frp702003
Hello, Kamakiri. Are my connections correct? The negative to "COM" and positive to "8ohms?"
Thanks
Click to expand...

Yep, that's how I have mine hooked up.

I'd have to say that it's not related to efficiency, as my MC2105 sounded fantastic hooked up to Altec A7 VOTs, which are ~108 dB efficient.
 
ron-c correct me on this, as I'm not really up on McIntosh specifics, but in general tube terms hooking an 8 ohm load to a 4 ohm tap should get you less power (about 2dB), but damping will be better and distortion lower.
 
Originally posted by Wardsweb
ron-c correct me on this, as I'm not really up on McIntosh specifics, but in general tube terms hooking an 8 ohm load to a 4 ohm tap should get you less power (about 2dB), but damping will be better and distortion lower.
Click to expand...

if i recall correctly, i read that on the 2100 / 2105, one of the taps is supposed to sound worse than the others, due to it being plugged into a feedback loop. .... although i would have thought most of these SS amps were feedback designs on all outputs anyway

sorry i can't find the link or vouch for its authenticity.
 
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If an 8 ohm load is connected to the 4 ohm taps the power will drop 3 dB, as in ohm's law. The output autoformer is not in the feedback loop on the earlier MC SS designs.
The Klipsch is rated at 8 ohms but we all know a speaker has dips and rises in the impedance curve. I am just suggesting the four ohm tap may be better balanced as an experiment.
If the amp sounds harsh it may need to be checked for power and distortion.
The MC2105 should be below .1% THD at 105/105 watts out and clip around 135 watts per channel. These amps are 30 years or older now. I have replaced the capacitors, power and signal caps in mine and it sounds like new. New caps for the power supply are over $200 and the signal caps are not expensive.
Having a tech check out these older amps is a good idea as a simple cleaning of the chassis and connections on the boards should be in order.

Thanks again,
Ron-C
 
I found the same thing with an MC-2100 (the same guts as the MC-2105, I believe) and Klipsch Cornwalls. I think that the classic Klipsches and the first-generation ss amps (autoformers notwithstandingf) is (are) just not a good combination. I absolutely couldn't stand the sound of the MC-2100 and the Cornwalls, so I put the MC-2100 in a box and put it in my attic (no mean feat!). I do suspect that it would sound better with speakers that made it work at higher average power levels, but I haven't had the energy to lug it down again & try it with, e.g., a pair of AR-3's.

Free advice (worth every penny!): Try a nice 2A3 SE amp (I use Bottlehead Paramours) with your LaScalas.
 
MC-2105 Not Class A?

I thought all McIntosh Amps are pure Class A. Has anyone else heard the MC-2105 not being Class A? What a drag, as this is the sole reason I purchased the amp. To enjoy the purest sound possible.
Regards,
Fernando
 
Re: MC-2105 Not Class A?

Originally posted by frp702003
I thought all McIntosh Amps are pure Class A. Has anyone else heard the MC-2105 not being Class A? What a drag, as this is the sole reason I purchased the amp. To enjoy the purest sound possible.
Regards,
Fernando
Click to expand...

the 2105 is DEFINATELY not class A, ..

if you are looking for a class A amp to run lascalas, look for single ended tube amps, ... they run in class A, though most only put out a handful of watts and probably have a bunch of (desirable) 2nd order harmonic distortion. even a relatively cheap 6bq5 amp should do the trick.

you could get SolidState too, but i doubt you'd need more than a few watts for lascalas.


without getting into speculations, also check that your 2105 is operating correctly (you could try listening to it on more conventional lower efficiency speakers,.. and it SHOULD NOT sound shrill)

regards
 
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Fernando I can bring over a 2A3 SET, if you would like to hear it with your LaScala's. It runs about 3-3.5 watts per channel and works well with high efficiency speakers, especially horns. Then we can try the MC240 for a higher watt push pull setup. I'll give you a call this weekend.
 
Ward:

There's a synergy between 2A3's and Klipsch Heritage speakers... maybe you should start with the 240, and then try the SE :)


BTW, as to the "Class A" issues above... since Class A basically means "always on", I would guess that a 100 wpc class A ss amp would be dissipating 100wpc all the time, even at zero input signal. You could cook omlettes on an MC-2105 running class A! BTW, most ss amps are (well, were) class AB, thus class A at low power and class B at higher output. So I guess that you do get the class A flavor at low output power with a typical ss amp and efficient speakers. Too bad most of 'em sound so durn bad at low output!

The better late 1970's Yamaha ss integrateds had switchable class A output. They deliver a lot less power, with great transparency in class A, and they run HOT!
 
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