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Scotty, I need more power!

twiiii said:
I have seen curves by others for Acoustats where the impedance approached 1 ohm in the highs.
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When you say "the highs", to what range do you refer? Care to reference your source? Mine is from designer Jim Strickland found here. Nor is that assertion validated by the Stereophile test found below. At any rate, there is so little current to be found above 15k to be meaningful.

Indeed, the larger Apogee ribbons were very demanding in that respect and pretty much required Krell amps due to their 1 ohm impedance.

twiiii said:
and varied a lot more in the bass.
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Perhaps you are thinking of the hybrid using a cone woofer driven by a single amplifier. Not the pure electrostats using the MK-121 interface as the panels really have nothing to do with it. Stereophile observed that with the Spectra 1100 here.
 
above 10 KHZ and no I mean electrostatics not hybrids. You realize we are talking ancient history 50 years will be here shortly.
 
twiiii said:
above 10 KHZ
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Ok. Neither Stereophile nor Strickland's measurements as previously linked validate the assertion of 1 ohm impedance at 10k. And there's so little energy to be found in the top octave.

My modest Emotiva amp has no difficulty driving 1+1s to high levels and my interfaces are modified by former employee Roy Esposito with the "air" setting that bypasses the HF level control.
 
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E-Stat said:
Ok. Neither Stereophile nor Strickland's measurements as previously linked validate the assertion of 1 ohm impedance at 10k. And there's so little energy to be found in the top octave.

My modest Emotiva amp has no difficulty driving 1+1s to high levels and my interfaces are modified by former employee Roy Esposito with the "air" setting that bypasses the HF level control.
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My speakers are the hybrid type with satellite woofer and the 131 interface so if the curve you posted above is for a full range system, it may not apply to mine although I would expect the upper frequencies to be similar.

I, on my own, removed the 16-Ohm, 3-tap tweeter leveling resistor a long time ago. With the resistor in the circuit, part of the resistor is in series and the rest of it in parallel with the speaker (tweeter panel & transformer). So, if the panel gets down to 1 Ohm, the amp may see like a 4 Ohm resistor in series with maybe something just under one Ohm. With the resistor removed, then the amp sees 1 Ohm or 3 Ohms or whatever. But I really don’t know what the curve is.

And I don’t see a phase response curve so I cannot account for the power factor.

Also, I recall reading somewhere that the leveling resistor served also as a damper for a higher frequency resonance for these highly reactive speakers. I would think such a resonance might show up on the impedance curve and I don’t see such. But I might wire it back in to see if it tames the top end a bit.

Maybe reverse engineering these speakers is not a good idea. Especially at a bar. With wine.

Anyway, I realized that while I thought I was listening critically to see if the MC452 is better than the MC2505, I am really evaluating my speakers to see if they’re up to the task of running with this great Mc stuff. This is a very useful conversation but I think I need to move it to the Speaker forum at some point soon.

The MC452 is assume and will stay.

Posted from the bar at the Hilton Oakland Airport Hotel, venue this weekend for the California Audio show. Maybe I can get some perspective on what i’m hearing at home.
 
TSmith8605 said:
My speakers are the hybrid type with satellite woofer and the 131 interface so if the curve you posted above is for a full range system, it may not apply to mine although I would expect the upper frequencies to be similar.
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Yes, that document was created before Acoustat added dynamic woofers to the one panel model. It's true that cone woofers typically generate wide impedance swings.

TSmith8605 said:
Anyway, I realized that while I thought I was listening critically to see if the MC452 is better than the MC2505...
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How could it not given the latter is a first gen SS design? I found its higher powered sibling, the 2105 to be insipid sounding.

TSmith8605 said:
Posted from the bar at the Hilton Oakland Airport Hotel, venue this weekend for the California Audio show. Maybe I can get some perspective on what i’m hearing at home.
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Definitely visit room 5201 with Sound Labs! Of the many electrostats I've heard since the 70s, they are the best IHMO. Not sure which model Dr. West brought, but all have a transparency, neutrality and lack of beaming as compared to the larger Acoustats.
 
E-Stat said:
How could it not given the latter is a first gen SS design? I found its higher powered sibling, the 2105 to be insipid sounding.
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And here's an opinion that contrasts that one - http://vinylhive.com/mcintosh-mc2505-the-solid-state-amplifier-that-change-the-world/ ****, I guess most of us here are just daft beyond comprehension as the MC2505 and MC2105 are quite revered here. Obviously, it's because we can't tell good from bad, lighted faceplates from good sound, a green field from a cold steel rail, etc.

I digress however . . . you may have had the speakers connected out of phase, not grasped the concept of the autoformer coupling when selecting taps, or possibly both.
 
damacman said:
You really should listen more and talk less - nobody said anything of the sort.
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Nobody? It seems you're not paying attention. Perhaps you should revisit post # 47

"Everything is better, instruments, especially higher freq / percussion is more articulated, correct in timbre and more precisely placed in space."
 
The MC2505 is the best sounding amp I have owned up until the MC452. That means it beats Kenwood integrated, Pioneer integrated, Spectral Acoustic (junk), Dyna ST 70 & Mark III, Bryson 2B & 3B, ARC D52 SS, ARC D90B and D115 MK II, and MC275 IV.

If your 2105 was insipid, something was not working correctly.
 
E-Stat said:
Definitely visit room 5201 with Sound Labs! Of the many electrostats I've heard since the 70s, they are the best IHMO. Not sure which model Dr. West brought, but all have a transparency, neutrality and lack of beaming as compared to the larger Acoustats.
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Just was in that room and went back 3 times. Liked them better than the ML CLX but they are a bit in your face in the upper midrange on some recordings. They need taming there but maybe worth the effort. Cheapest models are $14K, half the price of the CLX.

I had the chance to hear their A1s a lot 30 years ago. In fact, for awhile a local dealer I knew used on loan my current VPI table to demo the A1s. Roger West is here at the show.

I also really liked the little Audio Note speakers which are about $11K and a completely different sound.
 
TSmith8605 said:
Just was in that room and went back 3 times. Liked them better than the ML CLX but they are a bit in your face in the upper midrange on some recordings.
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Which model and what was the rest of the system?

edit: I read elsewhere they are showing the Majestic 645, a mid level offering.
 
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TSmith8605 said:
The MC2505 is the best sounding amp I have owned up until the MC452. That means it beats Kenwood integrated, Pioneer integrated, Spectral Acoustic (junk), Dyna ST 70 & Mark III, Bryson 2B & 3B, ARC D52 SS, ARC D90B and D115 MK II, and MC275 IV.

If your 2105 was insipid, something was not working correctly.
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It does no good to attempt to have a friendly conversation with him. He came into this thread, like he does many others, to exert his intellect and superiority. He also looks down on anyone that thinks anything made by McIntosh is HiFi.

@Mike Gibson ... it gets old.
 
I'm not an engineer or a spec hound --- but after purchasing my MAC6700 and MAC7200 for installation into two separate systems, I'm not planning any further amp adjustments. Having been through Fisher and HH Scott tube gear, Yamaha, Denon, and Marantz for home music systems, stretching back to 1965, I'm done. I'm using Marantz for less critical home theater applications, through.

Most recently, when I purchased the MAC7200, I flirted with an MA9000 but passed because of the weight of the unit. At 69 years old, handling the beast is just beyond my physical limitations.
 
Home audio / music equipment is for the enjoyment of the listener, there is no bad.

If I still had my 2505-2, which sounded very good to me, and still had my Acoustat 1+1s, I would never pair them as I expect the 2505's meager 72wpc would have sounded rather lifeless on those speakers at anything above a whisper.

True that the 2505 series doesn't match the specs of today's gear, but paired with the right speakers it is very enjoyable to hear and if that's what you're looking for you're in the right place.

I spent part of my Friday looking for a new amp to add to the system, trying to decide between Krell, Mark Levinson, and McIntosh. Hard to decide because at similar price points they all sound magnificant. It doesn't mean that any of my vintage tube or SS stuff is going anywhere because I still enjoy that sound also.
 
If considering used the MC 2002 should fill all of your requirements, drove my Infinitys without breaking a sweat, wish I still had the Mac gear I sold when my lady passed.

$_59.jpeg
 
I don't know if this is a discussion about the MC2505, accoustat speakers, or just another time for EStat to parachute in and regal us with his prose.....

The accoustat speakers were a interesting engineering experiment that along with so many engineering experiments end up in the dustbin of real world use.

If you like them you like them and if you don't well, there are some many other options that work do much better in real world rooms.

The MC2505 amp was and is a class act. Designed by tube amp engineers that had to face the reality of a failing supply of good tubes there are many updates that have been learned over the last 4 decades to upgrade these classic amps to improved performance.

Now to collectors making these upgrades may be sacrilegious but to those who just enjoy them or want to pass them on to our grand kid, a practical decision.

I feel the same way about the MC2125 or 2155, practicle good sounding amps with adequate power to deliver 100+ dB continuously in my LR.
 
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