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Scotty, I need more power!

Acoustat had a 200 watt per channel amp they made to be used with their panels it was a flop, too. The problem with Acoustic panels is their impedance drops below 2 ohms in the highs and the bass impedance swings all over the place. The amp you want is the MC 7200. Its direct coupled giving you the voltage you need for lower spectrum and the current you need above 7 kHz. As I remember a 7200 can putout over 500 watts below 2 ohms. It isn't the power you need but the current something a 2505 and 275 can't cope with. Now a 7300 and 2255 with very low impedance taps can drive the highs using those taps but they can't develop the voltages need from the taps to get the levels you want from the mid and very complex bass impedance curve. I will admit when I first heard Acoustat panels driven by the 150 watt Audio Research I was impressed at first. But even they can't compare with the MC 7200, which was designed to drive the Apogee , KLH and Acoustat panels. At least Magnepan panels have a very well controlled impedance curve making them relatively easy to drive as compared to other panels. All paneled speakers do have very low sensitivity and high output issues. I loved the Tympani IV's, even with all the issues. Spent a lot of time listening to 3 and 4 Acoustats. They were special when installed and amplified properly. My favorite amp for them was a MC 3500, using the 1 ohm tap at the time. But the MC7200 was the ideal choice for me.
 
You need both high power and high current to run these.

A friend had them on an Adcom 555 (200wpc, not high current), didn't work. Another Adcom 555 (bridged, but he didn't blow any amps up; they will when you do this) and worse (loss of current for voltage; bad.) Early Adcoms had a penchant for blowing outputs when used on high current speakers.

I got him an Aragon 4004 (200wpc; high current) and it worked fine and actually got loud. The 108dB rating on those is phony as is the 30Hz low end; they're probably 87dB and 70Hz.

twiii is right about the 7200, it was designed for these loads, older autoformer amps will work too, but you give away power as you drop autoformer taps.Powerguard is very helpful as well.

Anything Mcintosh from the 7xxx series will work, the 7300 would be fine, a 2600 (heh) would be optimum. I'm sure anything modern would be OK as well.

And they do sound really nice, but the sweet spot is so tight you need a dentist's chair as a listening seat.

Mike
 
Well the single-panel 1s with a normal (dynamic woofer below 100 Hz) are a lot more easy to drive than the full-range Acoustats.

I remain completely amazed at how well the MC 2505 drives them - good enough for 95% of the time. The MC 2505 is 45 Watts/per with a damping factor of 10 and it drives the panels very well. The MC 452 with 10 times the power should have no problem with current drive. It has a damping factor of 40 so should be more immune to impedance variations at high frequencies.

If the MC 452 can't do this, something is very wrong, or very right with the MC 2505.

Anyway it's a done deal, although Audio Classics offers a 10-day I-hate-it return policy with full refund.

Since the single panel is relatively narrow, the dispersion pattern is not as bad as you might expect and is perfectly fine off-axis for less serious listening, like friends on the couch watching a movie. I do have the venetian-blind effect, though, when trying to find the perfect sweet spot. After 30 years of listening I am pretty aware of the weaknesses and strengths of the speakers.

Email for AC, amp is on the way.

Thanks again to all for the info and help!
 
Academic at this point, but the 2505-2 is (according to McIntosh) 72wpc at distortion spec. and with changes in the Service Bulletin so is the 2505 and "more".

The 452 should be just enough, ...
 
CruzBay said:
. . . The 108dB rating on those is phony as is the 30Hz low end; they're probably 87dB and 70Hz. . . .
Click to expand...

The 108 seems high to me too, but the 30 Hz is correct - these are hybrid speakers with the panels going from 100 Hz up and a dynamic satellite woofer below 100 Hz. They do go down into the 30s - I can easily tell the difference between 70 Hz and 30 Hz.
 
Are your accoustats the ones with the separate woofer cube or those with the cone woofers integrated into each speaker...hybrids?

If you have the hybrids I had a few of the prototypes in the shop back in the day.

The woofer section was being designed by Carboneau, the panels in Florida, and two pair were being shipped back and forth as they tried to sort out the mismatches between them.

I actually ran a 1/3 octave analysis of one set showing the disparity for the local designers which got sent back to Florida........of coarse it was on Mac graph paper.
 
c_dk said:
Are your accoustats the ones with the separate woofer cube or those with the cone woofers integrated into each speaker...hybrids?

If you have the hybrids I had a few of the prototypes in the shop back in the day.

The woofer section was being designed by Carboneau, the panels in Florida, and two pair were being shipped back and forth as they tried to sort out the mismatches between them.

I actually ran a 1/3 octave analysis of one set showing the disparity for the local designers which got sent back to Florida........of coarse it was on Mac graph paper.
Click to expand...

Mine have the separate satellite woofer cubes with a 10" acoustic suspension dual-voice coil speaker. They are designed to run from a single amp but I've always used a separate amp for the woofer. I call it hybrid although that might not be the correct term since they are a satellite configuration. The bass sounds way better to me than I would expect from such a design but, compared to full-range acoustats, you can here the change in character of sound for the bass sound vs everything else and that's a down side (mismatch). But the set up allows a lot of control of the woofer vs tweeter and is much easier to drive. I do have experience with a friend's Acoustat 2+2 which are very large full-range stats - a bitch to drive.

Thanks for whatever help you contributed to fine-tuning these.
 
I only saw the ones with the cone woofers built into the lower "stand" for the panel. Never saw the two piece units.
 
UPS freight called and made an appointment to deliver a 160-lb load on a pallet "curbside" this coming Monday (an MC 452 from Audio Classics). UPS says they can't take it into the house or even the garage. It's just me here so starting to stress a bit about this. Maybe the driver will let me use his pallet jack to move it into my garage. Or I should be able to wrestle it off the pallet onto my 2 / 4 wheel cart and get it into the garage so it's off the street until I can get help getting it the last 10 feet. I might need to buy some tin snips for the straps that holds the box to the pallet.

I've recruited and confirmed at least one neighbor to help unbox it and place it on the shelf although this may be a 3-man lift job so I sent text to a second neighbor. That will cost a couple bottles of wine at least. Otherwise I have no relatives in the area and all of my local friends live 15 to 20 minutes (+ rush hour delays) or more away. Who do I have to annoy, friends or neighbors? Don't even want to think about what happens if it breaks say out of the box or in 15 years from now and needs to go somewhere for repair. Guess I'll have to store the pallet in the shed.

Anyway, any advice for getting the amp the last 30 feet, out of the box and onto its (floor) shelf.
 
TSmith8605 said:
UPS freight called and made an appointment to deliver a 160-lb load on a pallet "curbside" this coming Monday (an MC 452 from Audio Classics). UPS says they can't take it into the house or even the garage. It's just me here so starting to stress a bit about this. Maybe the driver will let me use his pallet jack to move it into my garage. Or I should be able to wrestle it off the pallet onto my 2 / 4 wheel cart and get it into the garage so it's off the street until I can get help getting it the last 10 feet. I might need to buy some tin snips for the straps that holds the box to the pallet.

I've recruited and confirmed at least one neighbor to help unbox it and place it on the shelf although this may be a 3-man lift job so I sent text to a second neighbor. That will cost a couple bottles of wine at least. Otherwise I have no relatives in the area and all of my local friends live 15 to 20 minutes (+ rush hour delays) or more away. Who do I have to annoy, friends or neighbors? Don't even want to think about what happens if it breaks say out of the box or in 15 years from now and needs to go somewhere for repair. Guess I'll have to store the pallet in the shed.

Anyway, any advice for getting the amp the last 30 feet, out of the box and onto its (floor) shelf.
Click to expand...
I'm a silly old fart, and I can still wrestle my MC452 up onto the workbench after carrying it from the lounge, its not something I like to do and haven't had to do very often given McIntosh reliability.....
You'll be fine with one other person.

You need a dolly of some sort, can you hire one from somewhere? Or hire a Pallet Jack? Thats what I would do.....The box is bigger than you think its going to be.....

Exciting times!!! Getting a new amplifier!! Nice work!!
 
I have a folding hand-cart that I keep in the closet of my media room for moving speakers, ... IIRC around $30 at a hardware store.

Getting it in the cabinet is a 2-person job, if you have something the same height in front of the cabinet to put it on first that will help a lot.
 
TSmith8605 said:
Anyway, any advice for getting the amp the last 30 feet, out of the box and onto its (floor) shelf.
Click to expand...
If there is a Harbor Freight in your region, you could buy a dolly for about 30 bucks.
Otherwise, put the box on a long throw rug, and drag it into its final destination. - Maybe slip the UPS driver a 10 spot to facilitate the process.
I spend 3 days looking at my Mc452 in the open box, game planning the best way to do a solo removal.
 
Thanks for all the advice.

Well I do have a fridge dolly / hand truck thing that also has two little wheels up top such that you can lay it flat and have a 4-wheel cart. That should be OK for moving it short distance once it's off the pallet. I also have one neighbor lined up to help.

I've also been studying the packing instructions in the (downloaded) MC452 Owner's Manual. I've never done that before.

It'l get done.
 
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Two folks is all that's needed to lift the amp into place. One on each side - one handle in the hand and one hand under the rear of the chassis.

I can still remove / reinstall the MC2600s from my main rack by myself. You just have to think about what you're doing before you do it.
 
TSmith8605 said:
Thanks for all the advice.

Well I do have a fridge dolly / hand truck thing that also has two little wheels up top such that you can lay it flat and have a 4-wheel cart. That should be OK for moving it short distance once it's off the pallet. I also have one neighbor lined up to help.

I've also been studying the packing instructions in the (downloaded) MC452 Owner's Manual. I've never done that before.

It'l get done.
Click to expand...
You'll be right with your dolly there and maybe a hand to get it in the shelf or cabinet.....I still move mine on my own, I brought it home and got it into my house on my own, I have since moved but that house was a PIA to get it into!!
There's mine on the dolly just before I gently rolled it into the house!!
IMG_1195.JPG
 
I Don't know if it will help, in your situation, but will UPS redirect your package to a UPS Store? If so, someone there should be able to help you load it into your truck, or at least loan you a dolly to do so. Then you can pull up as close as possible for unloading. I moved mine, by myself, with the help of a hand truck, but it wasn't fun.
 
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