Ultimate Advice MC2300/MC2500/MC2600

quartersaw said:

Cool that it is factory reconditioned. I had to upgrade the driver boards on one of my Mc2300's. (1Y975) The longer I run my pair of 2300's together, the more I am put off by the full throttle fan noise @ idle.
I simply crank them up so I don't hear the fans

Click to expand...

Tonight, the initial listening session with the so demanding QLS:
>Bi amp MC2300 on lows using 4 ohm taps; MC30 tube pair on highs - the tubes ran out of power and distorted while the bass was tight
>Bi amp MC2300 on lows: Sunfire 300~2 on highs - sweetness!

MC2300 was initially flickering the VU lights on the 110 volt house tap and I plugged into my new 20 amp dedicated circuit and hardly a flicker even with the VU meters going all the way to right side on some high dynamic bass tracks - Steely, Donald Fagan, Bela, but never heard any audible clipping or distortion, never saw a red protection LED.

Only got in 30 minutes so this is preliminary, more tomorrow.

The QLS are the most demanding speakers I've ever encountered, but when fed correctly, the most rewarding.

quartersaw said:

Cool that it is factory reconditioned. I had to upgrade the driver boards on one of my Mc2300's. (1Y975) The longer I run my pair of 2300's together, the more I am put off by the full throttle fan noise @ idle.
I simply crank them up so I don't hear the fans

Click to expand...

Seriously, with all my experience with 2300s if you're not using them at some rock festival you could easily disconnect the fans and the thing would never warm to dangerous levels. My 5Y only had its fans on twice the whole time I ran it in the San Diego heat (96 degrees). To me the fans are overkill if running on any 1Y. You don't need them for home use - especially if you are running all new output transistors to the latest spec.

Interesting reply Count. Both of my MC2300s are racked and the fans in each do periodically kick on even at low listening levels. As the fans are part of the thermal design, I'd be reluctant to switch them off. As far as the 1Y units w/ non-thermostatically controlled fans go, it really isn't that hard to add the circuit - which is fully outlined in the schematic.

I've used one of my amps outdoors on the 4th of July in 118 degree weather - no problems at all running all day long at party levels. This is the kind of stuff that blows up lesser designs ...

Not directly connected to the 2300, but I've never had a 2600 turn its fans on anywhere other than on the test bench. In a residential setting that amplifier is loafing.

CruzBay said:

Not directly connected to the 2300, but I've never had a 2600 turn its fans on anywhere other than on the test bench. In a residential setting that amplifier is loafing.

Click to expand...

Yeah, my thermo switch may be out of spec but I do keep the screws out of the tops of my 2300s. When the 5Y kicked on I pulled the top and felt the sinks. They were warm but not hot. Other than these couple times on real hot days I never heard the 5Y fans on again.

I'm probably going to mod the 1Ys even though they are historical artifacts. I don't mind the fans on - I mind all the dirt and dust they pull through the sides and cake everything up.

damacman said:

Interesting reply Count. Both of my MC2300s are racked and the fans in each do periodically kick on even at low listening levels.

Click to expand...

Having airflow in and around 2300s is pretty important. If you look in the manual, and I'm sure you have a hundred times, the recommended mounting instructions say they need minimum inches around mounting so I suspect as I run mine sitting on road cases they are completely open to the outside air therefore radiating the heat. They are not rack mounted as I often move them to keep in shape, so having one out in the open definitely keeps the heat down.

CruzBay said:

Not directly connected to the 2300, but I've never had a 2600 turn its fans on anywhere other than on the test bench. In a residential setting that amplifier is loafing.

Click to expand...

That makes two of us ... now we have a goal!

Now that I've had the MC2300 amp in the system a few days, couple observations:

>interesting how the fans are configured - the right fan pulls air out of the amp as soon as the power is on. the rotary switch when set to low will only operate this fan. As I turn the rotary switch up, the left fan engages, but it pushes air into the amp. I guess they felt the flow would be better this way, what do you think? should I change to have both sucking air out or is this cool? no pun intended realize the way is set up now will introduce more crap into the amp but that can be cleaned out easily periodically.

>I am running this amp on a dedicated 20 amp circuit. When i crank it up, not fully, but reasonably loud, the VU meter lights are dimming and flickering with the harder bass demands from the Infinity QLS speakers. I'm running this amp on the 4 ohm taps for just the woofers and a Sunfire 300~2 on the upper drivers, plugged into the rest of my system on the normal house outlets. I would think the 20 amp circuit would be quite enough for the amp to not fluctuate - any thoughts here? The sound is great, but I am cautious to push really hard as when I'm way into the right side of the meters, the lights are really dimming a bit. Less than when it was plugged into the rest of the house on the shared circuit but I expected this would be rock solid?

Any advice appreciated, but wow, what a great amp!

All MC2300s will have the meters dim when pushed hard. This is simply a byproduct of the power supply design. As for the fans, I'd personally want both connected to the variable controller (assuming it has enough current capability) and both pulling.

damacman said:

All MC2300s will have the meters dim when pushed hard. This is simply a byproduct of the power supply design. As for the fans, I'd personally want both connected to the variable controller (assuming it has enough current capability) and both pulling.

Click to expand...

Thanks for the reply and very good to know on the power supply.

I will have to see what I can do with the fan piece….but agree, drawing the air out is better than having one blow in and the other pull out.

I have an MC2300 powering XRT 24s. Is there any reason to purchase a second MC2300? The speakers are rated 1000, but I don't run them near peak now. There may be an opportunity for me to pick up the second MC2300 for a good price. I'm on the fence about second MC2300 vs. just waiting to find a pair of 501s or one of the more modern Mac amps. I welcome your thoughts for use with these speakers.

A 2nd MC2300 will give you 3dB more output than a single. I ran strapped MC2300s for a long time. There may have been some additional advantages - IE: better stereo separation, etc. - but I honestly can't remember it was such a long time ago.

A pair of MC501s will give you some additional output but it's the difference in S/N that will floor you. I use an MC2600 on my XRT22s and there's no background noise to speak of with the gains at max and the volume set to minimum. I could not say that about my MC2300 - it was quiet, but not that quiet. MC501s are even better in this regards.

Why not an MC602? Those come along somewhat often and they're reasonably priced compared to a pair of MC501s.

Personally I found the quieter the preamp with higher SNR the amp disappears into blackness. After i changed my preamp there is zero detectable noise out of my MC2500 at any volume unless the source is noisy. I would do for the watts with Mcintosh speakers. Less chance of clipping the MC2300 and burning out a tweeter. My XRT20s had four blown tweeters from being underpowered at 200 watts without power guard.

damacman said:

A pair of MC501s will give you some additional output but it's the difference in S/N that will floor you.

Click to expand...

Not a huge knock on the 501's, but all the problems one of us had using them with a MEN 220 makes me view them with trepidation.

Oh, and that's just me, without the full story.

Something about how the high side and low side worked, the MEN processor was unbalanced and shut off one side of the amplifier.

I don't remember anyone other than the one 501 owner (forgot who, but you're on this site) having problems, and it's probably only the fault of the MEN device. But if it's the MEN device (I suspect it was) then all balanced and devices would have been affected, not only the 501.

There's also some talk of the amplifier shutting off thermally while being used- leading me to think it should have more iron in the sinks, or a fan from the factory.

The short version is I'd ask for some clarification on these things before looking further at that amplifier.

One other thing, you mention the 602, I think that's the heaviest single chassis amplifier made by Mcintosh so far.

Yep. I'd of recommended an MC500 or even MC2600, but those amps are nearly impossible to find on the used market.

In all fairness, given the title of this thread, I really do like the idea of strapped MC2300s! I know the Count would approve . . .

IndyAudio said:

.......I would think the 20 amp circuit would be quite enough for the amp to not fluctuate - any thoughts here? The sound is great, but I am cautious to push really hard as when I'm way into the right side of the meters, the lights are really dimming a bit. Less than when it was plugged into the rest of the house on the shared circuit but I expected this would be rock solid?

Any advice appreciated, but wow, what a great amp!

Click to expand...

When I did a capacitor upgrade to my two Mc2300's, my meters stopped flickering with the stock lamps in place.
The canned caps were deemed by Audio Classics to be fine, but every other electrolytic capacitor was replaced in advance of the Audio classics inspection.
The yellow mylar caps on the meter board basically came apart as I removed them, so that is a red flag as well.
I'm running both amps on a single 20 amp breaker. I don't drive them nearly hard enough to trip the breaker.
(Maybe 30-50 watts a side, and that is LOUD)
I also replaced the stock bulbs with LED's, which makes somewhat of a difference in current draw vs. the 16 (total) #47 light bulbs.

damacman said:

In all fairness, given the title of this thread, I really do like the idea of strapped MC2300s! I know the Count would approve . . .

Click to expand...

And the Count doesn't sign off on just anything!

Making your own nostalgic (and nonexistent) 601.

I'm going to make my own 1201's someday with my 2600's, 501's with my 2255's (on and on from there)...

And you like strapped anything! (I'm in that camp too )

Hey buddy - we're still waiting on pics of your pair of MC2600s!

I am not sure where I belong in this discussion. But since I have four 2255s, two 2500s, two 7270s, and one 2205, I could not help myself from jumping in.
Right now at the office I am using MS750 feeding MX118 going through MEN220 which feeds the left and right lower frequencies through a pair of 2500s (one for each channel) and the left and right higher frequencies through a pair of 2255s (one for each channel). If I count watts correctly, I have 1500 watts each channel. (Need I say I must wait until "after hours" to really crank it up).
I have Legacy Signature IIIs with bi-amp capability (thus I can feed separate signals for upper register and lower register). I double wire each connection with 10 gauge speaker wire. Bi-amping and bi-wiring means four pairs of10 gauge wire runs to each speaker (eight wires in total). I am trying to have as little signal loss as possible in the 25 foot run from the power amps.
There is no problem when the cannons in Wellington's Victory come in.
BUT - for really close detail listening, I have Sennheiser 600s wired with balanced cables driven from the eight ohm taps from the MC2205. The detail through the Sennheisers driven in balanced mode by the MC2205 is the closest I have ever heard to being in a live orchestra pit.
In my early years I spent a lot of time in a live orchestra pit (50 piece amateur group) and "think" I know what to listen for.
HOWEVER - I am 71 - my hearing is not nearly as good as it used to be. Plus, I have pretty bad tinnitus (at about 2500hz) in my right ear. So, I cannot claim to be a good judge of various amps.
My 7270s are running in mono mode at home, each driving a separate channel in the home two channel system (MS300 to MX130 to "consumer" equalizer, to the pair of 7270s).
Given my limitation on hearing, do not use me as a "reliable resource." But - candidly - to me there is MUCH more difference in the speakers you are using than between any of the four amps (2500s, 2255s, 2205s, or 7270s).
As to whether output transformers (or autoformers as they are now called) are helpful or harmful,I think is it significant that McIntosh tried not using them, and then went back to using them. If they created a problem, McIntosh would not have gone back to using them.
Personally I like the 2255s (I have four of them). Probably because they were the last chrome chassis, they have power guard, speaker on/off switch, and headphone jack.
The biggest downside is weight. That probably puts the 2500s at the bottom of my list of favorites. I CANNOT lift one by myself. Since I have two 2500s, two 2255s, a 2205, a MX118, a MEN220, and a 3000KV double conversion Liebert power supply in the credenza behind my desk, I have to hire help every time something needs to be addressed from the back! I believe the fully loaded credenza unit probably weighs in at 700 to 800 pounds. Even with 12 rollers under the credenza, it really is a three man job to move it across the carpeting.
I don't think you can go wrong with any of the amps in this discussion.
Thanks for listening.
Jim

Jim,

When I'm 71 I'm gonna' be cool JUST LIKE YOU! Hell yeah!

Now, post up some pics of these setups!