Using the 4100 as a preamp

[sberger]

I recently got the 4100 receiver, and really have enjoyed it. But even at 100 watts @ 4 ohms, I found it lacking just a bit for driving both my AR 3's and 3a's to their full potential. So I started experimenting with a couple of more powerful amps that I own and using the 4100 just as a preamp, and I'm loving it. I don't know what, if any, pre in the Mac line that the 4100 employs, but it's easily one of the best pre's that I've used . Easily as good as a Yamaha C4 (and that's pretty high praise) that I recently had, as well as others that I've used over the years. It's tuner, which is important to me is also top notch, as is it's phono pre.

Just curious if others are using the 4100, or any Mac integrated/receiver as just a pre. Would like to hear what brought you to that decision and how it compares to other pre's that you have used.

 

[c_dk]

The MAC4100 design was very much a clean sheet design back in 1977/78. McIntosh used many of it's circuit designs in later designs, like the EQ, variable loudness, amp section etc.

Have you had the power supply rebuilt?

I on many occasions used the MAC4100 or MA6200 preamp section with y plugs to run a main system amp and then the internal amp to run speakers elsewhere in a client's home.

 

[sberger]

I bought it restored. It was restored in May by a well known local tech. His receipt indicated most/all caps in the PS were replaced.

Thanks for the info it.

 

[62caddy]

It is said the MAC4100's preamplifier section is similar to the C504 preamplifier but I would defer to c_dk on this.

Perhaps an MX117 is in your future?

 

[sberger]

Perhaps an MX117 is in your future?

Troublemaker. But maybe you're right.

There's a "serviced to factory specs" (by well known local tech) MX115 for sale nearby for what seems a pretty good price($700). Would I get similar preamp/tuner performance from it?

 

[62caddy]

Troublemaker. But maybe you're right.

There's a "serviced to factory specs" (by well known local tech) MX115 for sale nearby for what seems a pretty good price($700). Would I get similar preamp/tuner performance from it?

Welcome to the land of McIntosh where it's impossible to stop at just one.

 

[c_dk]

MX115 is a earlier generation preamp and tuner. Next grownup step would be a C33 or later preamp. There really is no baby step forward.

 

[sberger]

Welcome to the land of McIntosh where it's impossible to stop at just one.

Well when I bought the 4100 I assumed it would be more then adequate to drive to full potential my AR speakers. While they sound good with it, amps that I own with 200 plus watts do a better job of really opening them up. So potentially just going with a preamp/tuner might make more sense.

 

[sberger]

MX115 is a earlier generation preamp and tuner. Next grownup step would be a C33 or later preamp. There really is no baby step forward.

While I own a couple of nice stand alone tuners, I think I'd prefer to have the tuner/preamp bundled. Is there much sonic difference between the 115 and 117?

 

[damacman]

Is it safe to assume that you are lighting the Power Guard lamps often when using the MAC4100 to drive your ARs?

 

[c_dk]

The MX115 used a adaption of the C26 preamp designed by RR in the late 60s, tuner was a stripped down design taken from a MR77. Nice vintage units but not in same league as late 70s designs.

I have a tough time believing your MAC4100 is running out of gas trying to run two pair of AR3s. How much are you seeing the PG lights?

I would get a bench test done.

 

[62caddy]

MX117 tuner section is slightly more advanced with the ability to blend L & R stereo channels to reduce noise on weak stations. Again, I believe the MX117 shares essentials with the MAC4100.

Frank McIntosh was an advocate of the tuner preamplifier of which the MX117 was the last in McIntosh's distinguished line of tuner preamps.

I greatly enjoy my MX110 tube tuner-pre but the MX117 would doubtless be my next if the time ever comes, followed by the MX113.

 

[sberger]

Is it safe to assume that you are lighting the Power Guard lamps often when using the MAC4100 to drive your ARs?

I knew somebody would ask that. No I never get that loud. But loudness isn't really the issue. In fact, it's how the AR's sound with a bigger amp when the music is not loud. At lower levels the overall bass response and tonality stays pretty much the same with the bigger amp then it does with the 4100. I can get similar results with the 4100 but I have to jack up the volume quite bit, so that overall it's much louder. And that is something I prefer (and a certain women in the house) would prefer I didn't do.

I used to be skeptical when the recommendation for driving older AR speakers was big watts/high current, but I think I have a better understanding as to why that is now that I own them. It's so they open up completely without having to raise the volume too much, lest you blow out the fragile tweeter/mid.

That all said, I haven't given up on the 4100, especially since I can use it as a preamp anyway, and it's been restored.

 

[sberger]

The MX115 used a adaption of the C26 preamp designed by RR in the late 60s, tuner was a stripped down design taken from a MR77. Nice vintage units but not in same league as late 70s designs.

I have a tough time believing your MAC4100 is running out of gas trying to run two pair of AR3s. How much are you seeing the PG lights?

I would get a bench test done.

See above response. It's not running out of gas at all.

 

[c_dk]

You are certainly pushing any amps limits driving two pair of 4 ohm speakers, even the Mac design which expected to see 3 ohm loads on a regular basis. Your poor Adcom must be gasping for breath..........

Mac's advertising department did not invent engineering pseudo copy to sell amps, the engineering department just built amps that could deliver power reliably into low impedance current demanding loads.

What amp are you using that makes them sound right to you?

 

[motorstereo]

Count me in as using my 4100 as a pre-amp only as well. My 4100 sounded fine on my parallel wired stacked ML1C's but curiosity got the best of me. So using the 4100's pre-outs into a 200wpc Onkyo M508 power amp now has produced some of the best sounds I've heard on that particular secondary set up. Yes the 4100 imo has an outstanding pre-amp section that matches it's similarly excellent tuning section.

 

[sberger]

You are certainly pushing any amps limits driving two pair of 4 ohm speakers, even the Mac design which expected to see 3 ohm loads on a regular basis. Your poor Adcom must be gasping for breath..........

Mac's advertising department did not invent engineering pseudo copy to sell amps, the engineering department just built amps that could deliver power reliably into low impedance current demanding loads.

What amp are you using that makes them sound right to you?

I'm not using both pair simultaneously. Sorry for the confusion. One pair at a time.

 

[damacman]

I tend to agree with c_dk here. If the 4100 isn't the equal of another power amplifier at low levels, then it could be a sign that its frequency response does not meet spec. I for one would love to think that my XRT22s sound way more awesome at a tenth of a watt per channel when run with a pair of bridged MC2600s (1.7kw each) than an MC2505 at the same power level but that may very well not be the case.

Of course, there is always synergy and it's a fact that some components gel together better than others. I've personally never experienced a lack of synergy with McIntosh amplification but that's not to say that it isn't possible. I remember vividly preferring the Nakamichi PA-7 to my MC2200 on my Altecs when used in a biamped system - mainly because the PA-7 could play louder. Ultimately, the PA-7 moved on when I used an MC2300 to drive the Altecs full range and compared that versus the PA-7, also full range. The Altecs could shake the floor while the PA-7 was unable to do so - both with tone controls set absolutely flat. In looking back, I've often wondered if the PA-7 needed servicing or of the MC2300 just had better synergy. SPL wise, the MC2300 just killed the PA-7, that wasn't a comparison at all.

Ah to be 25 again . . .

 

[sberger]

I tend to agree with c_dk here. If the 4100 isn't the equal of another power amplifier at low levels, then it could be a sign that its frequency response does not meet spec. I for one would love to think that my XRT22s sound way more awesome at a tenth of a watt per channel when run with a pair of bridged MC2600s (1.7kw each) than an MC2505 at the same power level but that may very well not be the case.

Of course, there is always synergy and it's a fact that some components gel together better than others. I've personally never experienced a lack of synergy with McIntosh amplification but that's not to say that it isn't possible. I remember vividly preferring the Nakamichi PA-7 to my MC2200 on my Altecs when used in a biamped system - mainly because the PA-7 could play louder. Ultimately, the PA-7 moved on when I used an MC2300 to drive the Altecs full range and compared that versus the PA-7, also full range. The Altecs could shake the floor while the PA-7 was unable to do so - both with tone controls set absolutely flat. In looking back, I've often wondered if the PA-7 needed servicing or of the MC2300 just had better synergy. SPL wise, the MC2300 just killed the PA-7, that wasn't a comparison at all.

Ah to be 25 again . . .

I would be fairly surprised if it didn't meet spec since it underwent a full restore/check up by a very well respected tech group in May. And ultimately, that pretty much anybody who knows these speakers will endorse "the more power, the better" argument for them, it boils down to what sounds better to me. And with the Adcom, I'm getting a fuller, less lean result then I'm getting with the 4100. Again, if I had to live with the 4100 only to drive these speakers, no doubt I could. But I don't.

 

[motorstereo]

Even at low volumes I feel the same way with my 4100. I've also had it paired up with a pair of strapped 2100's with similar results. The 4100 by itself is fine but there is a little something extra and better when paired up with a 200 wpc amp. In my case my thinking is it's the not so efficient ML1C's benefiting from the extra current. I'm thinking the same thing may apply for your AR3's as well. But with a pair of Klipsch, Altecs or some other very efficient speaker where 75wpc is on the verge of overkill the synergy just might be with the 4100 all by itself.