Discussion in 'McIntosh Audio' started by sancho22, Feb 10, 2018.
62caddy -- was there any difference in midrange liquidity in the tube models vs the SS 2505?
If there was/is, I'll be damned if I could hear it. I've also tried comparing the amplifiers both on high sensitivity horns as well as suspension type speakers. No differences there either.
Do I regret buying the tube units? NO! I bought them for their beauty and because for being examples of the finest consumer amplifiers at the time of production. The MC240 was McIntosh's first stereo amplifier so that has special significance for that reason. MC30 was the first McIntosh product with chrome chassis - so that has significance as well. The MAC1500 was Mc's first receiver and the only with tube amplifier section. So you see there is a method to my collecting madness.
It's splitting hairs between the two.
Mc-30 advantages, tube rectified to experiment with variants and different high end 5U4 tubes for different results.
Not sure if this is really a plus or how effective, variable damping, I don't think all Mc-30's have this feature.
Both amplifier won't do any great shakes in the Bass octaves, use a sub if you're a bass head.
Mc-30 Disadvantage, more tubes to purchase and maintain for two amplifiers, but vintage Mc gear lasts forever.
Mc-225 plus, 7591 tube is quite special on its own but a little pricey for a quad. The new Tung-sol 7591 are quite fabulous, I say slightly better compared to the WH 7591
My comparison from hearing both amplifiers over the years, The Mc-225 is a little more airy and sparkle on top and the midrange is the best of all the Mcintosh amplifiers.
Mc-30 is just a little rolled off on the top, still sounds nice but just didn't compare to the Mc-225 more 3D presentation. Mc-30 had a tighter soundstage between the speakers, front to back in a large room with efficient speakers is very pleasing.
Keep in mind both amplifiers will respond to tube rolling especially in the V1 position 12AX7. I use a 1950's Amperex BB D getter with unbelievable 3D results and a pair of tele smooth plates for the 12AU7 positions. 12BH7 black plates always a great choice but expensive, the RCA grey plates work well and seem to last forever.
Enjoy your purchase
Thanks guys! A LOT of great information - as always.
Both would be equally well rebuilt by a very reputable shop both would carry 1 year warranty so no major diffrence there. Price is similar.
I am really in a place where it is not an easy decision - hop eto get both maybe in 1-2 years time?
UNLESS i do find a nic epair of Fairchilds...but I really want an all McIntosh system first.
Ok not to throw a monkey-wrench in here I listened to VAS Citation II monoblocks today. With some rerally great VAS cartridge and VPI TT, modded CJ preamp and Focal 1308...it was amazing to say the least...I could get a pair quickly if i want to.
The MC30 & MC225 are both wonderful amps. Top class. I have both, but the MC225 sounds better on my Tannoys than the 30's and the 30's sound better on my Rega R7's than my 225 does. Speaker dependent IMO. I have not heard the Quads or the Altecs.
What speakers are you planning to have.
The MC225 and Marantz 8/8B were considered rivals in class for best overall SQ, from what I've read on them.
Discouraging actually, in a way. But somewhat understandable, given the variables. From my own experience, I expect power amps to sound individually unique between makes and models, and they do, ime.
Not having lived here with various Mac amps in my house, I can't speak specifically for them, but would expect a pair of MC30, a 225, 250, and 754 to each sound uniquely individual, outside of any generic sound signature bias.
Altec Flamenco and Devore O/96 (and a few WLM) - all high efficiency but different character.
A lot of personal choice, and depends on which output tube you like. I have both. Not a huge difference, but the 225 may be a tad sweeter sounding than the MC30. But that also depends on condition of internal parts etc. When I first got my 225, I thought it sounded fine. Then a couple of years later decided to replace all the PS caps with new versions. What a difference, much more dynamic with greater bass authority.
The 225 also has a choke filtered power supply which the MC30 does not. But not a biggie, there are a couple of folks out there that add a choke to the MC30. Will reduce the noise floor by 6-8db. Have even seen one amp that had a custom aluminum bracket fabricated to hold the choke. the bracket bolted the transformer studs, so the top would remain stock looking, i.e. no added holes to be drilled in the chassis.
Don't think you could go wrong with either amp though....
The other thing you can do with either amp (as well as many of the other MAC tube amps), is change out that 100uf 3v polarized cap in the GNFB circuit. If its still original it most likely has high ESR. Should be at least replaced with a nichicon audio grade bypolar, or better yet, a bipolar with a film cap bypass on it.
Another fav is the MC240, with a set of re-issue Tungsol 6550s in place of the 6L6GCs. The 240 comes to life with this tube swap. Bias will be close, but you can tweek it if desired. Would be a very dynamic sounding amp with a pair of Altecs.
If you are using Altec horns, you may want to make sure you don't have any power supply noise on either amp you end up with. Most of the Altecs are pretty efficient, so any AC ripple over a few mv on the power supply may become audible.
Can the MC240 handle an additional 2.8 A on the 6.3 V heater circuit? Seems like a lot.
6550 heater current draw = 1.6 A
6L6GC heater current draw = 0.9 A
I wouldn't do it. There's the 275 for those.
had the same concerns. Talked to a EE who had been doing it with his 240 for years. so decided to try it.
the power trans runs at the same temp with either the 6L6 or the 6550s. so have been using the 6550s for the last 4 years with no issues.
Temp rise monitoring is a significant observation, it would be interesting to see how it bench tests.
I never had the balls to try that!
An ir temp pistol is a good accessory for monitoring the cdx of these amps with exposed transformers.
I don't know who this Ron C guy is But my 225's put out 35 watts thanks to Terry D.
To the OP, depending where you are in NJ, it's possible that you can borrow my extra 225 so you'll know what it sounds like in your system before you buy.
Given McIntosh's conservative output power ratings, this result is not atypical. After restoration my MC30s test @ 48 w each. RonC has been with McIntosh for many years and he is correct regarding the MC30s - particularly due to its tube rectification. Solid state rectification greatly limits these options in the MC225. This is not in any way a slur against the fine unit it is.
Listen to your MX110Z and establish a baseline, if you need more sparkle and air get 225, if you like warm and a natural presentation get 30. Also, I disagree with people that think MC30 is rolled of on the top, you can make 30 sound sparkly by rolling V1 and V2 small tubes.
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