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The Hub: Does a pair of 5's beat an 8?

From a purely philosophical basis, a pair of mono amps just HAS to sound better than a stereo amp of similar circuitry and construction, right? For example, I've never compared a pair of McIntosh 75's to the 275 (which is always in higher demand than a pair of the mono amps), but no less a Mac authority than Steve Rowell of Audio Classics told me decades ago that a pair of 75's will wipe the floor with a 275. I was commenting at the time that a pair of 75s was always cheaper than a 275; the price disparity seems to have continued to this day.

Just as true believers readily acknowledge that a pair of McIntosh 75s will kick the booty of a 275, Marantzophiles know that a pair of 5s beats an 8. Right??

I *THINK* so, but I don't KNOW so. The rarity of the Model 5's (like this pair for sale) has a lot to do with that. In comparison, 8's and 8b's seem to be falling out of trees. I've heard all three models (four if you consider the 8b a distinct model), but have never A-B'd them. Anybody? Buehler? Buehler??

I have a confession to make. This won't shock anyone who has read more than one of my entries, but here goes: I'm not a tech- expert. I'm a middle-aged guy who has spent way too much time buying, selling and occasionally (!) listening to audio gear. Do I have a philosophical construct in place, as a result of my experience? Kinda: everything matters, but sometimes, none of it makes sense.

I think of it as zen meets gestalt, or my karma ate your dogma. I know enough to know that the more I know, the less I understand. Don't expect me to quote from Don Henley again.

My point is that while I can provide some generalities as to why two monos are greater than one essentially-similar stereo, I'm not one of those guys who can look at a schematic and say, "well, that's because this has a long-tailed emitter and this one has a speckled flycatcher." Or whatever.

So what I hope to do is provoke those hands-on experts out there to submit your opinions, experience and expertise on this topic. I know a little about a lot, but I'm more likely to be able to tell you who played Mr. Green Jeans on Captain Kangaroo (A: Lumpy Brannum. Really.) than why 5s beat an 8. Or 8b.

Having laboriously explained that I'm not to be trusted as a tech-expert, let's look at the tape... or schematics, in this case. John Atwood's educational and comprehensive website "One Electron" has a bit of everything, including schematics. LOTS of schematics. If you go to this web page and scroll down, you'll find schematics for both the 5 and the 8. Incidentally, John's ClariSonus blog elsewhere on that site, is always an interesting read.

So, armchair EEs! Tell us what you see by comparing the 5 and the 8. Anybody compared the two by, y'know, LISTENING? Let's hear about your experiences.

Really, that's it for me. Discuss amongst yourselves, and report back to me!
audiogon_bill
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almarg
9,670 posts
 
Surely just the elimination of crosstalk or power supply cross-modulation has to make two monos better than a stereo amp?
Yes, certainly, but to a degree that may or may not be significant in any given system, and only if everything else is equal or close to it (especially including condition, in the case of vintage equipment).

In this particular case, the GZ34/5AR4 rectifier tube used in the power supply of the 5's I know to be particularly highly regarded. I don't know the specific reasons for that, but based on its reputation I would expect it to be preferable to the solid state rectifiers used in the 8's/8b's.

Best regards,
-- Al
hifitime
715 posts
 
The tube rectified 5's amp may outperform the 8 for that reason alone.The mono 5's performance otherwise may be similar.I find tube rectified amps better sounding in general.
audiogon_bill OP
155 posts
 
I thought that, as well. I've generally preferred tube-rectified amps, all else being equal.
dertubemeister
3 posts
 
As a general rule, no, monos don't in my experience beat single chassis stereo amps. I've compared a number of projects that were the same in every respect except that the monos had the obvious separate chassis and power transformer and found the if all else is the same, the end result is the same. Monos are more trouble to build and situate though which is not a minor consideration. The theoretical advantages of fully separate supplies giving more complete separation and greater power reserve just don't play out in practice. As long as the power supply on the stereo unit is double the supply on the monos and the circuit on both is identical, take the stereo unit.
audiogon_bill OP
155 posts
 
...and thank you for the contrarian viewpoint, Lance!

One of the fascinating and frustrating aspects of audio is how often obvious and brilliant ideas just don't hold up in practice.

During my time with a builder of very expensive tube amps, my favorite models were their integrateds. Admittedly, at $6k and $19k, they'd better be damned GOOD integrateds, but still: they were playing against separates costing over $30k. I found their sound to be more cohesive and natural than the pre/power set-ups.

I've had similar experiences with use of electronic xovers and multi-amps. Perhaps tweakmeisters like Jim Smith or Clark Johnsen can make such systems sing, but I felt I was always chasing ground-faults, hums, imabalances--always somethin'!
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