Monoblocks vs. Stereo Amps?

[Early B.]

I ran across this post on audioasylum re: the value of using monoblocks vs. stereo amps:

1. Ability to physically locate amplifier close to speaker to minimize speaker lead length thereby reducing losses.

2. Less noise interaction between stereo channels yields quieter operation and lower noise floor. Stereo amplifiers utilize shared component and circuit design.

3. Vibrations of the amplifier stages themselves can interfere with other channels. Separating into monoblocks helps to eliminate this common noise source.

4. There is less crosstalk (leakage) and greater stereo separation which yields enhanced stereo and fidelity effect.

5. Monoblock isolated power supplies permit least possible electronic and mechanical interaction between channels and promotes maximum linearity and stability.

6. Seperate power supplies do not rob power from the other channel under heavy loads.

7. Greater heat dissipation of two independent chassis.


Any thoughts, additions or corrections to these?

I'm also interested in hearing comments from folks who have used monoblocks in their 2-channel systems. I realize it's low mid-fi, but I've used Outlaw monos but don't recall any particular differences. Just wondering if there are more distinct differences, in general, between using monoblocks or a stereo amp when moving up the quality chain.

Thanks.

[TroyD]

I've used both, I've found the differences to be, generally, subtle.

BDT

[Zero]

Well, we may have to mark this down as one of the occasions to where my experiences mirrior BDT's.

In fact, the only time I've ever felt mono-blocks had a true *worthwhile* sonic edge is not from the design aspect, but more from the flexibility of placing the amp closer to your speakers for a shorter wire-run. Just run balanced to the amp, and maybe 2 feet *or less* of speaker wire, and the difference becomes more digestable given the added cost... otherwise.. I got nothin' over here.

[Joey_V]

I think one of the most important difference between a monoblock and a regular stereo (non-dual mono design) is the cross talk. Independent power supplies and torodials mean better separation.

Add to this comparo a dual mono (stereo amp) and true monoblocks.... and really what's left is that with dual mono you get a single chassis (albeit separate inside) and with true monos, you get two chassis. The good thing about this is that you can use shorter speaker wire since, like EarlyB said, it is easier to position near the speakers and you get the subtleties that go with separate chassis; mainly isolated vibrations, heat.

[TroyD]

While the crosstalk issue has some validity, IMHO, the noise level is so preposterously low in most cases as to be not worth mentioning.

BDT

[heiney9]

8. effing cool when friends and family come over :D

Actually my next amplifier is probably going to be a pair of Monarchy SM-70 pro's run in full balanced mono. To me it's just seperating the seperates even more. Space maybe an issue I'm not sure yet. A well designed dual mono amp will probably not show too much difference over the same amp done in mono-block. It's just that extra step and I believe there are sonic diiferences even if they are slight.

H9

[heiney9]

I understand the whole shorter speaker cable runs.................but what about the longer pre to amp runs of IC's? Which is more detrimental? A 6-8 foot run of speaker cable or a 6-8 ft. run of IC's from the pre to each amp?

H9

[audiobliss]

^^ Exactly my question. I would assume that the longer IC's would contribute a greater loss than would longer speaker cables.

[Zero]

hence; balanced. It's not just there for pretty looks..

[audiobliss]

So, what's the deal with balanced? Do preamps put out more voltage into a balanced connection and so there is less of a loss? Or is the balanced connection just more efficient?

But now we're getting into costs. I'm not 100% for sure, but isn't it conceivable that a balanced connection 6-8 feet long would cost more than speaker cables 6-8 feet long? And I guess here I'm bringing in something that has no effect on the sound...just something the average hobbyist would have to deal with. I would love to have my ASL monoblocks sitting on top of a piece of glass on top of my Klipsch, but I can't imagine how much I would have to pay for interconnects to have my amps 8-10 feet away from my preamp!

[unc2701]

balanced has a positive and negtive signal- they're the exact same, but opposite direction. any electronic noise will effect them the same, so when the signal is amplified/unblanced the noise gets canceled.

In my experince the only real benefit of a monoblock vs a dual mono is the heat dissipation and the shorter runs.

[W WALDECKER]

I am on my 2nd pair of monoblocks. i dont have mine located on the floor ,instead mine are sitting in a welded steel audio rack that is modular and each shelf is isolated with spikes on the bottom of the legs and a top cap with a conical pocket to accept the spikes. i use 1M IC cables and 10 ft speaker cables. monoblocks add another degree of seperation just as with a seperate preamp and power amp. a seperate power supply for each channel means that the amplifier does not have to work as hard and seems to smooth things out a bit. thanks...WCW III

[Zero]

AB,

As Unc stated - the two are mostly one in the same sans the cancellation. You will find the professional industry uses balanced in most applications as the integrity of the signal seems to maintain itself better over longer distances, vice your standard rca.

Expanding more, I've found the balanced circuit to be wonderful, especially when you can utilize it in an all balanced system (cd player, pre, amp). I had a chance to do that with some BAT and MARSH gear awhile ago... could switch between xlr and rca on the fly - the differences were not subtle. But then again, we are drifting away from the whole mono block question...

I think we have reached a point to where a good integrated can sound pretty damned fine compared to seperates of the same caliber. Mono blocks have their purpose and benefits, but these days, its difficult to tell a difference between a dual mono stereo amp in one chasis, versus the same piece thats seperated. Honestly - I feel that if you have the cash, its worth it for COOL factor, alone..

[madmax]

It is my understanding there is more sound quality loss from longer speaker cables than from long interconnects. I have no opinion of my own at this point. I have had both stereo and mono-block amplifiers and there is no real way to compare as you will never have the same amp in both configurations. Logically, everything in EB's original post would be true. Balanced I/O would only be required if there is a lot of RFI in the area. Remember, balanced setups normally have an extra stage to convert from single ended to balanced and the fewer stages you have the better, as far as theories go.
madmax

[reeltrouble1]

I am using the silver 9t mono, unbalanced 1-2m connects, with 8ft speaker cables in the Shed. They have a cool factor and have more current power than when I was using the NAD bridged mono. Prior to that I was using the NAD in stereo, not a fair comparison there. Anyway the Carvers drive the Amazings in the Woodshed with substantial power, control and dynamics for transient sounds with deep controlled bass. There GREAT like Tony the T says.

I am very happy with the mono blocks but really would not hestiate to go with an integrated or single chassis design amp if I felt it would improve my rig.

I generally agree here with everyone and Early's list, I am considering the MF Kw 500 as a power and pre integrated. However, you can hardly think of this piece in terms of "regular" integrated. Or possibly keep the Carver mono's and go with a pre upgrade, heck, the possibilties are wide open, with todays designs if you go with a solid company who does not compromise itself, any of the products they offer are all going to give you great performance. So how is that for sitting on the fence.:D

RT1

[unc2701]

MF KW500 kinda takes a different view on things- it gets the power supplies into their own box... and judging by the result, this isn't a bad idea. On my shortlist, too.

I guess the bottom line is that with proper design, any layout (seperates, intergrated, dual mono, monoblocks) can work. Take the adcom 565 monoblocks vs the 585 dual mono. Basically the same amp, but the 585 sucked. Compare against the bryston 7b and 14b... again same amp. one mono one dual mono- people seem to prefer the dual mono 14b.