Do Mono Block amps provide better sound ??


My question: do monoblock amps, that is, one amp per speaker, provide better sound than one box stereo amp?? I have read that a pair of mono amps provide the best stereo separation, imaging, soundstage depth.... Besides, taking up more floor space or rack space, and the necessity running a longer interconnect if each amp is behind the speaker, is it really worth it?? Thank you Jim
sunnyjim

Showing 2 responses by atmasphere

The issue of monoblocks vs stereo is more than just cosmetics.

Normally, stereo amplifiers share a common power supply. Some manufacturers will go through the extra effort (and cost) to build separate power supplies in the same box, but if single supplies are used, quite often this is audible as a compromise in the amplifier. Even if common grounds are used there can be problems; anyone who has heard the difference between 3-wire headphones and 4-wire headphones will know exactly what I am talking about! (In case that last comment sounds odd to you, there is such a thing as a 4-wire hookup for headphones, and you can hear the difference in a heartbeat.)

Another benefit of monoblocks is that they allow the amplifier to be placed as close to the speaker as possible. This minimizes the effect of the speaker cable. In all cases, the longer you make the speaker cable, the more artifact it imposes on the sound you get (usually less bass impact and less definition- for example vocals can be made out easier with shorter speaker cables).

Of course, this means you may need longer interconnects. If your equipment rack is between the speakers, this may not be an issue at all. I have my equipment rack by my listening chair, so I run long interconnects (30 feet) but the preamp I use has no trouble driving lengths like that.

While there is always the YMMV factor, and while not all things are equal, you *will* find that the stereo amplifiers that sound better then their monoblock brethren are a distinct minority.
Roscoeiii, the size of the amp is not important in this conversation- the benefits are the same. Price certainly has a lot to do with it too. You have an extra chassis, and certainly the need for more power transformers. These can be some of the most expensive parts in the amp.

In the S-30, the filament transformer is shared between the two channels. The B+ transformer has separate windings for each channel. In the driver supply, there are separate power supply legs for each channel. Since the driver is fully differential, it has fairly constant power draw on it, but even so we found it better sounding by having separate legs in the power supply.

Had we built the amp on separate chassis, it would have cost nearly as much as the M-60.