Switching between A\B speakers on Vincent SP991 Plus monoblock amplifiers

[Charles_b]

Hello,

I have a pair of Vincent SP-991 Plus monoblock amplifiers and Vincent SA-93 preamplifier.

I also have 2 pairs of floorstanding speakers. I wanted to switch between the 2 pairs of speakers, but there is no "A\B" switch on any of the amps. There is however, 2 pairs of speaker terminals on each monoblock amplifier. Are these for bi-amping\bi-wiring or can they be used to switch between 2 pairs of speaker?

Or is the only way to do this to buy an A\B switcher box?

I have posted a picture of the rear of a 991 plus taken from the internet.

Many, many thanks for your help!

 

[coonmanx]

You need a switch box.

 

[Charles_b]

You need a switch box.

Many thanks, I suspected as much

 

[Zek]

If you are skilled with a soldering iron, you can make that switch with two kip-switches yourself.

 

[staticV3]

Two things:

1. Without matched levels, A/Bing is pointless. Putting the switch box between Amps and speakers means that you cannot feed them different levels in the likely case that they have different sensitivities.

2. Studies have shown that humans are better at discerning sound quality differences between speakers when listening in mono. A stereo setup masks sound differences.

I cannot trust the Harman speaker preference score

Y Most of this research is available at AES e-library, and much of it Floyd's book Sound Reproduction. Some of it is in by blog (www.seanolive.blogspot.com) We seem to be heading to a loop if I question the methodology and the interpretation of the data then and you refer to said methodology...

www.audiosciencereview.com

My recommendation therefore is to compare one speaker of your first pair to one speaker of your second pair. Each fed by one of your monoblocks, playing mono content.

Your setup could then be:
Left output -> Monoblock -> Speaker 1 / DAC -> SA-93 \ Right output -> Monoblock -> Speaker 2


You'd have to set up your audio player software to downmix to mono and to switch between left and right output. That should be possible with something like foobar2000, Audacity, or Adobe Audition.

Level-matching can then be done with the SA-93's balance control (or in software) and your smartphone placed at listening position, recording white or pink noise with a dB meter App (or with a dedicated microphone and REW if you'd like)