[rlw3]

if you use one amp for the bass and another for the mids/highs; how do you keep one amp from being louder than the other?? i guess this would be a problem for any of the dual binding post vsa speakers?? seems you would need to use exactly the same amp for the bass and the mids/highs?? why is this not a problem?

[Pez]

Depends, are you active biamping or passive?

[Delacroix]

This has been discussed before on the VSA circle -- check, for example, the comments from Albert himself:
http://www.audiocircle.com/index.php?topic=59529.0

and on another thread:  http://www.audiocircle.com/index.php?topic=75241.0

[Jaco Pastorius]

There are good descriptions in the threads Delacroix linked to on how this should or can be done.
What I mostly did when biamping with a class D 400w into 4 ohm on the bass-cabinets of VR4Jr and VR4genIII,was to use different integrated tubeamps on the mid/tweeter.That way I could tailor in the overall balance I wanted with the volumecontrol on the tubeintegrated. For me much of the fun-part was having the ability to adjust that balance a little bit from day to day,if me ears are tired I usually prefer a warmer balance if I want to listen to music,when ears are fresh I might like things more upfront.And that also give the nice opportunity that you can tailor it to recordings as well.

The best result I think is when you have "the best" poweramp on the top,one without volumecontrol,and then a higher gain amplifier on the bass with volumecontrol.If you find out that you like one setting of the volumecontrol only,then all volumecontrols can be measured in that prefered position and be replaced by very high quality resistors to get the most transparency. 

[jazzcourier]

You can pretty much use any two amps as long as the gain matches.On VS 7's i was able to use a Spectron Musician for the lower terminals and a McIntosh 275 mk v on the tops-class D on the bottom-tubes on the top.
These are two very different amps,surprisingly the gains are almost an identical match when you  run the McIntosh unbalanced.The sound was very good.On some bass heavy recordings the mismatch of the amps was slightly more pronounced.On the better engineered recordings the effect was as you would hope for-holographic and humane on the highs and mids and spacious and voluptuous on the bottom.File this amp combination under just plain lucky,i won't take credit for having the foresight to exact this duo with the VS speakers.Each amp was bought way apart and for different reasons.

[azhtnut]

Thanks for pointing out Albert's prior advice on bi-amping VSAs.   I have the current setup and would like to add bi-amping of my VR4sr-MKIIIs.

Pre-amp:  Mac MX135
Front Channel Amp:  Mac MC402
Center/Side and Rear Surround Channel Amp:  Mac MC205


Which of the following options for bi-amping would be preferred:

1) Purchase 2nd MC402 amp and use 1 amp for each VR4sr-MKIII.
2) Purchase a MC275 tube for high/midrange and use the MC402 for low-end
3) Same as 2) but sell MC402 and replace a lower cost SS amp for low end.

I am leaning toward 3) for budget reasons, but could be swayed to 1) or 2) if there are advantages to staying in the Mac family of amps.

Thanks,
Max

[thebearded1]

I  have a Mac 252 on the bottom and an mc275 on top (with my unifields) and recently added a mac men220 room correction unit.  This fixed the volume balance challenge but I wouldn't get one for that alone as it is way too expensive a fix...if your room is acoustically challenged as mine is, it is well worth it.  A tube on top is awesome with the u3s....