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Bi amp pros out there I could use some help! First time Bi Amping...

Just picked up a BAT vk 200 for the bass and using my Pass Aleph 5 for the mids and tweets. Ive never played around with bi amping so I apologize in advance for any lame questions My speakers are Dunlavy SC3's original 5.5 nominal load. The pass is 90 wpc at 4 Ohm and the BAT is 200 wpc at 4 ohm so Im guessing around 75 wpc off the Pass Amp and 150 plus with the Bat Amp. My pre amp is a Aleph P and Im running the Single ended through a XLR adaptor (cause the Bat is Balanced inputs only) and the pass Aleph 5 off the XLR outputs of the pre and inputs of the Pass amp. The PASS Pre Amp manual says there is a 6db differential between the RCA and XLR outputs  two and both can be driven at the same time. So the RCA is 9db and the XLR is 15 db. Gain is within 2db on each amp. So whats the best way to do this? Get a custom XLR "Y" connector and drive both off the XLR output of the pre? Or is there a way better way to get the magic? This is past my "WORLD" Map and experience so Id thought Id ask for the smart people for advice. 

Thank you in advance!

-ALLGOOD
128x128haywood310
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almarg
9,670 posts
 
Looking at some rear panel photos of the Hsu ULS-15 it appears that it may have a two-prong IEC receptacle for its power cord. If so I don’t see any issues regarding the presence of the subs in the system.

However if they have a three-prong receptacle, and a three-prong power plug, I would suggest that you connect their speaker-level inputs to either the output terminals of the Pass amp or to the mid/hi terminals of the Dunlavys. Connecting the negative speaker-level input terminal of a powered sub that has an AC safety ground connection to the negative output terminal of a fully balanced amp (such as the BAT), which as a fully balanced amp has a full amplitude signal on that terminal, may cause problems and conceivably even damage depending on the impedance through which circuit ground and AC safety ground are interconnected within the particular amp and sub. And of course that would also apply if the connection is made to a speaker terminal to which the negative output terminal of the balanced amp is connected.

In the biamp configuration you have described the Pass amp won’t be supplying a great deal of current or power at bass frequencies, of course, but since it will be approximately gain matched with the BAT amp the subs will receive essentially the same full-range signal voltage and hence similar bass information regardless of which amp they are connected to.

Regards,

-- Al
haywood310's avatar
haywood310 OP
56 posts
 
Ive decided Bi amping is just too much for me... Not to mention my OCD is off the charts with all the variables that were discussed in this thread. So Im gonna stick with the Pass for the Dunlavys and try to Swarm (mutil sub) the bass. Ive spent at least 60 hours A/B ing the BAT and the Pass. I really really like the BAT VK 200 and it  sounds just like a Levinson 334 to me and I cant recommend this amp enough to anyone especially given the used market price. There was one review I read that said "It just sounds good enough" and I cant agree more. But there is something about that 2 stage Aleph that grabs my soul every time I listen and I just cant get rid of. I cant even turn off songs I dont like. Its a trophy wife well actually much better I had one of those. haha. Thanks again for all the input.   
bdp24's avatar
bdp24
9,510 posts
 

@sleepwalker65, I’m all for bi-amping, but haywood310 needed to be alerted to the fact that to do it correctly is much more involved than merely putting an external x/o and a second amp onto a pair of loudspeakers. The internal speaker-level x/o must be discarded, the outboard line-level x/o doing all the filtering. And that will NOT work if any of the drivers used in the speaker required any compensation network filtering to sound as the designer intended them to.

As I said above, Magnepan used to make their speakers so as to be easily bi-amped, and endorsed doing so. The .6 and earlier Maggies had parallel cross-overs and two pair of speaker cable connectors (which made bi-amping simple), but switched to series x/o’s for the .7 models (bi-amping them requires cutting into the x/o, installing another set of binding posts, etc.). Some of the monitoring loudspeakers used in recording studios come with filtering and a separate power amp for each driver, but they sound very different from audiophile speakers.

On the other hand, adding a sub or four to just about all loudspeakers provides many of the benefits of bi-amping, plus more. They present their own challenges to optimize in a room and system, of course.

georgehifi's avatar
georgehifi
10,312 posts
 
o do it correctly is much more involved than merely putting an external x/o and a second amp onto a pair of loudspeakers. The internal speaker-level x/o must be discarded, the outboard line-level x/o doing all the filtering.
The whole idea was simple, to vertical bi-amp using the speakers internal xover.
All the other talk now has just confused the s**t out of OP into now giving up, so sad.
He could have have a great sound with the KISS horizontal bi-amp setup with these two amps.
Cheers George
bdp24's avatar
bdp24
9,510 posts
 
The thing is, to bi-amp using the internal speaker-level x/o is to not reap some of the major benefits of bi-amping: keeping the woofer frequencies out of the m/t amp, eliminating the effect of the woofer's emf on the m/t drivers (they remain electrically connected through the x/o), etc. May as well just bi-wire, in the opinion of some.
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