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Bi-Amp success story

Hello all-

This is a follow-up to many threads I have posted already (using my e-mail address - [email protected] before I signed up officially) Rather than tack this on at the end of any one of them I wanted to start a new thread summing up my experience. In doing so I will cover what I did and what worked and what didn't work for me.

My Gear (that matters to this discussion)

Yamaha CX-1000 pre-amp (I also use this for my d/a)
Yamaha MX-1000 power amp (330 wpc into my 4 ohm speakers)
and another MX-1000 power amp for bi-amping (effective 660 wpc?)
Paradigm X-30 line-level active crossover
Infinity Kappa 9 speakers.
Phoenix Gold ZEROpoint Reference II Inner Space reference speaker cable (2 10 gauge conductors) for the low end and Phoneix Gold 12 gauge for the highs.

(1) I tried bi-wiring and that produced no noticable effects for me. (using 1 MX-1000 amp) Maybe with better wire there might be a difference.

(2) I tried bi-amping using no active crossover, and while the soundstage was a bit better the amps were working hard for just a bit of extra volume and in my opinion without an active crossover before the amps it is just a glorified bi-wire.

(3) My final arrangement was very satisfying. My Kappa 9 speakers each have 2 12" drivers that cross-over at a low 80hz. I used the Paradigm x-30 with the 80 hz high pass (a choice of 50,80,120 hz) after the pre-amp and ran it to the right side of each MX-1000. Then I ran the sub-out for each side to the left side of each MX-1000. So one MX for the left speaker, one for the right. I chose this rather than the lows to one amp and the highs to another for a few reasons. (1) elimination of cross-talk (2) decrease in overall demand on each amp during segements with high bass or high highs.

The results were great! I have a much clearer soundstage, and I get a louder, clearer sound than I have ever had before. If I had the gear I would try putting a specialized amp on the lows/highs. One suited best for each purpose. But before I would go to that level I would upgrade everything I have except for the speakers. If I can scrape together the cash I want to try a Sunfire Classic Tube pre-amp and a Sunfire Signature Stereo amp in a non-biwired configuration too. If I like it better (as I am sure I will) I might liquidate my Yamaha gear. However I run my pre-amp "source direct" by-passing all tone controls. Since my Kappa 9's have a strong high-end it is nice to be able to compensate for that just by adjusting the level of the amp or the crossover.

Anyway thanks for all the advice that has gotten me this far!

Regards,

Joel
a71spud

Showing 3 responses by sean

sean
6,231 posts
 
I think it's great when someone joins in with their "projects" or experience in similar threads. While it might divert a small amount of information away from the original post, i think that it typically gives them even more info that they they might not have considered or asked in the first place. As long as it's done in good taste, i don't think that anybody here objects to such posts.

Don't take my word for ANYTHING. I only know what has worked for me in my systems. Your components, installation and personal tastes might be measurably different than mine. As such, you have the opportunity for a GREAT learning experience at your disposal. Don't pass it up. Sean
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sean
6,231 posts
 
Craig, just for your info i had run a set of 4 way / 5 driver towers in a passive arrangement. I had two different amps from the same manufacturer horizontally configured. This gave me 400+ wpc on the top side ( 200 Hz and above ) and 600+ wpc on the bottom ( below 200 Hz ). Since these speakers are "thirsty", i could still drive the amps into compression if really cranking hard.

I then went into a set-up where i had identical amps on top and bottom ( both 600+ wpc ). I could still drive them into compression.

I later switched this configuration to running a single amplifier that is rated for 1200 wpc at the same impedance. Even though i had 900 to 1200 watts per channel driving the speakers before, going to one larger and more efficient amp made a MASSIVE difference. I could now play measurably louder and measurably cleaner with far less listening fatigue. The only drawback to this is that i did have greater bass impact with the specific amp that i was previously running on the bottom end.

In case your thinking that the first amps were just "wimps", take my word for it that these are STURDY. They can run bridged into VERY low impedance loads without any fuss at all. I have seen people running these models bridged into speakers that normally give unbridged amps a fit.

In plain English, i would not bother doing passive bi-amping ever again. To me, it was a waste of time, money and power. I wish you better luck in your efforts and ask that you keep us posted after you've played with your set-up for a while.
sean
6,231 posts
 
While i have never run any amps in bridged mode myself, most of the manufacturers that i have spoken to tell me that sonics DO take a hit in the nose. Some manufacturers will advise against this even though they do acknowledge that it can be done. Like any other company, they are simply trying to give the customer the most options for their money even if they don't think that it shows their product at the best.

As such, i would contact Steve and see what he thinks about your situation. He should be the most familiar with his products and know what to expect out of them. He might not be bridging them but doing something else.

As a point of comparison, I have disabled one channel of two identical stereo amps and then run them as monoblocks before. This gave the entire power supply that was designed to run both channels over to just one channel. No real power gain but more "oomph" on the bottom end with better control and stability into tough loads. This is most beneficial to amps that are not "big brutes" in the power supply area to begin with. Some examples as to what this works well on are old Phase Linear's, Quad's, etc...

As long as your comparing apples to apples with amps of similar sonics, i would rather have two big monoblocks than two smaller amps passively biamped. If i took that one step further, i would rather have two good sized amps actively biamped. Obviously different speakers and situations can negate some of these options. Like i said, try giving Steve a call and you might even want to run your options by Richard Vandy. Advice is a LOT cheaper than first hand experimentation, especially if you don't like the results and have to back-peddle. Sean
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