Currently own #3a Speakers looking to bi amp them spoke to richard vandersteen himself ' he did not recommend this others have said to definetly do so any suggestions thanks
I wonder why the oscillation occurs with only solid state amp. Sounds like a strange interaction btw Vandy's 1st order cross over hi-freq load and solid state amp.
Perhpas when both hi-freq and low-freq are connected to the same amp, there are some compensating effects from the cross-over interaction.
Tube amp probably is more stable due to transformer at the tube amp's output stage.
Sorry this took so long to get this back to you but this is straight from the Vandersteen Q&A. This way you can decide for yourself what you would like to do.
Bob (1/12/07): Bi-Amping the 3A Signatures From: Bob HoshallI would assume Bi-Amping any speaker could be advantageous, if you had two MATCHING POWER AMPLIFIERS, but what if you don't??? In my case I have a Parasound HCA-1200II High Current Power Amplifier rated at 205 Watts RMS X 2. My second is a PS Audio Amplifier, the Delta 200 rated at 200 Watts RMS X 2. If I were to take a guess, I would think the PS Audio is a bit better amplifier, even if the Parasound has some bells and whistles the PS Audio doesn't, neither have balanced inputs. What is your view of Bi-Amping, especially with two very different power amps? Thanks.
Answer: HELLO BOB, I NO LONGER RECOMMEND BI-AMPING OF ANY KIND UNLESS BOTH ARE TUBE AMPS. MANY SOLID STATE AMPLIFIERS ARE UNSTABLE DRIVING THE TOP OF ALL OUR SPEAKERS. THIS CAN RESULT IN AMPLIFIER PROBLEMS OR SPEAKER FAILURE. IF CONSIDERING THIS MAKE SURE YOU USE A O' SCOPE ACROSS THE OUTPUT OF THE AMPLIFIER AND LOOK FOR OSCILLATIONS ON TRANSIENTS. MANY REPORT IMPROVED TRANSPARENCY ONLY TO FIND LATER THAT THE AMPLIFIER HAS SHORT BURSTS OF OSCILLATION TRAILING ALL TRANSIENTS. LISTEN TO BOTH OF YOUR AMPLIFIERS AND PICK THE BEST ONE, BI-WIRE TO YOUR 3A SIGS AND PLAY MUSIC.
I would seriously consider Davemitchell's advice. While I don't use Vandy speakers, I have gone to the stereo subwoofer paradigm (with sealed cabinet mains) with much more bottom octave clarity and impact. Takes a bit of time using a test cd/SPL meter to get the best result for one's unique room characteristics, but time well spent. Of course dual line stage outputs are needed and I had to change line stage to eliminate a ground loop issue unsolvable otherwise, but this former skeptic is now firmly in the "mains w/stereo subs" camp. My room puts a 60Hz +10dB node right at my preferred listening position and being able to tame it with eq in sub amps like the Reckhorn A400 is not possible with a generic passive crossover 2 or 3-way loudspeaker alone, even with full round corner bass traps (have 'em). Even if one can afford something like the Rives PARC, it's nice to have it ONLY in the subwoofer signal path.
I biamped mine for years with a Rotel RB 985. Sounded MUCH better than biwiring, but this could have been due to the amp. The midrange and bass really opened up with biamping. It was like going from mono to stereo.
I had a pair of 3A Signatures that I vertically bi-amped with Counterpoint SA-220s. The combination sounded amazing, significantly better than running a single amp.
Perhaps those amps were the exception, being able to handle the load.
Biamping is not a good idea with Vandersteen speakers, especially with solid state amplifiers which can become unstable due to the capacitive load of the mid/tweeter crossover.
What is recommended and is superior to biamping is adding two 2Wq powered subwoofers to take over the deep bass. This is going to add 300 watts per channel of power where it is needed most and simultaneously free the 3A Sigs from a tremendous burden in the low frequencies.
I used the 3A Signatures a few years back with a pair of stereo Theta Dreadnaught I's. I used one amp for each side, left and right with 1 channel driving the upper section and the other channel driving the lower. After evaluating the sound over several weeks, I came to the conclusion that the sound was not as good as using a single Dreadnaught for both channels. For whatever reason, the sound seemed to become a little disjointed like the blend between the upper and lower sections was not right. Changing back to a single amp brought everything back into focus and the speakers sounded better-actually, noticeably better. That ended my biamping. Biwiring is a must though. It is better. I have heard that with these speakers, an oscillation can occur because of the characteristics of the crossovers with a biamp. Richard now recommends against biamping because of this possibility. I don't really know if that was in play with my system but for whatever reason it just didn't work out. So I sold the other amp.
I've been Vertically bi-amping my 3A Sig's for a few months now. I'm using a pair of McCormack DNA-1 DLX Golds with a McCormack TLC-1 DLX with outstanding results. I use the TLC's passive outputs to drive the mid/tweeter section and the buffered section to drive lows. You might want to read through the Vandersteen Q&A section there is some good information in there concerning this subject. When I get the chance I will dig the information up for you. But this mostly comes down to the equipment that you are using. P.S. Right now I'm experimenting with the McCormack MicroPre that has the Gold upgrades and its actually sounding better than the TLC, so now I'm thinking the TLC might have to go in for the Platinum upgrade.
The Vandy speakers manual actually talked about how to bi-amp. I don't see how the sound can be worse if amps are identical. Easy to achieve with solid state, not so easy w/ tube amp w/o auto-biased circuit.
Trying different amps however will cause possible issues with gain matching.
In any case, what specific amps are you thinking about bi-amping with would be the better questions?
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