AR90 bi-amp

[rrcrain]

Ever since I rewired my pair of AR90s to allow them to be bi-amped and discovered the passive bass crossover doesn't block harmonic multiples, Shania Twain as an example, I've been hunting for a decent active crossover to place in front of my two amps. Well, I finally did it and I am more than a little stunned and impressed with the results. I had been running without an active crossover till now.

I opted for a Marchand XM26 crossover with the crossover points one octave over and under 200Hz. Along with removing some of the solid state "edge" and giving a warmer tube sound, the sound stage is dramatically improved as is the bass response, they now sound as if they are reproducing a much lower frequency than without the crossover.

My best guess is the soundstage improved when all of the "garbage" was removed from the bass drivers thereby removing a competing audible signal to the front facing drivers. Why the bass response improved, I've no clue.

[ar_pro]

I heard similar results on the AR-9, with an Audio Control Richter Scale...it provides 6 bands of 1/2 octave equalization from 22.5 to 125 Hz with a 24dB/octave electronic crossover.

Bass was clearly improved, and there seemed to be a smoother transition to the upper range drivers.

How do you like the Marchand crossover? Is it quiet, or does it seem to introduce any noise?

[rrcrain]

I can't state strongly enough how wonderful this crossover sounds. It's provided a major improvement to the soundsage, improved the high end sweetness, enriched the low end warmth, removed the sold state "edge" and extended the bass response downward. At idle, it's absolutely dead quiet, no noise popping or artifacts.

Physically, the crossover points and slopes are changed by swapping out 2 inexpensive cards which set the crossover point, slope and type of crossover it performs as. It can be set as a Butterworth, Linkwitz-Riley or notch with a change of a card.

I built this unit as a kit and there were a few glitches in the instructions, but a phone call connected my directly with Phil Marchand himself who was very friendly, patient and absolutely customer focused. I have to rate Phil, his company and product a perfect 10.

Overall, it made a remarkable and wonderful change in the sound of

this old pair of AR90s.

quote

I love it and it doesn't add any noise of any form that my ears can detect.

[ar90fan]

I own a pair of AR 90's since 23 years. Four or five years ago I reconed the woofers and now, I think it's the moment for doing something with the crossovers or why not, to contemplate the possibility of bi-amp replacing them by the XM26 from Marchand Electronics as you did it. The other chance would be to keep the old crossovers but replacing the old electrolitic caps, by audiophile ones, Solen perhaps, but I'm not sure if this is a good choice.

I frankly have a big problem to go ahead: I don't have any idea on "how to undertake the job". For instance, and since the AR 90's aren't initially bi-amped, i don't know which are the internal changes to face in order to reduce from 4 to 2 ways.

Since your outcomes are so good, and for sure you have now the best know how, I'd thank you very much if you explain to me the whole process, step by step.

Ah, sorry for my English. I am Spanish and I live in Madrid.

[rrcrain]

I did rebuild my crossovers using Solen caps, and I thought the new caps alone would address what I'll refer to as bleed through but it didn't. Since I'm not a speaker engineer, I'm assuming that this may be a common issue with most low pass passive crossovers.

The best way to start is to locate the prints, sit down and study them. I even redrew them to help clarify the wiring. The prints for the AR90 crossovers are available on this web site and are wonderfuly detailed.

You will want to decide upon a budget next. What are you willing to spend and start locating capacitors that will fit in your price range. The general concensus seems to be a mix of Solen and north Creek Zen caps give the best results.

Once I had the parts, I removed one crossover and again studied it before I did anything. I removed the attenuation switch block, this made the rewiring job easier and I never used it anyway. Do not eliminate the bass crossover, just split it from the rest of the circuit. If in doubt where to do this, take a look at the AR9 crossover since its similar and already wired for biamping.

I chose to install a new 4 post connector block, which meant I had to lay out and route an appropriate sized hole in the back of the speaker. The cabinet is thick, dense and will likely burn up a router bit in the process.

A few others here have done something similar and can perhaps offer better or at least different advice than I have.