Why not just the Bryston without the complications of biamping?
Kal, I tried Bryston 4b sst in my set up and treble sounded a bit harsh. The bass was slightly tighter but not much deeper. I'm not sure if the problem was the source. Toshiba SD 9200 is considered a decent one but it is a DVD player. Single ended, class A MF did a better job with treble in my system.
To me Bi-amping is hard with two different amps, you have to keep in mind the different gains, and the input sensitivity of the different amps, to try to match the levels so it sounds right. Not to mention the different input impedences, and the output impedence of the tube preamp interacting with each input stage of the amps! Plus you are loading down a tube preamp with TWO amp inputs, as well, argh.
Its too complicated for me. I personally would sell the MF and buy monoblocks, or a big amp if you need more power. The idea of monos appeals to me as they are identical, you give each stereo channel a separate power source, and signal path, so there is no chance for cross-pollution, and maybe a better stereo image. Also I like shorter speaker cables. Also, you might experiment with an upgraded source. Maybe that is your weak link causing the brightness. try a few high end CD players in your system first. If your source cannot produce smooth sound and good bass, more power will just amplify a bright sound. I myself have always wanted to try tubes for the tweeters and mids, of my Revel speakers, and solid state for the woofers, but these variables drove me crazy.
There's nothing scary or hard about bi-amping, and the audible benefits are many. I've been actively bi-amping for years(tube top/SS bottom), but it's much easier with two identical amps. Read this: (http://www.soundstage.com/synergize/synergize031998.htm) It contains tips/facts on vertical bi-amping that you might find enlightening.
In my opinion neither of those amps are "nice" on the top. I was an MF dealer and used a 4B for an hour in my system before I just had to remove it. Very metallic sounding to my ear. Too bad too I really wanted it, they are well built and as it was a trade in I could have gotten it cheap. I settled on CJ SS amps. I first got the 100WPC MF2100. Nice. I then got a MF2500- 250WPC and put the 2100 in the closet. I then bi-wired the 2500. Big improvement. I then decided hey these two amps both have the same gain,input impedance and sensitivity. I then implemented a horizontal bi-amp. Again another level of improvement. Not subtle either, especially in image and soundstage. Read Rodman's link too, it's good.
I agree with most here, sell the amp and get one amp which will do both or two the same to bi amp. I like electroids reccomendation, MF2500, but maybe I'm biased, trying to sell my MF2500A, ha, but I did biamp with two amps diferent manufacturers, cj mf2250 and rotel 1080, when I got rid of the rotel and added just the mf2500A it was much better. I didn't try the biamp with the two cj pieces because I just decided to get a whole new system. I geuss the point is the 250 watts not biamped was much better than two lesser amps biamped. I have a large room though and needed more speaker and more power, so selling all.
I biamp my 801Ns with Mac tube and solid state amps, and am very happy with the results. That being said, I think that if your system sounds bright to you, adding more power to the bottom end won't change the way your current amp comes across in the mids and highs. The brightness is what you really want to address. Another amp on mid and high frequencies might do the job for you. Also, as Cxintx suggested, another source might be the answer.
I think that the major problem is the amp. I have Cornwalls and Aleph 3 and SD9200 does not sound too bright with them.
I agree with Electroid neither Bryston no Musical Fidelity are nice on the top, both sound metallic. I want to try CJ and may be Classe with my B&W. Im also thinking about trying Rega Apollo after I sort out the problem with the amp. People say it sounds very decent and its not too pricy.
Everyone thanks for your input.
Alexv- Unless your amps have identical gain and sensitivity, your frequency response is going to be skewed. Anyone that understands freq. response will understand that it will be skewed in favor of the section receiving the higher gain. IE: If your mid/high section's amp has higher gain/greater sensitivity than your low's- You'll end up with a "too bright" or "thin" sounding response. It takes very few DB to sound wrong, especially when the disparity leaves a notch at the cross-over point. Find out the power output of the tubed amp you intend to use, and it's sensitivity(IE: 100W output @ 1.75V input) and find a SS amp to match, one with adjustable gain(a lot of studio/pro amps have that feature), or obtain a passive level control to attenuate it (http://www.creekaudio.co.uk/products/product_downloads/instructions/obh22.pdf).
Here's a pro amp that some of the contributors in here are in love with: (http://www.samedaymusic.com/product--BEHA500) It sports level meters, gain controls and 250WPC. That should give you the flexiblity to match the highest powered tube amp you can afford, and at it's price- you'd be able to afford much more. Below the midrange crossover point of the 802, any loss of transparency from using a pro amp should be irrelevant
The Bryston would be light years ahead of the Adcom, even though you're only talking about the lows. Are you certain the Toshiba is not the source of the harshness? Do you have an analog source available(TT or tuner) for comparison? Any triode based amp will give you a slightly relaxed top, but- a single-ended amp might not have the power to satisfy your SPL requirements with the 802's(even bi-amping). I don't know how loud you like your music(of course), so that's just speculation. I'm using a pair of modded Cary SLM-100's(98wpc into 6 ohms) to drive my Maggies(86db/1w/1m) and getting about 105db on peaks(without distress), crossed at 250hz(10th order) to my woofers(255wpc). You'll be crossed at a higher point(about 1 to 1.5 oct), but- I'd still wonder about your SPLs with an SET amp(your slope will be nowhere near as steep as mine). How many watts are you thinking about for your top? What kind of listening levels do you like?
I don't have analog source but I don't think it's Toshiba. Tweeters don’t sound too bad with well recorded music. Only bad recordings sound really harsh. Unfortunately a very significant part of my CD collection makes my eyes bleeding.
I can’t listen to music as loud as I wish thanks to the neighbors (I live in townhouse). I tried to bi amp my speakers with 30WPC Pass Aleph3 and 120 wpc MF and I could make my speakers sound loud enough. I think that I need at least 20WPC of tube power but I’m not sure.
Should you find that the bi-amping doesn't alleviate the problem, here's another option: If you open up your 802's: You should be able to easily find the tweeter section of the crossover. There should be two 3 ohm Vishay resistors in parallel with each other, and in series with the tweeter. If you take one out, that should reduce the output of your tweeter by somewhat more than 2db. Hopefully the assembler left enough lead showing for you to simply clip one, so it can be soldered back whenever need be. I'd see if I could find a higher-end CD player to audition before I went to that extreme though. Maybe even one with a tubed output/buffer section.
I could unsolder resistors, but I’d rather upgrade speakers if be-amping does not work. I already looked at Proac D25 but did not like its bass.It was a bit slow and not very tight. I prefer overall tonality and speed of b&W802. I’m thinking about Audio Physic.
I m planning to get a new CD player. I was considering Rega Apollo, but I see too many used on the market. It’s a little bit strange for a relatively new model. I’m using decent tube preamp so I’m not sure if tubed player or especially buffer would make a big difference.
I'd do the new player, or at least audition one, before any of the other options. I've never had a Rega, so I can't advise you there. I've got a BAT VK-D5, and love it(six NOS Siemens CCa's in the buffer). If your pre-amp is clean, it will convey whatever's fed it, good OR bad. A grainy/glaring/strident signal will be passed without mercy. It's possible you have some poorly engineered CDs, but- more likely that the player is the problem.
I just bought a pair of VTL 100 compact mono blocks (100 wpc in 5 Om I believe). It’s a little bit more than I need for the top and I’m not sure if I can run them in triode mode. After I try them with my speakers I will look for a new source. BAT VK-D5 sounds like a very nice player, but it’s a bit pricy. I’ m planning to spend around 1K.
Rodman9999- thanks for all of your advice and suggestions. Actually SCD 777 es was one of my options. From what I found out about VTL 100 they are not switchable. It means that I need to rewire them. It should not be a big deal I need to couple anode with one of the grid pins but I’m not sure if I need to re- adjust bias.
On a different subject. Since my SS amp will be active only in 27-400 Hz range amp’s sonic signature would not make any impact on the sound. The only two things that matter are damping factor and S/N ratio. Is it correct?
A fast slew rate would be nice as well. That will lend more definition to your lower octaves. Actually, between 100hz and 400hz, there's a whole bunch of music present. Baritone thru Soprano, trumpet, piano, cello, french horn, sax, a lot of percussion and harp all have over half of their fundamental tones below 400hz. In other words: If you skimp on an amp to use there, it's gonna mess up a lot of your reproduction. You also have to consider that the slope of you crossover will have the bass amp still contributing to the music for at least another octave above the 3db down point. That means it will affect almost your entire midrange to some degree. If you don't use a well defined, fast, accurate amp: expect your music to suffer greatly. I'm bi-amping, crossed at 60db/oct(10th order) at 250hz, using a Hafler TransNova 9505. It's fully Class A and differential thoughout, JFET input stage and MOS-FET output. I don't know if I could live with it full-range, but it's wonderful as a bass amp. Then again: With a sixty day satisfaction guarantee from Same Day Music on the Behringer A500, I'd have to give it a try at least(could be a pleasant surprise). (http://www.samedaymusic.com/product--BEHA500) Contact VTL and I'm certain they will give you all the info necessary on triode operation of the 100's.