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Need advice for B&W 804 diamond amplification

Hello all,

I purchased a pair of B&W 804 diamond towers about a year ago. At the time I purchased them, I also got a rotel rsp-1570 processor and a rmb-1575 5-channel amp. The rotel amp delivers 250 wpc all channels driven @8 ohm. Rotel calls this amp a true high current amp but doesn't list the current capacity in the specs. This amp is also a class D. I have lived with this amp for over a year now and have never really been satisfied with it. I have read alot of bad press about class D equipment in general. I hope to find some owners of the 804D here to gain some knowledge from. My main goal is to improve my 2-channel listening experience. I have set aside roughly 15k to upgrade with. I have done a bit of searching and I like the parasound JC1 mono amps and the JC2 pre-amp with the bypass option. This equipment is appealing to me because I have the B&W towers as part of a 5.1 setup. The JC2 would allow me to bypass the rotel processor and go to the amps during 2-channel listening. I could then switch it back for TV/Theater use. From the reviews I have read on the JC1 amps they seem to be good quality equipment that is in my price range. They are a class A/B amp but, they operate in pure class A up to 25 watts. I like to listen to my music fairly loud. Not enough to disturb the neighbors but still pretty loud. I'm just not sure how loud this would allow me to play without exceeding the 25watt class A operation. If I understand correctly, at the point it surpasses the 25w it then operates in class A/B. I'm not quite sure how that works. The B&W 804D does have a dual set of mounting post for bi-amping. I Guess to take advantage of this I would need either two seperate amps or a dual mono. would it be worthwile to purchase a stereo 2-channel amp and use it to bi-amp with or, should I just find the best mono amp that pairs up with these specific towers and use the included jumper cables. Another option would be to use a monoblock with a single output and run a cable that splits to four connectors and bi-wire them. Is there really any benefit to this over using the jumper cables that came with the speakers? I'm sorry for the long winded post. I am about to spend alot of money, atleast for me. I just want to make sure I am getting the most out of it. To make a long story short, If you owned the rotel Processor/Amp combo and the B&W 804 towers, what upgrades would you make to the system with a 15k budget? Please limit yourself to pre-amp,processor,amps,powerline conditioners and interconnects. I am not looking to upgrade source components at this time. All of my source equipment is pretty good. Thats another story for another time when I have more money. Thank you in advance for your suggestions and advice.

Andy Price
andyprice44
lewinskih01
909 posts
 
I don't have 804D, but 804S. When I upgraded the speakers I had a Rotel RB1080 amp, which worked great with lesser B&W, but wasn't on par with the 804S. I auditioned some amps, narrrowed down to Classe and McIntosh, preferred Mc, and ended up with MC275 (tubes) over MC252 (SS). I really like tubes with my speakers (later got a tube pre).

At the time I was auditioning for amps I did listen to a pair of 802D driven by huge VTL (tube) amps and the sound was outstanding too.

With 15k you could even buy 2 MC275 and try them as monoblocks or to biamp (I myself would love to listen to that!). Or if you preder SS 2 MC252. Classe is also great. Rowlands are said to work great with B&W too, but I haven't heard them. Have you checked the audiokarma forum?
jimmy2615
440 posts
 
B&W - it's ALWAYS Rotel, McIntosh, and Classe. Why is that. Hmmmm...every dealer I've ever been to that sells B&W sells either Rotel and McIntosh or Rotel and Classe. Has anyone ever tried with another amp?
dave_72
1,399 posts
 
I've heard them with Pass Labs and Bryston. Both were pretty good. Pass was the better of the 2.

As far as why Rotel and Classe, I believe B&W owns Classe and I think Rotel too.

Not sure on McIntosh, that could be one of those coincidences.
andyprice44 OP
133 posts
 
Thanks for all the responses guys. There is a Hi-Fi shop that is in a bigger city about an hour away. They deal Mcintosh gear. I am going to see if they have any demo models they can loan me for a home audition.
I Think I am going to stay with SS amps. I like the idea of using 2 of the MC252 for Bi-amping. The specs on the MC252 also state it can be bridged mono. I sure would like to try this model out in my system. Now I just need to get out there and listen to some amps.

Andy
mark_nz
48 posts
 
Hi Andy,
There are many worthy options in your quoted price range.

I own the 803Diamond, and previously the 803D and 804S. I currently use a Classé CA2300 (300W stereo) amplifier, and previously the Cambridge Audio Azur 840W (200W stereo) bi-amped.

I can highly recommend both amplifiers - the CA2300 is more precise and transparent, particularly in bass/mid-bass whereas the 840W has a slighter sweeter mid-range. Both amplifiers run a few watts Class A mode before transitioning to Class AB. Both amplifiers are superior to the very good Marantz Class AB amplifiers I have previously used. My conclusion is that Class A is desirable and the benefit of the resulting warmer/sweet tonal sound quality is obvious through the B&W Diamond tweeter and midrange.

The Classé CA2300 is overall a good match for the 803Diamond (and should be with 804Diamond). The 840W is bargain given the sound quality, but note there is a replacement due because it was recently discontinued.

I once precisely measured how power I used for typically music listening sessions and was surprised that it averaged a few watts(!) with a peak of around 40Watts when I very occasionally turned the volume up. So you can assume that for moderate listening sessions that 25W Class A will be more than adequate.
However for home-theater you need more Class AB power - I haven't measured peak power in my home theater - but I guess aim for 150W or greater.
Do consider the amount of heat generated from a full class A amplifier (e.g. Pass Labs XA100.5) in a confined home theater room.

I am big fan of bi-amping – it will allow lower power amplifiers to sound less stressed (greater headroom) – the primary benefits is improved sound-staging with more precise imaging and delineation between instruments. However a superior amplifier is better than a two lesser quality bi-amped amplifiers because instrument tonal quality is more critical than sound-staging for long-term listening pleasure.

The Pass Labs X.5 series and Parasound JC1 amplifiers should be auditioned based on their consistent good reviews. The McIntosh is a favorite choice on the HTGuide B&W forum. Unfortunately I have no personal experience with these amplifiers.

Regards
Mark
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