Bi-amping 803S

[Pookie007]

I have a previous post about a new amplifier and one option since I only have a 5 channel system was to get a 7-channel amp and bi amp the mains. Will this provide an advantage over using a 5 channel amplifier (assuming the same amplifier, just different channel configuration)?

How do you make the connection from your pre-amp to the amplifier? I would need to send the same signal to both channels. Do they make cables to do this?

[Kal Rubinson]

1. You use a Y connector for each biamped channel.
2. Why bother?

Kal

[Pookie007]

When I did the price comparison, it is much cheaper to get a 7 channel amp now than to buy a 5 channel and add a 2 channel later. I only need 5 now, but the 7 would leave options for the future. Since I would have the channels available, I didn't know if it would benefit me to hook them up.

[georgev]

What amplifier are you talking about? Rated at what power?

[Pookie007]

I have decided yet. I am bouncing between a couple brands. If bi-amping doesn’t gain much, I will most likely get the Anthem Statement. They have two version the A5 (180W at 8 ohms all channels driven) or the P5 (325W at 8 ohms all channels driven). They both have the current, THD, damping factor, etc. as well to back those number up. The dark horse is the Rotel 1095 (200W).

If bi-amping provides a significant advantage, I might go something like Lexicon or Audio Research. The initial cost is more, but over the long term, it is the better value if I add the channels later.

[Angioguy]

803S Biamping

How much power are you talking about? I have a pair of 803S's. I think you're really going to need minimum, 250 wpc, to really appreciate what these speakers can do. I started with an Arcam AVR-300 (100 wpc). Even though people suggested biamping as a solution to increase power, I decided to use this receiver as my 7.1 and get a really good power amp for those times I wanted to hear the B&W's purely in stereo. I got the McIntosh MC-402 (400 wpc), and I haven't looked back!

[Pookie007]

I am not in a position to only add a 2 channel amp. I am upgrading to a pre-amp in the fall to add some video switching options I am currently lacking. I need to get at least a 5 channel first.

I guess the core question is what is the advantage of bi-amping?

[miner]

As others have suggested, your amp needs to be at least 250 w/ch for the 803S. And, if you are insistant on 5 ch you may need to get a couple of 2 ch and a mono amp to meet the power requirements. The power end is something you should not scimp on. Don't bother iwth a AVR receiver for the 803S.

[htsteve]

Rotel 1077

Pookie007,

I recently bought a Rotel 1077. I bi-amped my front three speakers, N804's and HTM1 center. My N804's had the Rotel 1080 stereo amp before. The 1080 was a definite upgrade over the Rotel 1095 I had running the N804's. The bi-amped 1077 was another step up again. Read my 1077 review below. I know there is a lot of discussion around passive bi-amping and it's benefits. My own experience was that it made an audible improvement. My opinion of the benefits of passive bi-amping are that the the upper and lower ends benefit from the ability to draw from individual amps channels. These drivers are not 'competing' over the same current, thereby not taxing the other drivers. To answer your original question; yes, a 7 channel amp and bi-amping the mains is a good idea. The 1077 ($2500 US) might be a great way to get alot out of the main's and still have enough channels left over for the rest your speakers.

http://www.htguide.com/forum/showthread.php4?t=20480&highlight=1077+owner

Hope this helps.

[Charles]

Going through a similar issue as well. My B&K AVR 507's amp is just not enough for the 803s. It is rated at 150wpc at 8 ohms and 175 at 4 ohms. The 803s has a rating down to 3 ohms which really requires the juice!! Bi amping I was told was not the answer, more power is the only way. I've been looking at the Krell KAV 3250 which has 3 channels rated at 250 at 8 ohms and 500 at 4 ohms. This seems like a good match for my fronts and I can use the 150 B&K channels for my surrounds for now. In the future (if and when 7.1 material is readily available) I will pick up a 5 channel B&K (200@8 ohms, 375@4 ohms) or an HTS Krell (if a rich uncle passes) and a new prepro (Mine will surely be outdated then if not now) to complete with 1 channel to spare. This seems to be the most logical path since it seems nobody makes a good 7 channel amp with enough power that I've found. Any suggestions welcomed!!

[Pez]

This seems to be the most logical path since it seems nobody makes a good 7 channel amp with enough power that I've found. Any suggestions welcomed!!

Earthquake just came out with a 7 channel Cinenova (300 x 7 - 8 ohms). The 3 and 5 channel models are very highly reagarded.

[B&W 700 Guy]

Check out the Sunfire GTA 5XXX or 7XXX amps. you can get them in 200 or 400 watts. When I purchased my 703'S, this was the amp I wanted. I also listened to this amp with the 804/803 speakers, biamped. :T

[kurtholz]

I would go with the Krell HTS 5 channel for the fronts, bi-amp the mains and run the center off the 5th channel, which is how i drive my 802d's, it's a better sound than my kav3250 was, which is now relegated to surrounds and rear center, much cleaner sound, you can also change the settings internally on the HTS if you don't want to bi-amp,and bridge 4 of the channels which doubles the output,you could find a used HTS for around $4500 i'm sure on audiogon or ebay,

Kurt

[stewfoo]

I truly believe that if you are using 800 series speakers you need to do them justice. You are wasting your money on speakers if you use Rotel, Sunfire, and especially cinenova. All of these electronics are fine for their intended uses. However, when I bought my 803s I found myself in upgraditis hell with Rotel. Even their new class d line ( which I use to run my whole-house in ceiling and WM series outdoor speakers) you are doing them a disservice. You will save money at the end of the day if you do it right up front. The minimum level of electronics that I would use with any 800 series speaker is the Halo line from parasound. But, If you want to eliminate your upgraditis, go Classe Period.
If these electronics are beyond your financial reach go with the 700 series. Trust me, you want to buy a matching system up front if possible.

[Ade]

How much power are you talking about? I have a pair of 803S's. I think you're really going to need minimum, 250 wpc, to really appreciate what these speakers can do. I started with an Arcam AVR-300 (100 wpc). Even though people suggested biamping as a solution to increase power, I decided to use this receiver as my 7.1 and get a really good power amp for those times I wanted to hear the B&W's purely in stereo. I got the McIntosh MC-402 (400 wpc), and I haven't looked back!

Is that 250wpc into 8ohms? A minimum you say?

So let's do some simple math.

The 803S has a sensitivity of 90dB@1m/1W. Given the worse possible case load of 3 ohm 90dB@1m would require 3W - this is using the "power doubling rule" when you halve the impedance.

So let's assume you're deaf or angry at the neighbours and need to play at 100dB; At 1 meter with a nominal 8 ohm load you'll need to draw 8W (that is actually 99dB but what's 1dB between friends?). With a 3 ohm load that'll be 24W.

OK, now we have to take into account the distance you are from the speakers - every doubling of the distance between you and the speakers reduces the sound you hear by 6dB. So at 2m that 99dB will be reduced to 93dB and at 4m that goes down to 87dB. Let's say that you're 6m away; that'll be 84dB. Taking this back up to 90dB will require 32W with an 8 ohm load and 72W with a 3 ohm load.

My new Honda lawnmower (the mulching function is really cool and highly recommended btw) is rated at 89dB and it's VERY LOUD and that's outside.

Also remember that unless you live in an anechoic chamber you're going to get in-room gain in addition which could boost the sound you hear by 3 dB or more.

OK, I'll give you that there can be short lived transient peaks that exceed normal listening levels but seriously, you're not going to be using 400W from your McIntosh amp. Any differences you may have heard is probably down to larger capacitors that help with those transient peaks. But large capacitors can be had in amps with much less max wpc.

Of course, this is all just my opinion.

And, um, it’s early here so excuse any arithmetic errors – they are probably minor and the point still remains the same.

[B&W 700 Guy]

I truly believe that if you are using 800 series speakers you need to do them justice. You are wasting your money on speakers if you use Rotel, Sunfire, and especially cinenova. All of these electronics are fine for their intended uses. However, when I bought my 803s I found myself in upgraditis hell with Rotel. Even their new class d line ( which I use to run my whole-house in ceiling and WM series outdoor speakers) you are doing them a disservice. You will save money at the end of the day if you do it right up front. The minimum level of electronics that I would use with any 800 series speaker is the Halo line from parasound. But, If you want to eliminate your upgraditis, go Classe Period.
If these electronics are beyond your financial reach go with the 700 series. Trust me, you want to buy a matching system up front if possible.

well, you are correct about Classe 8)

[Charles]

Thanks for all the great info!! I've done many hours of research on amplification for my 2-803S's, 1-HTM3S and 2-SCM1's and have narrowed the picks down to Classe or Krell. It seems getting down to the least common denominator on the sound of each reveals Classe for music and Krell for HT. We are 90% HT, so I'm leaning toward Krell at this point. Probably TAS to start with. Please feel free to correct or better educate me as I still have not got the opportunity to listen to both. The Classe dealer has their 5200 hooked to 802's and the Krell dealer has no KAV's, just FPB's wired to 803D's. Not really a good acid test for my setup. Thanks again,
Charles

[Pookie007]

I went with the Audio Research 300.2 for the 803s and got a 3 channel Anthem for the center and surrounds. I like the Audio Research over the Classe. I ignored the published numbers and auditioned both in my house. The ARC was my choice with no second thoughts. I didn't bi-amp the speakers.