Bridging Versus Bi-amping?

[Chas_T]

Just took delivery of a Sherbourn 7/2100 (Bridgeable) and I am curious what your thoughts are on bridging versus passive bi-amping.

The amp is connected to all Paradigm and for the fronts (Studio 100's) I am thinking of bi-amping only because I have some Cat Cables XLR Silver Cats that are cut specifically for bi-amping into a "Y."

If I go the route of bridging, then I'll need to send them back for more work into a single cable versus the "Y" configuration. Lex is busy enough!!!

Bridging versus bi-amping. Any thoughts?

Thanks,
Charles

[sfdoddsy]

I'm not sure there is any real benefit to passive biamping, so if you need the extra power I would try bridging.

It's easy enough to try out, just biamp them then bridge them and use the cable without connecting one set of leads.

Steve




Steve's DIY Dipoles

[JohnT]

I had the Sherbourn 5/1500 older bridgeable version and tried bridging it (I have nht 2.9s) and for me anyway I didnt like the results as the sound became edgier and sharper to the point of fatigue. I thought it sounded better not bridged, but like Steve said there may not be to much benifit in bi-amping either.

[dsmith]

Bi-amping may or not have audible results, but at least its safe if done right. Bridging can cause instability into low impedance loads. Personally I would just buy a bigger amp and avoid either approach. That's what I did with the Innersound ESL (300@8ohms and 600@4ohms).

Don

[Chuck G]

Hummmm. Different stokes so they say. I have the Sherbourn 5/1500a and passively biamp my NHT VT2 speakers. I will never go back as 1 channel from the Sherbourn to the VT2 was ok but biamping improved the bass and gave me a smoother upper midrange into the treble.

I can see the merits of just using a larger amp (but, knowing me, I WOULD even try to biamp with that). I say try both but IMO, I'd biamp the 100's in a heartbeat. You are already setup for that route.




Chuck

[Lex]

Be sure and read your amp specs when bridging, and your speaker manual, as some loads are not allowed in bridged mode except for the finest of amps. For example, bridging can have the same effect as putting 4 ohm speakers on a single channel, as putting an 8 ohm one on a bridged channel. Consequently, you would wan't to approach any speaker less than 8 ohms with the utmost caution, as you may overload your amp.

Your amp will run hotter, likely affecting some component's service over the long haul, and as I said to someone I know recently, it's rather much a dirty way to generate more power. Much better off with higher wattage single channels than bridging, any day. Quiter noise floor.

Of course, for a subwoofer, it's not as critical as for your mains. Sometimes, gobs of power is fine, without worrying about the finesse stuff.

FYI, some amps aren't rated below 6 ohms, others go to 4 ohms (good amps), the best? Krell down to 1 ohm loads and rated for that!

Lex




Cable Guy DVD Collection

[Chas_T]

Gents,

Thank you for your responses on this post. I've decided to go with the passive bi-amping as I've done in the past with the 5/1500A. The bridging seems a bit precarious and the Studio 100's respond well to the passive bi-amping. I'd rather be safe then sorry.

For the record, this 7/2100 is quite the amp for the cost/performance if anyone is interested.

I had the 5/1500A in the rack and this one actually has a different soundstage and sounds richer in nature. I've always sucked at trying to describe sound, so that is the best I can do.

I talked to Sherbourn today and it actually is a 220 Watt per channel amp, but the designer wanted to be conservative about it's power rating. Their words, not mine.

Also, I am checking with the engineer to find out if their new series of amps are true balanced components. If anyone is interested, I'll relay the information when I receive it. Thanks again guys.

Charles

[Chas_T]

As promised, if anyone is interested, here is Sherbourn's response on their amps being balanced with their permission to post Mr. Tang's response to my question.

Dear Charles:

By definition a "Full" balanced amp truly consists of two identical amps from the input to output.

We called our 7/2100 "comes with Balanced Input," which is of course not a "Full Balanced" amp, but it'll sum balance input signal and provide good common mode rejection to some system noise.

In the real world, it is my opinion that the differential outputs of a full balanced amp will eventually get summed together at the speaker load anyway. It is a matter of where you sum the differential signals together, and in our case we do it at the power amplifier input. Why?

Because we feel you gain very little to drive a pair of speaker leads, which carry large signal, in a balanced fashion. A power amp with well designed balanced input in fact may give you better noise performance because every amp has one time of its internal noise contribution to a system and a full balanced amp contribute, technically speaking, a square root of two times noise output noise.

Another concern we have is for a HT amp, the heat is always something every engineer needs to deal with when designing it. I believe, with our amp design we outperform many others in delivering higher power/volume ratio, we are a lot better in terms of power efficiency is concerned if you compared our amp with a full balanced amp.

Best Regards,

E. Tang
Sherbourn