Bridging amps? Bad?

[phuz]

Another forum member has told me that bridging channels on an amp will not sound as good as not. Opinions anyone?

I've already got a Rotel 2ch for my mains, and I've just found a Rotel 6ch amp that I'm thinking of getting to bridge into 3 channels for my center and rear chans.

Can anyone tell me why I should not do this? Thanks.

[RuSsMaN]

I can't think of a reason, and haven't ever heard that bridging as a general rule will degrade the quality.

Bridge on broham.... Sounds like a stellar plan.

Cheers,
Russ

[phuz]

Originally posted by RuSsMaN
I can't think of a reason, and haven't ever heard that bridging as a general rule will degrade the quality.

Bridge on broham.... Sounds like a stellar plan.

Edit:

Cool, thanks man. :)

I'm going to wait a bit to see if this place will go down a bit over the next month or so. They still want $300 for the amp since it just came in. I know I can get it for cheaper so I'll be patient..........

[mantis]

I also have heard that bridging sometime loses sound quality.I can't speak of it with experience,I never tried it myself....If your buying another Rotel amp,I can't see the need for doubling up the power.Try bi amping...that might actually work out better.Let me know what you think....Rotel makes it easy to Bridge,they have switches on the back of some of there amps just for this.....

[TroyD]

As der Russmeister says....bridge on. I can't think of a reason of how it would damage the amp (otherwise, I would think that they wouldn't offer it as an option).

I've listened to El Roma's amps bridged on a few occaisons and thought they worked just fine and, sh!t, he's had 'em bridged for a decade probably with no issues.

BDT

[mantis]

I don't think it's an issue but I have talked to some of my audiophile buddies that said they lost sound quality when compared...........I never said anything about damage....that must be your thinking or something......

[TroyD]

hmmmm, I wasn't refering to your post Dan but since you asked, here is my way of thinking:

If it sounded worse to the owner (which is a subjective call) he always has the option to UN-bridge them. I figured that was a no brainer. My opinion is that it sounded swell to me.

I was thinking more along the lines of possible damage to the amp and from what I've seen, it's not an issue.

BDT

[mantis]

Troy,
have you ever done a side by side or a-b compare with a given set of amps bridged and unbridged??I never did this and would like to get your thoughts..........you a 2 channel guy,I figure you tried this at one time or the other.

[TroyD]

No, not side by side. However, El Roma's amps are Carver mt series amps, which are the same series as mine. I've heard some say that it gives amps a 'harder' or more 'electronic' sound and I didn't find that to be the case. I'm not saying that I'm anywhere near an expert on the merits of bridging, and I think in the end how it sounds is largely a matter of opinion.

My main thing, since I can't really speak as to what would sound better to Phuz in this case, is if it is actually damaging to the amp as some folks worry about. That, I can say reasonably certainly is not an issue.

BDT

[mantis]

They are basically the same comments I have heard about bridging amps together.

I'm waiting to hear what Phuz comes across.

[niles300z]

Late add as usual for me. I just fooled around with a rotel amp in bridged and unbridged. I agree with most others that report a loss of sound quality upon bridging. Oddly there was no loss of bass but for me it seemed to fatten the sound a bit with a more notable loss of imaging and air or what i think of as musicality. However if i was doing a dance and needed more power i would bridge and let er rip.

[Blownrx7]

Late add as usual for me. I just fooled around with a rotel amp in bridged and unbridged. I agree with most others that report a loss of sound quality upon bridging. Oddly there was no loss of bass but for me it seemed to fatten the sound a bit with a more notable loss of imaging and air or what i think of as musicality. However if i was doing a dance and needed more power i would bridge and let er rip.

I would never have expected that. Thanks for actually doing the comparison!

[BlueFox]

I can state that bridging the Cambridge-Audio 840W is an improvement over a single amp in stereo mode. I have been doing this for about 5 years. Friday night the right channel amp died, and I went back to stereo mode on the other amp. Aside from having to turn the one amp up louder to reach the same listening SPL, the sound stage feels compressed. It does not have the open, full sound that resulted from two bridged amps.

It turns out that there is another benefit to bridging amps versus two dedicated monoblocks. If one dies you have a spare to tied you over until the other amp is fixed.

[hewlew1]

Some people say some amps have trouble when they are bridged into a 4 ohm load. I have 4 Carver M500T amps bridged each one plays into an 8 ohm load and the neidgbors really love them P.S. They have been used in this manner for about 5 years now with no Ill affects that I am aware of.

[snake1]

I'm glad I stumbled upon this thread!! I've been having the same thoughts about bridging 2 amps for the front 2 and possibly a 3 ch. down the road for center and rear duty. Thanks for info guys!

[tonyb]

Lets not take one bridgeable amp and apply it across the board. Yes, some amps are perfectly fine bridged, others can be, but don't like very big impedence swings. Even some manufacturers state that. Has more to do with design of the amp but one should pay attention to a manufacturers suggestions. For instance, even though my Butler amp can run in mono, it's suggested that while in mono to not use with speakers below 8 ohms. Now, if you have a speaker than occasionaly dips to 6 ohms chances are you'd be fine,but if your speaks dip to 4 ohms, you could be asking for trouble. My advice before bridging is to check with the manufacturer beforehand to avoid any problems down the road.

[Face]

Lets not take one bridgeable amp and apply it across the board. Yes, some amps are perfectly fine bridged, others can be, but don't like very big impedence swings. Even some manufacturers state that. Has more to do with design of the amp but one should pay attention to a manufacturers suggestions. For instance, even though my Butler amp can run in mono, it's suggested that while in mono to not use with speakers below 8 ohms. Now, if you have a speaker than occasionaly dips to 6 ohms chances are you'd be fine,but if your speaks dip to 4 ohms, you could be asking for trouble. My advice before bridging is to check with the manufacturer beforehand to avoid any problems down the road.

+1... When you bridge an amp, it's minimum impedance changes. A 2 ohm stable amp will only be 4 ohm stable when bridged, etc...

[snake1]

I'll add this about parasound amps. I spoke with tech there yesterday and he said impedence swings weren't an issue with theirs.

[tonyb]

I'll add this about parasound amps. I spoke with tech there yesterday and he said impedence swings weren't an issue with theirs.

Cool, as long as SQ isn't either, then your golden.

[cconklin1]

bridge on...

[trav0810]

glad I found this thread. I am considering bridging a pair of M1.0t Mk2's for my SRS 1.2's and someone told me about reduced SQ when you run mono.

[FTGV]

SQ aside you cannot use bridged amplifiers with SDA's as they will no longer be common ground.

[trav0810]

Ahhh...you are correct. You eliminate the common ground when you bridge. Damn!

[gp4jesus]

I've already got a Rotel 2ch for my mains, and I've just found a Rotel 6ch amp that I'm thinking of getting to bridge into 3 channels for my center and rear chans. Can anyone tell me why I should not do this? Thanks.

SQ on that amp. I'd considered doing the same until I found a revue on a low power 6 channel Rotel, words to the effect: "SQ wasn't up to Rotel's otherwise excellent standards." and ".. while bridging did increase output, it degraded SQ further."

Shortly thereafter bought a 5ch Rotel off eBay, using as a 3ch for my CC & LR tops(see my sig). BTW What model Rotel do you have, irrelavant I know, & what model are you looking at?

My $.02, Tony

[F1nut]

Ahhh...you are correct. You eliminate the common ground when you bridge. Damn!

You'd have to use the AI-1.

[trav0810]

You'd have to use the AI-1.

What's the AI-1?

[FTGV]

What's the AI-1?

It's a special isolation transformer that prevents there being a direct short between the negative outputs of bridged amplifiers.By bridging the amplifier it's output now operates differentially with the negative half of the signal now taken from the positive terminal of the inverted channel instead of the normal negative terminal which is at ground potential.Shorting the outputs of bridged/differential amplifiers together is a recipe for grief thus the reason for the AI-1.

[trav0810]

Ahhh! Thank you!