Monoblocks vs Bi-amping

I am considering buying 2 Spectron Musician 3s to drive my Revel Ultima Salon2s. Which is do you recommend 1) monoblock configuration or 2) both amps set up in stereo, one driving mid-ranges/tweteters of both speakers & the other driving the woofers? I would think bi-amping would be superior since the each amp would see a more stable impedance profile.

Set it up both ways and compare it for yourself...that's the only way you'll be sure.
I'm not too sure you would be gaining anything vertically biamping your speakers.

My understanding for biamp considerations are that the usual inspiration comes from the desire to alter the realized sound via the use of two dissimilar amps.

I’ve run two sets of mono block amps. One pair being SS, and now I’m using two tubed monos. FWIW I’d recommend keeping things as simple as possible and apply one amp to each Revel.

There too, you'd save the cost of another set of speaker cables, and interconnects... although that might not be an issue here.

‘Course, you could just attach ‘em like ya want and see for yourself if there is some gain or issues… then connect them back to a more standard setup if a problem is perceived.

I sure can’t see how it could harm anything if volume levels are kept reasonable.
You'll want to read the post dated 2-19-09 in this thread, by the noted designer Steve McCormack. Among other things, he makes a strong case for why vertical biamping is generally preferable to the horizontal biamping arrangement you are contemplating.

Re the bridged monoblock possibility, if you don't necessarily need the added power capability that would provide, probably the only way to judge is by listening, as was suggested.

As you probably realize, bridged mode will cause the amplifiers to see the speaker impedance (6 ohms nominal, 3.7 ohms minimum at 90Hz) divided by a factor of 2 (in other words, the amplifier would see 1.85 ohms at 90Hz). Your amplifier can certainly handle that, but it would stand to reason that the character of its sound might be affected by that difference, in unpredictable ways.

Also, in vertical biamp mode both channels of each amp are amplifying identical signals, while in monoblock mode the two channels would be amplifying signals that are inverted internally, relative to each other. Again, hard to predict what the consequences would be, but it stands to reason that there would be consequences.

-- Al
Hi Brian,

Let me preface this by saying that I'm no expert on Bridging or Biamping, however, I'm not a fan of Bridging. I do agree with Blindjim though, that bi-amping is usually associated with SS on the bottom and tubes on the top, to better taylor the sound towards ones preferences.

I wouldn't go out and by an Amp for the sole purpose of Bridging as the Plan. Now, if someone needed to do this out of necessity than I'm all for it.

The way I understand it, is that if you Bridge the Amps, then you will basically be reducing the load that the Amps could drive by 1/2 so if it could drive 4 ohms previously unbridged, then it will only be able to drive 8 ohms bridged, and I don't think that's as a good thing, unless you have 8 ohm minimal speakers to start with. My experiences although limited, have revealed higher levels of distortion, compression, heat, and clipping in bridged modes. I see that the Revel Salon 2's have a minimum impedance down to 3.7 ohms, so if you bridge your amps, then you may clip them with your particular speakers.

From the Spectron Website:
"Balanced Design: Musician III Mk2 is capable to operate both in stereo and mono (fully balanced) modes. While not necessarily an advantage in every speaker, Spectron monoblocks configuration triples the power and doubles the head room. The major advantage of this mode of operation, however, is noticeable improvement is dynamics and resolution of details in the music."

They say it triples the power, but then, wouldn't the amp have a difficult time delivering this power into a minimal impedance of 3.7 ohm speakers, which your bridged Amps will be viewing as a minimal impedance of 1.85 ohms.

I would think that in this case, bi-amping would be better, for less power output, but, improved power transfer to the speakers.

"...I would think bi-amping would be superior since the each amp would see a more stable impedance profile"


Spectron claims that their amp is stable to the load up to 0.1 Ohm so this should not be concern to you.

I own B&W 802N and drive them with two Spectrons. Of course, as suggested above I tried them in both configurations. Unquestionably (for me , at least) monoblock configaration was much better then bi-amp stereo. No slightest question about it. If your speaker impedance is more gentle then extremely difficult 802 then you will be even better off.

Somebody above mention that minimum impedance of your speakers is 3.5 Ohm. If true then its great. The problem with speakers is that practically no customer asks and no speaker and amplifier manufacturer alike volunteer to describe... the speaker impedance PHASE behaivor and amplifier ability to deal with it. Its ain't easy...the demand for delivered power increase substantially.

Good Luck
I've experimented with biamping quite a bit, and have had limited success. My first advice to you is if you're buying two amps anyway try different configs for yourself and see what you like best. That said, here's my own findings:

- I've tried horizontal biamping with multiple amps - identical SS amps, and SS for bass, Tubes for mid/treble. None of these were preferable to a single stereo amp (ie one of the amps used in the biamping), and all were materially inferior to a set of higher power mono-blocks.

- I've tried vertical biamping with identical stereo SS amps and have experienced favorable results - but it's speaker dependent. One set of speakers preferred the higher power mono-blocks. Another appear to be optimized for vertical biamping. You really, really need to read the thread that Almarg references - especially Steve McCormack's post.

- Finally, I know nothing about your amps, but have been told by amp Mfg's previously that stereo amps bridged to mono configs will NOT sound as good as running the amps in non-bridged mode. Parasound recommended running their amps in what they refer to as "single stereo" rather than bridged, saying that the power output is greater because the the single channel has full access to the power supply which will increase the rated power by about 30%. "Single stereo" is using only one channel from a stereo amp, and letting the other sit idle. You should consult your amp mfg about this as amps differ a lot. You should also consult your speaker mfg to hear what they recommend (ie high power mono, or biamp with 2 stereo amps).
You gotta take this on a case by case basis, considering both the amps and the load. Not just the minimum impedance but the reactance. For example, I've got bridged Plinius amps with 4 ohm Genesis ribbons but the ribbons are purely resistive so there is no problem. With the Spectrons and Revels, I would think monoblocks would be the better choice. The Spectrons were designed for this and benefit by going into differential operation.
Hey Brian,

Since you have to buy 2 of these Amps and they're not cheap, does it make any sense to look at other high-end Monoblocks, that don't require Bridging, or Bi-Amping?

"Since you have to buy 2 of these Amps and they're not cheap, does it make any sense to look at other high-end Monoblocks, that don't require Bridging, or Bi-Amping? "

Hey Rich, why to discuss things you have no idea about ???

Spectron does not require bridging or bi-amping !!!! Brian wants to use two of the amps. Eacch Spectron runs very well in stereo mode and it was produced as a stereo amp. Excellent sound. I used it for two years before I went to two amps.

It just happenned that as designed this amp can run also in FULLY BALANCED monoblocks - without a single additional switch or op-amp. it has two phase "in/out" switches - one per channel. No other amp or preamp has this features. At best - phase in/out for both channels. It was done to control phase which on many recordings is simply mixed. I know it because I can hear and I use these two switches extensively - to "focus" sound presentation.

Since you can switch one channel's phase then by sending the same signal into amp's two channels you have on output two signals equal in amplitude but with oppose phases - you continue it to your speakers and that's all. No other amplifier in the world can do it..
Hey Dob,

That wasn't very nice! Let me explain further..., I wasn't suggesting that Spectron requires it.

I was referring to the concept that, he feels he requires bi-amping or bridging may be necessary for his particular application.

He didn't buy them yet, he said he's considering it, can't he consider other amps as well.


".. I wasn't suggesting that Spectron requires it"

Hello Rich,

I am terrible speller but ...I can read. Read again your statement:

".....does it make any sense to look at other high-end Monoblocks, that don't require Bridging, or Bi-Amping? "
... see again this word: "REQUIRE"

Moreover, neither did you or any other contributor (as far as I could note) to this thread mention immensely important, I would say vital conditions of bi-amp versus monoblocks. For example, if Brian speakers use active crossover then he MUST use bi-amp, he has no choice or if monoblocks operation is in FULLY balanced mode (FULLY as in from amp input to the speaker binding posts) - which change immensely sound presentation - and please, not to confuse with balanced input which require XLR. I use my amps in full balanced mode using single ended RCA inputs (just two of them: "plus" and "minus" thus fullfilling definition of "balanced").

From Spectron web site (note that in first phrase instead of power outputs they mention efficiency of speakers):

"Regardless of the efficiency of the speakers, balanced mode of operation doubles the slew rate and bandwidth by virtue of the out of phase transmission. This also suppresses the noise and buzz originated upstream from the amplifier. The other major advantage of fully balanced mode in Spectron amplifiers is that transmission of both positive and negative signals (in each amplifier) is maintained separately from the amplifier's input to the speakers binding posts. Assuming that the signal path electronics are matched, all of the intrinsic amplifier distortions arrive at the speakers with practically identical amplitude but with opposed polarity and essentially cancel each other. The result is a largely noise and distortion free sound transmission, leading to a spectacular improvement in three-dimensionality and resolution of detail in the music"

And, if yourself would try two Spectrons first as two stereo amps and then as two monoblocks you would HEAR, HEAR immense improvements in the sound, like huge veil is removed and instruments are razor sharp located, and with their IMPROVED palpability "look" like a statues within huge soundstage etc etc. Anyone with two ears would hear it.

I am not alone - see reviews of other owners of monoblocks on-line, see professional reviews - by now may 10, look on their awards - just Best Sound at CES alone should say something.

I describe Spectrons only because original questions was directed at these amps and I use them for five years. You and others so far did describe other amplifiers (may be better, I don;t know) other situations for sure etc. Brian ask simple question - deserves simple answer.

If you want to compare Spectrons to other amplifiers in identical mode of operation (i.e. stereo vs stereo and mono vs mono), particualrly fully balanced mode then you MUST compare part tolerance first of all. As Spectron web site stated (see above) that if parts matching is excellent then distortions are canceled and thus if there is mismatching then new resulting distortion could be equal or worse or much worse then original stereo distortions. So go ahead, compare - this forum is all about it - just apples with apples, please.

Good Luck
Dob, since my first post misled you, that's why I clarified my intent in my second post.

I'm familiar with the well deserved accolades of Spector.

Dude Chill Out!


Sorry.., I meant Spectron.