Why use monoblocks?

[PristineSound]

Seems circular…

I mean, circular answer for circular question?

But let me give you a thoughtful and long-winded answer.

First, let me kindly refer you back to this post below. The OP asked about monoblocks, I made a statement based on science, which is monoblocks have better channel separation as a result of better crosstalk performance due to the explanations I provided in my other post on this thread (at least in theory, but we know it can't have worse channel separation baring some serious edge cases of engineering flaws that I can't think of). I think at this point, no one is disputing that monoblocks have better channel separation? If we are still disputing this then I will not further engage as this all can be confirmed by some simple Google search.

Then it appears to me that I am being accused of saying such said channel separation in monoblocks is indeed needed as the crosstalk in stereo amplifiers under one chassis is indeed audible. I would like people to take a screenshot and show me where I said that. In fact, below screenshot is more than sufficient clarification on something that some here imagined me saying but never said. So yeah, I am getting circular questions, so I was replying in kind with circular answers.

Now, there is a philosophical and personal preference on how much crosstalk performance is needed.

This question can be interpreted in two ways (1) "need" in terms not being audible? Or (2) "need" in terms of what you, the consumer, want? (2) is the philosophical and personal preference.

Most modern-day stereo amplifier under one chassis that is competently designed shouldn't have audible crosstalk performance. Just like most DAC, preamps and amps at 100dB SINAD, the distortion and noise *shouldn't* be audible (or at least discernable with music rather than test tone); this is based the common cited .1% THD+N (60dB SINAD) to be the audibility threshold. Then why are people still chasing 110dB SINAD or 120dB SINAD? Why is Amir gloating about the 120dB SINAD Topping B200?

There is no right or wrong answer for someone wanting 120dB SINAD and that answer is whatever the individual wants. Similarity, this also applies to crosstalk performance, there is no right or wrong answer on what a consumer is chasing after.

I can tell you why I want 120dB SINAD DAC and the 110dB SINAD Benchmark AHB2, because I can . . . and I will. Actually, not that "I will" because I already own them and I own them for exactly this reason, because I effing can.

EDIT: this is my last post here about crosstalk performance in monoblocks, any more reply on that, it would just be more circular answers to circular questions.

 

[respice finem]

It depends, the less compromised 8381A uses two pieces of external amps to drive 9 drivers.

(pro amps, with fans and everything but still... )

Others too.

Still better IMHO than to have a monoblock before a passive crossover.

 

[Sokel]

Still better IMHO than to have a monoblock before a passive crossover.

100%

 

[RexrothPigeon]

The OP asked "why use monoblocks?" so when you ( @PristineSound ) answered that they perform better in terms of channel separation and cross-talk, you surely meant that people should (or simply do) use monoblocks because of their superiority in crosstalk. Which means you think the crosstalk difference is meaningful to the user and not merely an imperceptible technicality.

If you didn't mean that, then your answer is a non sequitur and irrelevant to the question, which, again, is "why use monoblocks?" and not "in what technical ways are monoblocks different?"

 

[Sokel]

I already had a take in this thread but it's worth noted:

Traditionally, monoblocks are associated with high power/current applications usually driving difficult loads
(have a look at the datasheets to see power losses down there at 2 Ohm, no matter the class)

Higher power = more heat = more weight if passively cooled.
So easier to cool (adding heat sources together is never a good thing and 2 of them (PSU+amp) is easier than four if we take advantage of side heatshinks , easier to handle, closer to speaker, etc, etc.

Now, are these special demands became a trend sometime ago? Yep.
(strange thing is that little things like the fosi ones can also benefit by the better cooling to a degree, even if their real estate don't add up for great heat dissipation)

 

[Mike123]

ASR makes you think on Sunday . I had two-channel amplifiers. And now I have monoblocks. After thinking about it, I came to the conclusion that engineering perfection is important to me, DAC with 122 sinad is more interesting to me than a DAC with 120 sinad. Therefore: cables with maximum current are made as short as possible. Signal cables are made balanced. Not because I can hear it. But because it is beautiful, correct and perfectly measured. What I really do not understand is two monoblocks standing next to each other in the center. And I also do not understand two monoblocks with one power supply. I recently saw such in some reviews. IMHO, even the engineering and aesthetic meaning of monoblocks is lost.

 

[RexrothPigeon]

ASR makes you think on Sunday . I had two-channel amplifiers. And now I have monoblocks. After thinking about it, I came to the conclusion that engineering perfection is important to me, DAC with 122 sinad is more interesting to me than a DAC with 120 sinad. Therefore: cables with maximum current are made as short as possible. Signal cables are made balanced. Not because I can hear it. But because it is beautiful, correct and perfectly measured. What I really do not understand is two monoblocks standing next to each other in the center. And I also do not understand two monoblocks with one power supply. I recently saw such in some reviews. IMHO, even the engineering and aesthetic meaning of monoblocks is lost.

This is a great comment, and a terrific reminder of the porosity of the membranes separating religion, empiricism, and aesthetics.

 

[xanalog]

I thought that the power amps traditionally had step down transformers in them to get some current ?
Starting with a high voltage and low current from the tubes…

You are not allowed to talk about that stuff, what do you think this is a "201" class?
Some of us are still doing 101 ditties... on and on!

 

[Holmz]

You are not allowed to talk about that stuff, what do you think this is a "201" class?
Some of us are still doing 101 ditties... on and on!

My math is pretty average… I knew I must have slipped a digit somewhere.
(Probably my 10th grade math and physics.)

 

[Holmz]

I mean, circular answer for circular question?

I thought you gave a link to this thread as the answer to this thread… hence circular.

But let me give you a thoughtful and long-winded answer.

First, let me kindly refer you back to this post below. The OP asked about monoblocks, I made a statement based on science, which is monoblocks have better channel separation as a result of better crosstalk performance due to the explanations I provided in my other post on this thread (at least in theory, but we know it can't have worse channel separation baring some serious edge cases of engineering flaws that I can't think of). I think at this point, no one is disputing that monoblocks have better channel separation? If we are still disputing this then I will not further engage as this all can be confirmed by some simple Google search.

Then it appears to me that I am being accused of saying such said channel separation in monoblocks is indeed needed as the crosstalk in stereo amplifiers under one chassis is indeed audible. I would like people to take a screenshot and show me where I said that. In fact, below screenshot is more than sufficient clarification on something that some here imagined me saying but never said. So yeah, I am getting circular questions, so I was replying in kind with circular answers.

View attachment 465926

Now, there is a philosophical and personal preference on how much crosstalk performance is needed.

This question can be interpreted in two ways (1) "need" in terms not being audible? Or (2) "need" in terms of what you, the consumer, want? (2) is the philosophical and personal preference.

Most modern-day stereo amplifier under one chassis that is competently designed shouldn't have audible crosstalk performance. Just like most DAC, preamps and amps at 100dB SINAD, the distortion and noise *shouldn't* be audible (or at least discernable with music rather than test tone); this is based the common cited .1% THD+N (60dB SINAD) to be the audibility threshold. Then why are people still chasing 110dB SINAD or 120dB SINAD? Why is Amir gloating about the 120dB SINAD Topping B200?

There is no right or wrong answer for someone wanting 120dB SINAD and that answer is whatever the individual wants. Similarity, this also applies to crosstalk performance, there is no right or wrong answer on what a consumer is chasing after.

I can tell you why I want 120dB SINAD DAC and the 110dB SINAD Benchmark AHB2, because I can . . . and I will. Actually, not that "I will" because I already own them and I own them for exactly this reason, because I effing can.

EDIT: this is my last post here about crosstalk performance in monoblocks, any more reply on that, it would just be more circular answers to circular questions.

You have maybe 30dB of channel separation at the ears, so maybe add 10-30dB and 40-60dB should be more than enough.

 

[diablo]

On a more serious note, it's easy to test this, how much it really matters. Play some music at your usual listening volume and then some. On source level, simply disconnect one channel, and on speaker level disconnect the other. That way all you get to hear is the actual crosstalk of your chain. Congrats if you can even hear it at all without creeping into your speakers. Then compare that ever so faint crosstalk to the full volume and then decide whether it matters at all. Brotip: it doesn't, even with "really bad" channel seperation of 40-50dB or so. You'll still get immersive stereo sound with clear imaging.

A couple of years ago I was having trouble getting a sharp stereo image with an SMSL A300 amp. I'd noticed from Amir's review that crosstalk was quite high, so I tested it in the way you describe. It was quite audible from my listening position - but only one way. I got the crosstalk from left into right but not from right to left. Presumably due to circuit board design.
Anyway, as I had two A300s I ran them as monoblocks for a while, which solved the problem and I got a sharp image.
Though more recently I tried one of the A300s in another system and the stereo was totally fine. So maybe the original problem was caused by something else?

 

[voodooless]

So maybe the original problem was caused by something else?

Yes, like imagination, lack of proper testing rigor.

 

[diablo]

Yes, like imagination, lack of proper testing rigor.

It wasn't imagination. I was testing two sets of speakers against each other using my MiniDSP Flex 8, adjusting the delays by fractions of a millisecond to get the image sharp. It wouldn't work with the A300 on that occasion. One set of speakers wonderfully clear and the others woolly. So after I'd tried the crosstalk test I went immediately for the obvious solution of monoblocking them - which worked. Nothing else changed.
I did wonder thereafter if the problem was something else - which is why I did the later test. Still don't know.

 

[voodooless]

Amps don’t have propagation delays in the ms range… none of this makes any sense.

 

[diablo]

Amps don’t have propagation delays in the ms range… none of this makes any sense.

Amps don't, but MiniDSPs do.
I look at the impulse response in REW to set timings but I fine adjust by ear. MiniDSP adjusts by tenths of a millisecond. A millisecond difference can move the image from right to left by a large amount.

 

[voodooless]

Amps don't, but MiniDSPs do.

But the MiniDSP is not subject of inquiry here. Even sub-ms settings is not in the realm of amplifier propagation times, which are at best 10uS, probably less.

 

[antcollinet]

It’s better to use long interconnects than long speaker cables.

I disagree with that. The potential for problems with long interconnects is far greater than for long speaker cables of an appropriate cross sectional area. Double that if the interconnect is RCA.

 

[diablo]

But the MiniDSP is not subject of inquiry here. Even sub-ms settings is not in the realm of amplifier propagation times, which are at best 10uS, probably less.

The main point of my original post was that even clearly audible asymmetric crosstalk doesn't really matter very much.
I waffled on about the detail too much. Sorry I posted now.

 

[mhardy6647]

There were myriad full featured mono preamps in the Golden Age, e.g., Dynaco PAM-1. Marantz and Mac made nice ones, too. Two mono preamps for stereo. Seventeen mono preamps for Atmos. I am just musing...

 

[PristineSound]

The OP asked "why use monoblocks?"

Semantics, but if you read the OP's entire post with context, the OP is asking why uses specific Topping monoblocks over specific Topping stereo amps.

I answered the question in the form of why does monoblocks even exist by stating channel separation and why the B200 had to be a monoblock. Feel free to give that post another read.

Regarding channel separation, I refer you back to this post, as all of your questions and assumptions are already answered here many times over:

Why use monoblocks?

Seems circular… I mean, circular answer for circular question? But let me give you a thoughtful and long-winded answer. First, let me kindly refer you back to this post below. The OP asked about monoblocks, I made a statement based on science, which is monoblocks have better channel...

audiosciencereview.com

If you or anyone else like to further analyze/interrogate/interpret my statement about channel separation wrt monoblocks, feel free to message me as I am sure no one else here is interested in circular questions and circular answers.