is there an advantage to using monoblocks?

JimBRICK

I've noticed somepeople on here using monoblocks in their 2 channel rigs. I there an advantage to using monoblocks? this is just for my own curiosity

Gaara

I would imagine more power and better channel separation. Instead of your L + R channel using the same unit using monos would keep them completly separated. Audibly there may not be a difference depending on the rest of the system.

Mike682

Each channel gets its own power supply. Running monoblocks also eliminates cross-talk (better channel separation)

Early B.

Do monoblocks generally sound better than a comparable 2-channel amp?

Probably not. If that were the case, monoblocks would be the preferred choice for most audiophiles.

Gaara

I thought monoblocks were the preferred choice of most audiophiles? I don't see how a monoblock could sound worse, and definitly see how it could sound better.

I think the main reason they are not as common is they are more cost prohibitive.

I thought of another benefit, shorter speaker wire runs. Some people say longer speaker wires are more detrimental on the sound then interconnects, if you feel this is true you could have monoblocks directly in back of the speakers giving you extremely short runs. This can't be done with a stereo amp.

phuz

Gaara wrote: »

I thought of another benefit, shorter speaker wire runs. Some people say longer speaker wires are more detrimental on the sound then interconnects, if you feel this is true you could have monoblocks directly in back of the speakers giving you extremely short runs. This can't be done with a stereo amp.

Then you would need longer interconnects...........

Whether or not there is an audible difference is debatable, almost as debatable as cables.

Gaara

Thats what I am saying, some people have the opinion that a longer speaker cable run is more detrimental to the sound then longer interconnects. They feel that having 2ft speaker wire runs with 10 ft interconnects is much better then having 2ft interconnects with 10ft speaker wire runs. If a person had this opinion then it is another benefit of having monoblocks.

hearingimpared

Early B. wrote: »

Probably not. If that were the case, monoblocks would be the preferred choice for most audiophiles.

They're not?

wingnut4772

That's all I see in higher end 2 channel configurations.....

Early B.

wingnut4772 wrote: »

That's all I see in higher end 2 channel configurations.....

Those of us on this forum and other audio forums are more likely to have 2-channel amps. Sure, cost is an issue, but if monos typically sounded better, I betcha more of us would be saving our money to get a pair.

Personally, I'd love to get a nice big pair of monos, but primarily for the cool factor and bragging rights. (Hmmm --- just like a true audiophile.)

JimBRICK

yeah all the crazy expensive systems I see have mono's and when you see high end speakers at the audio shows they always have mono's

hearingimpared

Early B. wrote: »

Those of us on this forum and other audio forums are more likely to have 2-channel amps. Sure, cost is an issue, but if monos typically sounded better, I betcha more of us would be saving our money to get a pair.

Personally, I'd love to get a nice big pair of monos, but primarily for the cool factor and bragging rights. (Hmmm --- just like a true audiophile.)

I've heard good integrated amps as well as good stereo amps. Many companies are making stereo amps with two individual power suplies and two individual chasis even though they share the same box. Although I believe that a well designed/well made stereo amplifier will sound very good and there are some out there that kick the daylights out of some mono blocks, I've been using mono blocks or stereo amps bridged mono since the mid 80s. I believe just the inherent design makes for a better sounding system.

janmike

hearingimpared wrote: »

I've heard good integrated amps as well as good stereo amps. Many companies are making stereo amps with two individual power suplies and two individual chasis even though they share the same box. Although I believe that a well designed/well made stereo amplifier will sound very good and there are some out there that kick the daylights out of some mono blocks, I've been using mono blocks or stereo amps bridged mono since the mid 80s. I believe just the inherent design makes for a better sounding system.

Right on Joe, good point. My Proceed AMP5 has 5 separate amps inside one cabinet and really makes a difference.

Jim, while many high end speaker systems are voiced mono amps, not all my friend.

dorokusai

75% of "audiophiles" wouldn't be able to tell the sonic difference between a monoblock and a stereo amplifier while blindfolded. They usually have them because they can.

No offense to anyone here and naturally I have some monoblocks as well

hearingimpared

dorokusai wrote: »

75% of "audiophiles" wouldn't be able to tell the sonic difference between a monoblock and a stereo amplifier while blindfolded. They usually have them because they can.

No offense to anyone here and naturally I have some monoblocks as well

Don't you mean non-audiophiles?

I would think that audiophiles can hear the slightest changes for better or worse in any rig with a blind fold on. They may not be able to identify what made the change but they can identify that change. That being said if the quality of music is "better" with a better mono-block than the stereo amp, I would think an audiophile would be able to discern the difference.

Gaara

I think he meant audiophiles. The difference is so slight that very few of us would be able to notice the difference.

Personally I would think that having a stereo source and stereo pre-amp would negate the benefit of using monoblock amps. I doubt the difference between two of the same quality would be drastic.

cfrizz

Well I can at least respect your honesty to admit it Mark. I think you & Early are right on the money. It's about bragging rights & the cool factor, not what you can actually hear!

hearingimpared

cfrizz wrote: »

Well I can at least respect your honesty to admit it Mark. I think you & Early are right on the money. It's about bragging rights & the cool factor, not what you can actually hear!

I disagreed with EBs remark about "bragging rights and cool factor" and now you Cath. If I purchased gear based on "bragging rights and cool factor" I would never be able to sit and enjoy the music because the money I paid for the equipment wasn't producing the required results. Bragging rights and cool factor don't amount to better sounding music from my rig. I have a butt ugly rig with a room that looks like a mess but sounds good. . . I don't show people how beautiful my rig is, I demonstrate how great it sounds.

EDIT: speaking of butt ugly, my Spectral preamp is butt ugly but sounds wonderful. It is completely manual and old fashioned looking but sounds wonderful.

JimBRICK

so what you saying is BIG mono blocks = compensating for something else LOL

MacLeod

I think there is a difference in cross talk and it can be measured - but as Mark said, nobody would be able to hear the difference.

You can measure total harmonic distortion of .004% - but you cant hear any below around 1%.

I guess its like the tree in the forest thing. If you cant hear the difference, then does it really make a difference?

A car audio guru recently measured the seperation difference between several 2 channel amps on the biggest car audio forum to see if there was a big difference. The results were interesting but the differences were usually less than 1 decible. And as y'all know, its virtually impossible to hear a difference between anything less than 3 db.

http://forum.elitecaraudio.com/showthread.php?threadid=140145

JL Audio 300/2
left speaker, balance to right

---

62.4dB
right speaker, balance to left

---

62.1dB
right speaker, rt RCA unplugged

---

63.6dB
left speaker, lt RCA unplugged

---

64.3dB



DLS A3 Twin Mono
left speaker, balance to right

---

61.0dB
right speaker, balance to left

---

61.2dB
right speaker, rt RCA unplugged

---

60.6dB
left speaker, lt RCA unplugged

---

60.4dB



Sinfoni Amplitude 150.2X
left speaker, balance to right

---

61.2dB
right speaker, balance to left

---

61.5dB
right speaker, rt RCA unplugged

---

61.1dB
left speaker, lt RCA unplugged

---

66.5dB(yikes)



Arc Audio 2150SE
left speaker, balance to right

---

61.1dB
right speaker, balance to left

---

60.9dB
right speaker, rt RCA unplugged

---

62.1dB
left speaker, lt RCA unplugged

---

61.7dB



JBL Power PX300.4
left speaker, balance to right

---

63.1dB
right speaker, balance to left

---

61.7dB
right speaker, rt RCA unplugged

---

66.1dB
left speaker, lt RCA unplugged

---

67.2dB

mhardy6647

You can measure total harmonic distortion of .004% - but you cant hear any below around 1%.

That is probably true, but perhaps should be qualified a little. 1% THD from a single-ended amp will be predominantly second harmonic of the fundamental tone. This may not be inaudible, but it will be pleasant (euphonic)

Any push-pull amp will produce odd harmonic distortion products, primarily third harmonic (edit: as well as crossover distortion). 1% THD that's primarily third HD might be somewhat unpleasant.

http://en.wikipedia.org/wiki/Tube_sound#Harmonic_content_and_distortion
http://www.audioasylum.com/audio/faq/tubeprimer.html

cfrizz

Thanks Mac, I actually understand what your saying.:D

MHardy, would you mind running that by me again in english!!!:eek:

mhardy6647

Take a look at the links or around about page 40 of
http://www.anthemav.com/OldSitev1/pdf/taste.pdf

This has to do with harmony.

Say the fundamental is 440 Hz (A4, which I believe is A above middle C). The (edit: so-called!) second harmonic is 880 Hz which is A an octave above (A5). Two tones an octave apart sound good :-)
The (edit) third harmonic will be dissonant.
And so it goes, up the scale.

http://www.phy.mtu.edu/~suits/notefreqs.html

MacLeod

Obviously MHardy is a whole lot smarter than me!

THD isnt really a measure of how dirty or clean an amp is but rather how hard the amp is being driven at a given power.

Say amp A makes 100 watts at 2% THD and amp B makes 100 watts at .004% THD. Amp B is a much more powerful amp because although theyre both making the same power, amp A is having to be driven much much harder to make it. So in that case, amp B would make a whole lot more power if pushed to the level of 2% THD.

All that being said, its unlikely youll ever push your amp into the audible distortion range unless youre just trying to push its guts out. NORMAL listening to NORMAL music at a musical level wont tax an amp to that point.

mhardy6647

THD isnt really a measure of how dirty or clean an amp is but rather how hard the amp is being driven at a given power.

That's not exactly wrong, or even inaccurate, but it strikes me as sort of an odd way to think about how an amplifier works.

What happens is this: as an amplifier is driven to its limits (e.g., for a transistor amp, approaching the +/- power supply DC voltage "rails", which is as far as it can go), a pure sine wave (e.g., that 440 Hz pure sine wave "A" on your electronic "metronome") will begin to distort. This manifests itself as a flattening of the top and bottom of the waveform. The sine wave starts to look like a square wave. A square wave is (by definition) a sum ('superposition') of sine waves: the fundamental and "all" of its odd harmonics (out to infinity). In terms of this discussion, the square wave has "rich harmonic content". :-)

The flattened sine wave no longer has just the fundamental frequency; it has considerable harmonic content besides the fundamental. You can deconvolute the waveform (trivial with computers today) and look at this qualitatively and quantitatively. That, folks, is harmonic distortion.

At lower power, though, an amplifier will not reproduce a sine wave perfectly, either. Since most real world listening is often at very low average power, the harmonic distortion of most amps at low power is really where the sonic differences come from. Many amps (especially solid state amps) have surprisingly high levels of distortion at sub 1-watt power levels. This, I think, is why so many SS amps sound not so great on high-sensitivity speakers (e.g., Lowthers) and why they tend to lose transparency at low volume levels on less-sensitive speakers.

Finally, there are other kinds of distortion besides harmonic (like the crossover distortion suffered, to some extent, by ALL push-pull amps), some of which may be more audibly objectionable than THD.

So, yes, at high power, high distortion means the amp is going nonlinear. But amps can be nonlinear at lower powers, too, and in a frequency dependent way.

The well-trained and discerning human ear is still an awfully valuable instrument in deciding what sounds "good" or what sounds "best" (to an individual).


http://www.allaboutcircuits.com/vol_2/chpt_7/5.html
The math in this reference is a little esoteric, but the text gets at the heart of why "all amps DON'T sound exactly the same" in the real world, no matter how they measure for relatively simple, static parameters like THD.

We can also apply the superposition theorem to the analysis of a circuit powered by a non-sinusoidal voltage, such as a square wave. If we know the Fourier series (multiple sine/cosine wave equivalent) of that wave, we can regard it as originating from a series-connected string of multiple sinusoidal voltage sources at the appropriate amplitudes, frequencies, and phase shifts. Needless to say, this can be a laborious task for some waveforms (an accurate square-wave Fourier Series is considered to be expressed out to the ninth harmonic, or five sine waves in all!), but it is possible. I mention this not to scare you, but to inform you of the potential complexity lurking behind seemingly simple waveforms. A real-life circuit will respond just the same to being powered by a square wave as being powered by an infinite series of sine waves of odd-multiple frequencies and diminishing amplitudes. This has been known to translate into unexpected circuit resonances, transformer and inductor core overheating due to eddy currents, electromagnetic noise over broad ranges of the frequency spectrum, and the like. Technicians and engineers need to be made aware of the potential effects of non-sinusoidal waveforms in reactive circuits.

MacLeod

I dont have the techinical expertise to go toe to toe with ya brother so itll be real easy for you to get over my head but I suppose Im coming mainly from a view of power ratings. For those, the THD isnt a measure of amp cleanliness. That would be more for the signal to noise ration. But there again, anything over 100 db and youre getting into the inaudible range again and virtually all amps will do 100 db standing on their heads.

mhardy6647

Dynamic range is a somewhat different beast. At extremes, yes, the noise will start to predominate as the waveform distortion. You'll even see amp performance represented as "THD+N" sometimes.

As to the "100 dB"...
100 dB versus what? Full output? 1 watt? It is important, and nontrivial. For a 100 watt amp, it would represent two orders of magnitude difference in noise...

Actually, we're in violent agreement!

Listening is where it's at... but it is nice to know a little about the physics behind why things sound the way they do, too.

MacLeod

Totally agree. Im pretty well versed in general theroy, I just lack specifics!

I couldve been a physicist. It was just the math I had a problem with.

Gaara

This is all familiar from either "The Complete Guide to High End Audio" or "The Master Handbook of Acoustics" can't remember which.

I follow everything except I have never heard of "crossover distortion". I could make some assumptions on what it entails but could you describe this for me mhardy?

Thanks.

Jared

MacLeod

Ooh ooh! I know this one!

Its nothing to do with the crossovers. In a Class AB amp, one transistor handles the positive part of the signal while another handles the negative side.

Ideally you would have both transistors turned partially on so that the transfer between them is smooth. In lower quality amps, the transistors dont "handoff" smoothly because theyre not on when not in use so there is a slight interuption of the transfer and this shows up as distortion.

Think of it like a baton race. Say runner A is going to hand off to runner B. If runner B is slowly running in front of him, when they hand off itll be smooth and there wont be a drop in speed. If runner B is standing still, there will be an interuption.

Excessive levels of crossover distortion can signifigantly raise the noise floor.

Systems

MacLeod wrote: »

Ideally you would have both transistors turned partially on so that the transfer between them is smooth. In lower quality amps, the transistors dont "handoff" smoothly because theyre not on when not in use so there is a slight interuption of the transfer and this shows up as distortion.

Correct. If bias level is set too low crossover distortion will be present.