Curious about monoblocks

nicholas2381

nicholas2381

Super Member
I've never used monoblock amplifiers and thus don't know much about them other than the basics. If I were to investigate some "entry level" models, what should I look for? I'm open to thoughts on tube vs. solid state, brands, models, eras, you name it.

Educate me oh knowledgeable ones.
 
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They aren't all that much different than having both amps in the same case, functionally speaking. I swap between mono and stereo amps and don't really notice anything glaring that jumps out at me, performance-wise.
 
Jeffery said:
They aren't all that much different than having both amps in the same case, functionally speaking. I swap between mono and stereo amps and don't really notice anything glaring that jumps out at me, performance-wise.
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So I pay 2x as much and get the same performance? Seems goofy to do that.
 
The speakers your using and how sensitive they are is important. The higher the sensitivity, the less power you may need. Lots of options. I prefer tubes and recently built a couple 125 watt tube mono blocks from kits. With tubes there can be more maintenance involved depending on the type of tube amp. Single ended or push pull. Single ended will be lower powered. Like 15wpc or less is common. With push pull amps, two or more power tubes per channel, will get you higher output depending on the tubes used. Big power tubes can get expencive also. Once the bias is set, it will need to be checked from time to time as the tubes age. Thats the maintenance part. Some are biased with a fixed resistor or resistors and can't be adjusted. Solid state is pretty much set it and forget it. I personally like how tubes sound over SS, but Tube amps do generate some heat and draw more current. All that being said, in the last 10 or so years I've only lost one power tube, one driver tube and a rectifier with all the amps I've had or have. If you have an idea of the power you want or need, you can ask about various tube amps in the tube forum.
 
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Unless the supply in a stereo amplifier is really mushy and the amplifiers have less than stellar power supply rejection ratio, you are not likely to hear a difference between mono-blocks and the same two amp run on a common, adequately stiff supply.
 
egellings said:
Unless the supply in a stereo amplifier is really mushy and the amplifiers have less than stellar power supply rejection ratio, you are not likely to hear a difference between mono-blocks and the same two amp run on a common, adequately stiff supply.
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True, but when looking at higher powered amplifiers, especially tube, the more powerful the amp, the heavier it gets. My 125 watt tube mono's are right at 33lbs each. This is due to the weight of the power transformers and output transformers. A 125wpc stereo tube amp is going to be heavier.
 
Weight is an issue for sure. I have a pair of vacuum tube 75 pounders, and my vertebrae are glad I did not decide to built them as a stereo unit. Sonically, though, it should make no difference so long as the common supply in a stereo version can adequately support both amps playing at once.
 
I don't have much experience with tube amps; I've had two in my life (a tiny cheap one from Massdrop that was fine; and a Laney guitar amp). I had my share of solid state amps and am more familiar with them, but that knowledge is hardly encyclopedic. But I do like to test and play with things just for fun. I just don't want to spend thousands to do it. So, for example, if I could get a pair of Harman-Kardon HK775 or pair of Dynaco MK IV for the same price (I dunno if those are even similarly priced), does it just come down my preference for tube vs. solid state?
 
Preference plays a big role in amplifier selection. Competent S.S. amps will have no sound of their own at all, and different speaker models will sound more similar when driven with a S.S. amp than when driven with a tube amp. Tube amps will have a sonic personality that varies with the speaker they are driving, so it's either divorce court or a marriage made in heaven, depending on how the tube amp and speaker interact with each other, and what you find to be euphonic. The avenue of interaction is the tube amp's rather high output impedance and the speaker's impedance acting as a voltage divider, which allows the speaker's varying impedance vs. frequency to color the sound in tune to the variation. The S.S amp, having a tiny fraction of an ohm's worth of output impedance looks at the speaker and says, "Speaker, you are coming with me. Period-no ifs, ands or buts." Poor thing does not get to add anything at all.
 
nicholas2381 said:
So I pay 2x as much and get the same performance? Seems goofy to do that.
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We don't know what you are looking at, so hard to say it's 2X more.

nicholas2381 said:
I don't have much experience with tube amps; I've had two in my life (a tiny cheap one from Massdrop that was fine; and a Laney guitar amp). I had my share of solid state amps and am more familiar with them, but that knowledge is hardly encyclopedic. But I do like to test and play with things just for fun. I just don't want to spend thousands to do it. So, for example, if I could get a pair of Harman-Kardon HK775 or pair of Dynaco MK IV for the same price (I dunno if those are even similarly priced), does it just come down my preference for tube vs. solid state?
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I have an ST-70 and a pair of MkIII Dynacos. I honestly don't hear a load of difference between them. The MKIIIs were more expensive, but I think there were a lot more ST-70s made.
 
It was a general statement. I'm not looking at anything in particular. I'm trying to get a sense of "hey, if I want to explore monoblocks, this is what I SHOULD be looking for."

If the guidance is "it's only worth it if you have room-filling power-hungry speakers" that's cool. Just thought I'd get an education on the topic.
 
Going mono block would be more expensive since you are buying two separate power supplies, but I doubt twice as expensive, though. I do have a Bryston 4Bst stereo amp that is actually two mono blocks in a single box. It has two separate power toroidal transformers and all the rest. Only thing in common is the power cord, switch, and safe housekeeping circuitry. It is truly dual mono.
 
All good information so far. A lot of high end amps are indeed "dual mono" in design, some stereo receivers are as well. So the idea of having monoblocks is based on solid technology.
That being the case, most people who say they notice a difference are already at the upper tier with all their other equipment, being preamps and speakers. For most of us, the monoblock route would not pay dividends unless their speakers were begging for more WPC, and getting 2 amps was the best way to do it.
 
nicholas2381 said:
It was a general statement. I'm not looking at anything in particular. I'm trying to get a sense of "hey, if I want to explore monoblocks, this is what I SHOULD be looking for."

If the guidance is "it's only worth it if you have room-filling power-hungry speakers" that's cool. Just thought I'd get an education on the topic.
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I use them for aesthetics, amps and speakers next to each other, plus I don't have any room left in the smallish rack in the center. Monoblocks can be physically smaller than their stereo counterparts, although I do have some monoblocks that come in the same case as the stereo version - but with more output than the stereo amp.

I don't think there's any grand scheme to using monoblocks, if they fit in with your system and do the job, then there's no reason not to use them.
 
The whole point of using monoblocks is to achieve better channel separation. I converted a stereo amp to a pair of monoblocks last year. Aside from the individual amps being quieter, they had more impact, speed, and channel separation.

My main reason for doing this was to get more heat out of each amp. It worked well. I could scale them up to 100 watts pretty easily now. Having each amp on its own power supply noticably improved channel separation and the kind of instantaneous power they could deliver to a transient.

It's a much more expensive way to go. Chassis and power supplies are far and away the most expensive parts of an amplifier. It's just a question of how far you want to go for the best possible sound.
 
nicholas2381 said:
I think I'd have to replace a lot of things to get the best possible sound. :rflmao:
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I say possible because possible infers limits. I certainly have financial limits. I've only got about $8000 in my stereo, but I try hard to get the best possible bang for the buck. That's why I ended up building my amps. It's the only way I was ever going to own Pass monoblocks.
 
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