Need Your opinion on a Yamaha amp

[JerryD99]

I have been looking to upgrade my system with some external power amps. Current I have a Yamaha DSP-A1
and for now using it as a pre, also planning to upgrade it to maybe cx-a5100 Pre. Anyway back to the question about the power amps.
I have been looking at the Yamaha m45, m60, m65, m80, m85, and mx1000 and mx800. My question is as follows:
1. Which runs ones can you turn the class A off and when turn off will it run cooler?
2. Which on sound better m series or mx series?
3. Which is more reliable? I know the m series is older.

This is my plan:
have a main amp either m80, m85 or mx1000 for music listen. Then have a output from that pre-amp feed into a Processor for all the surround sound processing and that processor would feed external amps. Those amps would be Main amp m80, m85 or mx1000 for L & R then the same model amp for center. Surround sound amp for LR RR, SL, SR would be m45, m65 or mx800.

Main and Center would be 2 amps
LR, RR, SL,SR would be 2 amps

All comments welcome.
Thanks
Jerry

 

[whoaru99]

At one time my HT ran from two M-80 and two M-40.

The front left, center, and front right were powered by the two M-80s while the surround and back speaker pairs each ran from their own M-40.

Worked quite well. All those had the switch for Auto Class A on/off.

 

[rottalpha]

The MX will ran cooler by a long shot.
It sounds to me that you might be considering a rack to locate this equipment, which is not recomended. If you need to hold your equipment in a rack, look for a pro amp solution. Yamaha has many good choices there as well.

as far as the M and MX,
The M will have class A for the first few watts, then it runns in class AB if I understand correctly.
MX has a sliding bias and will hold class A performace all the way to max power.

M-85 is mighty fine amp, but I made my choice long ago and opted for the MX-1000 for more than one reason.

Very unforgiving amps, very transparent. A restored MX-1000 sounds so fine, it is really hard to whipe the smile off my face anytime I get to listen to one.
I am sure that a M-80/M-85 would sound the same.

good luck in your quest

 

[Electone]

I'm thinking you have a DSP-A1 and not a "DPS-1A"? If so, you've already got a fantastic sounding amplifier. Sure, it may not have the raw power of separate power amps, but most reviews are almost always positive.

 

[JerryD99]

Yes Sir you are correct it is a DSP-A1 and I purchased this new in 1994 or so. It has been and still is a great unit. The only problem is that is a 5.1 Doby or DTS. It is staying for sure, but wanted to move to a 7.2.2. currently room is small and don't need a lot of power, but hope that will change.

Rottalpha:
Will the MX be cooler that the M80/85 as you have stated, but is that with Class A Off on the M80/85? I was reading a post on here, don't know who posted it, but they were saying their MX1000 ran hotter than there M80. However they did not specify at what load each was running.

Thanks for your input, just trying to get as much info as possible before purchasing.
Also What kind of prices are reasonable for these amps? I have see some m45 for about 315 plus shipping. These would be for the surround speakers and the speaker are 8 ohms. MX800 534 with shipping and everything is working.

I have also looked at the M4, but they are older, but I think Class A is on all the time so Maybe this amp would run hotter?

 

[amr2]

M80 with Class A off doesn't run very hot. I think that more or less like a MX1000.

 

[JerryD99]

At one time my HT ran from two M-80 and two M-40.

The front left, center, and front right were powered by the two M-80s while the surround and back speaker pairs each ran from their own M-40.

Worked quite well. All those had the switch for Auto Class A on/off.

Do you still run those amp in HT or did you go with something else and if you did may I ask what?
Thanks
Jerry

 

[whoaru99]

I changed out the Yamahas with four QSC PLX-series pro audio amps. Two PLX 3402 for the fronts and center (700wpc each) and two PLX 2402 for the surround and back speakers (425wpc each).

Changed not because there was anything wrong, per se, with the Yamahas. I was just on a "no clipping allowed" kick and, you know, I needed that bigger power 1% of the time. LOL.

Sold one of the M-80s some years back but still have the other three Yamaha.

 

[JerryD99]

I changed out the Yamahas with four QSC PLX-series pro audio amps. Two PLX 3402 for the fronts and center (700wpc each) and two PLX 2402 for the surround and back speakers (425wpc each).

Changed not because there was anything wrong, per se, with the Yamahas. I was just on a "no clipping allowed" kick and, you know, I needed that bigger power 1% of the time. LOL.

Sold one of the M-80s some years back but still have the other three Yamaha.

How do you like the QSC, I know they are a fine amp, but thought the home stereo amps would me more refine sound and match up better. I did not know you could use commercial sound system amp in home stereo and HT.

Reality trying to do some research on this as want to make a good decision. Of course there is maintance to do on the 40 or so years amps. would I be better off by getting new. I have look at Emotiva, but have read good and bad things about them and no way to listen to them. One of the reasons I was looking at the Yamaha is I have the DSP-A1 and it has been a great product and kinda like the meters.

 

[savatage1973]

I did not know you could use commercial sound system amp in home stereo and HT.

Pro amps are certainly an option for HT--helped a lot of folks set up HT rigs with pro amps. Stuff from QSC (as mentioned) or Crown, Urei (JBL) or Mackie are really clean, and they are designed to be tightly packed in road cases, so they are perfect for hiding in cabinets with poor ventilation (most are fan cooled). The main differences between pro amps and home amps are that pro amps are not "voiced"--they are very "neutral" (which I consider a plus), but they can be "ugly"--they are designed to put out a ton of power and be used and abused, so they are rugged chassis that are not so "aesthetically pleasing"--no "pretty" meters or wood cases/endcaps--all business--and high wattage pro amps tend to be a lot cheaper per watt than home amps, in terms of purchase price.

As for the Yammies, I prefer the M-series over the MX-series, but that is just me. But they do require "breathing room" so they will take up a lot more space for proper ventilation, but are "pretty" enough to have out in your system rack.

 

[whoaru99]

Yeah, the QSCs are not as pretty as the Yamaha but I have all that stuff set up behind me anyway. It's not part of a big entertainment type setup because I don't want all the blinky lights and stuff up by the TV.

In terms of sound quality it is my opinion the QSC are not a step backward. They do have fans as savatage1973 pointed out, but I've modified mine with low flow fans and by doing so reduced the fan noise to an immaterial level.

 

[JerryD99]

I will be using this for 2 channel listen and then feeding that 2 channel into a HT bypass somehow. The room could house 2 separate system a 2 channel and a HT, but prefer the bypass option due to the space available. No other room available. The way I understand it commercial amp can be use for HT but not necessarily for 2 channel listen.

 

[whoaru99]

...The way I understand it commercial amp can be use for HT but not necessarily for 2 channel listen.

I use mine right along side Levinson and Audio Research. The QSCs work quite well driving my Thiel CS3.6 in a two ch system.

I've even used a parallel mono'd pair of Crown MT1200s (rated 1300 watts each @ 1 ohm) on the Thiel speakers. Sounded good too, but the fans in those are too noisy and not conducive to modifications so they're sitting in the back room gathering dust.

 

[whoaru99]

FWIW, I'm not trying to convince you to buy a pro audio amp. Simply relaying my experience since you asked.

If you are uncomfortable with the idea of using a pro audio amp in your system, HT or otherwise, then I suggest not to.

 

[Chris Brown]

The way I understand it commercial amp can be use for HT but not necessarily for 2 channel listen.

What is important to understand is that "pro amps" or "commercial amps" is more of a label than an actual category. An amp having that label doesn't automatically mean that it's unsuited for anything. There isn't any general rule where "pro amps" have to have worse specs than "home amps" or any nonsense like that. There is as much variation among "pro amps" as there is among "home amps". No one in their right mind would lump all "home amps" together and rely on generalizations made about that label, and it doesn't make sense to do the same for "pro amps" either.

The key is, to evaluate each individual amp based on it's own merits. Ignore the labels. There are "pro amps" that are good and bad; there are "home amps" that are good and bad. The good "pro amps" give up nothing in terms of sound quality.

 

[zaibatsu]

The M amps run cool when the Class-A switch is off, but I think it's wise to have them restored by a professional at least for the minimum tasks (removing corrosive glue, replacing corroded components, retouching any dry/cracked solder joints). Failing to do so might risk more expensive repairs in the future. If it were me I'd pick an M for music listening / stereo mains (factoring in basic restoration cost), and then just use pro amps or MX amps for surround and other duties.

The M will have class A for the first few watts, then it runns in class AB if I understand correctly. MX has a sliding bias and will hold class A performace all the way to max power.

That's not really true, the M is a true Class-A amp and under most average speakers and listening levels it is unlikely that it will leave the pure Class-A region anyway - especially in the case of the M-80 and M-85 which provide a large ~30W region.

The HCA on the MX is not a true Class-A implementation, Douglas Self does a pretty good job of explaining the pitfalls of the sliding bias claims, and from memory in one edition of the power amp design book he debunks the HCA specifically. The key point of (real) Class-A is to kill crossover distortion by holding the transistor permanently at high bias, with secondary benefits from the consistent loading (and thus less current load variation under dynamic peaks). If you do neither of these things you don't gain either benefit. From memory the implementation in the MX-10000 is very different, but on the other MX amps it's nothing special.

I think most of the M / MX Yamaha amps sound great for reasons unrelated to the quiescent / bias scenario (just good circuit design in general) but if you want true Class-A then the proper switchable amps are the answer. Please correct me if I'm wrong, just my understanding after a bunch of reading, and certainly there might be other good reasons you prefer the MX.

 

[rottalpha]

The HCA on the MX is not a true Class-A implementation, Douglas Self does a pretty good job of explaining the pitfalls of the sliding bias claims, and from memory in one edition of the power amp design book he debunks the HCA specifically. The key point of (real) Class-A is to kill crossover distortion by holding the transistor permanently at high bias, with secondary benefits from the consistent loading (and thus less current load variation under dynamic peaks). If you do neither of these things you don't gain either benefit. From memory the implementation in the MX-10000 is very different, but on the other MX amps it's nothing special.

wait, what
you would pick the M because the M in class A has less cross-over distorsion
..and the sliding bios is somewhat non relevant, or nothing specilal because it was debunked by someone...albit a very respected persona

how about this for a fact check: The lowest distorsion in a production amp was achieved...guess what, by a sliding bias amp (the MX-10k from what I remember), not by a pure Class A

so yeah, show me the most beautiful woman in the world and I bet that I would find something wrong about her too...

Lets just say; to me the distorsion of the MX is not a problem..

Based on other accounts, both amps have a similar sound...a very revealing and transparent Yamaha sound that is, thus I assume that in terms of sound there would not be much concern or valid reason to pick one over the other.

Here are the reasons why I would still pick the MX if I had the choice to either or:

The MX is a more modern design in terms of tapology, yes I actually preffer the sliding bias to the hybrid Class A, then AB setup. That is not to say I dislike Class A...more on that in a bit.
The MX has better cooling under all conditions, idles cooler to begin with and will disperse heat faster by design( more on that in a bit too).
And I am willing to bet that the MX will putt out more actual watts if anyone would care (no, not rated watts, those would be the same)...deviating form being objective here...bad me

Fact: the MX actually idles at only ~70w...that is same as the average PC. With nothing above it, the MX will stay cool to the touch for hours. The transformers have the chance to get hotter than the heatsinks...


now more granular stuff;

No dreaded sony glue in the MX
The components, particularly the outputs are easyer to find...and cheaper.
No idle to adjust or to worry about...because the idle in the MX is allways "perfect"

and did I say that the MX runs cooler, yea, because heat kills any electronic components, given that they are exposed to it for a long period of time. Even if the two amps look similar on the outside, the MX has better cooling built in...not just from the perspective of the circuit design, but also from perspective of mechanical design...like even going to the extent of placing holes into the PCB's everywhere, albeit, yamaha did it at the expense of the screwed up way they mated the sub boards and main board which makes the MX a real PITA to service, so from that perspective the M has the upper hand (from what I can tell from other's photos since I never been inside an M ...yet).

Now please do not take me wrong....I will have a M85 one day...I allways wanted one.

In the meantime, I have my own Class A prefference....No A, AB hybrids, no sliding bias, no compromise! Pure Class A, all the way

...
only problem with them is that they are sitting in their boxes for over one year now :tears

 

[zaibatsu]

..and the sliding bios is somewhat non relevant, or nothing specilal because it was debunked by someone...albit a very respected persona
how about this for a fact check: The lowest distorsion in a production amp was achieved...guess what, by a sliding bias amp (the MX-10k from what I remember), not by a pure Class A

I certainly wasn't saying any Yamaha product didn't sound great, I was just pointing out that the MX-1000 is not actually Class-A as you claimed. If one wanted that feature, then the M-80/M-85 implement it correctly. As I also stated, the MX-10000 is a very different amp and the HCA implementation is completely different to the other MX amps, so unless one is actually considering buying that (which the OP isn't) then it's not a relevant parallel to draw. I have no doubt that the MX-10000 is one of Yamaha's finest works, if not the finest (though those BX-1s look nice!).

There is a very basic explanation if you click "user" and read the last 3 paragraphs on the TVK MX-10k page:
http://www.thevintageknob.org/yamaha-MX-10000.html
I also shared 3 more detailed discussion links in post #6 here:
http://audiokarma.org/forums/index....perbolic-conversion-amplification-hca.737425/
Douglas Self's claims have been verified, and in fact covered in much more detail across these links.

Don't get me wrong - I'm yet to hear a Yamaha product that doesn't sound pretty damn good, the MX-1000 being no exception - and your points on cooling and no bad glue are useful too. Just thought it was best to clarify that small detail.

 

[rottalpha]

still unsure what you tried to clarify. I know exactly what I said and what the MX design is

MX has a sliding bias and will hold class A performace all the way to max power.

Class A is preffered...or was preffered exactly for the point you mentioned...as it is not affected by crossover distorsion. This was prevalent in the old days of amplification design when the alterantives would have yelded human hearing, noticable IMD.

Since the sliding bias offers non-perceivable distorsion, then the MX 1K offeres Class A performance. As in: provides Class A performance all the way to full power.
Wheather the sliding bias implementation is same or differnt than other sliding bias implementations, it is irrelevant from this perspective.

Now, I drew the paralel to the MX-10k as it bests most Class A designs in terms of low distorsion. So pure Class A ....no longer the king, per se.

If the amp sounds good, that is all that matters. If you want to add instrument tested performance into the mix...that is fine too. Point is, whether MX-10k or MX-1K have differnt implementations of the sliding bias or not, the fact is that they rival the best Class A design in terms of distorsion, or lack thereoff. MX-10K bests most amps of any brand, any tapology and the MX 1K rivals most amps of any brand any tapology. Yeah, the MX 1K feels like a thin can of sardines in terms of physical construction compared to some monster amps, including some from yamaha, but it is no light weight in terms of sound and suceeds where many Class A amps would have fail to perform or compete, as in crystal clear sound at 300+ watts and be able to drive some of the most difficult speakers too.


and yes, I red those articles and others too. They mean nothing if the amp sounds the same as a Class A. What sliding bias and lower heat to performance coefficient really gives you over the A, AB design is longevity. While the MX unit otherwise sounds at least as good as the M when new, it will sound better at the units age, since its M sibling electrical components would be succeptable to higher temperatures for longer periods.

Yamaha's fault with most of their equipment of the era was the poor soldering job, from which the MX 1000 makes no exception. Additional to poor soldering, the M80/85 suffer from dreaded Sony glue and from a mechanical design, not really suited for sustained pure Class A use. I never saw an advantage of having the M over the MX...that is why at one point I had over 1/2 dozen MX's and no M's (at least not yet). This is of course only my opinion and it is not intended to mean anything to others.

 

[zaibatsu]

To clarify, this is incorrect (and is the only point I wanted to make):

MX has a sliding bias and will hold class A performace all the way to max power.

It does not actually hold Class A performance (at all) if you understand the circuit and how it works.
I never said it wasn't a good sounding amp (the opposite infact) - and of course I agree, if it sounds good the topology doesn't matter.

As for "no longer the king" - hardly, if you invest MX-10k kind of development time and money into ANY decent topology, it's going to be incredible. I don't think anyone is going to argue that a TOTL Class AB amp will likely sound better than a cheaper Class A one (with the inverse also being true). That's a straw man argument.

Not sure where you're getting "sounds the same" though - it's unlikely - possibly very similar but probably not the same. Distortion numbers alone mean little, and crossover distortion in particular tends to be composed of undesirable higher order distortions (i.e. not just 2nd / 3rd harmonic), so cutting crossover distortion can have audible benefits that aren't reflected in the single (averaged) number alone. In my experience, with good speakers it's fairly easy to tell the difference between the magic switch being on or off - but to each their own. By the sounds you haven't actually A/B'd the two in the same setup so I'm not sure how you can even claim they sound the same?

The reason the MX-10k is an incredible amp is because it uses a completely separate secondary error correction amplifier to cut down distortion very accurately, however this implementation is unique to the 10k and not shared by any other MX amp. Basically, the MX-10k is completely irrelevant to this discussion - the only thing it has in common with anything discussed here is a three-letter acronym - the circuit is completely different.

I don't think I need to comment further on the heat / solder joint stuff, that's all pretty common knowledge here and I already mentioned it. However I do believe all of Yamaha's Class-A amps are suited to sustained Class-A use provided they have been gone over thoroughly by an experienced tech, and ideally resoldered completely. The M-80/M-85 have extruded heatsinks with far greater thermal mass than the MX-1000 to cater for this. Even an M-40 has significantly bigger heatsinks than an MX-1000, so these amps are definitely designed to handle it. I'd be more worried about those beautiful BX-1s, they've a LOT more heat to dissipate!

I think the OP already understands the heat issues and desired the switchable setup for that very reason. The Auto Class-A amps run quite cool with the switch off, it's a useful feature when not listening critically.

I only wanted to comment on the circuitry.