Musmy a75 clone (not a review)

[Malohm]

I

The 2860-Plus has a lot of mediocre electrolytic caps in the signal-path, Most are same type/size. And for the tone-control board, I would change tweeter-caps for half the value, it rises too early (in midrange). + DC-blocking caps... (and opamp if you want..)

Interesting ... I can see that you have replaced some of the poly film caps on the main board. How did it change the sound?

Also ... my 2860-Plus uses (exclusively) Elna and Nichicon for the electrolytes. Is this perhaps yet again another version of this amp?

I can't get hot & bothered by a maker's attempt to exploit the appear of the prestige brands or even their circuitry. If, in fact, there are patent or copyright violations then if behoves the prestige brand to sue or take other measures.

The OP loves the appearance of the Musmy on his rack and can't say I blame him for that -- it looks great though it isn't likely fool any slightly knowledgeable person that it's an Accuphase.

Of course equal or (more likely) better performance can be obtained from, say, a Topping B200. So what? As long as the OP isn't under the delusion that he has an Accuphase, (which he isn't), then it's his clear-minded choice to go for the glamor over value.

I have tried Topping B200's. They come nowhere close to Musmys' A75. Main issues (with my SF Cremona speakers) were poor soundstage, and wobbly / weak bass (my speakers dip well below 4 Ohms in the bass region). Price-wise, the Toppings actually were about 10% more expensive after ship and tax. Also tried Fosi V3 monos. Not bad for what they cost (and tighter bass than Topping), but similar soundstage issues and too clinical sound overall for my taste. Last but not least, I compared with an Audio Analogue Donizetti. Which came close to Musmys, except for treble roll-off and slightly less well-defined sound stage. Still want to try higher-end class D, e.g. Nilai (which are double the price of my Musmys, though). Would love to hear from others on their comparisons.

 

[Malohm]

Sure.

Anyway, even if this kind of clone isn't badged Accuphase (or any other cloned brand), these makers are obviouly searching tocopt the appearance of well known original products and get profit from this imitation. I guess Accuphase and other copied brands have asked their lawyers if something could be done to suit such practices.

Even if these amps works fine (it's easy to make an amp work fine today, anyway) I'm shocked by this obvious imitation. As for me, it's not a proper audio industry.
You'd better buy an original good and cheap class D or AB from a maker of today, at least you'll own a real product and not an external copycat.

People who are ready to buy things like like this suffer in my opinion from an obsession for the object as an appearance, they're not in quest for an object for its function and its quality. It's the same as people who crave for a copy (often at a price) of a well known sculpture or painting. I have no will at all in such a confusion between object and artistic or technical creation.
I like Accuphase, or Mc, or Quad amps, but I would never buy such imitation products, good or not.

I would argue we talk rather different market segments. I had an Accuphase E305 which I strictly used for actual listening, and I have my Musmys for tinkering and learning the tech. Neither Musmys or their customers would seriously consider their products 'clones'. Plus: the majority of the products on their website are genuine products which perhaps deserve a little more attention.
Kind of reminds me of the Korsun/Dussun V8i vs. Red Rose / Mark Levinson story of some 20 years ago (ML back then sold copies at healthy margins of the V8i - which was a genuine Chinese design...)

 

[Gorgonzola]

I have tried Topping B200's. They come nowhere close to Musmys' A75. Main issues (with my SF Cremona speakers) were poor soundstage, and wobbly / weak bass (my speakers dip well below 4 Ohms in the bass region). Price-wise, the Toppings actually were about 10% more expensive after ship and tax. Also tried Fosi V3 monos. Not bad for what they cost (and tighter bass than Topping), but similar soundstage issues and too clinical sound overall for my taste. Last but not least, I compared with an Audio Analogue Donizetti. Which came close to Musmys, except for treble roll-off and slightly less well-defined sound stage. Still want to try higher-end class D, e.g. Nilai (which are double the price of my Musmys, though). Would love to hear from others on their comparisons.

I'm glad you're pleased with you Musmy A75's.

If you could see your way to ship the Musmy to Amir for actual testing & measurement that would be great, though the shipping would probably be prohibitive.

I'm not one to believe that super expensive internal components necessarily make for better sound vs. "mediocre" equivalents. Choosing were better ones are likely to make a significant difference to performance and/or reliability would be the trick.

 

[khaliss]

Well ... features taken from the original include look & feel (albeit not at same level of refinement), mosfets for both the actual power stage as well as speaker protection/switch, oversized power supply (transformer, capacitor bank), dedicated and fully balanced input stage. Not sure about the power amp stage but this looks similar on pictures at least. Then again, Musmys obviously had to cut corners so they biased this amp in AB mode (with quite some reserves to extend the class A range ...), the transformer seems to be E-I type instead of toroidal, there is no soft-start and I suspect this is why the they eventually put the power caps in series, to limit the start-up spike going through the rectifier bridge. I come from an Accuphase E305 myself and the Musmys A75 is more quite (zero transformer hum, zero output hiss), and is has (a lot more) bass power and stiffness. So this is all good, certainly for the money. As long as one doesn't expect the same performance as the original Accuphase A75...

Thanks for all your detailed observations & comparisons with an actual Accuphase E305... I don't have this A75 (I have the lower tier Musmys E406), and I'm already happy with my unit. Someday, I'll purchase a genuine Accuphase... but for the time being, I'm good with what I have.

I asked AI about the patent/copyright question... here's the answer:

 

[Cobra2]

Chinese clone = "based on a true story" ......

About cap-differences... they use whatever batch they find cheap... and change when they run out.

 

[mhardy6647]

Chinese clone = "based on a true story" ......

About cap-differences... they use whatever batch they find cheap... and change when they run out.

"True as remembered by the storyteller" (as they say on The Moth -- or words to that effect).
and, yeah, I suspect you're right re: the capacitors.

 

[mocenigo]

People mostly don't realise how little power is actually needed in most cases.... often what is more important is how the amp behaves into reactive loads, and the varying impedances that many real life speakers have...

True, but, at the same time, people mostly don't realise how much power is actually needed to represent transients. Which can become a quite hairy affair into reactive loads.

Roberto

 

[mocenigo]

I have tried Topping B200's. They come nowhere close to Musmys' A75. Main issues (with my SF Cremona speakers) were poor soundstage, and wobbly / weak bass (my speakers dip well below 4 Ohms in the bass region).

Well, a B200 provides 200W into 8Ω, and 200W into 4Ω as well. This is a sign it can't really go much lower than that. This is to be expected. it is not that the B200 is a worse amplifier, but it is definitely the wrong one for those speakers.

 

[Johnkeizer]

My big Klipsch speakers are about 95 dB/1 watt/1m. ( no I don’t believe the 98 or 102 I have come across)
I sit 2.5 m from speakers.
So about 85 dB for 1 watt input.
I PEAK at 90, average 75 to 80.
So even my 100 watt class a power amp is over kill.

 

[Mart68]

My big Klipsch speakers are about 95 dB/1 watt/1m. ( no I don’t believe the 98 or 102 I have come across)
I sit 2.5 m from speakers.
So about 85 dB for 1 watt input.
I PEAK at 90, average 75 to 80.
So even my 100 watt class a power amp is over kill.

Similar figures here, my 50 watt class A is overkill.

 

[Malohm]

My Cremonas have a 91dB sensitivity and (at my listening position) play really loud at 5W per channel. "Normal" listening sessions top out at 2W. I realize transients (temporarily) need way more power. Also, the factory setting of the Mumsys A75 sacrifies class-A range for safety, and in my opinion unnecessarily so.

Realizing that the amp's thermal design can easily handle higher idle currents, I have now shifted my bias from 13 mV (across the 0.22 Ohm source resistors of each of the 24 power mosfets) to 37 mV. This translates to roughly doubling the amps idle power (from 105W to 210W; slightly lower than Accuphase A75: 260W). Transistor temp when playing music loud is now around 50 degC, heatsink temp is 42 degC, top of case at 35 degC. All well within safe limits.

This effectively increases my class-A output range from 1.8W to 8W (at 4 Ohm) per channel, meaning all my listening is now class-A indeed. Transients, depth, mid-range liquidity and woofer grip have improved as expected. This is an easy (and reversible) mod which I highly recommend.

 

[Svend P]

This effectively increases my class-A output range from 1.4W to 8W (at 4 Ohm) per channel, meaning all my listening is now class-A indeed. Transients, depth, mid-range liquidity and woofer grip have improved as expected. This is an easy (and reversible) mod which I highly recommend.

The benefits of Class A amplifiers is just an audiophile myth. You have to test blind and be able to switch instantly to say anything reliable about changes to the sound.

Master Thread: Are Measurements Everything or Nothing?

A ‘better’ one? I didn’t by the way trade my Pass for another. Keith

www.audiosciencereview.com

 

[Malohm]

I disagree - although the differences are admittedly subtle. They are obvious (and AxB blind-tested) to me when listening to well-record classical or Jazz music at lower volume. And certainly a matter of personal taste honed over 40+ years in this hobby. No offense to everbody else here who might have different listening priorities.

 

[Svend P]

I disagree - although the differences are admittedly subtle. They are obvious (and AxB blind-tested) to me when listening to well-record classical or Jazz music at lower volume. And certainly a matter of personal taste honed over 40+ years in this hobby. No offense to everbody else here who might have different listening priorities.

But there is no way to reliably blind test changing the bias. All proper amplifiers sound the same when operating within their power limits.

 

[Johnkeizer]

Sigh- another one.
The man said “to me”, can’t people leave it at that? If you are convinced they all sound the same, good for you, please don’t try to force your view on people who have a different view.

 

[Svend P]

Sigh- another one.
The man said “to me”, can’t people leave it at that? If you are convinced they all sound the same, good for you, please don’t try to force your view on people who have a different view.

This has been common knowledge for the last 40 years. Manufacturers and reviewers just don't want people to know, otherwise they would stop buying new gear.

https://www.worldradiohistory.com/Archive-All-Audio/Archive-HiFI-Stereo/80s/HiFi-Stereo-Review-1987-01.pdf

Page 78

 

[Johnkeizer]

Nope, he can’t let go.
Thankfully he doesn’t have a gun and live near me.

 

[Svend P]

Nope, he can’t let go.
Thankfully he doesn’t have a gun and live near me.

ASR is a place for science. Not beliefs. Your attitude has no place here

Message to golden-eared audiophiles posting at ASR for the first time...

Hello friend. Hey, listen...we know how it is. Believe me, most of us have been there too. You've spent years toiling in the muck of audiophilia. You read ALL the reviews. You watched ALL the youtube videos. You visited ALL the other forums where everything always makes a difference. You...

www.audiosciencereview.com

 

[Johnkeizer]

I am in full agreement with science.
I also believe in tolerance.

 

[RickS]

Was worried this thread might need a major sweep, but have issued some warnings and am reopening.

Just a reminder to be more tolerant of newcomers and stick to the science please. Thanks!