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Review and Measurements of Accuphase E-270 Amplifier

sergeauckland

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#22
To finish, orchestral music needs more peak power (more Vpp)<- high DR. But it has very fast transients (or as it is said in English) too <- SR.

Maybe a new thread is better idea.
Whether orchestral music or just a sine wave, the highest SR needed is for 20kHz at full voltage swing. That's within the capabilities of just about any amplifier, so nothing whatsoever difficult. There's no benefit, except in making one feel good, in having a SR that's greater than that. Slew rate doesn't care whether it's a transient or a continuous tone, the voltage still has to swing from - to + full range.

S.
 

Frank Dernie

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#23
It confused the heck out of me initially. When a device has balanced input, I always start with that and in this case, I was amazed at the poor performance. I slept overnight and this morning thought of testing RCA and separating power amp/pre-amp from each other. Only then I figured out the issue with balanced input.
When I bought my Goldmund kit in the mid '90s I was advised to use the single ended connections for a domestic situation where electrical interference was unlikely. The balanced circuits had extra componentry of necessity so was inevitably slightly inferior and was only better if the benefit of noise rejecting balanced cables was needed.
This always has seemed technically logical to me, though it certainly doesn't look like the reason the balanced input is poor on this product.
 
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#24
Thank you for the great review! Bummer the Accuphase couldn't measure up to the Hypex. I just wish the Hypex could be found fully assembled as an unbox, plug and play product.
 

T-NYC

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#25
In back issues of The Audio Critic, you will see that the Technical Editor, Dr David Rich, notes that Accuphase below flagship level is quite ordinary except for the price. Parts and performance are Japanese-standard and mediocre. However, if for example you were to measure their E-650 model and look under the hood, you would find a superior product. Below flagship level there are many better choices available, usually for much less money.
 

T-NYC

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#26
Thank you for the great review! Bummer the Accuphase couldn't measure up to the Hypex. I just wish the Hypex could be found fully assembled as an unbox, plug and play product.
Many firms offer Hypex Ncore implementations across a wide price range, and a narrow performance range.
 

anmpr1

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#27
Really a mixed bag. Beautiful to look at, OK performance, but worth five large? The only imported Japanese product I know with this sort of 'high end' thing going for it would be the Luxman line of integrated amps. Some of those are class A oriented, for what that's worth. Yamaha makes one very high priced integrated, and a lot of lesser priced models. I'd think they should have decent specs. I guess the bottom line is that if you want a pretty good integrated, at a pretty high price, Accuphase might be the ticket. In the US McIntosh makes high priced integrateds. With this in mind, the TEAC hypex product has to be eagerly awaited.
 

anmpr1

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#28
In back issues of The Audio Critic, you will see that the Technical Editor, Dr David Rich, notes that Accuphase below flagship level is quite ordinary except for the price. Parts and performance are Japanese-standard and mediocre. However, if for example you were to measure their E-650 model and look under the hood, you would find a superior product. Below flagship level there are many better choices available, usually for much less money.
In one issue, tuner guru Richard Modafferi (MR-77, MR-78) tested one of the Accuphase tuners (don't recall off hand what model) and found it to be one of the best, if not the best he'd measured. That was the good news. The bad news was that the out of the box factory alignment was all screwed up, so he had to take the top off and scope it out. Now, if you're Rich Modafferi, this is not a problem. But for the average consumer? Next!
 
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#30

maty

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#33
Nelson Pass and slew rate, Jan 4, 2008:

https://www.stereophile.com/content/nelson-pass-simple-sounds-better-page-4

Pass: No, it was a factor. Subsequent to that, though, the Sheffield Drum Record was used in a test and we started getting figures into the 5V/µs ballpark. And those were rim shots. In fact, as far as I can make out, rim shots present the fastest transient that I've seen on a recording. The Sheffield Drum Record was the fastest example that stands out. I haven't seen anything like it since. But given that you're on the 5V/µs rate, we ultimately settled on approximately 50V/µs as a speed beyond which was fine, but it became a minimal figure that we deal with in our designs...
 

maty

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#35
Pass Labs XA25

https://6moons.com/audioreviews2/passlabs3/1.html

...Of course it remains pure Pass as 55bs of 17x14.4x6" WxDxH hardware that runs ~25C° at the radiators, consumes 240 watts at idle and presents your preamp with a 47kΩ input. Voltage gain is 20dB, bandwidth DC-100kHz, noise sub 50µV, slew rate 100V/µs...
 
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#36
Thank You for a very intersting review Amir. I have an Accuphase E-370, the next in the lineup. I’ve used the amp as integrated. As integrated I’ve found the amp pleasant, but not the very last word in dynamics and resolution. I now use the E-370 solely as a preamp. Poweramp is an Anaview AMS 1000. A High quality class D amp which is close to Hypex Ncore In specs.

Interestingly this subjectively outperforms E-370 with a comfortable margin. It sounds more nyanced, dynamic and relaxed at the same time. And yes, I use XLR input in the E-370. Guess I have to try RCA now.

I know this is all subjective, and not based on measurements, but what the heck. Thought I’ll share anyway
 

sergeauckland

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#37
Overkill is fine, if it makes you feel better. You do because you can, not because it's needed. Same as distortion. These days 0.001% isn't unusual, yet is 100x more than is necessary. A frequency response out to 100kHz or more isn't difficult, but is 5x what is necessary. It's very easy to get hung up over specs, and I accept that if I have the choice of two amplifiers, one with 0.1% distortion and one with 0.001% at the same price and all other things being equal, why buy the worse one? Slew Rate is just another specification point that gets some people exercised, but an inadequate slew rate is pretty rare these days. I haven't seen one since germanium transistors in the early 1960s.

S.
 
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