Review and Measurements of Purifi 1ET400A Amplifier

[Julf]

I listen to mostly 60's-70's Classic Rock and Pop. None of it is perfectly recorded. Nor was it intended to be. It's multi track overdubs. Analog tape has an organic sound. So the source material is already colored. I don't want to listen through a amplifier that sounds like an electron microscope.

If the source material already has the coloration you like, why would you want to add more?

 

[Labjr]

If the source material already has the coloration you like, why would you want to add more?

The source material has the musical content I like but not necessarily the coloration. Some of it sounds terrible. I don't want to hear every tape splice and the grain of the tape magnified. Listening for enjoyment requires a balance. I enjoy different types of music played on different equipment.

I'm starting to believe that people like Nelson Pass and to some extent Bob Carver have had the right idea all along.

 

[Ron Texas]

@amirm this has probably been answered somewhere else, but I wonder what kind of load is used to test power amps? Would it be any different from the typical passive crossover in a loudspeaker, or even the driver itself in an active speaker?

 

[GrimSurfer]

The source material has the musical content I like but not necessarily the coloration. Some of it sounds terrible. I don't want to hear every tape splice and the grain of the tape magnified. Listening for enjoyment requires a balance. I enjoy different types of music played on different equipment.

I'm starting to believe that people like Nelson Pass and to some extent Bob Carver have had the right idea all along.

Get the best versions of recordings, in the lowest noise and highest dynamic range format, you can.

If you buy an amp that filters out elements of the source material (no matter how pleasing at the time), then great recordings will never sound great on your system.

 

[Labjr]

Get the best versions of recordings, in the lowest noise and highest dynamic range format, you can.

If you buy an amp that filters out elements of the source material (no matter how pleasing at the time), then great recordings will never sound great on your system.

Well, if I don't listen because I don't like the way it sounds then it will never sound great anyway. I listen to Jazz and acoustic recordings on 300B SET amps and efficient speakers. There's plenty of resolution and the coloration is enjoyable. That system has impressed many visitors. I've also used a tube preamp to soften the sound of solid state amps a bit. And I don't think I've heard better Stereo FM radio than I get with my vintage Fisher receiver that's nearly 60 years old. So depends what you like.

 

[GrimSurfer]

Well, if I don't listen because I don't like the way it sounds then it will never sound great anyway.

LOL.

So depends what you like.

Transparency.

 

[Labjr]

LOL.


Transparency.

Transparency doesn't mean a whole lot with Rock and Pop music. It's not recorded to sound like a live event. And I don't expect it to. You can listen how you like and I'll listen how I like. I don't feel the need to sell my equipment every time the latest equipment comes out with a noise floor of -140db. That cycle will never stop.

Like I posted previously, buyers now want to add coloration to those "transparent" amps and DACs with different input buffers and "tube-like" settings. Why is that? Is that filtration?

 

[HammerSandwich]

@Labjr, many of us generally trust measurements, because they show more consistency than people. Case in point:

So the source material is already colored.

The source material has the musical content I like but not necessarily the coloration.

 

[ahofer]

Transparency doesn't mean a whole lot with Rock and Pop music. It's not recorded to sound like a live event. And I don't expect it to. You can listen how you like and I'll listen how I like. I don't feel the need to sell my equipment every time the latest equipment comes out with a noise floor of -140db. That cycle will never stop.

Like I posted previously, buyers now want to coloration to those "transparent" amps and DACs with different input buffers and "tube-like" settings. Why is that? Is that filtration?

I don’t think anyone is objecting to your preference. The question is-is there a more efficient and flexible way to achieve the same colored result, so you can adapt your colorations to the recording.

There is, and it is a lot cheaper and more flexible than boutique tube amps: EQ/DSP plus any number of effects processors you can buy from Sweetwater (the same ones used in the mix of some of your favorite recordings even) So for a few hundred bucks you could dial in those pleasing colorations to the exact quantity desired, instead of dealing with the unpredictable interface of low-powered tube amp to speaker, and the variability of recordings vs the static effects of your components. This is a point I’ve made to a number of dealers-swapping pricey colored amps and speakers is a really expensive and back-breaking way to EQ your sound. it’s not in the consumer’s interest, but it sure is in the dealer’s interest.

This was essentially what Bob Carver was getting at with the “Carver Challenge”.

 

[GrimSurfer]

Transparency doesn't mean a whole lot with Rock and Pop music. It's not recorded to sound like a live event. And I don't expect it to. You can listen how you like and I'll listen how I like. I don't feel the need to sell my equipment every time the latest equipment comes out with a noise floor of -140db. That cycle will never stop.

A live event? Like one recorded in a concert hall featuring a noise floor in the 50 dB range (as long as nobody in the audience coughs or snorts), or something like the Sydney Opera House whose acoustics are legendarily bad?

Wow. You know of equipment that has an effective resolution of 23 bits or a noise floor 22 dB below the range of human hearing? Do tell... LOL.

 

[VintageFlanker]

Transparency doesn't mean a whole lot with Rock and Pop music.

Transparency does mean transparency. There is no alternative meaning depending of the music style...

 

[Soniclife]

Transparency does mean transparency. There is no alternative meaning depending of the music style...

I'd also argue it's even more important in genres where the result has been heavily constructed in the desk or DAW, so that any pretence of perfectly reproducing a acoustic event had been not so much forgotten as deliberately rejected. In such recordings created in the circle of confusion any fixed distortion on playback will only confuse and mislead the listener.

 

[HiFiSoundFarts]

A live event? Like one recorded in a concert hall featuring a noise floor in the 50 dB range (as long as nobody in the audience coughs or snorts), or something like the Sydney Opera House whose acoustics are legendarily bad?

Wow. You know of equipment that has an effective resolution of 23 bits or a noise floor 22 dB below the range of human hearing? Do tell... LOL.

What about the manufacturers that make improvements that they themselves say should not be audible according to how they understand the physics, yet new amps like the AHB2 clearly sound better to almost everyone?

 

[GrimSurfer]

What about the manufacturers that make improvements that they themselves say should not be audible according to how they understand the physics, yet new amps like the AHB2 clearly sound better to almost everyone?

Like what improvements? Could you be specific about what you think Benchmark has said about its non audible improvements? How do you distinguish these from the audible ones?

Blind tested or expectation bias? (I.e. real or perceived.)

I'm not sure what you're contesting about my post. Do you believe a concert hall with people measures below 50 dB? Are you questioning medical science, which has established that normal human hearing range is 118 dB?

 

[HiFiSoundFarts]

Like what improvements? Could you be specific about what you think Benchmark has said about its non audible improvements? How do you distinguish these from the audible ones?

Blind tested or expectation bias? (I.e. real or perceived.)

I'm not sure what you're contesting about my post. Do you believe a concert hall with people measures below 50 dB? Are you questioning medical science, which has established that normal human hearing range is 118 dB?

Read up on the Banchmark AHB2 or the Chord DACs where the engineers made improvements that they said should not be audible or are already below the threshold of human hearing, but still made a dramatic impact on transients and other qualities that are readily audible to most people. This is the same idea about 8K versus 4k displays at a certain distance should be indistinguishable according to our vision limitations yet if you have seen an 8K screen versus a 4K screen there is clearly an better display on the 8K that is achieved by other aspects of the display being improved by the improved resolution (or by the elimination of the missing pixels which can be interpreted as noise from the perspective of the 8K tv)

 

[VintageFlanker]

Read up on the Banchmark AHB2 or the Chord DACs where the engineers made improvements that they said should not be audible but still made a dramatic impact on transients and other qualities that are readily audible to most people.

This is extremely evasive...

 

[HiFiSoundFarts]

This is extremely evasive...

Didn't take me long to find out more about the Benchmark AHB2 with a Google search. I read an interview with a Benchmark engineer about the improvements they made and how they were skeptical about making the improvements was worthwhile. Same goes for Chord, Rob Watts had a similar experience of lowering the noise floor to extremely low levels and found it still made an improvement on transients. Not saying this de facto proof but these are skilled engineers that sell A LOT of amplifiers and DACs so the proof is in the product pudding.

 

[GrimSurfer]

Didn't take me long to find out more about the Benchmark AHB2 with a Google search. I read an interview with a Benchmark engineer about the improvements they made and how they were skeptical about making the improvements was worthwhile. Same goes for Chord, Rob Watts had a similar experience of lowering the noise floor to extremely low levels and found it still made an improvement on transients. Not saying this de facto proof but these are skilled engineers that sell A LOT of amplifiers and DACs so the proof is in the product pudding.

Link? The info you've provided to this point has been vague and non specific.

I'm glad you're not claiming proof. The info you've provided so far doesn't even qualify as rumour. It's closer to innuendo.

 

[VintageFlanker]

Same goes for Chord, Rob Watts had a similar experience of lowering the noise floor to extremely low levels and found it still made an improvement on transients...these are skilled engineers

Rob Watts is without a doubt a talented engineer. Still, he's known for telling a lot of marketing BS as well:

The most amazing thing I heard was Rob Watts saying (again after yesterday's session) that he can measure and hear distortions at 300 dB down. Let me say that again, he is saying he can easily identify differences that are 300 dB lower than reference. That is 50 bits of dynamic range!!! Not 24, not 32, but 50 bits. He says this is impossible but that he hears it. Right.....

Not saying this de facto proof but these are skilled engineers that sell A LOT of amplifiers and DACs

Selling a lot of products means you're talented at marketing, not necessarily engineering. I guess, better be both.

Didn't take me long to find out more about the Benchmark AHB2 with a Google search.

Well, I'm afraid that's not how things work here. If you make a claim, it is not up to others to do the search.

 

[PaulD]

Didn't take me long to find out more about the Benchmark AHB2 with a Google search. I read an interview with a Benchmark engineer about the improvements they made and how they were skeptical about making the improvements was worthwhile. Same goes for Chord, Rob Watts had a similar experience of lowering the noise floor to extremely low levels and found it still made an improvement on transients. Not saying this de facto proof but these are skilled engineers that sell A LOT of amplifiers and DACs so the proof is in the product pudding.

In addition to the relevant comments above. Did they mention they did a double-blind, level-matched listening test? If not they were probably just confirming their biases. I've built and designed amps many years ago, and listening to mods to them only confirmed what I expected to hear unless I blinded it in some way...