Jeff Rowland 535 Stereo Amplifier Review

[Doodski]

I, personally, consider anything where I can't hear the noise, ie -80dB or distortion ie -60dB

Yes, I keep reading this from you and it is affecting my outlook. I look at a model I'm interested in and think the DAC 98 dB SINAD is more than enough for my PC w/ headphones and I should not be so picky on spec.
https://www.audiosciencereview.com/...d-measurements-of-evga-nu-audio-pc-card.9137/

 

[wwenze]

Any chance you can simplify and shorten the video into a small brief paragraph so we don't need to watch 1 hour and 2 minutes of video?

Summary: Numbers don't tell you what more numbers can tell you.

 

[Doodski]

Summary: Numbers don't tell you what more numbers can tell you.

What was the angle from the company representative engineer? If he's selling doubt in the metering then what is the advantage and benefit?

 

[Schackmannen]

What was the angle from the company representative engineer? If he's selling doubt in the metering then what is the advantage and benefit?

It's been a while since I watched the video and don't have time to watch it again right now, but IIRC the guy, who worked for AP at the time (and is a member here but forgot his username), mostly talked about specs that are not properly stated are pretty much meaningless, like if an amp is specified to have a THD+N of 0.01%, it doesn't tell you anything without knowing at what power output it was measured, into what load, over what bandwidth, if it was weighted or not, etc. He also performed a live demonstration to show that different kinds of distortion sound very different, and that our tolerance to the different distortions vary a lot. So I don't think the point was that measurements doesn't matter, but rather that they have to be done and stated properly to have any meaning.

Hopefully I remembered the gist of it, but I'd recommend you to watch it all if you have the time, I thought it was quite informative and interesting when I watched it.

 

[Doodski]

It's been a while since I watched the video and don't have time to watch it again right now, but IIRC the guy, who worked for AP at the time (and is a member here but forgot his username), mostly talked about specs that are not properly stated are pretty much meaningless, like if an amp is specified to have a THD+N of 0.01%, it doesn't tell you anything without knowing at what power output it was measured, into what load, over what bandwidth, if it was weighted or not, etc. He also performed a live demonstration to show that different kinds of distortion sound very different, and that our tolerance to the different distortions vary a lot. So I don't think the point was that measurements doesn't matter, but rather that they have to be done and stated properly to have any meaning.

Hopefully I remembered the gist of it, but I'd recommend you to watch it all if you have the time, I thought it was quite informative and interesting when I watched it.

Thank you for the summary.

 

[Geert]

Hey, I've been looking/druling at the Gato DIA 250. Great looking integrated, lots of power, runs cool. If it's the same Pascal class D modules as the Rowland - can we assume it will measure the same, i. e. mediocre?

Gato always stated they modify the Pascal module, so who knows.

 

[anmpr1]

Awesome power at a serious cost of distortion.

In the context of 1991, 1500 continuous watts into 2 ohms at one percent THD (clipping) was not shabby. It wasn't like that would degrade your sound. I don't know why anyone would 'need' that kind of power, but it was there if you did.

 

[anmpr1]

Next time I see judgment only based on cold measurement, without any prior understanding about what "enjoying music" means, in other words, no understanding of psychoacoustics in general, I might not give that review much credit either... I guess à balance between the two would be nice! Just a thought!

When I was a kid I was able to enjoy music on an inexpensive hand-held made in Japan 9-volt battery powered transistor radio. Special gear is not requried in order to enjoy music.

Psychoacoustics? I suggest you track down at Issue 19 of the Audio Critic (you can find it on line in pdf format) where Dave Ranada interviews Mark Davis, EE who did psychoacoustic work at MIT. Real psychoacoustics is not sticking a new preamp into your system and then 'hearing your CD collection for the first time'. I won't tell you about his conclusions, but it is worth it to take time to read findings of a real psychoacoustic scientist. You won't regret it.

 

[anmpr1]

Benchmark a several yoo toobs available showing their machining and manufacturing process. Worth a look.

 

[Doodski]

Benchmark a several yoo toobs available showing their machining and manufacturing process. Worth a look.

Beautiful work... All hand worked other than the mill.

 

[Laserjock]

Quick set up last night of the Red Dragon S-500 that uses the same Pascal module.
Not a great pic but I listened to about 2 hours worth of various Qobuz and Tidal music from Bluesound Node 2 > SMSL M500 DAC > Schiit Freya S > Red Dragon S-500 > Sonus faber Venere 1.5

Bedroom Size 11’ x 13.5 with bed, dresser etc (daughter’s room that’s living with sister during Covid-19)

I was fairly impressed considering.
Chris

 

[vrøvl]

This model?
https://www.gato-audio.com/eu/dia-250s.html
https://www.gato-audio.com/dia-250s-npm.html
Why not a Benchmark unit?
https://www.audiosciencereview.com/...-and-measurements-of-benchmark-ahb2-amp.7628/

Well the Gato is an integrated amp with built-in DAC (and optional streaming) in a compact box with a wife-friendly design.

The Benchmark is a power amp only.

 

[Frank Dernie]

Well the Gato is an integrated amp with built-in DAC (and optional streaming) in a compact box with a wide-friendly desigfn.

The Benchmark is a power amp only.

Indeed, it looks pretty good value IMHO, The Benchmark DAC, Preamp and power amp no doubt will have state of the art measurements but are £6,500 so in a different price class entirely, at least here in the UK.

 

[Doodski]

Well the Gato is an integrated amp with built-in DAC (and optional streaming) in a compact box with a wide-friendly desigfn.

The Benchmark is a power amp only.

Yes, I saw my mistake. I had too many windows opened, lost concentration and made that error.

 

[Speaker-Inquisitor]

In this Paper you can find measurements of 4 different Class D modules (including nCore 1200 and Pascal s-pro 2) done by Anselm Görtz. DeepL or Google translate is your friend.

 

[Wes]

Psychoacoustics? I suggest you track down at Issue 19 of the Audio Critic (you can find it on line in pdf format) where Dave Ranada interviews Mark Davis, EE who did psychoacoustic work at MIT. ...

I dunno if he is a real psychoacoustic scientist but research has moved on since 1993.

Here it is:

https://www.biline.ca/audio_critic/mags/The_Audio_Critic_19_r.pdf

 

[jam]

In this Paper you can find measurements of 4 different Class D modules (including nCore 1200 and Pascal s-pro 2) done by Anselm Görtz. DeepL or Google translate is your friend.

Thanks a million for this very juicy paper. Once again I kick myself for not having taken a German class in high school. Thank goodness for Google translate.

 

[Laserjock]

Thanks a million for this very juicy paper. Once again in kick myself for not having taken a German class in high school. Thank goodness for Google translate.

Can you share the translated page?
Mostly on the smart phone here.

 

[jam]

Can you share the translated page?
Mostly on the smart phone here.

Ehh... There's 21 pages of info with plenty of measurements à la Amir but no translation; it's all in German. I can post the summary translated through G00gle although you'll see that a German speaker will do a better translation.

Summary
----------------
- Signal to Noise/Noise level: Clear advantages with the Class-D power amplifier
- Damping factor: Primarily dependent on the circuit concept. Sense lines are a good solution.
- THD at 100 Hz / 1 kHz / 10 kHz: Class-D comparable to good Class-AB models
- THD (f) 100 Hz to 10 kHz: Class-D comparable to good Class-AB models
- Distortion spectrum at 1 kHz: Class-D comparable to good Class-AB models
- DIM 100 and DIM 30: DIM100 critical for all. Better with a low-pass filter at the input, then Class-D are comparable or better than good Class-AB amplifiers.
- Multitone TD: Comparable values
- Power values: Primarily a question of the power supply unit
- Efficiency: Clear superiority of the class D concepts

 

[jam]

Can you share the translated page?
Mostly on the smart phone here.

Guess that smart phone ain't so smart after all... Just kidding.