John Curl's Blowtorch preamplifier part III

[mountainman bob]

Mark, now that there are a few consumer versions of the 4499 out have you had the opportunity to ‘subjectify’ any?

 

[Markw4]

Bob,
Only heard about a few Chinese offerings ranging from several hundred dollars to a bit over a thousand.

Little or nothing in the way of listener sound quality opinions. When enough of those start coming in then we should know more.

 

[mountainman bob]

Saw some good reviews of the Topping D90.....but then again the unwashed masses are an unpredictable bunch.

 

[billshurv]

Bill,
Mediocre, of course in the context of a high end dac chip such as AK4499.

My interpretation of mediocre would be if the 4499 eval board sounded no better than an ebay £10 USB dac. Is that really what you mean?

 

[Markw4]

...Is that really what you mean?

More likely would have said something like 'utter junk' in that case. Of course I meant more like an average AKM-example implementation, or maybe a somewhat better one if taking their hints to use more separate power supplies/regulators.

It was just the way I talk when speaking frankly. Jam thinks I am his worst critic, but nothing is perfect is it?

Magazine reviews are for speaking the other way around...

 

[Evenharmonics]

Mediocre. Perhaps a poor choice of word.

Not a poor choice but a carefully picked one for a marketing plan. He is and has been pushing a business agenda which is geared towards supporting jam's audio company.

 

[billshurv]

I see no agenda. And even if there is something in the background that shouldn't cause you to just hound him all the time? What has he ever done to you? Honest question as you are close to my ignore list for the continuing hounding of a few people.

 

[chris719]

All are proprietary that I know of. For ESS, Benchmark DAC-3 is one example. I know of a few more things people have figured out, but not published.

An example of a evaluation board type ESS design would be Oppo's last CD player that many people (not all, of course) found not up to their expectations. Also, ESS did not provide a suggested explanation/solution for the hump problem in the data sheet or since then. People are still trying to figure it out.

Since I only know in detail about one AKM dac chip and evaluation board, I can talk about a few details. AKM opted to design the Reference Voltage supply with filtering that they plainly state produces more than minimal LF harmonic distortion. Why? Apparently because it sounds better that way in otherwise mediocre dac system design implementations. AKM also included an AK4137 ASRC on the board, but only designed the board to give an option to use the ASRC with SPDIF input. They also did not populate the reference clock for the ASRC, and the board layout only provides pads for adding a rather mediocre clock if one can find a source for one (not pads for commonly used good quality audio grade clocks). There is more, but enough for now.

Gross exaggeration to suggest that they don't know how to use their own product that they designed just because they don't subscribe to your belief system.

 

[scottjoplin]

Talking about preferred bit depth in recordings.
This recording (*) has a hefty 70 dB difference btn lowest and highest music level and if it was recorded without clipping it would have at least 3dB more.
Right at the beginning, during the first second, the fagotto changes from F to B#. Adjust the playback volume so that you can just perceive this change in note. This is the lowest music level. Now, listen the whole musical track at this volume setting.
What do you think, with the achievable dynamic range of the playback audio chain, the ambient noise level at your listening space and your highest allowed playback music level , would a higher bit depth recording be potentially advantageous?

(*) EAC wav rip: 2nd CD, 12th track from DECCA 467 314-2 (2001,DDD)
Dropbox - 12 2. Alles Vergangliche (Chorus mysticus).wav - Simplify your life

George

Thanks for this George. It's enough range for me, not too much and not uncomfortable, is it a realistic range? I can imagine some people wanting more.

 

[PMA]

@Pavel,
Just read your report on speaker distortion, voltage vs current drive.
Well done, very enlightening.

Hans

Thank you for your kind words, Hans. I have a good feeling if someone finds it useful.

 

[Evenharmonics]

I see no agenda.

"decided to try Jam's cables and get it over with. I connected them between the XLR outputs on AK4499 eval board and the Neurochrome HP-1 headphone amp input.

Wow! Everything sounded better, less distorted, and the difference was easy to hear! I was basically stunned, never expected it."

That looked like a sales pitch to me and it's not isolated to that thread. But YMMV.

What has he ever done to you? Honest question as you are close to my ignore list for the continuing hounding of a few people.

What he's done to me is no longer viewable because it was deleted by the moderator/s due to its severity but this is very similar to it, just milder.

 

[Evenharmonics]

Gross exaggeration to suggest that they don't know how to use their own product that they designed just because they don't subscribe to your belief system.

 

[billshurv]

"decided to try Jam's cables and get it over with. I connected them between the XLR outputs on AK4499 eval board and the Neurochrome HP-1 headphone amp input.

Wow! Everything sounded better, less distorted, and the difference was easy to hear! I was basically stunned, never expected it."

You snipped out the part about these cables not being for sale at the moment. So saying something that is not available to buy is hardly a sin in my book. Certainly not worthy of reduction in S/N on an already noisy thread it causes. Maybe I am more live and let live, but if the mods are ok with it then I will go with the flow.


Surely there is productive stuff that can be discussed and ignore the things that wrankle?

 

[gpapag]

Thanks for this George. It's enough range for me, not too much and not uncomfortable, is it a realistic range? I can imagine some people wanting more.

Thanks Scott for listening and commenting.
This dynamic range is realistic for classic, opera is even more demanding.
Not many recordings convey such dynamics and I don’t think that’s accidental.
Recordings with high dynamic range speak trouble for the majority of home listening (ambient noise, high SPL). Ed has posted some proper (frightening) numbers in the past, listening is always more informative.

George

 

[scottjoplin]

Not many recordings convey such dynamics and I don’t think that’s accidental.
Recordings with high dynamic range speak trouble for the majority of home listening (ambient noise, high SPL).

It makes sense, I followed your instructions regards setting the volume level. Probably many wouldn't listen to the opening passage so quietly.

 

[Evenharmonics]

You snipped out the part about these cables not being for sale at the moment. So saying something that is not available to buy is hardly a sin in my book.

"at the moment". Have you ever heard of a term "primer"? In order for the paint product to stick to the surface sell well, there needs to be a primer as undercoat desire for the surface consumers.

Certainly not worthy of reduction in S/N on an already noisy thread it causes. Maybe I am more live and let live, but if the mods are ok with it then I will go with the flow.

Do you have the same view on Jakob(#)'s actions here?

Surely there is productive stuff that can be discussed and ignore the things that wrankle?

We've seen many off topic subjects on this very thread over the months / years. At this point, it's simpler to ask how many posts are about JC's Blowtorch preamplifier. Perhaps off topic post is going with the flow.

 

[Jakob2]

@billshurv,

you know, the beauty of a conspiracy theory lies therein that no real fact/proof is needed.
Even the opposite of the alleged behaviour contributes just confirmation that is even more worse than expected.

 

[Tournesol]

Mediocre. Perhaps a poor choice of word.

That is the typical remark i dislike to read on the forum.

 

[Bonsai]

Are-you joking ?
In the history of art, all disciplines combined, the 70s represent a summit that, unfortunately, I think incomparable.

I would agree with that.

I look at my music collection and see rock, pop, jazz and classical recordings that have not been equaled since (for classical some of the very best recordings also took place in the 1960’s).

What’s the best on offer today? Bloody Taylor Swift (nice to look at but that’s all) and Ed Sheeran

 

[Tournesol]

Not a poor choice but a carefully picked one for a marketing plan. He is and has been pushing a business agenda which is geared towards supporting jam's audio company.

That will never end, mister LMDBT ?