John Curl's Blowtorch preamplifier part II - Page 237 - diyAudio
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Old 7th November 2009, 10:41 PM   #2361
anatech is offline anatech  Canada
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Hi John,
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If you don't believe me, just look at the wonderfully engineered designs by the Japanese designers for Sansui, etc, back in the '70's and '80's. They are now gone, where did they go? I am referring to the designs, in their own right.
They exist right beside my products from the 50's and 60's. I have items built in the 1920's as well. Varying sound quality to be sure.

The design of my favorite amplifier (right now, Marantz 300DC) has been continued in the current Marantz products. The basic power diamond buffer design direction continues to evolve. I rebuilt my amplifier a few years ago, matching transistors and some resistors, replacing some capacitor types with others. In it's current form, even tube amp guys really like it. It's the amp to beat so far. I can send you a schematic if you'd like.

Another new amp that I haven't touched yet is the Cyrus Mono X. I have a pair, first ones into North America. They have no loop feedback and are inspired by .... the diamond buffer (tweaked for performance where needed). The diamond buffer was also used in the Nakamichi 620 and others too. Certainly an old design direction by anyone's metrics.

I have rebuilt some Sansui products, older ones before plastic became the style of choice. They have sounded really very good. Same for some other products.

Some older tuners I have rebuilt, aligned have been excellent performers. However, the Revox tuners are the best I have ever worked on. No, I haven't seen Dick's tuners yet. I've worked on most over the years though.

We have the knowledge and technology to produce better products today. most manufacturers have decided to go a different way, sadly. I will say that a simple reproduction of past models would elevate the average level of performance though. How sad is that?

Look back to your own designs too John. They stood the test of time as well. You are still designing along similar lines as well.

Hi kannan,
That Nakamichi story is entirely true. Sound rooms were in LA I think, and they compared their products to live performances right there.

There are more than a few companies that still have serious listening tests. The English brand "Cyrus" is one I can vouch for.

Hi Jan,
Quote:
When I look at the data sheets for those high-current DSL drivers, that can drive 100mA or more into 50 ohms or less at -100dB distortion at 100kHz or so, I'm pretty sure that those guys licked the thermal transient problem.
Completely agree. I was referring to "audio" power output IC's. They may have licked the problem now, but earlier in time it was a problem. I should have been more complete in my post, so thank you for pointing these things out.

-Chris
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Old 7th November 2009, 10:47 PM   #2362
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Quote:
Originally Posted by stinius View Post
It seems like some posts has been deleted here.

I canít find the post by Joshua_G that syn08 is answering to in post 2351, but by seeing the quote in syn08ís post and the follow up answer by JC, it seems like Joshua_G thinks that only audio engineers that can hear the difference between cables can design an amplifier worth listening to, is this right Joshua_G?

John is it also right that you agree in this.

Cheers
stinius
Yes, I'm interested in checking out designs made only by audio designers (engineers or not) who can hear differences between cables.
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Old 7th November 2009, 11:16 PM   #2363
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Hi Joshua,
Quote:
Yes, I'm interested in checking out designs made only by audio designers (engineers or not) who can hear differences between cables.
So, does it help if they can hear voices also?

Honestly, I really have to hear what designers of cars you might like can sense!

All kidding aside Joshua, I think that limiting your choices on what people say they can hear both restricts your choices and leaves you totally open to being "taken" by someone sensitive to marketing strategies. Just read some white papers out there.

I also know of some designs by people who say they can hear cables and other things that are horrible to listen to. They also measure poorly, backing up the observation.

You stated much earlier in time that you listen to prospective products. You know, to verify what you may have heard as opinions from others. So, do you mean that if the designer can't hear cable differences, you may be fooled into accepting a design unless you exclude it from the selection process?

Another question. The listening test for cables. Do you make sure that the conditions are reasonable for that cable design and the equipment, or are these tests simply ad hoc with no regard to any conditions or equipment mismatching? Does a bad sounding cable in one system mean that the cable is bad in every system?

Just looking for your guidelines for these things. The statement you made is absolute with no conditions.

-Chris
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Old 7th November 2009, 11:17 PM   #2364
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Hi everyone, I tend to agree with Joshua, but then I can hear differences between cables. Therefore I am a prejudiced fool, not worth having an opinion, at least on this website.
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Old 7th November 2009, 11:19 PM   #2365
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Quote:
Originally Posted by stinius View Post
Amazing

BTW John do you agree in this statement made by Joshua_G?

stinius
I am not John, but it would make me wonder whether the designer is truly aware of what his circuits truly sound like if he can not distinguish sounds like from cabling, capacitors etc. I am quite sure that many people create great designs that do not seriously listen to them, but from my perspective, I would like to think that someone at least acknowledges that these differences exist and that they have taken the time to compare the design vs other well know references. If that is too much to ask, I would have a bit of an issue believing that they truly understand what it is that they are trying to accomplish. Good or bad that is how I would look at the situation. Just being honest.

The best designs that I have personally ever heard were done by people that used subjective testing as part of their final designs. They understood by learning what different topologies did to the sound of their products that they could achieve better overall sound by subjective testing as well as bench testing and good overall engineering.

Last edited by Curly Woods; 7th November 2009 at 11:22 PM.
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Old 7th November 2009, 11:35 PM   #2366
anatech is offline anatech  Canada
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Hi John,
Quote:
Therefore I am a prejudiced fool, not worth having an opinion, at least on this website.
Not a reasonable statement, you would have been gone years ago if this were true.
Everyone has expectations (prejudices) going into any situation. How strong these are make the difference between blind and opinionated.

Hearing differences between cables may simply indicate one or more were not suited to the situation. Reasonable? In that light, I believe that most anyone could hear differences. But then, many of us try to use cables suited to the application. Sort of like choosing which 'scope probe to use for a test.

Exaggeration is probably not that helpful in the long run.

-Chris
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Old 7th November 2009, 11:37 PM   #2367
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Syn08, do you believe in MC cartridge loading? If so, why? Can you hear the difference? Can you measure the difference? Please provide data.

Last edited by john curl; 7th November 2009 at 11:43 PM.
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Old 8th November 2009, 12:04 AM   #2368
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Chris,
I'll try to summarize my view on the matter.
Indeed, there are topologies, design rules and most of all Ė design experience.
Most serious designers put their designs to listening tests, both by themselves and by others, prior to the actual production. Of course, listening tests come AFTER measurements, not as substitute to measurements. This is because the experience is that there is no direct correlation, not necessarily, between how piece of audio gear measures and how it sounds.
Now, designers who don't hear differences between (well engineered) cables and who don't accept that such differences exist, will have listening evaluations that I cannot rely upon. Moreover, naturally, they'd choose people with attitude similar to their own for the listening tests.
This is in brief. If necessary, I'll expand.
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Old 8th November 2009, 12:58 AM   #2369
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Now, let us try again:
A parallel problem in audio design is the idea that MC cartridge loading makes any difference in sonic quality. I have been working on the problem for 35 years. I have contacted several cartridge manufacturers about this, even 35 years ago. Most cartridge manufacturers have little idea as to what to say, because, within reason, MC cartridges change their output very little with loading. However, like so many subtle aspects of audio, we have found it important to serious listeners. Yet, we cannot measure any significant difference, in many cases with a cartridge loading between 10 ohm and 47K , EXCEPT for absolute output, which can be easily compensated for. If there is no difference, why don't we set cartridge loading to 47K exclusively, as it is cheaper, quieter, and more efficient to do so? Syn08, do you agree? If you do, why then did you add variable cartridge loading to your phono stage?

Last edited by john curl; 8th November 2009 at 01:04 AM.
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Old 8th November 2009, 01:06 AM   #2370
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Then, why Syn08, did you add this 'useless frill' to your phono design?
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