That's not specs, that's a marketing speak. A spec is like: I want my preamp to have a S/N of -110dB referred to 2V signal.
You shouldn't care less whether the designer does that with internal compartments or a shoot of Broccoli.
jan didden
So we all know how to build amplifiers? Well, those of you how think you 'can' perhaps should move on, and leave the 'hi end' group in peace. I guess that is a little too much to ask. '-)
For me, audio amplifier design is still a mystery. It's not that I don't try to master it, I am surrounded by books and printed articles, to the point of not being able to easily move in my apartment, at the moment. I read most of the main hi fi magazines and collect them on bookshelves and in packing boxes. TAS#3? Sure, just give me a few minutes to find it. Stereophile from the beginning? WW? HFN mid 90's?
What about the modern engineering world? EDN, ED, EE, EP, IEEE, MJ, DN? Get them by subscription every month. I don't know any other way to keep up with engineering design.
Now what do I design, and is it worth it?
Well, over the decades, I have refined my preamp designs, each one, up to the Blowtorch, better and better. At the same time, I made other, more practical, designs, with more features. I will most probably never make a better line amp than the CTC Blowtorch.
It IS possible, however, for a better design than the Vendetta Research SCP-2, still acknowledged as one of the best phono stages ever designed, even 20 years after production had stopped. How is that for longevity? And I am now working on its 'successor' by using either 'brute force' or further design insight to make a REAL improvement.
Now what do I try to convey here? NOT SCHEMATICS, at least not schematics that 95% looking here, would have no hope in duplicating. However, my earlier JC-2, and JC-80 schematics are available elsewhere on this website, and people are happily duplicating them, as best they can.
What I attempt to convey here is the 'essence' of quality audio design, giving free advice as to what works and what does not work.
For me, audio amplifier design is still a mystery. It's not that I don't try to master it, I am surrounded by books and printed articles, to the point of not being able to easily move in my apartment, at the moment. I read most of the main hi fi magazines and collect them on bookshelves and in packing boxes. TAS#3? Sure, just give me a few minutes to find it. Stereophile from the beginning? WW? HFN mid 90's?
What about the modern engineering world? EDN, ED, EE, EP, IEEE, MJ, DN? Get them by subscription every month. I don't know any other way to keep up with engineering design.
Now what do I design, and is it worth it?
Well, over the decades, I have refined my preamp designs, each one, up to the Blowtorch, better and better. At the same time, I made other, more practical, designs, with more features. I will most probably never make a better line amp than the CTC Blowtorch.
It IS possible, however, for a better design than the Vendetta Research SCP-2, still acknowledged as one of the best phono stages ever designed, even 20 years after production had stopped. How is that for longevity? And I am now working on its 'successor' by using either 'brute force' or further design insight to make a REAL improvement.
Now what do I try to convey here? NOT SCHEMATICS, at least not schematics that 95% looking here, would have no hope in duplicating. However, my earlier JC-2, and JC-80 schematics are available elsewhere on this website, and people are happily duplicating them, as best they can.
What I attempt to convey here is the 'essence' of quality audio design, giving free advice as to what works and what does not work.
Again, I haven't heard any such design in any playback chain.
Indeed, I said so.
Understanding has nothing to do with hearing.
1. Again, I was referring only to the home playback chain.
2. Until today I didn't hear a single piece of gear which is absolutely transparent, without any sonic signature. It applies to EVERYTHING in the playback chain, including interconnect, power cables and fuses.
The recording chain is out of my control.
On the playback chain I have full control, while the only limitation I'm confronted with is the amount of money I have.
As I wrote earlier:
I'm cautious of blind tests; in at least some of them, people cannot distinguish between Tube and SS power amps (when the differences are big, significant and measured). For any test to be valid, blind or sighted, the validity of that test need to be established first, before drawing any conclusions from it. So far I haven't see it done in any test I know of. Apparently, at least some of the blind tests, the way they are done, mask and veil sonic differences between various pieces of audio gear.
Furthermore, to me, the one most important attribute of my sound setup is it's 'musicality', that is, the degree to which music reproduced by the setup is exciting, convincing and enjoyable. I don't care at all what does make my sound setup more 'musical' (to my taste). I don't care at all whether it is some 'real' sound qualities, or 'imagined' sound qualities, or any combination of those two. Hence, I don't care at all if there are things that I may imagine – as long as my setup is more 'musical', or more enjoyable and consistently so – that is all I care about. Since I listen to music at home sighted, I don't care at all how my setup may sound 'blind', or in 'blind tests'. Therefore, blind tests are absolutely useless to me. I care about the degree I enjoy listening to reproduced music, not in any 'scientific' proof of what makes it more or less 'musical', or enjoyable.
On top of that, I found out that meaningful listening evaluations need prolonged listening. Few times it happened to me that when I evaluated various pieces of gear on my audio setup, on first listening it sounded good. After few listening sessions, on few consecutive days, some faults to sound quality emerged. Therefore, a brief, one time listening evaluations aren't the way for meaningful sound quality evaluation.
You are very perceptive, Mike. I would truly like to help you along with your 'project', but while this thread can show you the 'Zen' of audio design, the Blowtorch schematic itself is not here, nor it will be here, at least for the moment. However, from my designs, the the JC-80 line amp or the new Parasound JC-2 line amp would be optimum, IF you can find the parts, or effective substitutes. You are on the right track Mike, and it would be a pleasure to help you any way I can.
So far I haven't heard any piece of audio gear which is perfect, absolutely transparent, without any sound signature.
Indeed.
1. An amp having THD and IMD below 0.001%, it says nothing about its' sound quality and sonic signature.
2. Whatever the sound quality of any recording is, EVERYTHING on the playback chain have an impact on the sound quality and sonic signature.
A possible conclusion that because of the recording quality is mediocre, or poor, we can be satisfied with mediocre, or poor, playback setup – such a conclusion is erroneous. Experience shows that it is the other way around – the quality of the playback chain DO matter, as much as there are flaws in the recording chain.
Right on, Joshua. For me, the only ' absolutely transparent' component in MY sound system is the CTC Blowtorch, AND I could just have gotten used to it. Everything else, power amp, speakers, etc. I have heard better from the same sources, but I can't afford them, either with time, effort, money. Almost everything has an audio 'signature'.
Hi John,
Thank you.
That's sad, about the availability of substitutes.
Still I'm looking for available substitutes which are as close as possible to the old Hitachi and Toshiba parts.
Thank You Mr. Curl, I will call on you from time to time when I am stumped.
I see what you mean...this is a tough room.
But in my own defense I would argue that my post are more on topic than any discussion of Lucifer. Unless if you connect a diode backward you hear satanic voices...could that be their meaning?
It doesn't hurt to leaven the audio talk with a bit of humor from time to time, even if it means another post to read.
One topic that you bring up is partition of the various functions and channels. This is VERY IMPORTANT and not as easy as many engineers think.
My first experience was when I visited a competitor who made a much cheaper preamp than the JC-2. Playing a familiar record, and the same speakers I was then using, this competitor's preamp put CAT STEVENS right between the two speakers. MY set-up could NOT do that!. So, what is the problem? I found it to be asymmetrical X-talk between the left and the right channels. Now, was I alone in finding this?
No, at a hi fi show, I heard a glorious violin sound coming from one of the rooms. I said to myself, that is a REAL violin, you can't fool me, I married a violinist!
Well, I was fooled, by my own JC-2 preamp and Dick Sequerra's ribbon tweeters. However, taking to Dick about the JC-2, he independently stated that it was the best MONO preamp available, denoting that it had 'imaging' problems. Trust me, the JC-80 was deliberately designed not to have this problem, and the CTC Blowtorch, as well.
SO, partitioning is GOOD! Separation by air is good too. It must be remembered that most SPECS. are derived from IDEAL conditions, Zero drive impedance, input pot all the way down, etc. NOT real world working conditions.
My first experience was when I visited a competitor who made a much cheaper preamp than the JC-2. Playing a familiar record, and the same speakers I was then using, this competitor's preamp put CAT STEVENS right between the two speakers. MY set-up could NOT do that!. So, what is the problem? I found it to be asymmetrical X-talk between the left and the right channels. Now, was I alone in finding this?
No, at a hi fi show, I heard a glorious violin sound coming from one of the rooms. I said to myself, that is a REAL violin, you can't fool me, I married a violinist!
Well, I was fooled, by my own JC-2 preamp and Dick Sequerra's ribbon tweeters. However, taking to Dick about the JC-2, he independently stated that it was the best MONO preamp available, denoting that it had 'imaging' problems. Trust me, the JC-80 was deliberately designed not to have this problem, and the CTC Blowtorch, as well.
SO, partitioning is GOOD! Separation by air is good too. It must be remembered that most SPECS. are derived from IDEAL conditions, Zero drive impedance, input pot all the way down, etc. NOT real world working conditions.
That's the spirit, at least folks can take a stab at it. It's clear all the wining about IC's and op-amps is pointless, people want to try your discrete circuits. Do we need to repost the schematic, maybe a pdf hosted somewhere so we have something to talk around?
These somewhat contradictory comments still puzzle me. In that review it was stated that Bob Crump interviewed each customer so the BT would "fit in" with the rest of their components. This would conflict with "absolute transparency" at least to some.
Scott, Bob Crump did NOT mean that we would change the 'sound character' for each customer. We CUSTOM BUILT every one for our customer's needs. Some got a phono, some got balanced input , some only got single ended input and output, etc. Most ordered single ended input and balanced output. The parts, wiring, etc, were all the same quality, some just more complex and therefore more expensive.
Thanks, John.
Is it important to match the NMOSFET/PMOSFET pairs in designs like the JC80 or the Parasound JC-2?
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