john curl said:
Yes,, John, I have seen those posts, but you said {we might talk about the differences between the Parasound JC-2 and the CTC Blowtorch}.
I believe the BT consists of a three terminal followed by global shunt reg and an onboard MOSFET reg. I have no idea how this differs in either scope, implementation, or sonics to the JC2.
Enquiring minds, and all that...
- ken
OK. So the Ayre and Blowtorch are better competitors. Question. As I understand it, the new Ayre runs the signal through the gain stage and it is attenuated at the outputs. Most preamps seem to place the attenuator ahead of the gain stage. Any comments on the two configurations?
Both have advantages and problems. The Ayre approach can give superior CM rejection, because the tracking of 2 parallel volume pots is removed from being a problem.
The CTC approach can have even lower distortion, because the excess signal is removed BEFORE it reaches the active circuit.
DC clicking can easily happen with the Ayre approach, IF there is any residual DC offset on the input devices.
The Ayre approach can more easily and quietly handle a higher input impedance than the CTC. The CTC is happiest with 10K vol pots with 25K being OK to use. Ayre can easily go to 1 meg. as there is no added noise from the resistance of the input pots. The Ayre can actually get quieter as you reduce the gain setting.
The CTC approach can have even lower distortion, because the excess signal is removed BEFORE it reaches the active circuit.
DC clicking can easily happen with the Ayre approach, IF there is any residual DC offset on the input devices.
The Ayre approach can more easily and quietly handle a higher input impedance than the CTC. The CTC is happiest with 10K vol pots with 25K being OK to use. Ayre can easily go to 1 meg. as there is no added noise from the resistance of the input pots. The Ayre can actually get quieter as you reduce the gain setting.
Are the Ayre schematics available?
But as we started recently debating JC-2 vs Blow Torch, I would like to hear Mr Curl's opinion about this: I expect the BT to be more refined in many ways (we know cabinet-wise it is better, I think). However, I believe the JC-2 circuitry is more complex.
So my question is really, all else equal, would the JC-2 audio circuit topology be better or worse than the BT, in your opinion?
Thank you
RK
But as we started recently debating JC-2 vs Blow Torch, I would like to hear Mr Curl's opinion about this: I expect the BT to be more refined in many ways (we know cabinet-wise it is better, I think). However, I believe the JC-2 circuitry is more complex.
So my question is really, all else equal, would the JC-2 audio circuit topology be better or worse than the BT, in your opinion?
Thank you
RK
Regarding internal wires, switches and stacked boards - I can say that instruments with a lot of internal wiring, regardless wire material, have really hard times to compete with simple, shortest signal-trace design, provided it has good topology, PCB design and reasonable components.
Less complexity and more design elegance is best for me. Charles has a somewhat different opinion on this. The JC-2 is NOT as good as the Blowtorch, if I have to restate it. Ayre, is NOT releasing its schematics, to the best of my knowledge, and I don't blame them.
Yes, I also fell for the elegance of your JC2 (The Levinson one). I read Charles Hansen did the same. Likewise, the BT is - as you say - more elegant. Keep it as simple as possible etc etc
No, I do not blame him.
Thank for your reply.
No, I do not blame him.
Thank for your reply.
Sigurd Ruschkow said:
Mechanical noise control needs to be on that list. Motors are defined as current and thus voltage induction via motion in field.
This...Since the ear hears via sum totaled peaks and thus all additive signals, no matter how minute -COUNT- and are, in the final analysis -CRITICAL- in such a consideration.
Reflective and inductive considerations mean that proximity to metals is big NO-NO under all attempts at extreme 'high end'. This means that big aluminum milled chassis in close proximity to signals as a design exercise is not something I'd ever bring into my house. For example, some of the Japanese items from the days of yore sounded quite good. Why? the boards were in the exact middle of the chassis, far, far, away from any metal plates. Then plastic is no good either. Static induction means polarized pressures, thus skewing the transients and micro components in a deleterious fashion. There is a middle ground. Be aware of these issues and then it will become clear after a few single cause experiments in that area. Morecroft at DNM uses ceramic blocks at 0.5" thick to keep the main power transistors away from the heatsinks. This is good practice to avoid the smearing caused by the signal being induced in the heatsinks, and thus reflected as eddy currents (delayed smear) in the signal.
Pioneer did an experiment where they took their entire 'high end' system..and put it in an 'isolation box', anechoic, to be exact and mechanically decoupled as well. The difference was quite big.
I could tell you a story about a janitor who stole a company away from a guy via quite nefarious means...and started putting his name on the circuit boards due to the fact that he 'chose' the parts. Except he couldn't design a circuit to save his life. The hubris was and is palpable when he steps into the room. I know he'd sue if I mentioned his name. Too bad. One of those guys who needs to be hit when he's down. I don't know many I feel that way about but he's one of them. For all the right reasons. When he was in sales...he was even known to steal stock from the back room and add it to people's selected product and leave it off the invoice so as to 'make the sale'. Folks owning stores would wonder why they were going broke when they are paying this guy huge %'s on his sales.
I mention it as he had the nerve to put his name on the circuit boards. As if he actually did something useful, other than be one of the worst in the audio business.
Problems can occur in almost any part of a design.
Some years back I decided a passive pre was the way to go for me. Accordingly I bought a Shalco switch, some Vishay S102 resistors. Cardas silver wire and Cardas RCA jacks.
Because I didn't want to spend a lot of time on chassis or appearance, I bought an old "Mod Squad" passive. Internally it was very nicely done, I replaced the gain pot with my Shalco 1 dB step array. It sounded OK, but certainly nothing special. Nowhere near my $600 total investment
I removed the balance pot, a slight improvement. Next I installed my Cardas RCA jacks (the original Mod Squad units were pretty good). Another small improvement. The Mod Squad unit came with all silver wiring, I had not replaced it previously because of the very nice wiring and routing job they had done. no change with the Cardas silver wire.
I was still unhappy the unit did not live up to good commercial passive designs or my expectations.
It turned out the input selector switch was the culprit, after bypassing it the sound became liquid, clear and rich. The original selector was of the open wafer, phenolic with what appeared to be silver contacts type. I was quite surprised at the degree of trouble caused by a component that would normally be considered perfectly adequate.
Some years back I decided a passive pre was the way to go for me. Accordingly I bought a Shalco switch, some Vishay S102 resistors. Cardas silver wire and Cardas RCA jacks.
Because I didn't want to spend a lot of time on chassis or appearance, I bought an old "Mod Squad" passive. Internally it was very nicely done, I replaced the gain pot with my Shalco 1 dB step array. It sounded OK, but certainly nothing special. Nowhere near my $600 total investment
I removed the balance pot, a slight improvement. Next I installed my Cardas RCA jacks (the original Mod Squad units were pretty good). Another small improvement. The Mod Squad unit came with all silver wiring, I had not replaced it previously because of the very nice wiring and routing job they had done. no change with the Cardas silver wire.
I was still unhappy the unit did not live up to good commercial passive designs or my expectations.
It turned out the input selector switch was the culprit, after bypassing it the sound became liquid, clear and rich. The original selector was of the open wafer, phenolic with what appeared to be silver contacts type. I was quite surprised at the degree of trouble caused by a component that would normally be considered perfectly adequate.
After ANY change of power supply, wires, wiring topology, switches, relays and volume cotrol type I strongly recommend to MEASURE such behaviour:
http://web.telecom.cz/macura/snr.gif
I have a very, very good reason why I am saying that.
http://web.telecom.cz/macura/snr.gif
I have a very, very good reason why I am saying that.
While I wasn't happy with the sound, it would have measured fine with the equipment to which I had access.
When I still worked I was able to get my hands on analyzers that could achieve about 100 dB, retired I can't afford such things.
When I still worked I was able to get my hands on analyzers that could achieve about 100 dB, retired I can't afford such things.
Complicated wiring, switches and stacked boards ALWAYS result in worse noise background. We have the very fresh experience with single-board minimalistic concept (no output wires, 5cm of input wire) and pot soldered inside the PCB, against same circuit with input selector and rotary switch with resistor dividers instead of Alps pot. The more complicated version sounds les clean, though more "rich" (more mess), and the minimal version was preferred 10:1. When measured, the more complicated version differs in worse noise background, with mains components appeared and higher bottom residual.
The sound deterioration did have an effect like more bottom residual. Unfortunately therin lies the great component debate.PMA said:
With no power supply (passive pre), no active parts what could possibly generate what sounds like harmonics, intermods, spectral smear or contamination? It could be EMI or other noise pick up, but the unit sounded dead quiet. The increase in bottom residual or contamination was only present when music was passing through the unit. As I said, this is the heart of both the component and cable debate, how can a passive device generate spectral components not present in the original? It does sound a bit like magic and many scientific types reject the notion outright. I am of the school that there is a mechanism, we just don't really know what it is or how it works.
Several explanations have been proposed, as far as I know none of them withstand the test of duplication of test results. For now the lack of explanation does not interfere with my enjoyment of listening to music. I do trust me ears, they tell me there is a difference. I don't propose an answer nor am I excited about continuing the debate, that horse has been flayed enough.
My point with my recent posts is that details matter and that they can matter a lot.
Personally, I often worry about "clean" being the criterion.
There have been a whole lot of designs and products that sounded clean or "cleaner" than something else.
Maybe that is better. Maybe not.
In many cases that clean sound is due to a wee bit of overshoot - you can see it sometimes in the square wave (old school methods there).
Also, a bit depends on what your "standard" happens to be, and just how good the reproduction chain is. The fly in the ointment is that a whole lot of the result will depend on the combined response of the system being auditioned, as well as the ultimate "quality" (freq response, phase relationships and distortion, including the speaker) of everything from the source out through the room itself.
Finding a touchstone for making these sorts of judgments is non-trivial imho.
The holy grail I suppose is to maximize the approximation of reality, the most difficult part being the human voice (instruments interestingly are less determinant), especially in ensemble and in concert with other sound(s).
Just my 2 cents...
_-_-bear
There have been a whole lot of designs and products that sounded clean or "cleaner" than something else.
Maybe that is better. Maybe not.
In many cases that clean sound is due to a wee bit of overshoot - you can see it sometimes in the square wave (old school methods there).
Also, a bit depends on what your "standard" happens to be, and just how good the reproduction chain is. The fly in the ointment is that a whole lot of the result will depend on the combined response of the system being auditioned, as well as the ultimate "quality" (freq response, phase relationships and distortion, including the speaker) of everything from the source out through the room itself.
Finding a touchstone for making these sorts of judgments is non-trivial imho.
The holy grail I suppose is to maximize the approximation of reality, the most difficult part being the human voice (instruments interestingly are less determinant), especially in ensemble and in concert with other sound(s).
Just my 2 cents...
_-_-bear
No chance to solve in a long-distance virtual conversation, direct listening comparison is the only chance. We made some, even with JC-2, so I do have answers.
On th e discussion about th e effect of passiv e components, I had an interesting experience this week end trying out my new op-amp based pre-amp. It is very quiet - so no hiss/hum nois e of any sort with volume at any setting.
However, If I touch the volume pot to adjust it, there is a very low level buzz (ear right next to the speaker).
The cause: I wired 275VAC caps from nuetral to GND and then from Live to GND . . . but, this is Japan, so my chassis GND is not connected to the apartment electrical GND.
Take the caps out, and the problem is solved (or use a plastic knob which I would not like to do).
Reason I bring this up is on both active and passive pre-amps, wiring and grounding are critical, just like the earlier comments above.
Biut, also be aware of garbage getting into your system through the volume knob - I am using an Alps Blue Velvet pot - 10k log
However, If I touch the volume pot to adjust it, there is a very low level buzz (ear right next to the speaker).
The cause: I wired 275VAC caps from nuetral to GND and then from Live to GND . . . but, this is Japan, so my chassis GND is not connected to the apartment electrical GND.
Take the caps out, and the problem is solved (or use a plastic knob which I would not like to do).
Reason I bring this up is on both active and passive pre-amps, wiring and grounding are critical, just like the earlier comments above.
Biut, also be aware of garbage getting into your system through the volume knob - I am using an Alps Blue Velvet pot - 10k log
hermanv said:
In the video biz, dark rooms, ones that are naturally dark and with dark non reflective surfaces are key to the best in video. This is due to the fact that when the image is projected at the screen, the screen emits the image in all directions (relatively speaking) and then this light hits the surfaces in the room, and then reflects back onto the screen and interferes in the 'instantaneous' (single frame analysis) Contrast ratio..and not much at all in the full on/off rated and measured CR. Yet, the critical CR (contrast ratio) measurement is that of the re-infection by the room. It interferes in color intensity, and minute changes in colour..thus robbing the image of 'pop', depth, color saturation and '3-d effect' or 'dimensionality' of image. We are good enough with understanding and designing for these aspects that our products are becoming the standard in simulator systems. (besides Pixar, Disney, Paramount, Universal, USAF, USMC, DHS, etc, etc, etc) I went far enough to also re-execute video optics and electronics and to my recollection, not another single soul has made it as far as I did in that area. So far. I plan to return to it soon. Not just the 'replication' - but to know the source intimately.
Notably, John Curl has spent a considerable amount of time on the source side (audio) as well. I feel such things are important.
The analogy carries over almost wholesale to the world of electronics and audio signals. As for Video, I do certainly know my stuff. 😉 There are ways to improve the 'viewed by the human eye' contrast ratio of the screen/room/projector combination but this can also fail to show up in measurements. One can have, in a video screen, an obvious blue shift but it cannot be measured.
Same problem as audio: Clear as the day is long to the eye, but it does not exist to the currently used measurement design standards.
Nevertheless, we design for the unmeasurable, using our brains and eyes....and end up with a visibly or in this case..audibly superior product.
Same-same in the extreme high end of audio.
Folks -the buying public- like to be re-assured that all the tools are used, and many thousands of men in lab coats with clipboards are running around testing and muttering their lives away ----but it's all bullocks. We reach our muse in the shower, driving, or while on the throne. Then we make it real after that moment of inspiration.
I know the source of what it is you seek. But that particular item was hard won, and it allows me to get further down the road than the next guy. Kinda like the JW's ("Jehovah! Jehovah!"-Life of Brian). I'm banging on your door to inform you..to help you reach the promised land..but there are only so many seats....so I can't help you get too far.
😛Attachments
"To understand why DNM Design tries to minimize the amount of metal in their products, one has to understand Denis Morecroft's design philosophies; in particular, his thoughts on the critical effects of eddy currents (aka Foucault currents).
Theory tells us that in any setting in which a continuously changing magnetic field travels through any electrical conductor or even adjacent to it, that field will coax electrons in the conductor into movement. These electrical eddy currents induce their own magnetic field in the conductor, which will tend to oppose or distort the original field (footnote 1).
Esoterica? Minutia? Weirdness? Not at all. Morecroft suggests a demonstration, some variation on which takes place in science classrooms every day: "Go get a nice, strong magnet and a big bar of aluminum. Put the magnet next to the aluminum: Right, it doesn't stick. Now, arrange the aluminum bar as a ramp and try to slide the magnet down it. You'll find it will move, but only very slowly.
"This is well understood and applied in other fields," Morecroft continues. "In fact, there are eddy-current brakes—using electromagnets—on the propeller shafts of 50,000-lb trucks that travel through the Alps. Not small things at all." Of course, Morecroft's interest in the subject is limited to audio, where the effect is somewhat smaller than in 25-ton trucks—but decidedly unwanted. And in audio, one needn't look far before finding a constantly changing magnetic field traveling through a conductor. "
Theory tells us that in any setting in which a continuously changing magnetic field travels through any electrical conductor or even adjacent to it, that field will coax electrons in the conductor into movement. These electrical eddy currents induce their own magnetic field in the conductor, which will tend to oppose or distort the original field (footnote 1).
Esoterica? Minutia? Weirdness? Not at all. Morecroft suggests a demonstration, some variation on which takes place in science classrooms every day: "Go get a nice, strong magnet and a big bar of aluminum. Put the magnet next to the aluminum: Right, it doesn't stick. Now, arrange the aluminum bar as a ramp and try to slide the magnet down it. You'll find it will move, but only very slowly.
"This is well understood and applied in other fields," Morecroft continues. "In fact, there are eddy-current brakes—using electromagnets—on the propeller shafts of 50,000-lb trucks that travel through the Alps. Not small things at all." Of course, Morecroft's interest in the subject is limited to audio, where the effect is somewhat smaller than in 25-ton trucks—but decidedly unwanted. And in audio, one needn't look far before finding a constantly changing magnetic field traveling through a conductor. "
- Status
- Not open for further replies.