John Curl's Blowtorch preamplifier part III

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Oh, please, he his in my ignore list and he knows-it. I only read-him when he is quoted,
This proves <snip>
But I wasn't quoted. How did my post become visible to you? This proves something about you.

The problem is that usually nobody (of those people who demand "ABX results") tells listeners that they have to prepare for doing an "ABX" .

If they would do so (and eventually provide training examples and positive controls), chances are high that the situation would improve.
Where and when did it actually happen? Was it in Imagineville?
Btw, evidence for your claims (you know, about snake oil sales attempts of the "jakob(x)" over at hydrogenaud.io, you were talking about) is still missing.
Wouldn't it a relief for you, if you stop bending the truth and just concede that it only happened in your imagination?
After you answer my question on post #21590.
 
I'm not certain that "back emf" is the correct term.

Agree a heavily misused term. I can't see it properly used unless there is a motor/generator type system where there is energy storage/exchange between electrical/acoustical/mechanical domains.

I also would consider power supply "stability" to be a quantifiable and measurable quantity as opposed to putting cables up on myrtle blocks where there is no hypothesis for any measurable phenomena.
 
I'm not certain that "back emf" is the correct term.
Yes, you are correct - I meant to say noise of whatever frequency is being created in the driven device
Anyway, active devices like regulators can handle low frequency digital noise. It would have to be LF noise, otherwise you would not need a supercap;HF noise (the usual problem with digital) can be handled by an ordinary cap..
What do you consider LF? I think Joe is talking about ultra low frequency - what I call stability.
Adding a supercap to a regulator output might not be a good idea; the change might be audible but not an improvement. Regulators almost always have a low inductive output impedance so adding caps here can create resonance and raise impedance right where you may want to lower impedance.
I believe there are examples on DIYA of improvements from supercap powering many devices - dismiss them as mistaken, if you so wish

However, adding a supercap has the advantage of superficially looking 'different' or 'innovative' so it may be good for sales even though bad for the circuit.
Ever the cynic
 
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I have been using my design of SSR protection for years. The main advantage is it has stable parameters. Contrary to any mechanical relay, I have enough evidence and measurements that if the mechanical relay contact disconnects the load under faulty conditions it should have been immediately replaced with a new one, because of distortion occurrence. Also ageing of contacts raises distortion. Audiophiles and reviewers are a special, irrational class.

Mechanical relays are terrible. I had a fault on one of my earlier 200W DIY amplifiers back in 2012 and the relay contacts welded together.

Cost me about $350 to replace the woofers on one of my B&W 703's - plus the living room stank of burnt varnish from the speaker coil as well.

The nice thing about SSR's is that you can get them to switch in <100us, so you can exploit more of the SOA without letting the protection get in the way - which is what can happen in VI limiting schemes. And good OP trannies are so cheap nowadays you can parallel them to provide enormous output current capability.

I test one of my amps at 60A - 10ms pulses repeated every 50 ms. It trips at 62~63 Amps.

MCU controlled of course . . . and fail safe.
 
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We're into semantics and usage again. :) If he means people like johnego then I agree completely ;)
As for the semantics, there are audiophiles and then there are audiophiles. The former is the traditional definition which still casts a positive image. The latter is the contemporary definition which are seen on internet forums all over the place and the term carries a stigma.
 
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200W CFA that was built for Richard has very high margins PM=85 degree, GM = 21 dB (simulated of course, I don't have means to measure it in real amp). Lowering ULGF will not improve it much.
One of the reason I chose mosfet OPS is possibility to use fast drivers as KSA1381/KSC3503 (or even with no drivers at all) and get less phase shift and higher ULGF.
Even in my ThermalTrak VFA with triple OPS I switched to OITPC and get ULGF of 3.2 MHz, still working for some years with not problem what so ever.

There are a lot of comments here - people can guess all they like, but nothing will be known until you or Richard get to look at the amps in person and try to figure out what is going on.

Anyway, I am quite sure the problem is solvable :)
 
Citations, links, circuit solutions, please.

Reports in Iancanada's threads on his & others journey comparing supercaps/batteries to many regulators.
One factor reported is that putting a regulator between supercap/battery & device being powered usually/always results in a dis-improvement in sound Vs supply from supercap/battery alone especially when driving digital devices

What's to be concluded from this? Regulators are behaving differently to supercap/battery when driving devices - I put it down to stability/noise issues. Maybe you have another idea?

Have you tried/compared Vregs Vs battery/supercaps in driving devices?
 
I'm not certain that "back emf" is the correct term. /QUOTE]

Agree a heavily misused term. I can't see it properly used unless there is a motor/generator type system where there is energy storage/exchange between electrical/acoustical/mechanical domains.

I also would consider power supply "stability" to be a quantifiable and measurable quantity as opposed to putting cables up on myrtle blocks where there is no hypothesis for any measurable phenomena.
Yes, I believe it could be measurable too but is it measured? Any suggestions/thoughts on approach to doing this?
 
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Where and when did it actually happen? Was it in Imagineville?
If you read & comprehend what Jakob posts that is exactly what he is saying - it never happens that the ABX mafia on her suggest training is a necessary part of doing ABX testing of any worth - as is using positive controls but I thought it was already agreed by all (apart from the rabid few) that ABX testing/listening was just a bit of fun, that same as sighted listening so there's no real issue
 
And then ?
Do I have to be impressed because this aggressive and impolite guy had wrote a paper in a confidential technical magazine ?
I cannot: I not often read such papers, It bores-me, unless somebody told me that there is something revolutionary. And that do not happens so often and not in this paper.

There is a big misunderstanding in this forum between old guys, that worked on the bench and discovered many things by themself, long before somebody else put a name on it, and the younger that had an EE in university and an abstract and intellectual way to feel the things. See what I mean ?

Let's take compensations networks as an example.

I thought in the 70 that the extra load at HF of the traditional compensation cap was responsible of added distortion. Had the idea to take the current needed to charge-it from the output stage of higher current capacity rather than to the emitter of this poor VAS transistor.
Tried-it and it worked. Of course, after this I had explored all the possible ways to improve this and satisfy both sir Nyquist and sir Murphy.
It was a long research, with a lot of magic smoke, because there was no simulators available at this time. No computers neither.

I have to add that I was not an EE of any kind, had learned all that I know on the bench, since the age of 15, with passion.

If this does not allow me to shine on the forums using acronyms every three words, it has at least one advantage: the habit of going out as often as possible off the beaten track. The few things I know, may-be less than half of this guy, I possess them in a sensual way. May-be a deeper one ?.

Also, I have probably, like JC and others, spent more time listening than doing simulations for which I am far from being an expert. With some successes, at least for John ;-).

The attitude of this person was totally unjustified, his need to ride on his spurs, like a young rooster pushed him to become ridiculed. It's all the more stupid that, never, ever, I would have put on the market an amp such as the one I showed the simulations, although using it for my own use. i did-it to explore. So that, fundamentally, I agreed with him. My first answer, that was not unfriendly, being just to bring a nuance to his "impossible" as a wink. His stupid and flawed following attacks have no excuse.

My respects to Dadod, constantly exploring on his side, and all the others that take risks.

To conclude, most of the best musicians I had met in my life (out of classical music) are self made men. My friend Didier Lockwood (RIP) was a violin first prize at the conservatoire de Paris. He used to say that he needed more than 15 years to unravel what he had learned there and begin to understand ... music.
I remember how he was lost, in the 70, in a rehearsal room at Valauris, with a group of young freaks that were not able to read a note on a score, when it came to improvising on a series of chords.
Nowadays, most of the musicians are perfect technicians, issued from schools. Better instrumentists than Clapton at this age.
Where is the music, compared to the 70 years ? Where are the modern Beatles ?
Politically correct is not the best way to poetry, creativity, discoveries, emotions.
The aggressiveness is not even politically correct.
 
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And then ?
Do I have to be impressed because this aggressive and impolite guy had wrote a paper in a confidential technical magazine ?

You asked what he was doing about amplifiers. You quoted only half of my links. You did not quote

PGP Amplifier

which is a public resource with links to other schematics. So please play fair, jouer franc jeu, especially in case you ask not to insult.
 
Yes, I believe it could be measurable too but is it measured? Any suggestions/thoughts on approach to doing this?

Briefly from my archive. In-wall adapter ripple, power bank ripple, power bank output spectrum. Components for RME-ADI2.
 

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And then ?
Do I have to be impressed because this aggressive and impolite guy had wrote a paper in a confidential technical magazine ?
I cannot: I not often read such papers, It bores-me, unless somebody told me that there is something revolutionary. And that do not happens so often and not in this paper.

There is a big misunderstanding in this forum between old guys, .


So 60 is a young guy? You are funny.


Edit: I have to say this. I have admiration for bench taught guys who achieve good things, but just sometimes it might be worth considering that those on here with PhDs might just have some insights for you to learn if you opened your mind to science...
 
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