John Curl's Blowtorch preamplifier part II

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I think that the review is consistent with my opinion of the JC-3, and I think of it as a middle-of-the-road design, like a Honda. I can do better, or I can do cheaper. Take your choice. Sometimes, when extra critical engineers (those looking for a criticism) read some of the material reviewers print, after talking to the 'promoters' of the product, and note that it is a little off base, but it is not significantly so.
This design is based on an earlier one by Walt Jung in about 1979, and published in TAS at that time. It is IC based. The IC's have been 'upgraded' and a servo added, as well as serious power supply buffering. We did not ultimately use the AD797 or the LT1028, but found something as good sounding, just as quiet, and cheaper. However the
AD797 would have worked on the input just as well.
I have done listening comparisons between the Blowtorch with Vendetta, and the JC-3 and found it OK, but no 'Vendetta'. That is to be expected, and guess what, the reviewer found that too!
 
Jan, be careful with your loose criticisms. There are explanations for the changes.
 

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Jan, be careful with your loose criticisms. There are explanations for the changes.

Isn't that a great picture!

Anyway, not sure what criticism you meant, but I have a hunch that a) you're thinking of something you can't really recount or identify, and/or b) you took personally a critique of an idea or an implementation. But by all means, educate me as to what I am guilty of.

I try to never criticise people, but I feel that better understanding comes from criticising ideas or opinions, even if I turn out to be wrong.

OTOH, taking any criticism personally wasts the effort and closes the door to learning, for the criticiser and even more so for the criticisee.

Jan
 
Jan, you have been very cynical about my designs, and this is no exception. First of all, what Parasound had to do to get a decent load pot was real, but it was NOT what I was exploring for Constellation.
Second, how do you know that increasing the transformer did NOT improve the bass? It has in previous designs, and this was independently verified by both Brian Cheney and Gordon Holt on a design upgrade that we did on a preamp done by Nelson Pass, years ago.
So, be careful of your criticisms without trying it yourself.
 
Jan, you have been very cynical about my designs, and this is no exception. First of all, what Parasound had to do to get a decent load pot was real, but it was NOT what I was exploring for Constellation.
Second, how do you know that increasing the transformer did NOT improve the bass? It has in previous designs, and this was independently verified by both Brian Cheney and Gordon Holt on a design upgrade that we did on a preamp done by Nelson Pass, years ago.
So, be careful of your criticisms without trying it yourself.

Huh? I don't recall ever saying all these things? Improve bass yes/no? I never commented on that.
I DO remember commenting on whether it was worth the effort to make a continuously-variable load. That was criticising a design decision (or plan). Reading the review, where it says that the 'standard' 100 ohms is pretty much universally OK it seems I had a point.

But again, that was not criticising you as a person John. You forget that, knowing your tendency to take everything personal, many people here have repeatledly gone on record that they respect and admire your achievements in the audio world, but that they had a different view of (fill in your fav. implementation or parts choice).

Jan
 
Folks, it is very important to separate marketing from engineering.
Sometimes marketing might make something more important than engineering might think it to be. But that is marketing, and marketing talks to the reviewers, not the engineer. This does create some 'interesting' interpretations of engineering changes and additions, but it does NOT negate them. They still could be just as valuable, just for a slightly different reason.
 
If you believe (like I generally do) that 100 ohms is a great default resistive load, then just buy (or build) a JC-3 and save lots of money. Still, for my better designs, like Vendetta and Constellation, I DO have a variable load, and will do so in future. It is better, IF people want to bother with it.
 
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If you believe (like I generally do) that 100 ohms is a great default resistive load, then just buy a JC-3 and save lots of money. Still, for my better designs, like Vendetta and Constellation, I DO have a variable load, and will do so in future. It is better, IF people want to bother with it.

I will buy neither, for me the difference is not worth what I have available in discretionary funds, and I build my own. This is diy 😉

But that was not the point, was it John? The point was that I criticised your decision to go for the variable loading. Apparently, you were right to do it, and it paid off for you and/or Parasound.
Maybe that's another of your talents - having a feel for what the market is ready to accept. Or maybe it was the Parasound people who had an idea that panned out.

But if there's yet another design decision by someone here that I disagree with, I will try to explain that. After all, if that's no longer possible, why come here in the first place? Why did you bring up that idea in the first place, if not for getting feedback, positive or negative (sorry for the F-word).
I can't believe you only brought up that idea in the assumption that we would all fall silent, staring at the ground and drooling, except maybe Stuart.

Jan
 
So that Scott Wurcer's question is answered: What the reviewer what trying to relate was that I followed Ed Simon's advice to put a 50-100 ohm resistor at the INPUT of the IC to remove some difficult to fix oscillation, yet I bypassed it with a coil of wire to BYPASS the resistors noise at audio frequencies. Too bad I had to resort to this input resistor, because it would potentially reduce the S/N by 3dB or more. This is a 'flaw' in the IC design, in my opinion.
 
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