My apology if this quick question strays too far from this John Curl Blowtorch thread but I seek this groups opinions based on what I have read here.
Leave my 🙂John Curl🙂HCA2200ii on all the time or turn it off when not using it, in light of its age?
Thanks, your discussion here is a bit over my head and that's what makes it so interesting.
Matt
Leave my 🙂John Curl🙂HCA2200ii on all the time or turn it off when not using it, in light of its age?
Thanks, your discussion here is a bit over my head and that's what makes it so interesting.
Matt
I turn mine off when not is use, but it does take a few 10's of minutes to sound its best. I leave the preamp on, all the time, however.
This is one of the problems with 'fragmentary' input by individuals who input on technical subjects outside of the scope of the Blowtorch philosophy. This includes excessive concern with grounding when it isn't a problem with the Blowtorch, or related circuitry. It is NOT that grounding is not important, but that it has to be dealt with in a clear and straightforward way, if progress is to be made.
Now, discussion of modifications on somewhat similar Parasound products is not completely the same as discussing the Blowtorch preamp or its near relative the 'Bar-B-Q' HCA-3500 modification, but they were both done by the SAME designers and modifiers, and so they share a common philosophy.
For example, for ALL Vendetta designs, the JC-1 power amp, the Parasound JC-2 preamp, the modifications of the HCA-3500, and the Blowtorch preamp are the same, derived by the same designers and builders. This the use of .047uf to .1uf Reliable RT film foil polystyrene bypass caps for anything that directly connects to the audio signal in any significant way. This is a universal component that we always use up to this time. Even using Teflon from the same company does not appear to be as good for a bypass cap, but very good for phono EQ. Go figure. You will see very much the same thing in many of my esteemed competitors designs as well. Just look for yourself. These parts are NOT cheap, are sometimes unreliable, and just look OK, not fancy, BUT they seem to work better than most anything else, in my experience.
Now, discussion of modifications on somewhat similar Parasound products is not completely the same as discussing the Blowtorch preamp or its near relative the 'Bar-B-Q' HCA-3500 modification, but they were both done by the SAME designers and modifiers, and so they share a common philosophy.
For example, for ALL Vendetta designs, the JC-1 power amp, the Parasound JC-2 preamp, the modifications of the HCA-3500, and the Blowtorch preamp are the same, derived by the same designers and builders. This the use of .047uf to .1uf Reliable RT film foil polystyrene bypass caps for anything that directly connects to the audio signal in any significant way. This is a universal component that we always use up to this time. Even using Teflon from the same company does not appear to be as good for a bypass cap, but very good for phono EQ. Go figure. You will see very much the same thing in many of my esteemed competitors designs as well. Just look for yourself. These parts are NOT cheap, are sometimes unreliable, and just look OK, not fancy, BUT they seem to work better than most anything else, in my experience.
john curl said:
Boy, took you a while, eh John?
As I said, you solved various issues surrounding current path control by separating the supplies. No problemo dude, it's just a different solution, one that is horrendously expensive compared to the jellybean market.
You had a problem, you fixed it...simple. And it met your market price point requirements (which is, there were none)..😀
Calling my input "fragmentary" is funny. You either have no clue what I'm talking about, or your just trying to divert to keep your market advantage...my money's on diversion..
Honestly John, give Tom Van Doren a call. You can learn a lot from him. His two day course was only 2k per head, find out where he's gonna be in the near future..
Cheers, John
jneutron said:
I'm also not clear about your suggestions, though I'm aware of the problem.
You are welcome to make it coherent, either here (which I'm not sure is appropriate), or by a link to another thread.
I know John, I know.john curl said:
But since you do not like me, I have recommended a really nice guy who is also VERY well informed... as well as teaches the subject for a living, so that you can learn what he has to say..
Cheers, John
Joshua_G said:
Ask and ye shall...keep in mind, it is only the start.
The purpose is to define the problem, find a way to measure the problem in situ (as opposed to on a lab bench), measure a particular amp and pre combo, and clear up the problems shown by the test equipment.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=134500&perpage=25&pagenumber=1
Cheers, John
jneutron said:
Very good.
Now that you have your own thread and all here are aware of it – is there anything more you can add to this thread?
My interest in this thread is to learn how to better design pre-amplifiers.
Joshua_G said:
Yup..
As I pointed out far far ago in this thread..
Why would anybody in the world believe that a "pin 1" problem was simply a problem of the receiver???
Single ended OUTPUTS are just as susceptible to ground loop currents as are the inputs.
Single ended outputs, like those of a preamplifier.
As for getting to that point on the other thread, you will have to wait like everybody else. First the basic theory need to be understood, then how to test, then what to test..
I detailed the issue on march 31, 2004..I honestly don't recall which forum I put the scan of my hand drawing on..
It's all about current path control. That is actually the essence of all shielding and noise control. And shielding is a two way street, in and out. Interstage current path control to prevent crosstalk is just one example, which JC alluded to with the use of multiple supplies.
As another stated on this thread...having the best schematic in the world doesn't help if you put it into the box badly.
Oh, and another quote from this very thread...""Unfortunately, I see in the BEST audio design that attention to details is so important that it is almost like 'links in a chain', rather than most important to little importance.""
Guess who said that?? (italics are my doing, not the verbage..)
Cheers, John.
PMA said:I was quite disappointed when I saw this. Built (and design) quality? This??
What is the thing you are showing a picture of? 😀
Stinius
No. Company built.
BTW, this is a DIY project, of a member of our DIY community:
http://hifi.slovanet.sk/bb/viewtopic.php?p=64906#64906
BTW, this is a DIY project, of a member of our DIY community:
http://hifi.slovanet.sk/bb/viewtopic.php?p=64906#64906
Well, some DIY projects are designed and built better than some commercial products … (CTC excluded, of course).
PMA said:
Is this how it left the factory or has somebody done some tweaking here?
This is seriously not looking good, I’m speechless.
Stinius
😱 😕 
🙄 
PMA, I didn't do the layout, I just designed the basic topology. REMOVE all those extra caps. I don't design them into the unit, the Taiwanese did! The layout on some of those early units was so bad that I threatened to quit, if they did not improve. This was 15 years ago, and this 250W/per channel STEREO Amp retailed for something like $1700. What do you expect?
IF you want to see something within MY entire control, look at the Vendetta board in this section, or the new Parasound JC-2, or even the Parasound JC-1. They have my initials on them, because I have taken more control over the execution of the design. Before, I left the 'details' to others. Still, it was a bargain. Now, you have to pay $7000 for essentially the same basic circuit that has a 400W/channel output from Parasound. That extra 150W/ channel does NOT add up to an extra $5000 in cost, yet it is necessary, to do it right.
I might equate it to a Porsche 924 that used a modified VW engine to a Porsche Boxster. The 924 might have cost $10,000 new, the Boxster might cost $50,000. Both cars were designed to do the same job, by the same company, and one can enjoy a 924, IF you can live within the compromises that were forced by economics.
IF you want to see something within MY entire control, look at the Vendetta board in this section, or the new Parasound JC-2, or even the Parasound JC-1. They have my initials on them, because I have taken more control over the execution of the design. Before, I left the 'details' to others. Still, it was a bargain. Now, you have to pay $7000 for essentially the same basic circuit that has a 400W/channel output from Parasound. That extra 150W/ channel does NOT add up to an extra $5000 in cost, yet it is necessary, to do it right.
I might equate it to a Porsche 924 that used a modified VW engine to a Porsche Boxster. The 924 might have cost $10,000 new, the Boxster might cost $50,000. Both cars were designed to do the same job, by the same company, and one can enjoy a 924, IF you can live within the compromises that were forced by economics.
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