Hi QSerraTico_Tico,
Have you tried other devices in the same location as your 2SK389? You can try individual transistors as well. I suspect you will find that the circuit may have more to do with the sound than the part.
Did you get a chance to measure any distortion figures on it?
-Chris
Well, that might be the problem right there!
Have you tried other devices in the same location as your 2SK389? You can try individual transistors as well. I suspect you will find that the circuit may have more to do with the sound than the part.
Did you get a chance to measure any distortion figures on it?
-Chris
Tico, this is not getting us anywhere. It is true, that in Japan, the Blowtorch has sold for up to 5,000,000 yen. That is a LOT of yen! Yet, I know that one Japanese person has 2 'Blowtorches'. Yes, there are people with money to spare.
Now, who gets this 'money'? The dealer gets about 1/2. The importer gets about 1/4, the subcontractor of the case and the parts get about 1/8, and we, who designed and build it, get the rest. We have to live on what we get, and make the choice of doing every solder joint, ourselves, or hiring a tech at $20/hr MINIMUM.
Your circuit shows promise. The phono stage front end of the JC-80 had a similar design to yours. It got 'preamp of the year' in a major Japanese magazine back in the late 80's, much like Charles got for his power amp in Japan this year.
This is F1 racing, in the audio world, not making Yugos.
Now, who gets this 'money'? The dealer gets about 1/2. The importer gets about 1/4, the subcontractor of the case and the parts get about 1/8, and we, who designed and build it, get the rest. We have to live on what we get, and make the choice of doing every solder joint, ourselves, or hiring a tech at $20/hr MINIMUM.
Your circuit shows promise. The phono stage front end of the JC-80 had a similar design to yours. It got 'preamp of the year' in a major Japanese magazine back in the late 80's, much like Charles got for his power amp in Japan this year.
This is F1 racing, in the audio world, not making Yugos.
I faced pretty much the same sort of price complaints when I was handling the retail end of the business. Trust me, folks, I made house payments and bought food, but there wasn't enough left over to have fun with.
Which was one of many reasons I got out of retail audio, actually. The other major reason was that the owner insisted that I sell equipment that I knew to have an unacceptably high failure rate (I can't tell you their name, but their initials were B&O--egad, what junk!).
One of the inevitable--damned foolish--counter arguments that I'd hear was, "But if it weren't so expensive, people would buy more of it!" Yeah, right. And how many preamps do you need, bub? Do you really think I'd sell you two or three preamps during the course of a single year? Not bloody likely. And no, we wouldn't attract enough other, new customers to make up the difference. Most people don't give a flip about audio equipment, no matter how it's priced. If they did, they'd come buy an entry level mid-fi system here instead of a lo-fi system at a department store. Unless and until the average citizen begins demanding quality in audio reproduction, high end will remain a low volume, high price endeavor. The economics just don't work any other way. It's unfortunate, but there it is.
Grey
Which was one of many reasons I got out of retail audio, actually. The other major reason was that the owner insisted that I sell equipment that I knew to have an unacceptably high failure rate (I can't tell you their name, but their initials were B&O--egad, what junk!).
One of the inevitable--damned foolish--counter arguments that I'd hear was, "But if it weren't so expensive, people would buy more of it!" Yeah, right. And how many preamps do you need, bub? Do you really think I'd sell you two or three preamps during the course of a single year? Not bloody likely. And no, we wouldn't attract enough other, new customers to make up the difference. Most people don't give a flip about audio equipment, no matter how it's priced. If they did, they'd come buy an entry level mid-fi system here instead of a lo-fi system at a department store. Unless and until the average citizen begins demanding quality in audio reproduction, high end will remain a low volume, high price endeavor. The economics just don't work any other way. It's unfortunate, but there it is.
Grey
john curl said:
Thanks but it is not similar to the JC-80 schematic I have seen. It's like the AD817 opamp but then with FETs in the input.
http://www.analog.com/UploadedFiles/Data_Sheets/AD817.pdf
There may not be a dual, but you could hand match something from either the J17x or J27x series.
The disclaimer here is that I just recently went through the Seven Rings of Hell to get J271s to use with the J310s I had on hand. How easy it will be to lay hands on the P-ch single JFETs to use with the U430 is difficult to predict.
Grey
The disclaimer here is that I just recently went through the Seven Rings of Hell to get J271s to use with the J310s I had on hand. How easy it will be to lay hands on the P-ch single JFETs to use with the U430 is difficult to predict.
Grey
Tico might be on the right track, for his needs. IF you want the lowest nonlinear capacitance on an input stage, then his selection makes sense. Adding a P channel pair to the input would just make things worse. This would be important IF one were using typical moving magnet cartridges, or analog tape head reproduce electronics.
I have often used a single N channel diff pair on the input of phono, tape reproduce electronics, including the Levinson JC-2, analog master recorder tape reproduce stages, and the phono stage for the JC-80, for this reason.
While I can't find too much wrong with the 2SK389, it does have more nonlinear input capacitance than a real RF part.
I have often used a single N channel diff pair on the input of phono, tape reproduce electronics, including the Levinson JC-2, analog master recorder tape reproduce stages, and the phono stage for the JC-80, for this reason.
While I can't find too much wrong with the 2SK389, it does have more nonlinear input capacitance than a real RF part.
John,
with the 2Sk389 being hard to get, I remember that Jonathan Carr rejected the 2Sk389 for another N-ch JFET for his line amp 4-2SE. I do not know which one he used.
Jcarr:"Rather than the 2SK389, I'd look for the most electrically suitable dual-JFET that you can find in a compact, round metal-can package. Now this doesn't mean that the 2SK389 is a bad part, because it isn't. But it isn't suited for what I had in mind for the 4-2SE.
hth, jonathan carr"
More info from 2005 here
http://www.diyaudio.com/forums/showthread.php?postid=709276#post709276
With Toshiba phasing out some of their best audio JFETs (incl the 2SJ74, AFAIK), I would really like to know what Jonathan used for the 4-2SE.
Regards,
Sigurd
with the 2Sk389 being hard to get, I remember that Jonathan Carr rejected the 2Sk389 for another N-ch JFET for his line amp 4-2SE. I do not know which one he used.
Jcarr:"Rather than the 2SK389, I'd look for the most electrically suitable dual-JFET that you can find in a compact, round metal-can package. Now this doesn't mean that the 2SK389 is a bad part, because it isn't. But it isn't suited for what I had in mind for the 4-2SE.
hth, jonathan carr"
More info from 2005 here
http://www.diyaudio.com/forums/showthread.php?postid=709276#post709276
With Toshiba phasing out some of their best audio JFETs (incl the 2SJ74, AFAIK), I would really like to know what Jonathan used for the 4-2SE.
Regards,
Sigurd
john curl said:
There aren't many choices at the moment. You'll have to take what you can get. If you look at the main catalogs from any of the manufacturers of JFETs, you'll see that P-ch devices are almost non-existent and there are only a few N-ch devices. As for duals...forget it. There are probably less than a dozen candidates left and they're dropping like flies.
Grey
Grey
I have ordered some through the group buy.
I think he is still taking orders and proposes to offer the remains via a trading thread.
http://www.diyaudio.com/forums/showthread.php?postid=1356194#post1356194
I think he is still taking orders and proposes to offer the remains via a trading thread.
http://www.diyaudio.com/forums/showthread.php?postid=1356194#post1356194
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