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John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
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Old 2nd November 2018, 06:11 PM   #9001
john curl is offline john curl  United States
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It is interesting to learn what you guys do for a living. Also, I might say:'Keep your day job, guys!) '-)
I once had a chance to do that sort of thing. It was 55 years ago, I had left my computer operating job at Lockheed, (see my avatar) and was looking for another job. I saw an ad for a 'physics technician' offered at Fairchild Semiconductor. I applied, and got a tour of the facility by none other than Bob Widlar (I am pretty sure), and tried to show interest in the fancy gas using equipment that they were doing, but I failed, and did not get the job. THANK GOODNESS! If there is one thing that I am not good at, is running chemistry lab projects. I found this out when I shared a class with the guy is now my part time tech, and good friend. It was first year college chemistry. He was great at lab, and I was lousy. I only got through on the the theory part.
This job opportunity, if I had been hired, would have been a great opportunity for circuit development, but a disaster in showing my incompetence as a 'physics tech' Later, I learned everything that I could from Bob Widlar through his Fairchild and later, National Semi writings. The result gave me a big head start in advanced circuit design, that got me ahead of the pack, 45 years ago.
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Old 2nd November 2018, 06:40 PM   #9002
RNMarsh is offline RNMarsh  United States
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Originally Posted by 1audio View Post
Since the issue has come up before here is an unusual opportunity to own a Quan-Tech semiconductor noise analyzer, latest generation. You have less than 8 hours to bid: Quan-Tech 5173 Semiconductor Noise Analyzer | eBay

Looks like you will need to fabricate a test fixture for it.
The digital display version. I have the analog display prior version. Works very well except the knobs are hard to turn after years.

Still measures fine.


-RNM


marsh amp 2wks out.jpg


Power amps are two weeks out. Then ship to me. How much is that going to cost OMG !


Last edited by RNMarsh; 2nd November 2018 at 07:00 PM.
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Old 2nd November 2018, 08:14 PM   #9003
wrinkle is offline wrinkle  United Kingdom
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Listening to Linon Kwesi Johnson, Bass Culture.

And that talk of the new byby device makes me paraphrase Benjamin Britten, I havent heard any byby's but I may have trodden on some at some point.
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Old 2nd November 2018, 09:59 PM   #9004
john curl is offline john curl  United States
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Richard, I also have a new power amp in my lab. It is the new JC-1+, and it has a number of new internal improvements, like 50% larger power supply, Bybee-rails in the driver stage, etc. Unfortunately, they put the wrong value emitter resistors in, and it is impossible to bias for lowest distortion. I hope that Parasound will send a technician to replace (actually parallel) all 24 emitter resistors that need changing, soon.
On another subject, I did try the new devices that Jack Bybee wanted me to try in a new position (inside a working power amp). I opened the amp, then fired up my big system, especially the phono stage, and tried some brand new, as well as some older favorite vinyl records, adding the Bybee upgrade in the middle of the listening session. In this case, I decided that it sounded good, before, and it still sounds good, and that I am not in a good position to have a listening opinion with THIS particular test, and I told Jack Bybee that, this morning. I am just not calibrated up to the 'big system' at this time, to be effective with this sort of change. I listen almost all day, these days, to an all blues channel on Comcast through 4 Sequerra speakers, and my little HCA 1000 power amp. For blues, it seems to sound just fine. Then in the evening, I use the same set-up for TV. I have been lazy lately, because the 'big system' does sound better, but it lacks any remote control, and vinyl records have such a short playing time! Darn.
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Old 3rd November 2018, 05:35 AM   #9005
RNMarsh is offline RNMarsh  United States
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Originally Posted by john curl View Post
Richard, I also have a new power amp in my lab. It is the new JC-1+, and it has a number of new internal improvements, like 50% larger power supply, Bybee-rails in the driver stage, etc. Unfortunately, they put the wrong value emitter resistors in, and it is impossible to bias for lowest distortion. I hope that Parasound will send a technician to replace (actually parallel) all 24 emitter resistors that need changing, soon.
John. That should be a nice improvement to an already excel product. Hey, lets have a vote here..... JC and RM collaborating on a new power amp with all our combined tricks and means and methods in it. The best of the best - one for the ages. We are both really old now.... times running out. I am sure we could get lots of help. Lets do it.


-Richard


PS -- Wilson Audio is buying the REL-CAP company.

Last edited by RNMarsh; 3rd November 2018 at 05:46 AM.
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Old 3rd November 2018, 06:04 AM   #9006
dadod is offline dadod  Croatia
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Originally Posted by RNMarsh View Post
Hey, lets have a vote here..... JC and RM collaborating on a new power amp with all our combined tricks and means and methods in it. The best of the best - one for the ages. We are both really old now.... times running out. I am sure we could get lots of help. Lets do it.


-Richard
So, I am out now of that amp design?
I hope one you get from Thailand will be good enough for you.
Damir
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Old 3rd November 2018, 06:25 AM   #9007
RNMarsh is offline RNMarsh  United States
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So, I am out now of that amp design?
I hope one you get from Thailand will be good enough for you.
Damir
Nope. Not at all. <3 It would be another amplifier for the market place.


I am looking forward to using your design soon. :-)



-Richard

Last edited by RNMarsh; 3rd November 2018 at 06:42 AM.
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Old 3rd November 2018, 11:24 AM   #9008
Max Headroom is offline Max Headroom  Australia
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Originally Posted by RNMarsh View Post
..... JC and RM collaborating on a new power amp with all our combined tricks and means and methods in it. The best of the best - one for the ages. We are both really old now.... times running out. I am sure we could get lots of help. Lets do it.
Yeah, why not......open source ?


Dan.
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Old 3rd November 2018, 12:28 PM   #9009
Mark Johnson is offline Mark Johnson  United States
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John Curl's Blowtorch preamplifier part III
Quote:
Originally Posted by 1audio View Post
... here is an unusual opportunity to own a Quan-Tech semiconductor noise analyzer, latest generation. You have less than 8 hours to bid: Quan-Tech 5173 Semiconductor Noise Analyzer | eBay

Looks like you will need to fabricate a test fixture for it.
I won the auction, yaay!

Does anyone have a manual they'd be willing to sell, original or copy?
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Old 3rd November 2018, 01:22 PM   #9010
scott wurcer is offline scott wurcer  United States
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I won the auction, yaay!

Does anyone have a manual they'd be willing to sell, original or copy?
I only have the analog manual (in storage somewhere). I hope you have better luck than me with eBay gear.
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