John Curl's Blowtorch preamplifier part III

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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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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 !

:eek:
 
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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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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.
 
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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?:confused:
I hope one you get from Thailand will be good enough for you.
Damir
 
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I'm sorry to tell you this, Richard, but I added on a new client at RMAF and they are paying me to build a new power amp, larger than anything that I am doing for Parasound, so I am out of the game, here. You know what to do, just do it!

Well, that's too bad.... could have been a great collaboration with an end result greater than the sum of our parts.

Meanwhile, I look forward to hearing your new adventure. Keep on truckin'.

I am also involved with newly minted MS EE's in a new venture to do SOTA products. Doing a technology transfer and brain dump with them and over-seeing their efforts.

That should keep me out of trouble.


THx-RNMarsh
 
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Yes, it is best to stay out of trouble, Richard! '-)
In reality, I am very happy to share what I find makes a better than average audio design. However, many here don't believe most of what I contribute, and demand 'proof' of even the most PROVEN things, like differences in caps, TIM, etc. It gets kind of tiresome to repeat myself over the decades. If any here really want to know what I think about circuit design, etc, just google my name, add audio designer, and get the 100+ page compendium that Dimitri put together over 10 years ago called 'Condemnation without examination is prejudice'. (Or something like that) It says most of what I have had to contribute over the decades, for those who might be interested.
Of course, I still hope to update any new info here, but it IS an uphill course.
 
Yes, it is best to stay out of trouble, Richard! '-)
In reality, I am very happy to share what I find makes a better than average audio design. However, many here don't believe most of what I contribute, and demand 'proof' of even the most PROVEN things, like differences in caps, TIM, etc. It gets kind of tiresome to repeat myself over the decades. If any here really want to know what I think about circuit design, etc, just google my name, add audio designer, and get the 100+ page compendium that Dimitri put together over 10 years ago called 'Condemnation without examination is prejudice'. (Or something like that) It says most of what I have had to contribute over the decades, for those who might be interested.
Of course, I still hope to update any new info here, but it IS an uphill course.
I feel your pain. Beaten down by mediocrity.
 
File 2 is fatter and more compressed with some loss in vocal articulation and I can't hear the room as well so that is probably the added tube circuit. You used a mono source that is a tube recording from the get go so that means I had to go through it three times rather than once to get my bearings.

File 2 was a wire, file 1 was through the tubes. You can see how our ears work.
 
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