John Curl's Blowtorch preamplifier part II

[simon7000]

Believe it or not a good IC is a craft not a paint by number.

I didn't know you liked Iron City Beer. I can always send you a case.
They moved into the old Rollng Rock place and since they now use that mountain stream, the light beer to me tastes like RR. RR got bought and moved so it no longer is the same.

Can I also rib you about how anyone can do a simulation and design state of the art integrated circuits?

Now we can talk about models and IP.

 

[1audio]

I bought the Exar and another IC 'kit' It is amazing that anything 'linear' could be made at all with the parts.

The story I heard from someone close to the source in the early '70s was that the kit was used to create the 555 timer, possibly the most successful linear IC ever. At the time Exar's concept was pretty advanced and enabled a lot of projects and business that would not have been possible otherwise. It predated the concept of fabless semi house. It was also the days of 2" wafers and rubylith.

Its not an issue of how good the transistors are, but how good you are at working with the available tools and limitations. And recognizing you can't get there from here sometimes.

 

[dvv]

Demian, I don't think any linear IC can ever compete in terms of sales with the venerable 741. It was simply everywhere.

 

[john curl]

The 741 and it predecessor, the LM101 were designed by a 'genius', which it took to make something exceptionally useful in linear out of the IC parts available at the time.

 

[dvv]

The 741 and it predecessor, the LM101 were designed by a 'genius', which it took to make something exceptionally useful in linear out of the IC parts available at the time.

Agreed, John.

In my view, looking at it all from Europe, full God status goes to:
1. 741
2. 2N3055,
3. BD 139/140

and demi God status goes to:
1. 4558
2. 2SK170

Those devices simply refuse to die.

 

[scott wurcer]

The 741 and it predecessor, the LM101 were designed by a 'genius', which it took to make something exceptionally useful in linear out of the IC parts available at the time.

Different genii.

 

[scott wurcer]

Scott, a question, if I may.

I would like to know what's your opinion of AD 829. On specs alone, I bought 30 of them, but haven't had an opportunity to use any yet. Its low noise seems very desirable for audio purposes.

Perfectly decent part, folks have used them in audio.

 

[john curl]

The two op amps 101 and 741 are so similar, that I attribute this 'breakthrough' to Bob Widler. Sort of as you might take credit for the AD711, I would give the earlier design the most credit.

 

[dvv]

Perfectly decent part, folks have used them in audio.

Thanks, Scott. I thought as much.

 

[PMA]

Widlar, not Widler.

 

[mikelm]

@ Mikelm,

Ok, Sorry about that mis- understanding.


No i did not get to hear it, the owner did not get all of his amplifiers in time, his system uses 6 balanced monobloc's, he has only recieved 2 prs and is waiting on the last pr. I would guess and say in another month i will get the opporturnity to hear the system..

OK, I would be very interested to hear your impressions after you have heard it either here or by PM

Thx, mike

 

[john curl]

Yes, you are correct, PMA.

 

[john curl]

I am starting some tests with the SR-1 on linear op amps and their loading. Yes, I can find significant higher order distortion with heavy loading. Sometimes, excessive loading is used to meet a spec., or to reduce noise. We shall see.

 

[canyoncruz]

I can't wait, John. which Opamps?

 

[marce]

Yes, I can find significant higher order distortion with heavy loading.

Mathew 7:7

 

[john curl]

At this time, I am sort of 'practicing' with what is available. I still have to build a more flexible test fixture to measure a number of interesting prospects.

 

[scott wurcer]

At this time, I am sort of 'practicing' with what is available. I still have to build a more flexible test fixture to measure a number of interesting prospects.

Please spare us the uA741. 🙂

 

[jan.didden]

Maybe it's my fault; I shall change my avatar, it may lead to emotional fixation by some 😀

Jan

 

[john curl]

No, I am now testing the AD524.

 

[jan.didden]

Ehhhh... Are you following my avatar, John??