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Old 7th September 2012, 05:35 PM   #801
EUVL is offline EUVL  Europe
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Why use the 861 which is rather noisy ? Why not use the as suggested 862 ?
If you do not want so much current, then use 2SK170 or LSK170 instead.

Spice models for all of them are widely available.


Patrick
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Old 7th September 2012, 05:42 PM   #802
RNMarsh is offline RNMarsh  United States
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Default what is needed for sota -

Quote:
Originally Posted by Wavebourn View Post
Even in sockets and plugs of professional equipment used to record audiophile quality material?

My best tube amps use nickel alloy for anodes.

Also, speaking of PCBs and their orientation, it is better to orient them such a way so components are better cooled by convection. If you put it horizontally components in it's center will be heated more, and their temperature may be higher than be the PCB mounted vertically. Higher tempco have semiconductor devices, so what's the point in thermocouple effect of joints minimization maximizing overall thermal instability?

No rules of dumbs here. Everything has to be carefully designed. All pros and cons considered and calculated, in each and every different case.
Cute: Tubes need to use nickel. And we arent designing a tube circuit here. Not at all relavant. And, if we were, i wouldnt be interested in anything tube.

Wouldnt build recording gear without best parts, materials and practices. Including use of nickel when it can be avoided without penalty. Yes, i know why nickel is used. Doesnt apply to what we are attempting to make and dont have the same issues to deal with.

maybe higher -- maybe. maybe. Temp gradiant was the comment... in relation to gradients affect on thermal emf. your comment doesnt apply.

However, the points are to look at not as a hard rule. generalizations are useful when we are not yet making anything. -Thx - RNM
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Old 7th September 2012, 05:47 PM   #803
coluke is offline coluke  Italy
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Here is what I've got simulating Scott's design @ 1kHz, 0dBV into 30 ohm (12 dB gain, medium power output bjts running @ about 50 mA Iq - J113s in the front end - didn't have at hand BFs models - real 2 bjts CCSs in place of I1, I2). Impressive
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Last edited by coluke; 7th September 2012 at 05:50 PM.
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Old 7th September 2012, 05:49 PM   #804
RNMarsh is offline RNMarsh  United States
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Default SOTA design or what's the point?

Are we to bring up issues that will push the frontiers of discrete ss design and performance or what is the point here?

[Tubes need not apply !]

Last edited by RNMarsh; 7th September 2012 at 05:58 PM.
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Old 7th September 2012, 05:53 PM   #805
RNMarsh is offline RNMarsh  United States
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Default Impressive results in SIM -

Quote:
Originally Posted by coluke View Post
Here is what I've got simulating Scott's design @ 1kHz, 0dBV into 30 ohm (12 dB gain, medium power output bjts running @ about 50 mA Iq - J113s in the front end - didn't have at hand BFs models - real 2 bjts CCSs in place of I1, I2). Impressive
That IS impressive results from SIM. Let's build that one !! See if we can make one perform close to the SIM model. Congrates to Scott. Thx -Richard Marsh

Last edited by RNMarsh; 7th September 2012 at 06:00 PM.
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Old 7th September 2012, 06:10 PM   #806
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Holm's book on contacts is a good reference.
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Old 7th September 2012, 06:14 PM   #807
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Quote:
Originally Posted by bcarso View Post
Interesting. Although the harmonic structure is pretty clearly mostly 2nd with a little 3rd, how many harmonics are accounted for in the later plots?

Does your simulator have an option for log scaling?

Brad
What do you mean by the later plots?
Usually I'm using 10 or 20 harmonics, in this case I'm using 10.
No problem with log scaling, what would you like to see?
BTW: it takes more than an hour or two to run a trustworthy
simulation.

Stein
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Old 7th September 2012, 06:18 PM   #808
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Quote:
Originally Posted by coluke View Post
Here is what I've got simulating Scott's design @ 1kHz, 0dBV into 30 ohm (12 dB gain, medium power output bjts running @ about 50 mA Iq - J113s in the front end - didn't have at hand BFs models - real 2 bjts CCSs in place of I1, I2). Impressive
Which of Scott's design's
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Old 7th September 2012, 06:23 PM   #809
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Quote:
Originally Posted by EUVL View Post
Why use the 861 which is rather noisy ? Why not use the as suggested 862 ?
If you do not want so much current, then use 2SK170 or LSK170 instead.

Spice models for all of them are widely available.


Patrick
No problem I can use the 862 if you think that it will be a revolution.
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Old 7th September 2012, 06:28 PM   #810
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Quote:
Originally Posted by RNMarsh View Post
Cute: Tubes need to use nickel. And we arent designing a tube circuit here. Not at all relavant. And, if we were, i wouldnt be interested in anything tube.
Here is it, on the previous page: differential tube input, differential tube output.

Quote:
Originally Posted by Wavebourn View Post
Trimmers there left from previous drawing, with paralleled output tubes. Without paralleling it is better to trim gyrators.
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