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Old 11th June 2007, 05:46 AM   #111
lineup is offline lineup  Sweden
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Cool FFT AC Analysis Phase nad THD distortion of my Jfet BOZ

Quote:
Originally posted by lineup

I know I have 2SK170GR spice models. They are the ones easy-to-find.
And this is the variant of 2SK170 I can easily buy in my country.

I will also present a fourier analys:
- Level of 2nd 3rd 4th harmonics.

For one rudimentary No-feedback JFET circuit, like this one,
we can expect some 2nd harmonics
and considerably less 3rd harmonics

Regards
lineup
.

I promised to present FFT Fourier analysis
of my version of Jfet BOZ
I can report, that such analys has been done, today.


Diagram of 2nd, 3rd ....8th, 9th harmonies
confirm my earlier posted prediction, fully:
Quote:
.
For one rudimentary
No-feedback JFET circuit,
like this one,
we can expect some 2nd harmonics
and considerably less 3rd harmonics
.

If there are any much calls for it
- I publish/post my Analys Results***
If not, I keep it in my safe and for my own works.


2nd Harmonics regards lineup
Lineup Audio Lab Inc.

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*** Note:
I have the following
- FFT at several frequencies, 9 harmonies
- AC Analys, deci-Bell, dB, scale = bandwidth
- Phase Analys, degrees
- THD % distortion, at several different:
..frequencies within audioband
..loads
..amplitudes
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Old 11th June 2007, 05:50 AM   #112
steenoe is offline steenoe  Denmark
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Default Re: Re: Re: Re: Re: Re: Re: Pass 2SK170 BOZ

Quote:
Originally posted by mpmarino
On this pre - Do you guys think the attenuator (volume control) should go on the input or the output? I'm talking about a 'twisted' constant impedance relay setup - or similar.

Steen,
where ya been? I'm waiting for someone to comment on how this thing sounds. I'll give you an hour or two to get one together
Try to install the attenuator at the input, which is best in terms of output impedance of the preamp.
I am sure that with Manu and Twitchie handling the testing, its in the best of hands.


Quote:
Originally posted by Blues



The sound is . I love its sound more than the A3.

Now this Jfet pre-amp looks delicious...I'm thinking of using an sj74 instead to match my Zv4jC.
Excactly The simplicity of the J-fet-BoZ is very appealing. Could be fun trying to use it with the F4. What was the gain, 24dB?
Could be just the thing for an ultrasimple preamp/amp combo.
Greedy boy, signing out.

Steen
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Old 11th June 2007, 06:54 AM   #113
Vix is offline Vix  Yugoslavia
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Quote:
Originally posted by Blues
Battery PS would make it a killer...we won't worry on rectified PS noise.
I just bought two 9 V (270 mAh) Ni-Mh rechargeable batteries....

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Old 11th June 2007, 07:10 AM   #114
lineup is offline lineup  Sweden
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Quote:
Originally posted by jacco vermeulen

Vince,
a few years ago i bought a +10k package of metalfilms by the cheap, including values such as 1M.
Not that i was totally out of resistors, think the deal on Russian made resistors i couldn't resist was a couple of months before the big score.
Sooner or later, they always come to good use.
.
yah, jacco
( sounds like a dead parrot's name, to me = john cleese, monty ptyhons )

I also buy large packages with resistors.
At least 10 resistors per value.
I prefer 0.6 Watt MetalFilm and I can get these here locally
in those big packages.


> Sooner or later, they (metallized resistors) always come to good use.

.. in your Jfet BOZ, imagine
.. how is your setup?
----->Nelson's original, 2nd harmonics distortion
----->Lineup's special circuit, for lower THD distortion



Regards lineup
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Old 11th June 2007, 08:08 AM   #115
steenoe is offline steenoe  Denmark
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Quote:
Originally posted by Vix


I just bought two 9 V (270 mAh) Ni-Mh rechargeable batteries....

Vix, looking forward to hear about you results. How do you intend to implement the battery supply? Just a few 1000uF's after the batteries or do you have something else in mind?

Steen
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Old 11th June 2007, 08:39 AM   #116
Vix is offline Vix  Yugoslavia
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Actually, since it is a battery power, I was thinking to minimize the capacitance....just 10 uF electrolytic bypassed with 100 nF....

I see no reason to add 1000's of uF...please let me know if that is a bad idea...

By the way, after a bit of rechage, I measured 10.25 v on the battery (!). Seems like it contains 8 cells (1.2 volts nominal) so they are supposed to settle at around 9.6 V, giving me a 19.2 v for a preamp. Somewhat higher than 16 v as sugested by Nelson, but it should work...

Regards,

Vix
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Old 11th June 2007, 10:32 AM   #117
steenoe is offline steenoe  Denmark
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Quote:
Originally posted by Vix
Actually, since it is a battery power, I was thinking to minimize the capacitance....just 10 uF electrolytic bypassed with 100 nF....

I see no reason to add 1000's of uF...please let me know if that is a bad idea...

Regards,

Vix
Just asking out of curiousity I dont know what is needed for a battery supply in terms of capacitance.

Steen
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Old 11th June 2007, 11:07 AM   #118
Vix is offline Vix  Yugoslavia
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Quote:
Originally posted by steenoe


Just asking out of curiousity I dont know what is needed for a battery supply in terms of capacitance.

Steen
Me neither. But I think law of diminishing returns would apply for anything above 100 uF...

Vix
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Old 11th June 2007, 12:34 PM   #119
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Getting the mains power out would be real nice (I am pretty sure I have DC on mains at home). I would like to have a charging circuit that goes 'auto on' when the pre is turned off.

Also, it would be super nice to have a simple phono pre in the same case off the same battery supply. How about another Jfet BOZ in series with a RIAA filter hanging off of it - somehow.
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Old 11th June 2007, 02:24 PM   #120
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally posted by mpmarino
.........

Also, it would be super nice to have a simple phono pre in the same case off the same battery supply. How about another Jfet BOZ in series with a RIAA filter hanging off of it - somehow.

another lazy greedy boy........

google for "pacific riaa"

uh........

http://tiny.pl/fw6q
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