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Old 6th August 2008, 03:32 AM   #411
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Quote:
Originally posted by salas
Started organizing it a bit...
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Old 6th August 2008, 08:44 AM   #412
Skorpio is offline Skorpio  Denmark
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Quote:
Originally posted by Skorpio


Hi,

I understand your arguments, but:

1. Why use +100$ for audiophike capacitors if they can be avoided with >1$ components? The other thing is part size....

2. Capacitors do not sound as good without voltage accross them

3. I was not thinking of a bad servo, but a good one

4. I have allready matched JFETs in circuit (9.53 and 9.55mA)

5. I have low offset, but would like the servo for longterm drift and safety. I do not have DC-protection...
I have now build the servo in and made it optional with a jumber. I have change the servo to only work in one single point, the output.

There is no sonic influence to me if the servo is in or not, but it my be because the correction it makes is so small?
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Old 6th August 2008, 09:06 AM   #413
Tolu is offline Tolu  Germany
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Quote:
Originally posted by salas
Started organizing it a bit...
We are writing the year 2008 and these are the manufacturing tolerances of state-of-the-art producers!?



Shocking!
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Old 6th August 2008, 09:14 AM   #414
h_a is offline h_a  Europe
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Quote:
We are writing the year 2008 and these are the manufacturing tolerances of state-of-the-art producers!?
Please read the datasheet.

IDSS-classes are perfectly normal and don't affect much a circuit unless you parallel them. Manufacturing low-noise jfets does require strict quality control.

Don't forget jfets are not "state of the art" devices (not from a manufacturer point of view at least), the same and even better parts existed already in the 80ies.

Today jfets just consume area in the manufacturing plant, are phased out of production to allow manufacturing of higher $ parts.

Have fun, Hannes
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Old 6th August 2008, 05:10 PM   #415
Salas is offline Salas  Greece
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Default Basically what I have done by now

Found some spare time, and populated the perf-board. Done half the point to point also. I am putting together 1 positive & 1 negative regulated PSU, 1 output delay relay circuit and 2 channels of capacitor-less B1s. Hopefully in the next few days I will find time to finish it and test it little by little. Will report.
Next post includes the awfully sketched schematic.
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Old 6th August 2008, 05:11 PM   #416
Salas is offline Salas  Greece
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Old 6th August 2008, 05:31 PM   #417
Skorpio is offline Skorpio  Denmark
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Quote:
Originally posted by salas
Looks nice, but are you missing the 1M gate resistors to ground?

What type of resistors are you using?
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Old 6th August 2008, 05:33 PM   #418
Salas is offline Salas  Greece
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Kiwame. The pot closes the circuit to ground.
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Old 6th August 2008, 05:43 PM   #419
float is offline float  England
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Regarding the output resistor....

Does Nelson have a reason for making this 1k?
Is this to guarantee safety in the event of a short, or does 1k give better isolation from cable effects, or change sound quality relative to 330 ohms or so?
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Old 6th August 2008, 05:48 PM   #420
Salas is offline Salas  Greece
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These are against oscillations due to the wide bandwidth too. I will check with high frequency squarewaves. Such stuff depends on layout too. Mine are hardwired directly to the Jfets. This circuit is in experimental early stage.
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