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Old 21st June 2011, 03:34 PM   #21
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Quote:
Originally Posted by tomchr View Post
I'm not sure where you get that from. The Wima MKP are polypropylene caps. That's one of the lowest loss dielectrics and the one that contributes the least to distortion.

~Tom

I've notice when used in high impedence circuits ( tube circuits mostly) they have too much inductance that messes with the miller capacitance of the tube (inter electrode capacitance)

the dielectric is correct. But their construction techniques is flawed.

the balanced outs seem to have been modified weather it is an OEM mod, I don't know. I don't remember those wires when I looked at one many years ago.
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Old 21st June 2011, 03:40 PM   #22
240z4u is offline 240z4u  United States
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Well, I have no problem at all trying the preamp without those wires in place. I just wanted to do one thing at a time and it seems the diodes need attention first. Thank you for the info on the Wima's too.
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Old 23rd June 2011, 10:37 PM   #23
240z4u is offline 240z4u  United States
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Any help with the diodes guys? sorry to bug ya.
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Old 23rd June 2011, 11:49 PM   #24
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diodes doesnt matter as long as:
fits
has enough current capacity
can take the voltage.


this is way over kill for a preamp but they will work great if they fit.

MUR1100ERLG
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Old 24th June 2011, 12:47 AM   #25
240z4u is offline 240z4u  United States
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I have tons of space, those will fit fine. I wasn't sure what would work in this location but if those are overkill... perfect. The other diode I looked up was a zener diode.. does it matter?

Thanks!
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Old 24th June 2011, 01:33 AM   #26
240z4u is offline 240z4u  United States
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I totally forgot I have these on hand from another project that is done;

Digi-Key - CSD01060A-ND (Manufacturer - CSD01060A)

Digi-Key - HFA16PB120-ND (Manufacturer - HFA16PB120)

The first one is smaller and would fit easier, but i could squeeze choice B in there too if needed.

Evan
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Old 24th June 2011, 02:29 AM   #27
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Ah crap i just looked over the pics. The wad of 3 zeners is a voltage reference. He tripled them up because zeners cant handle much current. From what it looks like, those are used to make a high voltage regulator.

That being the case you need to find the voltage of the zeners and replace them with the same voltage.


HeadWize - Project: Designing an Opamp Headphone Amplifier (A HeadWize Design Series Paper)


Odds are its something like figure 20. So what ever those zeners are, is what the regulator is going to put out.

Zener Controlled Transistor Voltage Regulators - Electronic Circuits and Diagram-Electronics Projects and Design
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Old 24th June 2011, 02:38 PM   #28
240z4u is offline 240z4u  United States
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12b2 is the diode number that is in there. There are obviously three wadded together.
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Old 24th June 2011, 06:12 PM   #29
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well lets find out if the wad of 3 are zeners since you have one out to measure already.

testing zener diode-easy test method

Electronics Tips: Measurements: Testing Diodes and Transistors

For all i know they just look like zeners but are really just standards.

that 12b2 could stand for 12.2 volts.
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Old 24th June 2011, 06:13 PM   #30
240z4u is offline 240z4u  United States
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Alright, I will do that when I get home. As an aside, I kinda chuckle whenever I see the word zener, a child at heart I suppose. lol

Thanks!

Evan
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