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Old 28th November 2012, 04:08 PM   #8671
Salas is offline Salas  Greece
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News bulletin. I am at Vgeorge's Island studio room. Build and review of folded starting tomorrow. Today we calibrated his scope, and we are evaluating and tweaking his new TSSA V.16 CFB amp, calibrating his mic for rechecking the horns system so all will be under control. Making an antiRiaa also. Over.
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Old 28th November 2012, 04:12 PM   #8672
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A lot of work to do Salas but you are in good company, let us know how goes the folded & more about antiRIAA also.
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Old 28th November 2012, 04:14 PM   #8673
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Quote:
Originally Posted by RCruz View Post
Sorry, I did not realize you wanted a pic of the LCR

You can search for this: TENMA 72-8150

I used a bunch of 0.5% caps to calibrate it myself.

Inexpensive but effective... no kelvin thou
That's not a calibrate LCR, no Kelvin wire to measure, you are far to know real values are you measuring, you are just trusting matching seller without to know if is OK or not the value needed.
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Old 28th November 2012, 04:17 PM   #8674
studeb is offline studeb  United States
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Quote:
Originally Posted by Salas View Post
News bulletin. I am at Vgeorge's Island studio room. Over.
i am too curious, what island?
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Old 28th November 2012, 04:49 PM   #8675
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by RCruz View Post
.......... one could use two WW wired in parallel in reversed directions to minimize any inductance.
No. The two coils would still be wound in the same direction.
You would need to find a manufacturer who wound the coil in the other direction for this parallel trick to work.
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Old 28th November 2012, 04:50 PM   #8676
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by merlin el mago View Post
Styrenes are better if you are sure tolerance is 1% that isn't the same matched, matched only guarantees are with same value. MKP1837 are also foil better than metallized,
from the manufscturer !!!!!
Quote:
MKP1837 product information
Metallized Polypropylene Film Capacitor Radial AC and Pulse Capacitor
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Old 28th November 2012, 04:54 PM   #8677
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by RCruz View Post
Hi Merlin

Tolerance gives us an idea of the deviance from spec due to manufacture... that is why we match the caps. If we get two caps exactly the same value (say 15nF) one 20% tolerance and the other 1%, there will be no difference at all.
Quote:
Originally Posted by merlin el mago View Post
Sorry Ricardo I don't agree, if the cap is manufacturated with 1% is more accurate than if you match the caps.
Merlin, you are wrong !

If the two caps, one 20% tolerance and one 1% tolerance are measured and found to be close to an exact match, say within 0.1% then you KNOW that both capacitors are within 1.1% of true value, if you have used the same measurement procedure specified by the 1% manufacturer.
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Old 28th November 2012, 05:01 PM   #8678
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by RCruz View Post
................some russian micas have 0.3% spec !!!
Quote:
Originally Posted by merlin el mago View Post
Ricardo I don't see the calibrated LCR.
I have a small range of 0.3% capacitors I use to roughly calibrate my measuring procedure.
Same with my much bigger range of 0.1% resistors.

But I am aware of drift and I cannot guarantee 0.3% accuracy, maybe 1% accuracy for all my 5% and 10% and worse capacitors, if I need absolute values rather than component matching.

Most of my component matching can achieve better than 0.1% spread and sometimes if I take great care, better than 0.005% (1part in 20000 spread).
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Old 28th November 2012, 05:12 PM   #8679
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from the manufscturer !!!!!
My mistake is metallized

Last edited by merlin el mago; 28th November 2012 at 05:16 PM.
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Old 28th November 2012, 05:28 PM   #8680
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Phew !!!

Capacitor & resistor debate...HEATING UP !!!

I have to say...
...Capacitors & resistors have been my last 3 weeks of nightmares !!!

Mostly 'capacitor drift' though, is what concerns me at present.
Particularly for the RIAA caps ( not couplers ).
Also 'drift' in caps used for an 'inverse RIAA' ( took some figures, LOOKS BAD ! )
Well...relatively.

Cheers

Si.

Mica is the only thing I have found, with almost 'non measurable' drift.
Polystyrene - drift up to 3% on small values.
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