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Old 30th October 2012, 05:09 PM   #8381
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What do you mean with lossy capacitors? PIO?
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Old 30th October 2012, 05:13 PM   #8382
Salas is online now Salas  Greece
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PIO, MKT, electrolytics, show high DF. Low loss capacitors indicate "pulse" and/or adequate for filters in datasheets usually.
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Old 30th October 2012, 06:57 PM   #8383
RCruz is offline RCruz  Switzerland
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Hi Salas

The Wallis experiment is now a full on simplistic... you have e-mail.... GRAND
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Old 30th October 2012, 07:01 PM   #8384
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by andyr View Post
Can you provide more of an explanation about this? For instance:
Q1: what causes "Miller capacitance"?
Q2: is the effect of having "Miller capacitance" that you have to decrease the value of either C1 or C2 in the (passive) RIAA network, to compensate (so you end up with the correct values, according to the RIAA equations)?
Q3: can you calculate the expected Miller capacitance value?

Thanks,

Andy
Hi Andy

Second stage input capacitance (Miller) is parallel to the Riaa caps so it must be taken in consideration while designing the filter.

We can calculate the miller capacitance but we end up only with an aproximation.... real values must be measured with dedicated equipment or else, riaa caps must be fine tuned by hear

Anyway it is all system dependent
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Old 30th October 2012, 07:11 PM   #8385
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by MASantos View Post
What do you mean with lossy capacitors? PIO?
Hi Santos

IMO, styroflex or MKP are very good for the riaa filter... just make sure you get a good match between channels and the simplistic will sing

Do not use PIO caps... they sound too rounded and the magic is gone.

You can trim larger caps with smaller styroflex or very small SM (Only use good quality SM).

For coupling cap you can rely on a good teflon from russia.

On the output an average MKP (like Mundorf MKP or Auricap) bypassed by a 100n Obbligato gold can give you good results.

If you use a large obbligato gold on the output, do not bypass it.... these are really good as is
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Old 30th October 2012, 07:42 PM   #8386
Salas is online now Salas  Greece
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Quote:
Originally Posted by RCruz View Post
Hi Andy

Second stage input capacitance (Miller) is parallel to the Riaa caps so it must be taken in consideration while designing the filter.

We can calculate the miller capacitance but we end up only with an aproximation.... real values must be measured with dedicated equipment or else, riaa caps must be fine tuned by hear

Anyway it is all system dependent
Just a cascoding JFET did not reduce it very drastically as your RIAA HF cap tweaked to lower indicates in folded input experiment. That and the low Vds it inevitably provides VS solo JFET probably means this secondary to test addition is only more JFETs and no good, I will leave it out. The real change is the input stage design. So your test circuit basis without BF245C:
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Old 30th October 2012, 08:11 PM   #8387
andyr is offline andyr  Australia
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Quote:
Originally Posted by RCruz View Post

Hi Andy

Second stage input capacitance (Miller) is parallel to the Riaa caps so it must be taken in consideration while designing the filter.

We can calculate the miller capacitance but we end up only with an aproximation.... real values must be measured with dedicated equipment or else, riaa caps must be fine tuned by hear
Thank you for the explanation, RCruz.

Regards,

Andy
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Old 30th October 2012, 08:19 PM   #8388
Salas is online now Salas  Greece
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Quote:
Originally Posted by RCruz View Post
Hi Salas

The Wallis experiment is now a full on simplistic... you have e-mail.... GRAND
Time I put one under the iron to listen too. Thanks for good build early testing. Mine will be 63dB with 2x 2SK369 because I will use DL103R.
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Old 30th October 2012, 09:27 PM   #8389
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by Salas View Post
Just a cascoding JFET did not reduce it very drastically as your RIAA HF cap tweaked to lower indicates in folded input experiment. That and the low Vds it inevitably provides VS solo JFET probably means this secondary to test addition is only more JFETs and no good, I will leave it out. The real change is the input stage design. So your test circuit basis without BF245C:
Thank you Salas

BTW, I am using 1k4 for R11... the rest is as in the schematic.

Been listening to it for a while now.... Improved dynamics with great credibility... no harshness... very musical like the "normal" simplistic but with some added mid range detail and speed... Special

Can become something outstanding with some care and a good choice of components.
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Old 30th October 2012, 09:35 PM   #8390
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Who knows after big blue transplant even? Maybe one step beyond?

Madness - One Step Beyond - YouTube
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