What do you think the turn-on voltage is? 
0.6-Volt point would be Silicon, if I recall, Germanium was 0.2-0.3Volt. 



-PBS

--- stevenyi@GMAIL.COM wrote:

From:         Steven Yi 
To:           CSOUND@LISTSERV.HEANET.IE
Subject: Re: [Csnd] Diode Ladder Filter
Date:         Thu, 17 Nov 2016 18:29:42 -0500

The first thing that came to mind was:

Bridgekeeper: What... is the air-speed velocity of an unladen swallow?
King Arthur: What do you mean? An African or European swallow?
Bridgekeeper: Huh? I... I don't know that.
[he is thrown over]

:)

But more seriously, I couldn't tell you. I don't think the model takes
such things into account, as far as I've read through.  (Though,
there's a lot of this I don't quite grasp yet; my math fails me often,
but I'm happy enough to get the desired sound and move on at this
point.)



On Thu, Nov 17, 2016 at 6:01 PM, Richard  wrote:
> Is this a silicon or germanium diode emulation?
>
> Richard
>
>
>
> On 17/11/16 17:59, Steven Yi wrote:
>>
>> Hi All,
>>
>> I've done a UDO translation of Will Pirkle's Diode Ladder filter,
>> available at:
>>
>> https://github.com/kunstmusik/libsyi/blob/master/diode.udo
>> https://github.com/kunstmusik/libsyi/blob/master/tests/diode.csd
>>
>> Pirkle describes the filter and derivation in:
>>
>> http://www.willpirkle.com/Downloads/AN-6DiodeLadderFilter.pdf
>>
>>  From the document:
>>
>> "Background
>>
>> The Diode Ladder Filter first appeared in the EMS VCS3 Monophonic
>> Synth designed by David Cockerell in 1969. It is (more famously)
>> incorporated in the Roland TB-303 BassLine monophonic bass synth from
>> 1982. It is based on the Moog Ladder Filter (see App Note 4) but
>> incorporates multiple feedback paths between sections. The effect of
>> the feedback paths on the signal is two-fold: like the Moog Ladder, it
>> reduces overall filter gain as the resonance increases but the
>> reduction is more extreme (by about 12dB) and secondly, as the
>> resonance increases, the resonant frequency migrates upwards, but
>> never makes it to the cutoff frequency (which does not occur in the
>> Moog Ladder). Like the Moog Ladder it also self oscillates. At the
>> point of self-oscillation, the poles (and therefore the resonant peak)
>> will have drifted up
>> to fc/sqrt(2)."
>>
>> I've checked the translation a couple times now and I *think* it is
>> correct.  (It was a little tricky to convert from the use of filter
>> objects in the C++ code to the inline version in the Csound UDO code.
>> It sounds about the same as the version in the WPDiodeLadder chugin
>> provided with Chuck using k=17, though I have not done an exact 1:1
>> test yet.)
>>
>> Cheers!
>> steven
>>
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>
>
> Csound mailing list
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