Hello,

I'm trying to port Gutarix tubes emulations to Csound ( I know that is possible to export as csound plugins but want to try the long way).

Under Faust sources there are the examples

http://sourceforge.net/p/faudiostream/code/ci/master/tree/examples/faust-tubes/

and data used for transfer functions for each tube model (files valve.h, tube.lib, preamp.dsp, and .cc files for tubes).

Attached here is my tentative udo (plus a couple tube emulations transfer funcions used by gen23) and a file to test it but everything I can obtain is a nice noise generator with only one stage of amplification, go figure what happen if you add more than one...Suspect that there is a problem on how I implemented recursion with delayw/r.

Anyone would like to give a look to the code to see what I'm doing wrong?

I've put output to disk in the tubetest.csd to avoid bad surpises to the speakers.

Bye

Stefano

why the delay line? If it's a 1-sample delay you want to do, it's a bit cumbersome to use it for that.
It's simpler to do this (ksmps = 1), for example for a 1st order filter

adel init 0
ay = ain*ia + adel*ib
adel = ay

adel is a 1-sample feedback delay.


On 7 Apr 2014, at 18:07, vallste@libero.it wrote:

> Hello,
> I'm trying to port Gutarix tubes emulations to Csound ( I know that is possible to export as csound plugins but want to try the long way).
> Under Faust sources there are the examples
> http://sourceforge.net/p/faudiostream/code/ci/master/tree/examples/faust-tubes/
> and data used for transfer functions for each tube model (files valve.h, tube.lib, preamp.dsp, and .cc files for tubes).
> 
> Attached here is my tentative udo (plus a couple tube emulations transfer funcions used by gen23) and a file to test it but everything I can obtain is a nice noise generator with only one stage of amplification, go figure what happen if you add more than one...Suspect that there is a problem on how I implemented recursion with delayw/r. 
> 
> Anyone would like to give a look to the code to see what I'm doing wrong?
> I've put output to disk in the tubetest.csd to avoid bad surpises to the speakers.
> 
> Bye
> Stefano
>  <12ax7_250k.inc><12ax7_68k.inc><12at7_250k.inc><12at7_68k.inc>

Dr Victor Lazzarini
Senior Lecturer
Dept. of Music
NUI Maynooth Ireland
tel.: +353 1 708 3545
Victor dot Lazzarini AT nuim dot ie

In other words, removing the delayr/w,  we can have

			aFtubeOld init 0
			aIn_Ftube = aFtubeOld + aIn_tube - kVk0 
				;
				;itableValve;see table .cc
				;ktablow see table .cc for the valve type
				;ktabhigh see table .cc for the valve type
				;ktabistep see table .cc for the valve type
				;itabsize len of the table see table .cc for the valve type
				aVgk = aIn_Ftube
				af = (aVgk - ktablow) * ktabistep
				ki = int(af)
				if ki < 0 then
					aFtube tab 0, itableValve
				elseif ki >= itabsize then
					aFtube tab itabsize - 1, itableValve
				else
					af = af - ki
					kreadT1 tab ki, itableValve
					kreadT2 tab ki + 1, itableValve
					aFtube = kreadT1 * (1 - af) + kreadT2 * af
				endif
				;
			aFtubeOut = (aFtube + aVkC - kvplus)
			aFtubeOld butlp aFtubeOut * kRk/kRp, kfck


On 7 Apr 2014, at 20:04, Victor Lazzarini wrote:

> why the delay line? If it's a 1-sample delay you want to do, it's a bit cumbersome to use it for that.
> It's simpler to do this (ksmps = 1), for example for a 1st order filter
> 
> adel init 0
> ay = ain*ia + adel*ib
> adel = ay
> 
> adel is a 1-sample feedback delay.
> 
> 
> On 7 Apr 2014, at 18:07, vallste@libero.it wrote:
> 
>> Hello,
>> I'm trying to port Gutarix tubes emulations to Csound ( I know that is possible to export as csound plugins but want to try the long way).
>> Under Faust sources there are the examples
>> http://sourceforge.net/p/faudiostream/code/ci/master/tree/examples/faust-tubes/
>> and data used for transfer functions for each tube model (files valve.h, tube.lib, preamp.dsp, and .cc files for tubes).
>> 
>> Attached here is my tentative udo (plus a couple tube emulations transfer funcions used by gen23) and a file to test it but everything I can obtain is a nice noise generator with only one stage of amplification, go figure what happen if you add more than one...Suspect that there is a problem on how I implemented recursion with delayw/r. 
>> 
>> Anyone would like to give a look to the code to see what I'm doing wrong?
>> I've put output to disk in the tubetest.csd to avoid bad surpises to the speakers.
>> 
>> Bye
>> Stefano
>> <12ax7_250k.inc><12ax7_68k.inc><12at7_250k.inc><12at7_68k.inc>
> 
> Dr Victor Lazzarini
> Senior Lecturer
> Dept. of Music
> NUI Maynooth Ireland
> tel.: +353 1 708 3545
> Victor dot Lazzarini AT nuim dot ie
> 
> 
> 
> 
> 
> Send bugs reports to
>        https://github.com/csound/csound/issues
> Discussions of bugs and features can be posted here
> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe csound"
> 
> 
> 

Dr Victor Lazzarini
Senior Lecturer
Dept. of Music
NUI Maynooth Ireland
tel.: +353 1 708 3545
Victor dot Lazzarini AT nuim dot ie