Hello again, I've added libsamplerate for resampling/oversampling which - as expected - dramatically improves the quality of the ngspice processed sound. Here's some example 3sec guitar sound from current testing: http://mir.dnsalias.com/_media/oss/spicesound/git-fuzz64.mp3 (left channel: resampled input-sound, right channel: fuzz-effect out) http://mir.dnsalias.com/oss/spicesound/examples#audio_example The fuzz effect still sounds a little odd, but I believe that a DI-recording would sound just like that ;) - I have not progressed to simulating tube-amps or synths yet.. lack of time, netlists and tube-models; it's low priority ATM.

Hi, I read on spicy sound website: "However todays computing power allows to do so almost in real-time!"... do you think you'll get it real-time?

Il giorno gio, 07/06/2007 alle 09.20 +0200, Robin Gareus ha scritto: 4 mins? OMG! :-\

I have not progressed to simulating tube-amps or synths yet.. lack of time, netlists and tube-models; it's low priority ATM.

Hi, Some time ago I did a sim using LTSpice (http://www.linear.com/designtools/software/) under Wine of a Carvin Legacy tube amp. LTSpice was the only program that had wav in/out and would run on Linux at the time I tried this. The schematic for the amp is here (http://carvinmuseum.com/pdf/amps/VL100%20&%20VL212%20Legacy%20Amp.pdf)pdf). It's a complex beast that ngspice would have lots of troubles simulating because of the infamous "floating nodes" and other quirks. Everything is included into the sim, preamp, phase splitter, output valves , output transformer and even the model of a greenback speaker. Naively, I haven't set the sim time step to the a sampling freq related number, nevertheless it sounds Ok to me, I dont know how LTSpice deals with transient sims involving wav files in details. The ogg for the sim is here: http://siliconjoe.googlepages.com/legacy-swcadiii-1-cab-reverb-delay.ogg I played a bounch of fast licks to have the transient sim finish before the universe will collapse, yeah you guessed it it's pretty slow... I think it took 1 day to finish on an AthlonXP 2800+... Now days I am messing around with GNUCap and QUCS (http://qucs.sf.net) to which I just ported my first tube model whose plate voltage/grid current curves look like that: http://siliconjoe.googlepages.com/Schermata.png Hopefully a way to inject wav files in both GNUCap and QUCS will come true as they both seem better than spice derived programs. Cheers, -Giuseppe _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev(a)lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev

Now days I am messing around with GNUCap and QUCS (http://qucs.sf.net) to which I just ported my first tube model whose plate voltage/grid current curves look like that:

Hopefully a way to inject wav files in both GNUCap and QUCS will come true as they both seem better than spice derived programs.

Giuseppe Zompatori wrote: Wow, your ltSpice simulation sounds really real! I hoped to get ngSpice to do the same.

great! looking forward to listening to those ;)

the sndfile&resample wrappers that I patched into ngSpice just work with GNUCap and QUCS too. GNUCap is still quite unusable (segfaults on large data sets) but I've elaborated on the QUCS hack - It's much slower than ngSpice, but indeed more accurate (at least the timing); I'm still to run some tests.. http://mir.dnsalias.com/oss/spicesound/qucs - (highly experimental) - I did not get to clean it up last week as I intended to and can't spare any time this week either.. - but I plan to revisit the issue properly over the summer.

keep in touch,

hi Giuseppe would it be at all possible to provide a link to the ltspice file you made of the amp? i am having trouble finding out how to do things like output transformers well, and didn't even imagine the possibility of spice simulating a particular speaker. whilst i am eagerly watching the ngspice patchset i would like to play around with one that i know works so that i can make sure i'm doing things right. ps. where abouts did you get the models for the transformers, valves and speaker from? and how did you simulate the reverb section? cheers porl

Le Mon, 18 Jun 2007 21:59:25 +0200, "Giuseppe Zompatori" <siliconjoe(a)gmail.com> a écrit : The problem here is not the simulator but the valve models. Most of them don't modelise the grid current or have a very very poor approximation, they have a poor approximation of Ig2, they don't modelise the variation of the valves characteristics when Ug2 is changing, and they have a very poor approximation of the variation of the valves characteristics when Ig2 is changing. According to the data sheet, some tetrodes can get 2 watts on the command grid at full output. That implies huge grid current. At the same time, we will get huge Ig2 variations and Ug2 will drop (even with fixed Ug2 bias) because the voltage delivered by the power supply will drop at full output (around 100V drop on some peavey amplifiers!!! The saturation we can heard is for the half the saturation in the main transformer not in the amplifier or output transformer!!!). So, in short, don't expect a good or reliable result of a push-pull class B guitar amplifier with so limited valves model. And to simulate the whole amplifier is a must do, but without more reliable models, it doesn't make sens to try to optimize something with a simulation for that kind of electronics. In consequence, for me, and as long at we don't have better valves models, practical experiences are everything. Dominique _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev(a)lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev

2007/6/19, porl sheean <porl42(a)gmail.com>om>: i'm from the The "AX84 P1 Theory Document": http://annex.ax84.com/media/ax84_m35.pdf Noob-oriented introductory document to their simplest SE amp, the P1. ( http://ax84.com/index.php?pg=legacyprojects&project_id=p1 ) The Radiotron Designer's Handbook 4th Edition is online here: http://geek.scorpiorising.ca/RDH4.html The RDH is also pretty noob-friendly (everything you need to learn is there), it's a much longer read though. It starts by the describing the way a valve is made and works up to complex schematics. It's considered by many the "bible for thermionic valves(tubes)". for a to You need an OT with an higher primary impedance IMHO, 6V6 tubes need a higher load to operate correctly. Having a valve load mismatch might have bad consequences for your amp. At an anode voltage of 250V it should be a 5k5 ohm load and at 315V 8k5 ohm according to the RCA receiving tube manual. 4k is a bit low, you'd have to run the tube "starved plate" (at low plate voltages). The sound is usually considered poor when a valve is starved plate. it might be your kind of thing though. If it really is a 4k primary transformer I'd run it at a ~320V B+ and mis match the speaker wiring (old trick) to double the impedance to 8k (much closer to the ideal load)... i.e.: plug an 8 ohm speaker to the 16 ohms secondary tap (or 4 ohms speaker into the 8 ohms tap), that will effectively double the primary to secondary reflected impedance. And this configuration would give you around 5 Watts of power. Thats much cheaper then buying a new OT ;) Also a quick link to a well designed SE 6V6 based PA: http://ax84.com/static/corepoweramps/5W_SE/AX84_5W_SE_Poweramp_Schematic.pdf though Some blue glowing is usually pretty normal, I have an 6L6GC based small combo sitting next to me with a blue glowing power tube, and its pretty fine. If I swap this Electro Harmonix tube for a chinese made one the blue glow disappears. You should watch out for any other part than the filament in a tube that are red plating though, now that would be dangerous. Watch out for those big power supply caps! always make sure they're completely discharged before you operate on your amp... potentially lethal voltages inside, as you probably already know. Cheers, -Giuseppe _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev(a)lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev

Le Tue, 19 Jun 2007 20:51:58 +1000, "porl sheean" <porl42(a)gmail.com> a écrit : short but want to sound). i the project tactic and i so i used have You can try the diyaudio forum. It is a thread with a lot of links on vacuum tubes theory: http://www.diyaudio.com/forums/showthread.php?s=5fc6a5fdf8f4d9101e3f07260bc… You can find some with amule too. Just search for vacuum, valves or tubes. About the EL34, 375V for Ua is a very low voltage for such a tube. (You can find the datasheet from http://www.nj7p.org/Tube.php or with google). You can go up to 600 or even 700 V without problem. But you are right when you said at 375 is too much for the preamp tubes. Only some old japanese preamp tubes can handle such voltages, and they are very hard to find. The best is to made a separate and low-noise alimentation for the preamp. A simple R-C can be enough. For the tubes, I generally prefer new tubes over old ones. Some new tubes are even better as the best old ones. The engineers of today know what they are doing when they manufacture a new tube. Dominique _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev(a)lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-dev

I have written a small test application to calculate Average RMS and max RMS power of a wave file.

Wave file audio data having 16 bit sample and mono. i'm using the following algorithm : i=N-1 rms = sqrt(1/N ∑ sample[i] * sample[i] ) (1) i=0

AvgRMS = 20.0 * log10 ( rms /2^N-1)