Designing your own tone stack programs?

[RockinRocket]

Im not talking Duncan's tone stack calculator (its great though) but something simple that I can slap together resistors, caps and pots and see what happens to the EQ.

Theres a few original tone stacks that id like to simulate too to see the frequency range. Marshalls Silver Jubilee, Blackstars 4 band EQ, Dr Z single tone control, Oranges "Shape" dual ganged pot top boost circuit, vintage Hiwatts..

Any thing out there that's preferably free or cheep and easy to use available?
Thanks!

[teemuk]

https://en.wikipedia.org/wiki/SPICE

LTspice, for example, is freeware, very extensive feature wise, and has no restrictions in using external 3rd party models or subcircuits.

https://en.wikipedia.org/wiki/LTspice

http://gaussmarkov.net/wordpress/tools/ ... one-stack/

[Littlewyan]

LTSpice is great for simulating entire amplifiers

[John_P_WI]

I just wish LTSPICE had a bettet GUI. It is kind of a pain in the ass to use.

[RockinRocket]

I think I tried LTSPICE at one point and got lost real quick. I just tried downloading it and my computer said "the program isn't downloaded commonly and may harm you computer" Would you guys guess that is just a normal caution my computer is giving me?? Ive never seen that before

[Phil_S]

The download is always a gamble unless you are 100% certain the source website is a legitimate source. I don't mind sharing a story that demonstrates. I needed to replace my copy of VLC Media player, a program I was liking very much at the time. I had it, and then I needed it again. Well, there are lots of fake d/l sites. Yes, they'll give you the thing you are looking for, but they piggyback all sorts of malware. By now you've guessed, I got the program from the wrong place. I allowed the install (Windows makes you say yes a bunch of times) and as soon as it started to run I was sorry. It hijacked my browser and loaded up all sorts of cesspoolware -- the kind that make your computer run slower than slow and that let in additional vermin. Sometimes you think you deleted the bad stuff and it reinstalls itself. So, the moral of the story is that you have to be really careful. If your computer is giving you are warning, particularly on a d/l, please take precautions.

Fortunately for me, I have a backup that runs every day and the and an image of the hard drive is renewed every day. Of course, the backup is incremental and depending on the last full back datestamp, a restore could take a while. I only have enough room for one disk image, so that gets replaced daily. So restoring he image is iffy -- really, I keep that for a catastrophic hardware failure.

The bad news was that I got seriously hosed by a free d/l. The good news is that I had done adequate disaster planning.

Be careful! Fixing my problem took the better part of a day and I learned to get along without that particular software for a while. Eventually, I found the legit source and obtained it again and installed it without incident.

[Theashe]

I've used LTSpice for transistor amplifiers in the past, and it's very easy to work with - especially the simulations. I recently used it to modify the tone stack in my tube amp. Much easier than Capture and PSpice in my opinion, although the hotkeys make a lot less sense.

Adding custom models (like tubes) can be a bit confusing the first time, but you'll get the hang of it with a little patience.

[tubeswell]

... Any thing out there that's preferably free or cheep and easy to use available?

You could probably make a TS calculator with a large enough xcel spreadsheet, which approximates RC and/or CR filter relationships at the rate of 1 type of TS filter per spreadsheet. Maybe start with a simple tone control like a Vox AC4 tone control to start with, and then gradually build more and more complexity into it.

[RockinRocket]

Phils got me a bit worry of the LTspice download. I was making schematics on Digikeys site I think it was. That was easy enough. Was hoping there would be something out there easy like that. I highly dought Id be able to use xcel spreadsheet tubeswell but good idea. I really want to see how the Marshall Jubilee TS and Blackstars 4 band eq shapes the frequency.

[jazbo8]

You want simple... try PartsSim.

[Phil_S]

Phils got me a bit worry of the LTspice download. I was making schematics on Digikeys site I think it was. That was easy enough. Was hoping there would be something out there easy like that. I highly dought Id be able to use xcel spreadsheet tubeswell but good idea. I really want to see how the Marshall Jubilee TS and Blackstars 4 band eq shapes the frequency.

I didn't mean to worry anyone. What I did mean to emphasize is how very important it is to protect yourself. To put a finer point on it, I had a bad feeling from the get-go on that one and I ignored my gut. I was able to climb out of the hole I dug because I'm pretty good about taking care of this sort of thing. What I should have done was to make a fresh image backup immediately before the d/l and install. That would have made the restore process fairly quick (an hour or so) and much simpler.

(There is always with Windows registry roll back procedure, which is actually very fast and painless. In this instance, there was so much bloatware and mischiefware that it called for a more thorough cleaning.)

The time to run the backup is when you are finished working for the day. The backup can be scheduled so that it runs itself. The time to deal with a possibly suspect d/l install is the first thing you do while the backup is fresh.

These days we have USB 3, which is nearly 10x faster than USB 2, and external USB hard drives are now dirt cheap. 1TB will run around $60 and 2TB around $90. If you have an older computer without a USB 3 port, you can buy a PC card for your desktop computer for around $25 and maybe a little more for a PCI card for your laptop. Make sure the drive you buy is USB 3.0 compatible. There is just no excuse for allowing yourself to run naked.

Having said all this, the "right place" to get a free d/l of any software is to go to the publisher's website and not some middleman market site. While it is possible to get hosed at the publisher's site, the chances of getting a clean source file are excellent.

Linear Technologies is the publisher of LTSpice. While I make no guarantees of anything, this looks like the place to go for it: http://www.linear.com/solutions/ltspice

Here is an example of where NOT TO GO for a d/l: http://ltspice-iv.software.informer.c__ I've corrupted the link so it won't work, but wanted to show the example URL.

[jazbo8]

wow... Just download the program from Linear, don't know what's the hassle...

[Theashe]

If you plan on using LTSpice for simulating tube stages as well (and you should at least try it), you should get models from Duncan Amps:

http://www.duncanamps.com/technical/ltspice.html
http://www.duncanamps.com/spicevalvesgt.html

Drop the PSpice model in the same folder as where you save your simulation file and reference it by inserting the SPICE Directive ".include dmtriode.inc". Alternatively, you can put the file anywhere and reference it with the full file path (ie. ".include C:\Program Files (x86)\LTC\LTspiceIV\dmtriode.inc", if that's where you put the file).

LTSpice has a built-in triode.asy symbol, but Duncan's tube models include terminals for heaters, so you should download the triodeh.asy symbol file and drop it in the C:\Program Files (x86)\LTC\LTspiceIV\lib\sym\Misc folder. I'd use it to avoid getting a "too few connections" error.

If you do transient analysis, run them for at least 15s to get to steady state, since Duncan's models include the valves warmup period. You can speed up processing by putting a check in "Start external DC supply voltages at 0V" and "Skip initial operating point solution." Also, the simulation runs faster for lower frequencies (larger simulation timestep) - so I tend to use a few hundred Hz or less.


I attached the LTSpice model for a simple 12AX7 gain stage. AmpGarage won't let me upload the .asc LTSpice format, so I saved it as a .txt. Change the extension to .asc and it will open in LTSpice. Note that for the simulation to work as-is, you have to have Duncan's dmtriode.inc file in the C:\Program Files (x86)\LTC\LTspiceIV\ folder. Also note that LTSpice uses peak values instead of RMS.

[Phil_S]

wow... Just download the program from Linear, don't know what the hassle...

I was addressing the OP's expressed concern that he got a warning message when he went to d/l the program. I agree, get it from Linear. It should be fine. There is still every reason to be careful.

[RockinRocket]

Thanks Phil I downloaded from your link and didn't get a warning... Now the hard part and trying to figure out how to use this thing.