Ideas for modding my TS9DX

Started by Deny, May 16, 2012, 02:23:10 PM

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Deny

Hi there! This is my first post, so please go easy on me  :)

I did conduct a search on the topic, but couldn't find the specific info I'm looking for either here or anywhere else in the web. Besides I'm looking forward to discussing said mod with people a) just starting out with pedal modding like myself or b) who are experienced and willing to help others. If the topic doesn't interest you, by all means feel free to move along.

Now that disclosures are out of the way, let me start describing what I have in mind so far. I do intend to mod it to TS808 specs by changing the 2 output resistors, that one has been beaten to death and probably doesn't need further discussing.

Now I'm aware Robert Keeley does something called a flex 4x2 mod that includes the aforementioned TS808 mod plus a few other goodies like changing some components in the negative feedback loop of IC1A (51k -> 20k, 4.7k -> 2.4k, .047uF -> .1uF), and that's where it gets interesting. I've already ordered the 4558P for replacing the IC btw, but have some interesting possibilities ahead if I redesign the diodes and capacitors selectable by the turbo mode switch:

Position #1 (TS9) would be the basic TS808, so just the stock .047uF capacitor and 2x 1n914 diodes

Now I currently find the other positions basically useless because they introduce way too much bottom end, so one possibility would be keeping the same diodes as in position 1, but with a .1uF capacitor and therefore completing the Keeley mod (well sort of), that's pretty much what I have in mind for position #2 (which originally in the DX has 4 1n914 diodes in parallel with a 470k resistor and a .22uF capacitor - waaaayy too large for my taste).

I'm still open for suggestions for positions #3 and #4 but I'd like to use some sort of asymmetrical clipping with germanium diodes (ordered a bunch of 1n60 for that) and would pretty much like to keep the negative feedback loop capacitor of IC1 at .1uF or less, but have no idea which combinations would sound best. I know, I know, trial and error... still I'd like to hear from people who's been there and done that, no point on reinventing the wheel right? ;)

And last but not least, I've read somewhere that the switch on top of Keeley's flexi mod raises the value of the resistor in the negative feedback loop of IC1 (which was 4.7k, lowered to 2.4k) to a higher value, no idea what. Anyone has any more info on this? Not really sure I'd want tons of gain for this pedal, if that's all it does I might very well leave that one alone.

Just to put things in perspective, this TS9DX will be put on a pedalboard along with a (also modded) DS1 and a stock BB preamp, all three will be selectable via a custom switcher that I'm also building, controlled by my Triaxis. After going through the pedals the signal goes through a second custom switcher (already built and fully functional) that sends it either to the Triaxis or JMP1, and then to the FX return of a tube amp. In my experience the JMP1 doesn't take pedals well and after looking at the schematic it's easy to understand why, so pedals will be basically used with the lead 1 modes of the Triaxis (which are pre-eq gain modes).

Cheers,
Deny


aron

I think the problem is that only you can tell if the mods sound/feel good. Some of the diode mods change the feel of the pedal - more than the sound.
I always refer here:
http://geofex.com/Article_Folders/TStech/tsxfram.htm

And also look at this:

http://www.diystompboxes.com/wiki/index.php?title=Simple_mods

Deny

Quote from: aron on May 22, 2012, 05:10:26 PM
I think the problem is that only you can tell if the mods sound/feel good. Some of the diode mods change the feel of the pedal - more than the sound.
I always refer here:
http://geofex.com/Article_Folders/TStech/tsxfram.htm

And also look at this:

http://www.diystompboxes.com/wiki/index.php?title=Simple_mods

Ha, I was desperately looking for an article on clipping using diodes, thanks a million for that link! :D