My first mod, tsl602

[chee16]

I have modded my clone Tube screamer (and built it, though with the printed pcb and instructions that was really easy) and my Crybaby Wah. But I have now jumped into the amp modding hobby.....

My tsl602 has recently been getting the attention it deserves again, and with the help of Marty I got new speakers and have tweaked the preamp tubes to my liking. After all the tweaking I really like clean and crunch (love the crunch) but the lead has always left me desiring more. So I stole some ideas from some other spots and decided to try them one by one to see what I can get. Basic stuff, adding caps or changing resistors.

The first one I tried was adding a 68pf cap to the 1st and 3rd pin of the volume pot when counting from the gain pot over. Really easy to do as there was enough of the lugs sticking up I just put a piece of 2 sided foam tape on the back of the pcb where the volume pot is, stuck the cap to it, then soldered the 68pf silver mica cap to the lugs. Please note that I DID check that the large caps were discharged even though this amp is supposed to dot it automatically. I used my multimeter on pin 1 (actually checked all the pins) with the black grounded to the chassis to check for voltage. I was also very careful not to touch anything that didn't need touching just in case

 

[chee16]

Fired it up, and panicked for a sec, apparently I had left my wah pedal on in the down position and the sound was surprising, took me a couple secs to figure that out, haha.

First impression is that it makes a noticable difference but is not as much as I would like. Less fizzy for sure, but not enough.

My next step now is to put a 390pf cap on r74 to complete the de-fizzing. I wanted to try just the 68pf cap on the lead volume pot first as I wasn't keen on messing with the crunch, but maybe this will allow me to use a bit for gain on the crunch too.

There is also a mod that involves adding a 47pf cap to r109 that I am interested in, says it makes the presence more usable which would be nice.

Another that interests me is clipping c49, which apparently bleeds treble through on the crunch/lead channels. Clipping it makes the treble pot fully functional, as in no bleeding though on lower settings.

 

[chee16]

Upon further review, I think someone was a bit hasty in stating that C49 is the same as C9.
If you look at the schems they are in fact the same, but that is if you are comparing the mainboard TSL60 schem with the mainboard TSL100. But in the original mod blog (http://www.anchorstates.net/2009/01/amp-guts-complete-marshall-tsl-mods.html) he says that it is C9 from the LEAD CHANNEL CIRCUIT BOARD. Am I right in thinking that someone was mistaken?
http://www.drtube.com/schematics/marshall/TL60-60-02%20(2001)%20iss5.pdf
http://www.drtube.com/schematics/marshall/TL10-60-02%20(2001)%20iss4.pdf
http://www.drtube.com/schematics/marshall/TL10-61-02%20(1998)%20iss4.pdf

Any help with this would be great. I am still going to do the 390pf cap on R74 as that looks perfectly right, but the C49/C9 one looks like a no go as the schematics are a bit to complicated for me to decipher unfortunately.

Cheers
Wes

 

[chee16]

I messaged the guy who posted the original blog post about the tsl100 c9 clip mod and he said after looking at the schematics there didn't seem to be a cap that was exactly the same. Oh well.

I installed the 390pf cap on r74 today, exactly what I was looking for. Still some fizz, but not bad, more of a growl now rather then a rasp, haha. I am very satisfied with the mod now and can't wait to spend some time dialing in the crunch and lead channels again. The only thing I might try in the future is a 100pf instead of 68pf, but after reading some posts that may be too much, and since I don't have a 100pf on hand, it will be a while til I could do it anyways.

There is also the choke mod. I have no idea what this does and am in no hurry to do it, but as I have stated before I want to try to get the absolute best tone out of my amp that I can, so maybe that will be my next research projest

 

[StratoMarshall]

You're on the right track! Fun isn't it?

 

[chee16]

Yes it is. I am the type that once I am intrigued by something it is stuck in my mind until I figure it out. It is all I think about, haha. I will say though, the tsl board is really cramped, I had no issues as I have a very fine sodering iron but I can see how stuff can get messed up.

I am really looking into a kit build though. I think it would be really fun to build a blackface fender kit, not sure which one as I don't know my fenders all that well. But then I start to think that the perfect setup would be a 15w tweed build of some sort, and an 18w marshall-eque build, both with 2x12 cabs and I could a/b/y them. Lol, all this thinking and I have never even played the vintage stuff.

 

[Assumer]

I am about to put a couple of redcoats in my 602. Any suggestions for the change?

 

[chee16]

No it is a really easy install, make sure your speaker impedance is the same and connect them the same as the stock ones and you are done! Just remember to turn the amp off before you put the new speakers in! Lol, kidding.

Also keep in mind that all new speakers have a break in time, some people will hook them up to a stereo for a couple days at certain frequencies to break them in, I just used it as an excuse to play more, haha.

Congrats on the new speakers! I still haven't figured out what to do with the Wolverines......boat anchors maybe?