TS 808 question for those in the know...

[Young John]

I'm not up on all the mods available for the 808. I'm wondering if there is one that changes the value of the tone pot.
If there isn't a mod for that already, can it even be done?

Thanks for your help.

 

[jdel77]

What are you after exactly insofar as changing the value?

You can change the stock pot to a 2kB or 5kB which makes it react more evenly across the sweep. Stock, the action tends to bunch in the first and last 10% of it's rotation.

This is well worth reading up on:

http://www.muzique.com/lab/tstone.htm


You can thank Jack Orman for that!

 

[Young John]

What are you after exactly insofar as changing the value?

You can change the stock pot to a 2kB or 5kB which makes it react more evenly across the sweep. Stock, the action tends to bunch in the first and last 10% of it's rotation.

This is well worth reading up on:

http://www.muzique.com/lab/tstone.htm

Thanks for the reply and link.
I would just like the frequency that the knob effects to be higher. It feels like it's 2k and I'd like to try it at 5-6k.

 

[jdel77]

No worries!
I've never had to do that to a TS as the tone knob simply is a treble roll off, not so much a treble increase.
The frequencies are generated through low and high pass filters in the circuit.

When I've got time I'll go through it, but here's a good run down on the circuit:

http://www.electrosmash.com/tube-screamer-analysis

 

[Young John]

I sure appreciate the info man but I'm dumb as a box of rocks when it comes to the theory and such. If you tell me what to solder or un-solder...I can do it.
I guess I'd like the tone knob to act more like a presence knob...does that make more sense?
Would changing the value of one of the high pass filters in the path do it?

 

[Rydell]

If you look at the schematic, you'll see two .22uf caps in the tone control area. Changing these to .15uf will give you a tone control similar to the Lovepedal Eternity's "glass" control. You see variations of this mod on a lot of boutique screamers. Some simply change the first cap to .1uf and leave the second one alone. Be sure to save your old parts in case you prefer the stock values.

 

[dllb]

I've never had to do that to a TS as the tone knob simply is a treble roll off, not so much a treble increase.

It's an active treble boost when the knob is turned to the right.

Thanks for the reply and link.
I would just like the frequency that the knob effects to be higher. It feels like it's 2k and I'd like to try it at 5-6k.

The treble is boosting above 3.3k stock. Lower the .22uf that's next to the 220 resistor to .15uf like rydell said to change the boost frequency to 4.8k. A .12uf will get you to 6k.

That will change the treble roll off frequencies when the knob is turned full to the left to around 430Hz for the .15uf and 470Hz for the .12uf. The stock .22uf rolls off the frequencies at around 360Hz.

The way it's designed, it won't let you reduce just the treble/presence. It starts to roll off the mids as you turn it to the left.

 

[Young John]

Thank you for your advice. I'll be trying this soon.