Questions about the TS-9 to TS-808 Mod

[NoMoreMKIV]

Hi-

I've been thinking about doing the TS-9 to TS-808 modification to my tube screamer (it was a reissue, made in mid-90's with Ibanez label).

Here's my questions:

a) What specifically is the change in sound from the op-amp swap?

b) What is the change in sound from the resistor value changes?

c) Are newer 4558's such as the NJM4558D worth using (i.e. are they an improvement over the stock TS-9 chip? Mine is a TA75558P). I saw that these are available through Mouser.

What I'm shooting for is something that will save a little bit of the low end that gets lost with the TS-9, and also to keep the clarity of the notes a little better.

And I was wondering if anyone has liked the sound after just changing the resistors without changing the chip.

(obviously, i'm aware that i could spend some more money and buy any of a number of different overdrive pedals instead, but i'd like to see if this mod does the trick first)

Thanks!

[Dom L]

Re: Questions about the TS-9 to TS-808 Mod

For the price do the mod or have it done. I just did mine this week
with the TI RC4588p chip canged the output resistors to 808 specs
and did the drivre circuit mod
Sounds 10000000% better
I'm sure Stratdeluxer will chime in, he's the one that helped me out
Great guy to deal with

[kmcguitars]

Re: Questions about the TS-9 to TS-808 Mod

I can Field a few of your ?? But Stratdeluxer is the Expert on this matter.
I just did the mod to my TS-5. I find it to smooth out the tone ,And you'll
get more clarity. As far as the op-amp I used the JRC 4558 I got from
Smallbear Electronics. The two resistors I believe lower the voltage that's
going to the Op amp ( I don't rememeber the values off hand) If I'm wrong
John will set me straight At anyrate it's a great mod!! And don't
forget a 8-pin socket for the Op-amp.

[STRATDELUXER97]

Re: Questions about the TS-9 to TS-808 Mod

The TS9 uses a 470 ohm resistor and a 100k...The TS808 used a 100 ohm in place of the 470 ohm and a 10k in place of the TS9s 100k...The 808 mod gives your pedal a bit more output and gain and also sets the correct impedence match between your pedal and a tube amp's input...The mod is not something that jumps right out at ya but there is a difference in that the 808 always has this little something extra in it's tone?Both of these resistor mods are in the output stages of your Tube Screamers and not the opamp itself..

I've been messing around with older 1980s JRC4558D s and the recent NJM JRC chips that I too get from Steve at Small Bear and Mouser electronics..I personally can not sit here and tell you that I hear the difference in blind fold A/B tests...It's not the opamp on it's own that gives the series great tone because there are other cap and resistor mods that can be performed to the circuit for more lows and more gain...There's an awful lot of hype around with the JRC chips..I also like the TI RC4558P chip and I also use these in alot of my mods,and not just on Tube Screamers..