Tube screamer experts....what causes the difference between.....

[oczad]

....TS7 and TS5. The TS5 being the old black plastic "ladybug" and the TS7 being the grey metal one with the push down knobs and "hot"  switch. Heres the deal....i love the metal one because of the far superior reliability factor verses the flimsy knobs and generally cheesy nature of the plastic one. But the plastic one sounds better. the tone is thicker and i like it considerably better. I downloaded the schematics and i'm trying to decide what it is that causes the TS5 to sound thicker. the differences i see are at the output there is a 100k in place of the 10k on the TS5, plus the cap and resistor are reversed, and the output pot is different and looks like a typo. The pot had one side going to ground on the TS5 which is of course normal, but on the TS7 that side of the pot that normally is grounded like on the TS5 is going to the 4.5v PSU ! Is this a typo or what?

Considering all that and the fat the rest is identical, what do you think is the difference in tone? I'm assuming the output pot diagram is a typo and therefore it's the output difference. Then again, if the output pot is indeed a typo, then for all i know i can't even go by these schematics because theres a good chance the output differences are also wrong. Can anyone clear this up for me
? What say thou?

[frequencycentral]

http://www.analogman.com/ts9.htm#ts7

[earthtonesaudio]

This might help:
http://www.muzique.com/schem/ts808.gif

The output volume knob can be connected to 4.5V, ground, or 9V, any should work, not a typo.  Notice that the potentiometer is DC-isolated from the rest of the circuit by the capacitors on either side, so for AC signals, any stable DC level looks like "ground."

Check here for a detailed description of the differences between various TS models:
http://www.geofex.com/Article_Folders/TStech/tsxtech.htm

[oczad]

Ok, i'll check those links out, thanks. But since the output pot is correct on the TS7, that leaves 2 things as possible reasons for the tonal diff....the pot going to PSU instead of ground, or the output resistor value and cap/R orientation. Which do you guys think is the likely reason? i would think this would be common knowledge by now with the incredible amount of online chat and building of tube screamers over the years.

[Gus]

The IC number is most likely different.  My 7s had JRC4558 stock and the 5s I worked on had a different number.

Certain cap types and construction can cause distortion and this can be measured (I read a very good set of articles and when I collect up enough meters and things to build a measuring system I will check the findings in the articles)

Now When you turn the gain to full and tone control to max treble is the time you can hear IC differences.   With the gain not so high and tone in the middle it is harder to tell the difference between opamps.  IIRC R.G., Jack and others have posted about recovery of opamps from clipping years ago back in the early ampage days.

[earthtonesaudio]

Probably not the volume control.

Since you say your TS5 has a 10k resistor on the output, I wouldn't be surprised if someone had modded it to TS808 specs.  In my opinion, that's the only change you should have to make to get the same characteristics as an 808 (assuming the TS-9 "mode" is faithful to a real TS-9 circuit).

Try changing the output resistor on your TS7 to 10k, and see if that helps.  Better yet, just tack-solder a 10k resistor on top of the 100k, and if you don't like it you can easily snip the 10k resistor off with a pair of wire cutters. 

All this talk has me wanting to mod mine some more...

[oczad]

they both have the same 4558, but i may have done that. It looks like the IC was replaced, and i've had this since they first came out. So i can't remember. But i'm sure i modded it because theres also a 100R added in place of the 470 at the output with the 470 still there but one end lifted. So maybe thats why it sounds different. I see that muzique schematic show that 100R mod, so i must have got it there. I'll try that with the TS7 and see if that does the trick.

[oczad]

earthtonesaudio, it doesn't have a 10k. I was just saying the schematic does. I just opened them both and found they both are the same except I had replaced the 470k in the TS5 with a 100R. I apparently did this long ago and forgot, but i think thats why the tone is different. So at the moment i'm doing that to the TS7 too. I'll let ya'll know if it makes the difference.

[oczad]

Well, i changed the TS7 470R to a 100R like my TS5 but they still sound different. And the thing is, i never compared them till now and i'm noticing not only is the TS5 thicker sounding, it has considerably more output ! (with TS7 NOT set to hot) But the TS7 schematic i believe is very wrong because mine was not like the schematic in that the value of the out shunt R was not 10k as shown, plus the orientation of the C/R there is shown incorrectly. So i can't rely on that schematic and therefore cannot know what to do because the way the thing is assembled makes it very hard to see how the circuit is designed.

[earthtonesaudio]

I found a schem here: http://www.schematicx.com/schematic/ibanez-ts7-tubescreamer-schematic/

...which is hard to read, but shows the output shunt resistor to be 100k.  Try replacing that with 10k.
According to the geofex.com article, changing the 470 ohm resistor to 100 ohms should not make much of a difference, but it would be a more accurate "808 mod."

[oczad]

The TS5 has a 100k shunt, so it would be changing AWAY from that to put a 10k in the 7. Besides, one of the things that makes the TS7 different from the 5 is that it has a lot less output, and putting a 10k there would if anything reduce it even more.
i think maybe the best solution will be  to put the TS5 in a metal box with real pots and jacks and a metal momentary. (these little circuit board mounted momentarys go bad all the time and this one has been intermittent almost from the start)

[aron]

What about capacitor tolerances, pot tolerances too?

[earthtonesaudio]

Besides, one of the things that makes the TS7 different from the 5 is that it has a lot less output, and putting a 10k there would if anything reduce it even more.

I was talking about the 10k resistor to ground after the output buffer.  Lowering the value reduces (AC) output impedance, which allows it to drive whatever follows (i.e. your amp) harder.

[oczad]

Yeah, but the thing is the TS5 that i like so much has a 100k there and it drives much harder than the TS7. And i was wrong...the TS7 does indeed have less output, but it's not as huge as i thought....i noticed that AFTER i tried a 100R in place f the 470 series R. I put the 470 back and it's much closer now. Odd....i thought a 100r would have cause MORE output if anything. And I forgot to mention, i use the pedal exclusively as a clean boost. The dist pot is always all the way down. (tried a million clean boosts, but i just like this better !)