TS9 help needed! Drive seems to act as an EQ ?!

[Speeddemon]

I was modding a Ibanez TS9 RI, already installed a Bass + toggleswitch, that chooses either the stock 0.047uF cap (from drive circuit) or a 0.22uF one, did some other mods too, and everything worked fine.

Now I added another DPDT toggleswitch (sub miniature), to select either a Ge diode or a 1N4001 diode. The other diode is still stock.
This worked fine (although the Ge diode sounded very farty and like there was a noise gate active too...)

Then I screwed everything together, and now for some reason the drive control doesn't add distortion anymore.
The thing now functions as a sort of clean boost. 
Oh, and also maybe of importance; the Level control doesn't cut off the sound completely anymore.
Suppose it normally went from 0 (silence) to 10, now it looks like it goes from 3 to 10.

Anyone know what to look for? I checked all the parts and wires, but nothing seemed out of the ordinary.
I did replace 2 wires that were already broken from all the PCB-turning, but I placed them on their old spots.
(these original wires are REALLY crappy, thin AWG 26! I replaced them with AWG 22's)

Any help would be REALLY appreciated!

[johngreene]

Since both the level and volume controls are affected, my guess would be something happened to the 4.5V reference voltage. The volume control is connected to it as a virtual ground. The caps you added a switch for also connect to this supply.

--john

[Speeddemon]

so what does that mean? That the battery connection might be off, or that I screwed with the wrong resistor?

[johngreene]

Without somemore information I can't be much more specific. I'm just saying that your problem probably has to do with the 4.5V reference voltage. Either a lug from the volume pot is touching something it shouldn't or the mods you did to the Bass+ toggleswitch are touching something they shouldn't. If you have the ability to measure the voltage, check and see if it is still around 4.5V. Does it still not work right when you take it back apart? If it doesn't, check all the voltage on the IC pins. All should be around 4.5V except for 8 & 4.

BTW, a Ge diode as a clipper severely reduces the output level because it has such a low Vf. You could get a similar, but louder, result if you had put the Ge in series with the 1n4001 and shorted it out with the switch. This gives a higher threshold voltage but the clip will still follow the softer Ge curve.

[Speeddemon]

from which points should I measure the voltage then?

I've never done this, so forgive my noobness. I assume a battery should be attached?

[johngreene]

yes, the battery should be attached and there should be a plug in the input jack. Then measure all the pins of the opamp referenced to ground. While you are at it, measure the voltage on all three lugs of the volume control. I usually stick the ground lead of the DVM in one of the screw holes of the chassis and measure around with the red lead. Post your findings and we'll see what we can come up with.

--john

[Speeddemon]

Just checked it with 2 batteries (and old an a new one).

IC's pins 1 to 3, and 5 to 7 measure half the voltage (4.41V), pin 4 = 0V, and pin 8 is 8,81V.

And the guts are dangling out the enclosure, so there's no unwanted grounding of the pots against enclosure.

[Speeddemon]

PROBLEM SOLVED!

Turned out that one of the replaced electrolytics, had 1 loose foot. I was scanning the solder side, couldn't find anything. Then I was bending some components, so that they wouldn't make contact together, and my hand bristled against the big cap. It was looser than it supposed to be, so I pulled it a bit on one side, and the foot was loose.

It works, thank God!
It has a bass boost switch (VERY necessary, especially with the 'increased drive' mod), and a diode toggleswitch. But next time I might change one of the diodes to a LED, since the difference between the 1N914 and 1N4001 is hardly noticable. (the 2nd diode is still stock).

Also, the bass boost switch was on the right, next/below to the Levelpot and above the input jack. BAD IDEA! I had to put heatshrinks on a lot of resistors, because they were grounding on the insides of the enclosure. I recommend using the BIGGER space, in front of the Jack. You could even fit a 3PDT toggleswitch there!