Another Tube Screamer debug...help!

[mitzrecords]

thank you so much for this great site!

I just built this TS-808 clone. bypass is fine. but when i turn it on, there is weird, "boooom" noise and goes no sound. that "boom" sounds like circuit bending kinda sound.

Tube Screamer 808(El Griton 2.2)
http://www.tonepad.com/getFile.asp?id=81

parts substitution
instead of 51pf - used 47pf
instead of 1ufNP - used 1uf multilayer ceramic(both of them)
instead of 51K - used 57K
instead of 510k - used 470K
instead of 510k - used 570K

IC(my power supply is not regulated)
1- 13.6
2-14.2
3-14.2
4-14.2
5-13.9
6-13.9
7-14.6
8-14.2

I replaced ic and transistors but same result.
I realized that voltage is all wrong. 4 should be 0. so im guessing resistor or caps are faulty.....??

any advice would be great!

thank you always!

[mitzrecords]

ohhh I thought I read somewhere I can use any non-polarized caps for 1uf NP caps as long as right value.

This might be it then?

[mitzrecords]

someone please tell me if I can use multilayer ceremic 1uf for NP 1uf.

thanx!!

[anchovie]

Yes, your ceramics are non-polarised.

On your IC, you're reading full supply voltage at the ground pin and also full supply voltage at the pins that should be biased to half of the supply. Sort out the pin 4 problem and I suspect the bias will be fixed too.

What point are you using as ground for your multimeter? Have you checked the board for solder bridges and shorts? Have you only wired up your power supply direct to the board or have you done the full set of offboard wiring, including a battery snap connected to a stereo input jack? If so, double-check this wiring.

[mitzrecords]

hi, anchovie. thanx for reply.

i did the full set of wiring. im gonna double check.

so the ceramics are ok then for NP 1uf replacement?

i measure voltages, - on negative of power jack and positive on measuring the points.

so what do you think about pin 4 problem?

[mitzrecords]

i double triple checked my wiring. seems ok.

i replaced 2.2m resistor, 1uf caps. to make sure they are not faulty but same results.

this sound when footswitch is placed is very strange. it almos sounds like turning on chainsaw..."boooom" for like 1 second and nothing.

hmmmm?

[mitzrecords]

yes! i checked wiring again and realized very simple grounding and input wires were reversed.

i feel so stupid.

thanks sosososo much!!

[MikeH]

Ummm.... get a battery.  Your power supply is quite likely a big part of the problem; 14 volts a WAY too high.  You've possibly cooked some of your components too.

[anchovie]

I was under the impression from the original poster's last post that it's working now.

The way he had it wired before, it wouldn't have made a complete circuit so I doubt anything's fried. The high readings would have been made in a no-load situation because of the wiring error. Plus the op-amp should be good for 18v and the transistors 30v according to datasheets.

A regulated power supply would be a nice thing to own, though!

[mitzrecords]

ya, everything is working great. weird thing is that i tried with battery and it measured 13v too. maybe my multimeter's battery is low or something.

anyways, it is working perfectly fine.

thanx!

[johngreene]

Ummm.... get a battery.  Your power supply is quite likely a big part of the problem; 14 volts a WAY too high.  You've possibly cooked some of your components too.

Too high for what? 18V is commonly used in this circuit. The IC is good for 30V between pins 8 and 4 easily (max rating of 44 volts). I happed to like it with 18V. As long as the caps are rated for that voltage (i.e. no 16v parts).