rat clone build has poor tone and no harmonics...help

[pnak]

I have just built a Rat clone from tonepad..
http://www.tonepad.com/getFile.asp?id=89
and followed the schem except for using silver mica instead of ceramic caps for the pf's and
used a 33pf instead of a 30pf for attaching the 1 and 8 pin in the LM308.

the sound isnt "that bad "on the low strings but when you get to the g - b - and e string it
sounds as if i have the tone control on the guitar is turned down and you cant get a pinch
harmonic from the guitar to save your life.

I do have an original pro co Rat from 1987 seven to compare it to and the layout and schem
as far as I can tell are accurate except that the 87 rat uses 1N4148 diodes instead of 1N914.

Can anyone Send me in the right direction

[pnak]

here are some readings I took.

LM308

1.  8.8 vdc
2.  4.7
3.  4.3
4.  0
5.  0
6.  4.7
7.  9.4
8.  4.8

2N5458

G. 9.4
S. 1.8
D. 0

All measured to ground and with a new 9v battery reading 9.5 vdc

[Ronsonic]

Wiring error? 

Misread component value?

Sorry, all I got and my first guess when something goes wrong on my bench.

[pnak]

checked wiring and all looks good, also checked over component values and

everything is good except for the 33pf sub for the 30pf...wich I could be wrong but should

not affect the filter and tone.

the pedal is doing what is suppose to do .. distortion and volme controls work nicely

just not enough treble and I checked the pot and it is OK. It just sounds like a guitar with the tone control

turned down.

[StereoKills]

Does it sound like that throughout the sweep of the filter knob? It took me a minute to get used to the reverse setup of the filter, but the one I built sounds good once I have it dialed in.

[pnak]

it only sounds like its trying to put some high end back about the last 10% of the pot but still

has very little to offer.

My 1987 Rat has plenty of tone and sweeps very nicely over the pot and harmonics are

almost effortless unlike the clone build were they are impossible.

maybe a bad component?

[aron]

Did you compare it with a real one? Your description somewhat matches one of the Rats I have right now.

I still have my original big box rat somewhere, I need to pull it out and hear it again.

[aron]

Oh I see, your 87 rat sounds good.... hmmm.... well my smaller box rat doesn't sound so good.

[pnak]

what I'm trying to find out is what component in the circut could cause a poor sweep in the
filter control so maybe I could focus on that area and maybe start swapping out parts or values.

As it seems that the 2 pedals are identical circuits they should sound closely alike.

[aron]

There must be a wrong value component or maybe a solder or wiring problem.

Build an audio probe and trace through the circuit.

[dschwartz]

if i were you, i´ll double check every low pass filter in the circuit..

[pnak]

after taking another look at my original rat it has 2.2meg resistors to ground at the same points
were the clone rat has 1meg resistors, would that make any difference ?

I'll take a look again at the caps.

[aron]

I think it's an error in the wiring or component value.

[dschwartz]

after taking another look at my original rat it has 2.2meg resistors to ground at the same points
were the clone rat has 1meg resistors, would that make any difference ?

I'll take a look again at the caps.

i don´t think that those resistors would make any audible difference..