OCD, Buffered Pedals and GGG ITS8

[mindcapsule]

Hey Everyone,

I recently bought an OCD ver4 but noticed something weird with it.  When the OCD was used by itself straight into an amp with any other true bypass boxes  it sounded great.  However, when I used the pedal before buffered pedals such as an old Ibanez AD9 or Maxon AD900 Analog Delay the OCD sounded fizzy and really bright.  Not just an increase in tone, but like it added a nasty artifact to the the overall  tone.   After doing some searching I learned that some other people had this problem too. Does anyone know what is causing this? I emailed Fulltone as well but don't know if I will get a reply.  I never had this experience with a pedal before and I keep the delays last in the chain so this is a problem for me.  FWIW I use an SG and Les Paul.

Anyway I am approaching the return period at the place where I bought the pedal so I've been thinking.......

I've built a few dist/OD boxes in the past and one of the pedals I built that I really like is the GGG ITS8 Tube Screamer Clone with Red LEDs for clipping (I don't care for the Si Diode sound) and a .1uf cap to get the bass response down to about 30Hz or so.   The sound was close to the OCD in HP Mode but rolling down on the volume of the guitar to clean up tends to produce a dull tone.  Whereas on the OCD you could lower the volume on the guitar and the highs were left in tact-similar to a treble bleed cap on PRS guitars.  The OCD also seemed to have more of an overall clarity than the Screamer Clone.  Even with the Tone all the way up on the screamer clone the sound was brighter than the OCD but the OCD was clearer more punchy sounding, if that makes sense.

Is it possible to get these characteristics by modding my Tubescreamer clone?  I took a peek in the OCD and it has a TL082 opamp and two 2N7000 MOSFETs with a germanium diode which I'm guessing is for clipping.  Would swapping out the Opamp ( I have the JRC 4558 in it now) to a TL082 and changing the clipping from LED to MOSFET/germanium in the Screamer clone do the trick or am I off base here?  What accounts for this higher overall clarity as well as high end retention/clean up when rolling down the guitar volume anyway?

I'm really not trying to clone the OCD per se, but I do like the sound and dynamics of it.  I just hate that problem when using it with buffered pedals and I don't want to mod the delay pedals so I'm trying to find the best solution.


Thanks,
Robert

[petemoore]

 Loop pedal or some way to eliminate the signal being pre-buffered...[~ez], sure fire way....eliminating the buffer by routing around it.
  People have modded the TS to be non buffered, I'd say build a TS to your liking and leave the other one as is.
  Buffered signal has low impedance output, and drives the 'complete' signal to the next stage, [boosted impedance, not a voltage boost] in this case [as is often the case with unbuffered source Vs. buffered source] the OCD's response is altered.
  Another option [not exactly a 'fix' like connecting the source, unbuffered] is work with a coil [between buffered output and the input] to make the input resemble more of a guitar pickups response...see AMZ labs notebook 'pickup simulator' [IIRC].

[mindcapsule]

Thanks for the reply and info Pete. 

I thought about the bypass pedal route.  While it will solve the problem when not using the delay, would the problem arise when I switch the loop pedal to put the delay back in the signal chain?

The TS clone is true bypass-3PDT and has no issues with the buffered effects.

Robert

[Johan]

from your description, I would guess it has/uses low input impedance, to shave the highs from the guitar signal. then when you put a buffer inbetween, you dont get the expected result....but just guessing..
j

[DougH]

If the problem is with running another pedal on its output, sounds like the problem is with the output of the OCD. But I can't imagine what it would be.

[mindcapsule]

Thanks for the replies.

I emailed Fulltone and asked what would be causing this and if there were any mods that can be done to fix it.  They (a tech I believe) said they weren't doing any mods at this time but didn't tell me why I was having the problem.  Most likely I am going to return it.

It's really weird because I have quite a few stompboxes old and new, boutique and standard and never had a problem like this.

I'll just see if I can build or mod a pedal to give me the tone and characteristics of the OCD but that will also work well with buffered pedals.

Thanks,
Robert