Depth Control Question

[alerich]

A typical depth mod installation involves removing the negative feedback wire from the OT and installing the 1M pot/.0047uF cap assembly in series between the OT and the negative feedback resistor. I would like to install a variable depth control on my Marshall JCM2000 head since I do not care for their preset depth control push button affair. It would be much easier to install the pot/cap assembly on the other side of the NFB resistor between the NFB resistor and the presence control instead of between the OT and NFB resistor as is usually done. Would it really matter on which side of the NFB resistor it was installed? They are just basically two series resistances. I'm thinking it would not matter but am interested in a second opinion.

[92Volts]

I'm not familiar with this exact mod. Does the 1M pot provide series resistance only, or does it connect to ground (or anything else)?

If you're just dealing with series resistance/capacitance-- there are no connections to anything else in or between your assembly and the NFB resistor-- the order can be reversed.

[alerich]

Yes, it's just a series resistance - a pot with a cap bypassing it (see pic). I was pretty sure it would not matter but I always like to get a few opinions. Thanks for the feedback.

[jjasilli]

I agree that there should be no practical difference.  For the sake of completeness: If the depth mod is placed before the fixed NFB series resistor, then the depth cap must discharge through that fixed resistor.  This will have some effect on the phase of the NFB signal, as it will retard the timing of the cap's ability to discharge.