c o n f u s e d m a c h i n e s | v . 0 2


Hi Hats

OHH and CHH decay (and cutoff reversal)

OHH and CHH decay (and cutoff reversal)

This one is from Rob (cyborgzero). It allows the adjustment of the OHH and CHH decay. Note that these decays really just shortening the actualy sound rather than increasing the decay time, and there are some other decay mods around that will perhaps allow you to extend the decay. The cool thing with this one is due to the differential pair used in the hat mute circuit, that you can actually reverse the hat cutoffs to very good effect. Anyway, from Rob..

OHH decay - replace r167 with a 1 meg pot in series with a 470k resistor.
CHH decay - put a 1 meg pot in series with a 1k resistor across C42.

Great FX!! using the two knobs, you can transpose which one is acting as the CHH and which is the OHH and they will switch and cut each other off in the same manner as if they had been actually switched in a pattern. The reason they do this is because of the differential pair that is involved in cutting off the OHH with the CHH.


This mod is another flash of Plutonique9 brilliance. It adds a HPF to the final stage of the hi-hats which when swept down, can lower the tones of the hats, leaning towards that crunchy 909 type hat. Pretty cool indeed.

Anyway, it's pretty straightforward. Locate C70 on the PCB. It's near the bottom of the board, and near IC12. Now, solder a pot in parallel with it (across it). I just used a 25k pot. You may need to add a resistor to stop distortion at extreme settings, but I didnt need to with this value. Any more resistance, and you can get some nasty (and painful) noise.


This bandpass filter for the hi-hats is one area where Waterstone did actually get it right. There's a bandpass filter formed by IC15a and couple of resistors. You can alter this to give the hats a 'swishy' feel to them. Sweeping this up and down produces some nice results, but it does by the nature of the modification effect both OHH and CHH. Not a big deal.

Doing this mod is pretty easy. R222 controls the cutoff frequency. Simply replace this resistor with a pot and resistor in series. Waterstone recommended a 47R resistor and a 4.7k pot. I tend to agree with him, but of course, experiment with values to see what suits you best. The output can clip a bit, Waterstone suggests adjusting R189 from 47k to 22k. This will reduce the gain. I don't think that I bothered (I'll get back to you on it), a bit of distortion at extremes can be nice!