I have built two NAVAs. On one of them the BD is a bit too low, which I would like to change. On the site of colinfraser it says that R59 is responsible for the pitch of the BD. I measured them on both NAVAs but actually their values are nearly identical (46.0k and 46.2k). So I don't think the different pitch comes from this particular resistor. Any ideas where I should look next??

gihaume wrote: Also Greg Zifcak did some very interesting ones particularly on the clap. I already contacted him one time and he was very OK to share.
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Please if someone tries from those information, share the results here !

Thanks for sharing the info!!

To do the Clap Tuning mod, replace R207 (originally 150K) with a pot of larger value plus a smaller resistor in series. I am using a 250K pot, plus a 47K resistor in series, in an attempt to have the original 150K value at the center position of the pot (it's not quite, but close-enough). The 47K resistor keeps the pitch from going beyond the audible high-freq range when the pot is at full. Also note that the pot needs to be wired via the 2nd and 3rd pins, rather than 1st & 2nd.

The Clap Reverb Time mod does not seem to work, at least not with Greg's information, on the Nava. I tried wiring a 0.01uf in parallel with C61 and could hear no difference. So I tried a 0.022uf in parallel and still could hear no difference. Perhaps it is because the Nava uses a BA6110 unlike the 909, or perhaps an even larger capacitance needs to be used?

Meanwhile, here is an addition to the Bass Drum Overdrive mod: replace D10 & D11 (1N4148 diodes) with LED's of your choosing. Red LED's are known to work best. It is definitely preferable to use a switch (only SPDT is needed) to switch between the original diodes and the LED's, as even with the overdrive pot turned all the way down, the LED's will give a slightly different sound than the original diodes.

KlangGenerator wrote:I have built two NAVAs. On one of them the BD is a bit too low, which I would like to change. On the site of colinfraser it says that R59 is responsible for the pitch of the BD. I measured them on both NAVAs but actually their values are nearly identical (46.0k and 46.2k). So I don't think the different pitch comes from this particular resistor. Any ideas where I should look next??

It might not be the cause of the difference, but changing R59 will definitely change the pitch, so it seems you could still fix the pitch where you'd like it at R59? Perhaps use a trimpot there instead of a resistor and adjust as necessary?

On the hihat pitch mod, is it possible to add CV control?