e-licktronic Forum

EDIT:
Reading throughout the forum I noticed many people have a Nava that has low bassdrum volume. If anyone want to report this or have a solution, please write here.
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Hi Everyone! I'm struggling to find the issues in my last nava build and I hope someone can help me:

Kick Drum: no sound at all. Env 3, Vco, Trig and Pulse are ok. Env2 and Env1 and are nowhere to be found. Also the accent doesn't seem to work cause I get no signal at the test point. Tried to swap the opamps with good ones: nothing. Changed q3, q4, q5, q12: no luck. Checked all the resistors, components placing and diodes: still no luck. I probed this new Nava against the one I built last year that is fully functioning: the trig signal coming through d6 gets through r20 and r18 just fine but then behaviour of q3 is totally different: the transistors looks dead on the new build whereas the one on the working Nava exhibits a clear negative pulse that trigs everything beyond that. Tried to change it but the problem is still there.

Hi-Tom: the voice works perfectly but I noticed that the accent signal is different from LT and MT and also from the Toms in my previous Nava build. Probing the accent shows that the signal stays at +5/6v and then goes up little bit when it gets the "trig" signal, and returns to 5/6v, no zero. On LT and MT the accent signals peaks when the voice is triggered then goes all the way back to zero till the next "trig". Strange things is in my previous Nava all three Toms behave as this Hi-Tom. How could it be that the same circuit exhibit different behaviours and still works ok? Also changed the mux sh board on ic114 with a spare one that I had at hand: same behaviour. Last thing: one of the opamps on mux board ic114 gets INSANELY hot, meaning I can't touch with my fingers. This happens with both mux/sh boards.

Any hint will be great. Thank you very much,

NEWS: Think I've found the problem of kickdrum and hot ic114 mux/sh board: the accent pcb trace coming from ic114 to bassdrum ic11b is shorted to ground. That explains the hot opamp on ic114. I'm not so sure about the kickdrum, but it could well be.

The problem was a damn metal washer I put under the nut of the bolt I used to secure the lcd. It scratched the pcb paint and shorted the trace from ic114 to BD to ground. Such a silly thing. Now the bassdrum is there, but still the output is low compared to the output of my other Nava bassdrum. I can see it from my scope, and I clearly hear it with phones. Mind: the bassdrum is not unaudible, but it's quiet, too quiet. I compared every ENV between the two Navas with the scope and they are identical. Accent comes perfectly now. Anyone on this? Thanks

BUMP BUMP BUMP! Everything solved, except for the bass drum, the volume is still low, on individual outputs as well as on master out. This is strange cause in my other nava the bd volume is waaaay higher. Anynone? I'm quite desperate

Replace VR4G$1 with a 150 or 200K pot. (Volume will be much louder !!)

donzo93 wrote:BUMP BUMP BUMP! Everything solved, except for the bass drum, the volume is still low, on individual outputs as well as on master out. This is strange cause in my other nava the bd volume is waaaay higher. Anynone? I'm quite desperate

JvR wrote:Replace VR4G$1 with a 150 or 200K pot. (Volume will be much louder !!)

Already thought about this but I don't think it would solve the problem. The sound is unbalanced between the pulse part (comes through almost fine), and the oscillator part (very low). I'll try and recheck everything for the 10th time, maybe I missed something.

Recheked everything (pcb traces, resistors, misplaced components): everythings ok. Changed every diode and every transistor that I haven't already changed. Now the pulse part and the oscillator part of the kick are balanced, but still low volume. A little progress at least. The tone is very good nonetheless. I'll post an update when I solve the mistery.