[sdiy] dr-110 snare and 2SC945

[Fredrik Carlqvist]

Is it the click-, noise- or the tone-part of the snare sound that is
weak? Or all of them?

The transistors are probably not the problem (except if they're broken,
check the base-emitter and base-collector diodes with a DMM diode tester
in-circuit). 

If all parts of the sound are weak, I would check the trigger transistor
Q14. Or perhaps R86 is too low resistance and is swamping the snare
output?

If only the tone part is low, I would check the capacitors C28, C29,
C31. These should be close to each other in value. In my schematic, C29
does not have a value printed out. It should probably be 682 (6800pF)
like the others. Even if you have used 6800pF, You can try and match the
capacitors to improve the amplitude.

The capacitor C35 is the one responsible for activating the resonator.
It should be 1000pF. Also check the resistors around Q11.

If you have a scope, look at the output (collector) of Q11.

If the noise part is bad, look at the output (emitter) of Q13. Perhaps
the diode D9 is backwards? Or C52 is bad?


Fredrik C
 

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Karl Ekdahl
Sent: den 28 september 2005 22:43
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] dr-110 snare and 2SC945

So my clone is beginning to work but the snare doesn't, it sounds really
weak and too low volume. The orginial schematic uses a 2SC945 that has
"excellent hFE linearity" which is the only real difference i can see
inbetween it and the BC548C i replaced it with.
Does anyone know anything about this? If i do need the 2SC945, is there
any substitutes to be found for it since the original seems hard to get
here (sweden)..?

thanks a lot list

karl