hi,
now that i have the trimpots in the right place and have borrowed a midi controller keyboard, i’m trying to sort out the tuning.
the thing is, it all sounds really distorted or overdriven.
i think i’m following the tuning instruction right.
but when i turn the Reso the sound doesn’t go from silence to distorted, it just changes in pitch.
do you think i have a short somewhere?
i guess i will have to take a close look over the board to see if i got something wrong somewhere…
When turning the reso trimpot it goes from silent, not distorted, distorted with a change in pitch accompanying the transition from not distorted to distorted. So the raise in pitch is normal, but can you at least reach the “silent” zone?
Out of curiosity: put the oscillator 2 to none, and the oscillator 1 to fm, with prm = 0, and set mix to 0. The synth should now play a sine wave. Does it sound distorted or not? If this is the case, it might simply be the input level on your mixer/soundcard which is too high.
hi,
thanks for the quick reply!
i cannot reach the “silent” zome, all i seem to get is a change in pitch as i turn the trimpot…
i tried as you said, osc2 to none, osc1 to fm, prm = 0, mix=0
it sounds the same as the setting both oscs to none, with res@63 and cutoff@50.
i also tried plugging in to my mac, the sound was a little less distorted, but the other info above leads me to think something isn’t right somewhere…
oh, and i’ve now played the unit through a computer and two different mixers (one being my analog synth mixer) and do think that the output volume is really high!
so maybe i have put something in the wrong place and that’s causing distortion…
So even when resonance is set to 01 you have a sound when all the oscillators are set to none? If the output is too high, you can try swapping the 68k resistor above IC3 (which sets the output gain) to a 33k or 10k.
ok, i have followed your suggestion and swapped the 63k resistor to a 10k.
along with the advice above, i have also worked through Muldee’s post here: http://tinyurl.com/tunar
all to no avail
all the various settings just change the pitch, like before.
no turning of the Reso trimmer puts it into the silent zone.
i have had a close look to see if i have a short and can’t see one.
Nothing that comes to me that wouldn’t require a scope to inspect what’s really going on… Maybe it’s not a problem with the feedback path itself, but the resonance control signal generation (all parts above IC4). Are the two diodes and the two transistors between IC4 and IC5 correctly oriented?
grrr!
i swapped the resistors over (220k and 2.2k) and there’s still no silent zone…
i guess i’ll have to spend some time checking all the other resistors next.
i was having trouble seeing the colours on some of the resistors, a blue or black band on blue, next to a blue or black band… one colour influences another too much, so yeah, white resistors would be much more helpful!
I know it’s not easy to read those values, but all the resistors of similar values are bundled together, and the instructions show the board at each step.
Multimeters work by sending a current between the two probes, measuring the voltage, and doing the division. This works outside of a circuit, but once the resistor is soldered on the circuit board, current is flowing everywhere so you’re not measuring anything valid at all…
