Hallo,
This is my first post. I bought the Mode Machines XOXBOX 2 from someone and I am having big problems setting up octaves. For some brief moments I can get ok octave using the TM5 trimmer but then it jumps in pitch much higher and the octave sound as octave between C1-D2 (or up to E2 at the other end of the trimmer range). I replaced the whole 200k resistor network, resoldered all joints around the VCO but the problem persists. Its like some part is unstable or malfunctioning since as I said randomly it puts out good octave (accordig to the plugin, my tuner and my ears) and even the scale sounds ok . The 5,33 V and 12 V are OK. Otherwise it works (makes sound, filter, env etc all works. Please help, I dont know what to look for.
Thank you for any help
David
X0xb0x - problems with octave range
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- antto
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Re: X0xb0x - problems with octave range
how exactly do you tune it?
you mentioned a plugin - what plugin?
you mentioned a plugin - what plugin?
-
- Posts: 5
- Joined: Tue May 20, 2014 7:05 pm
Re: X0xb0x - problems with octave range
I used the AS_x0x_tune VST according to the tutorial and also my guitar tuner (or roughly by ear). I pluged midi out of my MPC1000 to midi in, switched xox to midi play and made short sequence of alternating tones (C1-C2). Also played by hand slowly. This way I found that when moving the TM5 I was unable to get to full octave when playing C1-C2. But when I played C1-D2 it was almost perfect. When I moved the TM5 to the other extreme I had to play C1-E2 to get the full octave. The actual frequencies varied but the interval worked this way. However sometimes - when I touched the trimpot with my screwdriver it suddenly completely changed (pitch dropped quite alot) and I got perfect octave where it should be. And then it mysteriously changed again back to the error. I thought it is the trimpot so I removed it, measured - it seemed to be ok. So I returned it back (didnt have a replacement at the moment) and for a while it all worked, octave was correct. And the it changed back to the error again. Then I measured the trimpot in the circuit and it shows correct values. I also measured the resistors around and all seem to have correct values.
- antto
- Posts: 1636
- Joined: Thu Apr 15, 2010 3:21 pm
Re: X0xb0x - problems with octave range
the note when you program "c" (the lower one) without any transpose - that's C2
for AS_x0x_tune you have to use C3 and C4 alternating, so program high-C and high-C+UP
now, in your case, i guess you should have replaced the trimpot with a new one
the pitch shouldn't just move around
for AS_x0x_tune you have to use C3 and C4 alternating, so program high-C and high-C+UP
now, in your case, i guess you should have replaced the trimpot with a new one
the pitch shouldn't just move around
-
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- Joined: Tue May 20, 2014 7:05 pm
Re: X0xb0x - problems with octave range
Thank you, ok I will try different trimpot.
-
- Posts: 5
- Joined: Tue May 20, 2014 7:05 pm
Re: X0xb0x - problems with octave range
So I replaced the trimpot with a multiturn one but the problem persists. The best I can get using the VST tuning plugin (C3-C4) is between 1.035 and 1.873. The other extreme is 1.072 and 1.764.
Thanks for any help
David
Thanks for any help
David
- antto
- Posts: 1636
- Joined: Thu Apr 15, 2010 3:21 pm
Re: X0xb0x - problems with octave range
okay.. maybe some of the surrounding resistors is of the wrong value
check all resistors in the VCO (including the two trimpots) if they are the right values
check all resistors in the VCO (including the two trimpots) if they are the right values
- mmm
- Posts: 517
- Joined: Tue Apr 24, 2012 1:51 am
Re: X0xb0x - problems with octave range
My guess is that R106 has a wrong value (probably 27k instead of 24k) and/or there's a problem with R100A/R100B (or a cold solder joint).
-
- Posts: 5
- Joined: Tue May 20, 2014 7:05 pm
Re: X0xb0x - problems with octave range
R 106 = 26.5k (in circuit)
however I found the culprit - it was the pin 8 of the IC9 - there was a cold solder joint. I followed advice of Malte from MM looking for the proper 1V/oct at pin 7 of IC11 (it was wrong) and while measuring I just tried various grounds and touched the pin 8 of the IC9 which resulted in instant pitch drop and correct octave behavior. So I resoldered it and now it seems to work ok. But the R106 value seems to be wrong. I should replace it too, I guess?
Thank you very much for your assistance!
Best regards
David
however I found the culprit - it was the pin 8 of the IC9 - there was a cold solder joint. I followed advice of Malte from MM looking for the proper 1V/oct at pin 7 of IC11 (it was wrong) and while measuring I just tried various grounds and touched the pin 8 of the IC9 which resulted in instant pitch drop and correct octave behavior. So I resoldered it and now it seems to work ok. But the R106 value seems to be wrong. I should replace it too, I guess?
Thank you very much for your assistance!
Best regards
David
Please be positive and constructive with your questions and comments.