Is There a Problem w/ My Pro One (DIY Repair Advice Needed)
I am wondering if there is a problem w/ my Pro One (or if I simply don't have the experience).
Essentially, I am wondering why my Pro One isn't going low enough?
Here's what I am experiencing:
when I play the lowest C on the keyboard, with only Osc A on, set to Octave 0
(with no modulation, no other Oscs turned on, etc) the note that sounds is G#2.
I am pretty sure this means I need to adjust the tuning, however, let's pretend it the tuning was intact and it sounded a C - Is C2 the lowest note that Osc 1 can play on the Pro One?
I have figured out, I can get lower if I use Osc 2 set to Octave 2, select two waveforms (in this case I did saw and tri), and if I turn Low Freq and Keyboard On I get notes in the 0 Octave range. Is this normal?
Thanks for any help with this, and sorry if this is noobish. Trying to determine if it's user error or if I need to get this synth serviced.
Try it just with Osc B, or try Osc A with the Osc Sync switch off (Osc A is tied to the frequency of B when sync is on and may be the source of your problem). If Osc B is not going near C-0 (or whatever) you may need to get it serviced.
The Pro-One should go pretty damn low even without low-freq engaged.
Okay, at the suggestion of Oli, I have recorded audio of the following patch:
The only difference is I have set both Osc A Octave and Osc B Octave to 0 (zero).
(Audio is attached below at the bottom of this post, also available HERE on Dropbox).
The audio contains 4 examples:
1. Osc A only, (set to Octave 0) playing the lowest C on the keyboard.
2. Osc B only, (set to Octave 0) playing the lowest C on the keyboard.
3. Osc A only, (set to Octave 0) playing the lowest C on the keyboard. With Lo Freq engaged. (this sounds the same as 1, as Lo Freq doesn't affect A)
4. Osc B only, (set to Octave 0) playing the lowest C on the keyboard. With Lo Freq engaged.
Does this seem right?
Set at Octave 0 (zero), w/ Lo Freq OFF, the lowest note that sounds is C3 (approximately 260 hz).
The manual states that Lo Freq "Extends OSC B range to sub-audio frequencies", however, based on what I am hearing and seeing (example 4) - it is indeed audible.
Is this synth somehow tuned an octave (or two) too high?
Thanks again guys! I am trying to do my best with the manual, however, having never owned an SCI, I don't know what "normal" is for this.
Last edited by Jean Luc Cougar; 14th July 2013 at 08:11 PM..
Yeah, your tuning (or something) is definitely off by a couple of octaves. I guess you could try adjusting the scale yourself but if (like me) you're in any way unsure about this kind of stuff take it to a tech.
If you have another cv source try connecting that to see if it's not a problem with the keyboard scale rather than the oscillators.
I am going to attempt to calibrate this myself before taking it to a tech. I have done some minor repairs, so I think adjusting the trims should be within my grasp.
Quick questions before I attempt this (Manual for reference - all on page 4 and 5):
1. Is this most likely "Tuning"? "DAC Scale"? or just the "User Trim"? Just trying to zero in on what I need to do.
2. It looks like adjusting "DAC Scale" or "Tuning" requires the synth to be opened. I assume this is fine to do / adjust with it powered on as long as I don't touch anything near the power supply?
3. Any other thoughts?
Last edited by Jean Luc Cougar; 16th July 2013 at 05:48 PM..
Can't help you with the pitch wheel, however if you do end up opening it up make sure you carefully disconnect the keyboard ribbon cable from the main board before you open it up entirely as the pins on the end seem to break quite easily. Replacement ribbons are available from Wine County if you do break it