[sdiy] Sequential Pro-One repair report

[Tom Wiltshire]

Hi Tony,

Yeah, perhaps tuning with the cover off has other problems, but it's so much easier to see what's going on that I prefer it. The synth was well warmed up, so that wasn't a problem. Draughts? Dunno, I wasn't in one, I guess.
I did it partly according to the Sequential Service Manual, which recommends multimeter (for the DAC) and beat tuning (for the oscillators), but I also used a guitar tuner, which made doing the scale trimmers easier.
The important thing I'd say having done it is to make sure the DAC is trimmed correctly first so you know you're getting good 1V/oct CVs, and then that the 1V source used for the octaves is a well-tuned 1V. That ensures that the CVs are accurate. From there, you've got a solid basis to tune the oscillators. It's *possible* to tune the oscillators to pretty much whatever the DAC puts out, but you're making problems for yourself in my view.

Tom

On 20 Apr 2016, at 13:30, Videotron <tokalo at videotron.ca> wrote:

> Thanks for sharing that story Tom. Only part that made me go 'hmm' a little was tuning with the cover open.. drafts, temp and all those nasty gremlins. Just curious what is your preferred method - beat tuning, strobe tuner, freq counter, guitar tuner etc I have used all three and at the same time. Did you factor in for "stretch" or a "fatter" sounds - accuracy v.s. musicality. Sorry if this sounds elementary but always been curious what methods people use (oh almost forgot about the Lissajous method of Sequential - never tried that one myself) 
> 
> With Peterson strobe app and line input for i-devices I no longer use my trusty old Conn strobe tuner. Miss that warm glow of that spinning disc ! 
> Been putting off my JP-6 calibration and tuning.. and it sure needs it after all these years. 
> 
> Didn't mean to hijack the thread.
> 
> Tony K