BBE Simpledrive2 help please

[norty303]

I've emailed Vladimir and PMed him here but wondered if anyone else might have the knowledge.

I've got about 10 of these 2ch drivers between 2 projectors that I built in 2015 and having them back for servicing and a new scanset am finding that even with no modulation connected and bias pot turned all the way down, I'm getting very dim output from some of them.

I notice that there are other pots around the centre of the board that are unlabelled and wondered if these might allow adjustment of the issue I'm seeing. I vaguely recall reading something about offset adjustment, but could just be imagining it.

Can anyone help?

Thanks

[logsquared]

I looked all over. I'm not sure I ever had instructions on the simpledrive. Sounds like a possible ground issue.

[norty303]

Me neither, I checked all the emails I sent to you too Chris.
In terms of ground, where could the ground issue be coming from? As I said, this is simply with the drivers powered but with the mod leads unplugged, so they should be 'doing nothing'.

[logsquared]

Hmmm. Physically unplugged rules out ground issue. Have you tried grounding the MOD input just to see what happens? Hopefully the small pot sets the suppression threshold. If you don't hear from BBE soon I can bench one of the left over drivers I have here..... Try to figure out the mystery pot.

[catalanjo]

What PSU voltage are you inputting to these drivers ?

Cheers

[norty303]

12volts.
15 chars

[norty303]

Hi all

I've had a reply from Vladimir/BBE so I thought I'd post it here in case anyone else finds it useful in the future.

Yes, that little pot controls the quiescent current. If you see a small leakage current, turn counterclockwise this small pot to full current suppression at output. After this procedure, you will need to re-adjust the gain and bias settings.

[dkumpula]

Sorry I missed this earlier. I've had two of my last 16 simpledrives requiring a small adjustment to the third pot to address the same issue. Other than this minor tweak, these drivers have been problem free for me.

[absolom7691]

lol, I just now saw this post. I can't find my docs for the dual driver but the single one is pretty clear. Looks like this has been answered but here is a snap of the single driver info.