Hohner Jack intonation shifts

[HarveyJ]

I have an interesting poblem with my Hohner Jack Custom. Originally I put it down to the venue I was playing - as I didn't really play anywhere else and could not think what it would be. Anyway, recently I have changed venues and have been getting the same problems again - I will play a sustained note, and the pitch can change as much as a quarter to a semitone. If I hold the note it can go up and down as I hold it.

Thought that it could be the strings, so I have soaked them in meths, dried them out and put them back on. I have now tried it with different strings, and it periodically happens - on different notes. The interesting thing is, that it only happens when amplified, and only when using the pick up closest to the fretboard! If I turn the pickup on and off, the pitch definately changes.

Can anyone shed any light on this - why it happens, and what options I have for removing it.

Thanks

Harvey

[daveman50]

Lower the pickup - you are probably experiencing "warbling".

[HarveyJ]

Thanks Dave, will give it a try.

[HarveyJ]

On the Jack there doesn't seem to be any way of changing the pickup height, only of adjusting the string height via the bridge, and I don't really want to do that. Any suggestions?

[markanini]

That sounds odd. Aren't the pickups mounted like in J-bass? Should be a way to lower them in case of excessive resistance by either removing some felt or rubber foam material underneath and/or carefully drilling the height screw holes a little deeper. Springs can be cut or replaced as well.