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Zx450 sensitivity pot

Posted: Sun Aug 18, 2019 12:25 pm
by zztunnell
Hey guys been out of it for a bit. I did get around to building to a system around my 2 zx amps. Love, love love the sound of these!

I swapped out the input caps on the zx450 and both input and rail caps on the zx350. Been jamming for about 2months now.

Now to the issues. I need to find out where to get and the part # for the input sensitivity pot for the zx450. Its cutting out on the left rear channel. But comes back in when you lightly tap or wiggle the pot. It only affects the left rear channel. I have swept it back and forth multiple times to no avail.

The next issue is that sometimes when the truck has been sitting for a day or so and I get in and fire up the truck sometimes I get a series of thumps through my subs going through the zx350. They start out louder then get softer and go away. Gonna say maybe 5 to 10 thumps. Only happens maybe 1 out of 10 times when I fire the system up. And happens before the music starts up. Takes my retrosound head unit a few seconds to boot up.

Any and all help is greatly appreciated! Thanks.

Re: Zx450 sensitivity pot

Posted: Sun Aug 18, 2019 7:13 pm
by Jacampb2
The pots are not available. I can point you toward a pot with the same pin layout, but the ones used in the zx amps have a electrical pinout that is backwards of what is still available. You can use parts from a new pot to rebuild an old pot. I'm pretty sure Eric D had a write-up on here. It's also possible to get the readily available pot and modify the board to use it, but the gain control will be backwards of normal.

Re: Zx450 sensitivity pot

Posted: Mon Aug 19, 2019 1:15 am
by zztunnell
I found the post from Eric D. I'll try to look up the ones he used to rebuild his on Mouser. Thanks a bunch.

Re: Zx450 sensitivity pot

Posted: Mon Aug 19, 2019 4:27 am
by Jacampb2
I believe that the part number on that thread is still valid. If it isn't, lmk, and I'll get you the number I've been using. In the thread we talked about how to relube the pots after cleaning. I've been using Dow Corning dielectric great that I recommended in that thread. It works great.

You should be forewarned that rebuilding the pot will only fix static and noise. If there are jumps out dead spots while adjusting, they are likely worn areas in the tracks, and the back track, which is the one that provided the resistance and taper characteristics, is the one you cannot swap out. Rebuilding it will also not fix a channel imbalance. If you have a significant channel imbalance (and these stupid 5 pin pots have horrible tolerance between the two resistive elements even when brand new) then you can slightly tweak the tracks to bring them back. I've got a detailed post on the pg classifieds Facebook group of you end up needing the info.

Good luck,
Jason

Re: Zx450 sensitivity pot

Posted: Fri Aug 23, 2019 5:48 pm
by zztunnell
Thanks a bunch. Got them ordered. I'll post my results when I get it done