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AUDIO FORUMS >> General Discussion and Support >> Need help-post here, more people looking...
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Message started by Dan on 04/24/09 at 06:20:30

Title: Need help-post here, more people looking...
Post by Dan on 04/24/09 at 06:20:30

Hello-
I'm a happy owner of a SE84C+ amp, and bought a ZSP1 kit a few weeks back. It was all together and working fine- but I have to mess with it. Play back through the preamp, the left channel is fine, but the right is very low. I also can't get the potentiometer to work- no affect to the sound when turning the pot. Steve Deckert said that if the sound volume won't change, its a bad potentiometer ground. I re soldered the pot and all connections- same result. I even drilled a hole, used a 8-32 screw with washers that dig into the metal, checked all connections, checked the pot with the multimeter. I plan to check all the solder connections on the right side tomorrow. The weekend is coming up and my wife has other plans for me other than playing with my preamp kit. I can prove my time is well spent if I fix this preamp soon...

Thanks,

Dan

Title: Re: Need help-post here, more people looking...
Post by Lon on 04/24/09 at 11:39:45

Wish I could help, but you have far more experience than I.

Have you called Steve about this?

Title: Re: Need help-post here, more people look here...
Post by Dan on 04/25/09 at 04:07:54

Can't seem to catch him...

However, tonight while playing a CD through the preamp and amp, I was reinstalling the knob back onto the preamp, and my wife came into the shop and started talking to me. As I screwed the setscrew into the potentiometer shaft, the sound changed- the same as a dirty potentiometer does. I'm wondering if during the three or more times I've had the pot off the aluminum plate if it got dirty inside. I'll buy some spray cleaner tomorrow at Radio Shack and see. Steve did tell me in an earlier email that if turning the pot has no effect on the sound, its a bad ground. I'll check Mouser and Digikey to for a ganged pot.

Title: Re: Need help-post here, more people looking...
Post by Dan on 04/26/09 at 04:18:52

Today I went to the local electronics surplus store (that was an adventure), and found an ALPS 100 k ohms, dual-ganged potentiometer still in the package for 99 cents. Installed it- it worked. Both channels now work, I can raise/lower the volume through the preamp.

I am now noticing some crackling in the right side only. Is that the tubes? I did some soldering with the tubes still in their sockets...

Thanks,

Dan

Title: Re: Need help-post here, more people looking...
Post by Dan on 04/27/09 at 01:49:20

Okay, thanks for all your answers- it was a cold solder joint on one of the resistors.

Thanks for all the help from everyone...

Title: Re: Need help-post here, more people looking...
Post by Lon on 04/27/09 at 01:50:26

Wow. Glad you found it! You did good!

Title: Re: Need help-post here, more people looking...
Post by Dan on 04/27/09 at 04:33:34

This has been a real learning experience for me- re-learned how to solder, read a schematic, earth ground vs. chassis ground, what a cold solder joint looks like, how to measure capacitors/resistors, how to test a potentiometer, soldering and soldering again, soldering RCA connectors and the nylon washers-all of it was learned or re-learned the hard way- by doing it over and sometimes more than twice...

Don't get me wrong- Steve has designed a great product- my skills needed work! Steve answered my questions via phone and email. Due to my work hours, it wasn't always convenient to reach him by phone.

Regardless, I'm listening to great sounding music again! The robustness of the kit was proven by me. Despite all the soldering and resoldering of almost every component, the only part that didn't hold up to repeated fiddling by me was the potentiometer. But I learned how to test it, and how to find another of equal value at the electronics surplus store we have here in town.

Take care!

Dan

Title: Re: Need help-post here, more people looking...
Post by Jeff on 04/27/09 at 22:40:28

this yours?
http://cgi.ebay.com/Decware-SE-84C-Amp-and-ZSP1-Pre-Amp_W0QQitemZ180350299639QQihZ008QQcategoryZ39783QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Title: Re: Need help-post here, more people looking...
Post by Dan on 05/01/09 at 14:07:22

No, those aren't mine- here's a picture of them...