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MC2505 - newbie question

C

carolinaguy

New Member
I'm really excited to get hold of a MC2505 amp and MX114 preamp. My father in law bought them new in 1972-ish. They had been in his attic for 10 years. I've hooked them up now and there seems to be problem in left channel. Not sure how to isolate. Is it amp or preamp? No sound from left channel unless I turn up preamp volume. It remains for a while at lower volume but soon cuts out. The amp gain doesn't seem to affect it. Ideas?
 
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I have a little Creative Labs MP3 player that I use as a temporary sound source for checking things like this. I had to get a cable with a stereo 1/8" plug on one end and two RCA plugs at the other. Plug it in the power amp and if it works plug it into one of the line level inputs of the 114. When you mention cutting out, are to talking about the tuner as the source?
 
Swap the connections from the pre to the amp. (L/R to R/L) If the problem chages channels its the pre. If not its the amp.
 
The problem occurs using all sources: phono, tuner and Aux.

I switched pre and amp connections and the problem moved to the other channel. So, then, the preamp sounds like the culprit? Where do I go from here? Service shop? I'm doubt we have any qualified service shops around Columbia, SC.
 
carolinaguy said:
The problem occurs using all sources: phono, tuner and Aux.

I switched pre and amp connections and the problem moved to the other channel. So, then, the preamp sounds like the culprit? Where do I go from here? Service shop? I'm doubt we have any qualified service shops around Columbia, SC.
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Doing some quick Googling, I came across http://www.palmettoelec.com/ in Columbia, they mention they do some vintage gear, I'd at least give them a call. Depending on how that goes, I'd ship it to Audioclassics, who had a very quick turnaround time with my pre-amp, and was competitively priced even with shipping costs included.
 
Thanks Rolltide. I just called them and they are able to work on it. If it turns out to be serious, I'll check out Audioclassics. I may need to do a re-furb at some point.
 
You can also try running your CDP straight into the amp, using the the gain controls on the amp for volume. That should further eliminate a problem with the amp.
 
Terry DeWick also does repairs on vintage units. He is in Knoxville, Tn. See his ad at the bottom of this page.
 
Work all the front panel switches on the MX, especially the tape monitor switch, switches tend to corrode with time and need to be exersized on a regular basis to keep them happy and self wiped.
 
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