Center Channel not working

[ocguy]

I have a carver CT-27 pro-logic pre-amp and AV-405 amp that I have had for years and love. I use them to run my JBL L5's and I have a set of JBL surround and center channel speaker that I have owned also since out of college. As of late I notice that my center channel when I am watching movies does not have any sound. After awhile the sound will come on, but only after the movie has been playing for awhile. I noticed if I try to turn up the center channel volume when playing a movie in 'Movie' surround mode on the pre-amp then the center channel will 'Pop' and the sound will come on.

Can anyone tell me what is happening. Is it that most movies now are encoded in Dolby digital and my pre-amp is a dolby pro logic processor so the sound signals are not correctly being processed?

Thanks,

[Resident Loser]

...the source of the problem...is it the pre-amp, the interconnects, the power amp, the speaker wiring or the speaker itself...

The only method to do this will require you to switch around these various potential trouble sources...process of elimination...

In keeping with the KISS principle and in my experience, I'd suggest look to the ICs first, perhaps "scrubbing" the contact surfaces will eliminate the problem...and by that I mean gently disconnecting and re-connecting them using a slight twisting motion.

Then the pre-amp would be my next logical guess, as it does the processing...but again, only the ol' P of E will reveal the true culprit IME.

"...Can anyone tell me what is happening. Is it that most movies now are encoded in Dolby digital and my pre-amp is a dolby pro logic processor so the sound signals are not correctly being processed?..."

I doubt it...as it would not happen in such an arbitrary manner IMO. I would think there should be a certain level of compatability with the various schemes. Although, since HT is not my ball of wax, I suppose there could be something to your theory, so I must defer to anyone with more familiarity with the medium...

jimHJJ(...now, two-channel analog music...that's the ticket...)

[N. Abstentia]

Sounds like your amp is going south. The fact that you can 'shock' it back into working by suddenly turning up the volume means the output stages are nearly shot. I'd upgrade to a DD amp.

[Resident Loser]

...while I couldn't find any info on your preamp, I did come across a picture of your amp...five in-five out, very straight-forward with a substantial looking power section...

With no real info on the CT-27, I wouldn't dare to hazard any thing more than a guess but, perhaps the trim pot for the center channel (which I assume IS on the pre)simply needs cleaning...with the system "off", "scrub" it...rotate it from stop to stop a number of times...it may be enough to clear the problem...Many unused pots develop the creeping crud which can mimic the symptoms you describe...unfortunately, they can re-appear if not cleaned completely. This means a trip to the repair shop, unless you have no qualms about some DIY...sorry I didn't think of it earlier.

It has been my experience that SS devices tend to cr@p out entirely with little or no warning...

jimHJJ(...but then again, that's just me...)