Audio Systems: adcom amp/pre amp issue, adcom gtp, poor quality control

Question
QUESTION: i have an adcom gtp 500 amp and a gfa 545 preamp w polk tower speakers.
one speaker works fine, the other only works when the audio is cranked up. almost like it needs more power to kick in.
I checkec the speaker cables and still the same problem.
Someone suggested it may be the capacitor? but I have no idea.
any help would be much appreciated.

thanks

ANSWER: That is a typical intermittent condition when there is a poor cable connection. You should use the working amplifier channel, then cable to test the other speaker. That should tell you where the problem is. I never suspect an internal component until I rule out all external possibilities. Remember that there is the preamp to amp connection in the equation. Start by testing all devices with the known functioning channel. Let me know what you find?


---------- FOLLOW-UP ----------

QUESTION: I did some troubleshooting on my amp and preamp issues.

I replaced the fuses, that was not the issue.

I swapped cables, that was not the issue.

I switched the R and L on the amp and the sound moves from one speaker to the other.



Now, when I have everything powered up and a disc playing, if I remove the “hot” cable from the line out R on the preamp and touch it to the L on the preamp a few times, it gives the line out some sort of a boost that then turns it on so both channels then work.

Strange. It also turns both L and R on when I drive the amp at mid to high volumes. I hear some crackling first and then the sound kicks in on the dead speaker.



Any help is appreciated. Seems like it is isolated to the preamp though, not sure



thanks

jeff

Answer
I hate to say it but from my many years of experience Adcom seems to have a higher failure rate from poor quality control. I would bet that it's an internal problem with a component, cold solder or internal connector. Being out of warranty, benching it could be pricey. You may do better finding an inexpensive preamp such as a Gemini PA 7000. It's made about as well as the Adcom in China but not overpriced. When you spend as much money as Adcom charges for their stuff you should at least have a well tested piece of equipment. To me there is no excuse for a faulty preamp other then changing their business to selling pet rocks.

.....or you might send them this comment about their product from a seasoned expert. Maybe they'll fix it for you No Charge.

Just be sure that if you decide to go the Adcom support route you test each channel to see if the problem remains on the same channel, coming from the pre-amp.