Somthing is WRONG with my amp (PLEASE HELP ME)

[Neatweak]

Hey guys I have an Adcom GFA 5400, and I use it to power 8 speakers through a speaker selector. All of a sudden the left channel starts putting out nothing but distorted signals. The distorition light is on, the speakers have no volume and sound like there blown, and I am mad. I checked and made sure that it wasnt the speakers, and I checked the pre amp to. What could be wrong with my amp and waht should I do in terms of getting it fixed or buying another amp?

 

[T2T]

It could be simple - something such as a capacitor going bad. I had a problem where my Hafler was putting out scratchy sound to one channel. I took enough of the components away to check the capacitors, and sure enough, one of them was loose - which prevented a good ground from being achieved. As soon as I tightened the cap down, the channel was producing sweet music once again.

Your situation could be different. Have you done some basic troubleshooting by removing the speaker selector from your chain of components? Then, try using just a single pair of speakers ... ensuring that there are not any wires fragments touching the other terminals, etc. If you've done all that, I'd seek out a list of Adcom authorized repair centers - or, send the amp directly to Adcom for repair. The number of components in an Adcom amp are quite a bit less than a more complicated Parasound HCA-2003, where layers and layers of components are built into the amp. Once the cover is removed from an Adcom, a tech can pretty easily work their way around the amp to resolve the issue.

Then again, maybe if you look at $50 in shipping to get it to Adcom and $250 in repairs, you're near the ballpark in price on buying a replacement Adcom.

 

[njedpx3]

It could be simple - something such as a capacitor going bad. I had a problem where my Hafler was putting out scratchy sound to one channel. I took enough of the components away to check the capacitors, and sure enough, one of them was loose - which prevented a good ground from being achieved. As soon as I tightened the cap down, the channel was producing sweet music once again.

Your situation could be different. Have you done some basic troubleshooting by removing the speaker selector from your chain of components? Then, try using just a single pair of speakers ... ensuring that there are not any wires fragments touching the other terminals, etc. If you've done all that, I'd seek out a list of Adcom authorized repair centers - or, send the amp directly to Adcom for repair. The number of components in an Adcom amp are quite a bit less than a more complicated Parasound HCA-2003, where layers and layers of components are built into the amp. Once the cover is removed from an Adcom, a tech can pretty easily work their way around the amp to resolve the issue.

Then again, maybe if you look at $50 in shipping to get it to Adcom and $250 in repairs, you're near the ballpark in price on buying a replacement Adcom.

OP, T2T gives you some great trouble shooting advice. Could easliy be a capacitor, but more likely a whisker short on one of the speaker terminals as he also suggests.

Peace and Good luck,

Forest Man

 

[Seth=L]

Before you jump the gun on blaming the amp, even though it probably is the amp, you could attempt to connect one pair of speakers directly to the amp bypassing the speaker selector. Sometimes speaker selectors fail as well. However, it's most likely the amp if the protect light is on.

Edit: I should read all responses, this has been covered already.

 

[Neatweak]

I switched the left channel, to a receiver and the speakers played fine. Ill try tightening the capacitor, and I will get back to you.

P.S. I bought this amp from seth lol.

 

[Seth=L]

P.S. I bought this amp from seth lol.

I am waiting for a response to a private message I have sent you.

 

[TLS Guy]

Hey guys I have an Adcom GFA 5400, and I use it to power 8 speakers through a speaker selector. All of a sudden the left channel starts putting out nothing but distorted signals. The distorition light is on, the speakers have no volume and sound like there blown, and I am mad. I checked and made sure that it wasnt the speakers, and I checked the pre amp to. What could be wrong with my amp and waht should I do in terms of getting it fixed or buying another amp?

It sounds like you have lost your push or pull. In other words you are only getting half the wave form.

I suspect an output stage problem. I doubt it is the power transistors, as when they fail a fuse usually blows. It sounds to me you most likely have a failure in the driver stage. I don't know the circuit of that amp, but in quite a few amps now the driver stage is an IC chip.

In conventional fashion there are driver transistors with diodes to make the push pull output configuration. So my guess is that it is either a driver transistor or diode, in the output stage. For some time it has been common practice to have all this circuitry in an IC chip.

The procedure is to feed a sine wave from an oscillator and see with a scope if either the positive or negative deflections are missing. If that is the case and the output devices are OK then you turn your attention to the driver splitter stage. If it is an IC stage that has to be replaced, if it is available. Unfortunately these chips on older gear have a frequent habit of being NLA.

 

[Neatweak]

I am positve that the amp is blown because of over use. As the story unfolds it was found out that the amp was turned to an extremely high level, which im guessing blew the left channel. In no was was it the fault of the person that sold it to me, it was my own misuse of the equipment. thanks for all of the responses.

 

[TLS Guy]

I am positve that the amp is blown because of over use. As the story unfolds it was found out that the amp was turned to an extremely high level, which im guessing blew the left channel. In no was was it the fault of the person that sold it to me, it was my own misuse of the equipment. thanks for all of the responses.

That amp is worth fixing. Fixing a power amp is not the end of the world, as they are simpler than most of the rest of the electronics.

Here is a list of authorized service centers.