Preamp intermittent channel

If your Adcom GTP-450 preamp is only working through an external processor, there could be several potential reasons for this issue. Here are some troubleshooting steps you can take to try to identify and resolve the issue:

1. Check Input Selection: Ensure that you have selected the correct input source on the preamp. Sometimes, if the incorrect input is selected, it may seem like the preamp is not working.
2. Inspect Cables and Connections:
   • Make sure that all cables (audio, video, power) are securely connected to both the preamp and the external processor.
   • Check for any loose or damaged cables. If you find any, replace them.
3. Verify the External Processor's Settings:
   • If you are using an external processor, ensure that it is set up correctly and functioning properly. Check its input and output settings.
4. Check for Mute or Volume Levels:
   • Verify that the preamp's volume is not set to zero or muted. Also, check the volume settings on the external processor.
5. Test Different Inputs and Outputs:
   • Try using different input and output connections on both the preamp and the external processor to see if there is any change in behavior.
6. Reset to Factory Defaults:
   • Consult the user manual to see if there is a way to perform a factory reset on the preamp. This can sometimes resolve software or configuration-related issues.
7. Firmware or Software Update:
   • Check if there are any available firmware or software updates for the Adcom GTP-450 preamp. Updating the firmware/software can sometimes address compatibility or performance issues.
8. Consult the User Manual or Manufacturer's Support:
   • Review the user manual for troubleshooting tips specific to your model. If the issue persists, consider reaching out to Adcom's customer support for further assistance.
9. Consider Professional Repair:
   • If none of the above steps resolve the issue, it may be a hardware problem. In this case, consider seeking help from a qualified audio technician or contacting Adcom for repair options.

Please be cautious when performing any troubleshooting steps, especially if they involve opening or modifying electronic equipment. If you're unsure about any step, it's best to seek professional advice to avoid potential damage.

check ebcelectronics.com they have flt rate service for that model.

Generally speaking, an amp protects itself from heat, shorts and overloads by refusing to turn on or stay on.

Overloads can be from excessive periods of high output or marginally low impedance loading by the speakers; and shorts would be wiring issues or a speaker blowing up.

You should be able to feel if it's hot. WHY is it overheating? Make sure it has sufficient ventilation on all sides and that vent holes are not blocked by dust balls. Ensure the fan (if equipped) is running as designed (some only operate on demand). Clean dust and debris from it.

If the amp comes back on after cooling, you're lucky. They only have so many self-protection cycles in their lives so continuously resetting or cycling their power without addressing the cause can do more harm than good.

If it protects immediately on a cool power up you should disconnect the speaker connections and try it 'naked'. If it comes up then diagnose which lead(s) are shorted. If it does not come up the problem is internal and should be left to an experienced and competent hands-on tech.

Check for loose speaker connections as a root cause for intermittent shutdown.

This is not likely a power supply problem, but is isolated before the pre-amp stage. This can be a defective IC in the preamp stage as well.

Adcom schematics are not generally available, but you may be able to isolate the problem with a little experimentation. Try to run a signal through to see if you can get the signal as well.

Please update this with your results.

Thanks,
Dan

Contact Adcom direct

Theyre very helpful

The filter capacitors are probably going bad is the likely cause.

It may also be bypass capacitor in the preamp section.

Noting whether the hum volume varies with the setting of the volume control would aid troubleshooters.

One might be able to isolate the bad component with freeze mist/circuit cooler.

Try just the power amp on ..nothing connected
no Dakiom thingy either. It's a matter of elimination. Start at the output device and work back. Keep the Dakiom out of the loop.
If there's hum with just the Adcom..then it's the ADCOM

By all-in-one amplifier that handles the surround I think you mean all-in-one receiver or preamp. Amps are just big dumb muscular power supplies for speakers.

The source control and digital decoding could be handled by a modern AV receiver with multichannel analog outputs for driving separate amps or you could get a digital AV preamplifier/control unit functionally like this Adcom. Prepare for sticker shock.

http://hdtvdreams.com/Adcom-GTP-870HD-7.1-Multi-Channel-Processor/Preamplifier-GTP870HD.aspx

Understand that EACH PAIR of Bose 901's will require its own DEDICATED two channels of amplification AND someplace to jack in its Active Equalizer - between the line level source and the power amp.

Conventional speakers can probably run off the receiver's amplifiers since they don't/can't/must not have the Bose Active EQ in line with them.

Having a single pair of 901's plus a passive subwoofer or two in the same room for accurate 6- or 7.1 surround would require at least four stereo amps or some combination that adds up to 8 channels.

In my own system I have a Pioneer VSX-36TX Receiver (with 5 potential channels of amplification for Left, Right, Center, two Surrounds) doing light duty as the control and routing center but ONLY driving the Center (two Kenwood 777's) and Surround speakers (Bose 301's). I have a Carver 5-channel amp pushing the Bose 901 Front speakers (100Wx2), two dbx Subwoofers (110Wx1) and the Bose 301 Rear Surround speakers (60Wx1).

You could probably get by with a powerful 2-, 3- or 4-channel amplifier to push the 901's and subwoofer(s) as I did. It's the cheapest way out if you get a decent AV receiver. Once you set up the levels and delays the receiver does all the thinking and controlling for you.

Hi...
Have you tried swapping speakers to see if the trouble moves to the other speaker?
It could be a dirty selector switch .

It could be a broken solder contact on the input or output RCA jacks

If pushing the power button does nothing, the unit is probably in "protect mode". This means there is an internal problem and will require professional service.