Before I blow out my ear drums...

[PsyOps]

Friday I became the caretaker of a friend's '70 RR for the summer. He recently added an aftermarket radio and says when he turns it on it 'pops' with a loud sound that is very painful to the ears but then the radio plays as normal. He has no idea what's going on. I want to be a good steward and try to fix the problem while I have custody of his ride. I have not tried the radio to experience the sound yet. Before I do that and bust out the multimeter to start checking connections, checking grounds, checking if it is 'hot' with the ignition off, sorting out the radio to speaker circuit, etc., I thought I'd maybe save some time and ask here first if anyone else has had a similar problem. What do we think? As always, any help is greatly appreciated.

 

[Geoff 2]

Sounds like an internal problem....

 

[PsyOps]

Sounds like an internal problem....

Thanks for the response. I've got a known 'good' radio, similar model from the same company. Maybe the easiest way to rule out his box as being the problem would be to swap them. If the problem persists with the good radio, we'll know it probably isn't the box itself.

 

[Mopar Hunter]

Does it have separate amplifiers?

 

[PsyOps]

Does it have separate amplifiers?

I have no idea yet. I really haven't looked into the problem. He dropped off the car and this was a warning from him. It's in the shop now and I'll get into it on Monday. I hoped this would be a "Yeah, the same thing happened to me and I fixed it by...." situation. FBBO (although the problem isn't likely a B-body specific issue) has a great collective brain trust and I am trying to minimize the time spent on the RR 'cause I've got my own junk to wrench on. The problem is complicated by the fact the car owner doesn't 'do' electronics and his brother (who installed the radio) has a remote history of wiring homes for a living. I'm scared I'm going to find contractor twist on connectors under the dash, etc. I'll post my findings Monday night and we can all go from there unless someone nails the answer in between.

 

[Mopar Hunter]

Sounds like a power surge and or grounding issue.

 

[The Rebel]

Perhaps power surge to the speaker?

Is the sound always loud no matter the volume?

Might be an issue with the knob.

If you can switch out radios to see what happens.

Good luck!

 

[RR Fan Dan]

Power surge to speakers. Check for an amplifier. More than likely the cause.

 

[R413]

Try it with engine off and engine running.

 

[Sinitro]

Sounds like the system has an aftermarket power amplifier connected... When turning on the system U are hearing the power amplifier power up 1st. The amplifier needs to have a filter added to its power line...

Just my $0.02...

 

[RJRENTON]

It sounds like the simple fix is: don't turn the radio on......just a guess......no need to check for bad grounds (?), loose wires....maybe it's just tuned to a C + W station......there is nothing worse than a C + W station.....except a LOUD C + W station.....????......just my opinion....
BOB RENTON

 

[PsyOps]

Sounds like the system has an aftermarket power amplifier connected... When turning on the system U are hearing the power amplifier power up 1st. The amplifier needs to have a filter added to its power line...

Just my $0.02...

The general consensus is it is probably an issue with an amplifier. I will check for one of those first. If there is an amp, what type of filter (i.e. rating, watts, ohms, time delay, etc.)? Is there a publication (HP Book, Cartech, S-A Design) anyone can recommend so I can learn more about car & stereo wiring for future reference? Not looking for PhD level info - something more along the lines of a basic primer like Auto Wiring For Dummies or similar. What is out there?

 

[PsyOps]

It sounds like the simple fix is: don't turn the radio on......just a guess......no need to check for bad grounds (?), loose wires....maybe it's just tuned to a C + W station......there is nothing worse than a C + W station.....except a LOUD C + W station.....????......just my opinion....
BOB RENTON

While I will solve this problem, I'm not above a little hijinks. Once resolved, I'm thinking about setting all the presets to a single 24hr/7days per week evangelical station or ????

 

[F4R/T]

Turn the gain down on the amp or disconnect or bypass the amp.

 

[Nxcoupe]

Should have a very large filter(capacitor) in the power wire going to the amp. If not, could be your pop.

 

[RJRENTON]

The general consensus is it is probably an issue with an amplifier. I will check for one of those first. If there is an amp, what type of filter (i.e. rating, watts, ohms, time delay, etc.)? Is there a publication (HP Book, Cartech, S-A Design) anyone can recommend so I can learn more about car & stereo wiring for future reference? Not looking for PhD level info - something more along the lines of a basic primer like Auto Wiring For Dummies or similar. What is out there?

Since what brand and type of system is not stated....HOW CAN ALTERNATIVE FIXES BE OFFERED???? For all we know, maybe it's the Pertronix Blaster II COIL or ACCEL SUPER COIL back feeding across the ballast resistor and ECU, either the MSD TYPE or Mopar Orange box which is causing all problems (excessively high voltage not converted to blazing horse power increase), in addition the back feed will likely cause the instrument panel gauges to react differently.....Empty is full and vice versa, etc. Since you proclaim no knowledge of auto wiring, the best thing for you to do is take you car to an expert, who does these repairs for a living and tell them what you want and remove all previous installed owners equipment?? Someone suggested adding a capacitor....what value and where to connect it.....and .....an amplifier......on the output of the system or an intermediate stage of the system,.....initial descriptions is too vague to make any determination.......sounds like an exercise in futility.......just my opinion.......
BOB RENTON

 

[Photon440]

Since it isn't your car, perhaps you'd be leery of digging too deeply into the unknown problem. You might want to pass on some suggestions to your friend to take care of on its return, such as: (SOLVED) Amplifier Pops When Turned On - BoomSpeaker

 

[Sinitro]

Since what brand and type of system is not stated....HOW CAN ALTERNATIVE FIXES BE OFFERED???? For all we know, maybe it's the Pertronix Blaster II COIL or ACCEL SUPER COIL back feeding across the ballast resistor and ECU, either the MSD TYPE or Mopar Orange box which is causing all problems (excessively high voltage not converted to blazing horse power increase), in addition the back feed will likely cause the instrument panel gauges to react differently.....Empty is full and vice versa, etc. Since you proclaim no knowledge of auto wiring, the best thing for you to do is take you car to an expert, who does these repairs for a living and tell them what you want and remove all previous installed owners equipment?? Someone suggested adding a capacitor....what value and where to connect it.....and .....an amplifier......on the output of the system or an intermediate stage of the system,.....initial descriptions is too vague to make any determination.......sounds like an exercise in futility.......just my opinion.......
BOB RENTON

Sorry Bob...
The audio system is totally separate from the ignition system..
The Turn-On thump is a common problem when installing mixed components for an aftermarket car audio system.
Note many aftermarket amplifiers have a soft-start or time delay circuit upon powering ON...
Basically this feature mutes the power amplifier outputs during its Turn ON surge..

Just my $0.02...

 

[Photon440]

Basically this feature mutes the power amplifier outputs during its Turn ON surge..

Just my $0.02...

Just like my Sansui 9090 back in 1976.

 

[RJRENTON]

Sorry Bob...
The audio system is totally separate from the ignition system..
The Turn-On thump is a common problem when installing mixed components for an aftermarket car audio system.
Note many aftermarket amplifiers have a soft-start or time delay circuit upon powering ON...
Basically this feature mutes the power amplifier outputs during its Turn ON surge..

Just my $0.02...

Sorry you cannot recognize sarcasm.....but no real information is presented....brand name of equipment, model numbers, schematic diagrams....either pictorial or physical .....without any actual information....as what's presented thus far is just conjecture.....like how high is up or similar undefined attributes......you say MANY (un named) amplifiers have a soft start feature.....undefined....strictly conjecture.....what is a typical circuit.....voltage dependent resistors as MOVs or are you just guessing????.......need specifics.....
BOB RENTON