Squeal over radio. Need audiophile help (Page 2/3)
RCR JUL 06, 11:07 AM
And a possible solution.

I bought a head unit tester on Amazon for $20 (ok, it was the cheapest head unit they sold).

I just connected the 4 wires (batt, ign, amp, gnd) and the RCAs.

Worked great. No noise when in accy, run, or with vehicle running.

I'm thinking it's the head unit. What else could it be??

I just took it apart, but didn't see any damage under magnification. I'll put it back together and give it one more chance.

Fingers crossed...

Bob

edit.. no workie... and 10 days past the return window...ugh...

[This message has been edited by RCR (edited 07-06-2025).]

RCR JUL 27, 09:02 AM
Boss replaced the head unit. That was awesome.

Still squeals. Not so much...

22 dollar chinese unit works great, Boss units squeal. WTF??

I'm probably going to tear whole thing out and build it on the bench and prove where the issue is. Not sure what else to do, short of put the chinese unit in.

Bob
Spadesluck JUL 31, 01:56 PM
What kind of quality RCA cables are you using? Are they shielded? Are they running next to your power feed? You are definitely experiencing electric interference, sometimes it is not easy to track down as you are finding out.
Spadesluck JUL 31, 01:58 PM
Bob,

I never really paid attention, but you live pretty close to my mom, she is in Macomb. I am up there a few times a year.
RCR AUG 04, 08:49 PM

quote
Originally posted by Spadesluck:

Bob,

I never really paid attention, but you live pretty close to my mom, she is in Macomb. I am up there a few times a year.



Small world.

Bob
RCR AUG 04, 08:56 PM

quote
Originally posted by Spadesluck:

What kind of quality RCA cables are you using? Are they shielded? Are they running next to your power feed? You are definitely experiencing electric interference, sometimes it is not easy to track down as you are finding out.



Something is wrong, that's for sure. I think the RCAs are Amazon brand, highly rated. They are shielded. The power feed to the amp is direct, battery right next to it. The head unit gets it's power through the stock radio feed. The RCAs and speaker lines come though a hole I made in the firewall.

A new head unit (#3 for different issue) will be here later in the week. It will be bench tested prior to going back in.

Bob
Spadesluck AUG 05, 11:27 AM
I remember chasing down some noise in my system a long time ago. If I remember correctly, it came down to doing a better ground. The problem is the noise can come from multiple places so it can be a challenge to find.
RCR AUG 05, 12:18 PM

quote
Originally posted by Spadesluck:

I remember chasing down some noise in my system a long time ago. If I remember correctly, it came down to doing a better ground. The problem is the noise can come from multiple places so it can be a challenge to find.



Once I test the new head unit on the bench, I think I will run the radio ignition wire direct to the battery, then pull fuses attached to the "ignition run" ckt to see what happens. Maybe try to narrow down on which circuit has the ground issue.

Right now it's a guessing game, so I need to narrow the options.

Bob
Mike in Sydney AUG 06, 08:55 AM
Recently, my radio began to squeal while the engine was running. (It’s a GM Monsoon radio from a 1994 Pontiac Grand Prix. No external amp and no premium sound base reflex speaker.). The squeal would get louder as the RPMs increased and would quieten when the RPMs dropped. While chasing the problem, I noticed the wire connecting the metal shield in the trunk lid over the engine was broken. When I repaired the wire, the squealing went away. I’m not saying this is your problem but it may be worth a look.
RCR AUG 07, 05:09 PM

quote
Originally posted by Mike in Sydney:

Recently, my radio began to squeal while the engine was running. (It’s a GM Monsoon radio from a 1994 Pontiac Grand Prix. No external amp and no premium sound base reflex speaker.). The squeal would get louder as the RPMs increased and would quieten when the RPMs dropped. While chasing the problem, I noticed the wire connecting the metal shield in the trunk lid over the engine was broken. When I repaired the wire, the squealing went away. I’m not saying this is your problem but it may be worth a look.



Hmm?? Thanx for the feedback. Curious, because I do not have a shield. Hope that's not it, because in my application, there is no place for one.

Bob