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Backstage: Paul's Workshop => Audio-related Tech Advice, Support & Discussion => Topic started by: Buffalo Budd on March 09, 2017, 09:00:37 PM

Title: Rotel Amplifier Help Needed
Post by: Buffalo Budd on March 09, 2017, 09:00:37 PM
Ok, I've googled the shit out of this problem and come up with nothing.
I have a Rotel RSX-965 and it sounds good but for some reason I have a slight hum/high pitch ring in the background.
I can work around it with the presets but that isn't optimal with every record as I find the mix isn't right.
I have checked the outlet, the speaker wire, and pretty much every setting on the set up but it is still there.
Is the amp shit, is the speaker wire too low grade or am I missing something?
Title: Re: Rotel Amplifier Help Needed
Post by: ph92 on March 09, 2017, 09:54:20 PM
Ok, I've googled the shit out of this problem and come up with nothing.
I have a Rotel RSX-965 and it sounds good but for some reason I have a slight hum/high pitch ring in the background.
I can work around it with the presets but that isn't optimal with every record as I find the mix isn't right.
I have checked the outlet, the speaker wire, and pretty much every setting on the set up but it is still there.
Is the amp shit, is the speaker wire too low grade or am I missing something?
Could be interference of some kind. Is it near any appliances or any kind? (Including like routers etc, it's far fetched, but possible)
Title: Re: Rotel Amplifier Help Needed
Post by: Hicks on March 09, 2017, 10:03:47 PM
Could be a ground loop from your subwoofer if you have one. 

Your turntable is another culprit if it isn't properly grounded. 

Unplug all your components one at a time to see if you can isolate it. 

Title: Re: Rotel Amplifier Help Needed
Post by: Caravan2001 on March 10, 2017, 02:19:29 AM
Could be a ground loop from your subwoofer if you have one. 

Your turntable is another culprit if it isn't properly grounded. 

Unplug all your components one at a time to see if you can isolate it.

Yeah, i was going to ask if it was all your components or just your TT.  But it sounds like a grounding issue.  Weird that you can get rid of it with an EQ preset though.  Is it a problem that just popped up or has it always been there?
Title: Re: Rotel Amplifier Help Needed
Post by: tet on March 10, 2017, 03:21:17 PM
it could be interference - try moving the wires, checking the connections too.  if you have spare wires, try that too.  that's the cheapest/easiest solution, unless of course your cables cost $20k per foot...  in which case, have you tried replacing the crystals?
Title: Re: Rotel Amplifier Help Needed
Post by: Buffalo Budd on March 10, 2017, 03:24:05 PM
No appliances nearby.
This turntable (Edwards TT) is already grounded internally and the amp is solely used for it. Nothing else plugged into it and when I check the other inputs with nothing plugged in, the same sound is emitted.
It's gotta be an issue with the receiver although the tuner does not make the sound so I am baffled.
I have not tried different speaker wire yet but it may come down to that.
Title: Re: Rotel Amplifier Help Needed
Post by: tet on March 10, 2017, 03:25:37 PM
No appliances nearby.
This turntable (Edwards TT) is already grounded internally and the amp is solely used for it. Nothing else plugged into it and when I check the other inputs with nothing plugged in, the same sound is emitted.
It's gotta be an issue with the receiver although the tuner does not make the sound so I am baffled.

what if you plug headphones into the amp - do you still hear it?
Title: Re: Rotel Amplifier Help Needed
Post by: Buffalo Budd on March 10, 2017, 03:37:31 PM
No appliances nearby.
This turntable (Edwards TT) is already grounded internally and the amp is solely used for it. Nothing else plugged into it and when I check the other inputs with nothing plugged in, the same sound is emitted.
It's gotta be an issue with the receiver although the tuner does not make the sound so I am baffled.

what if you plug headphones into the amp - do you still hear it?

Thanks for that idea as it's still happening with headphones so that rules out speaker wire.
Title: Re: Rotel Amplifier Help Needed
Post by: Caravan2001 on March 10, 2017, 04:47:44 PM
No appliances nearby.
This turntable (Edwards TT) is already grounded internally and the amp is solely used for it. Nothing else plugged into it and when I check the other inputs with nothing plugged in, the same sound is emitted.
It's gotta be an issue with the receiver although the tuner does not make the sound so I am baffled.
I have not tried different speaker wire yet but it may come down to that.

Might be the internal grounding or the wiring of the cartridge.  Check all connections.  Also the RCA cables between the TT and hotel
Title: Re: Rotel Amplifier Help Needed
Post by: ph92 on March 11, 2017, 02:39:04 PM
When you say you've checked the outlet, do you mean you've tired others? I've seen some strange issues when not using a good quality Surge Protector. I don't know where you live in the country, but not all power grids are created equally. If you have a sub par protector, or you're just plugged straight into the wall you can have issues with tiny surges knocking out or weakening passive components inside your devices causing you to have grounding issues or interference etc. (seemingly when everything looks okay inside).

Living in Florida with all the thunderstorms, almost every time after a storm I see a handful of customers with strange power/battery issues in their devices. Not ones that completely destroy the device. But issues that seems to be caused from power management IC chips going bad, weakened resistors/capacitors etc.

Again, this is like worst case scenario. But it's got me thinking that you checked all your I/O and still have the same issues.

Because of all the customers I see with these issues,  I've been eyeing some Pure Sine Wave UPS options for my computer/sound setup. I cant have this stuff getting knocked out by a storm!
Title: Re: Rotel Amplifier Help Needed
Post by: Caravan2001 on March 11, 2017, 04:09:41 PM
When you say you've checked the outlet, do you mean you've tired others? I've seen some strange issues when not using a good quality Surge Protector. I don't know where you live in the country, but not all power grids are created equally. If you have a sub par protector, or you're just plugged straight into the wall you can have issues with tiny surges knocking out or weakening passive components inside your devices causing you to have grounding issues or interference etc. (seemingly when everything looks okay inside).

Living in Florida with all the thunderstorms, almost every time after a storm I see a handful of customers with strange power/battery issues in their devices. Not ones that completely destroy the device. But issues that seems to be caused from power management IC chips going bad, weakened resistors/capacitors etc.

Again, this is like worst case scenario. But it's got me thinking that you checked all your I/O and still have the same issues.

Because of all the customers I see with these issues,  I've been eyeing some Pure Sine Wave UPS options for my computer/sound setup. I cant have this stuff getting knocked out by a storm!

Well, he lives in Canada, so that's obviously the problem.  Better move to 'Merikkka dude  :-P
Title: Re: Rotel Amplifier Help Needed
Post by: Hicks on March 11, 2017, 04:19:19 PM
Yeah from what you are saying it sounds like the amp's power supply is the issue. 

If you know a good stereo repair guy it might be salvageable, otherwise you'll probably need a new amp. 
Title: Re: Rotel Amplifier Help Needed
Post by: Hicks on March 11, 2017, 04:20:13 PM
No appliances nearby.
This turntable (Edwards TT) is already grounded internally and the amp is solely used for it. Nothing else plugged into it and when I check the other inputs with nothing plugged in, the same sound is emitted.
It's gotta be an issue with the receiver although the tuner does not make the sound so I am baffled.
I have not tried different speaker wire yet but it may come down to that.

Might be the internal grounding or the wiring of the cartridge.  Check all connections.  Also the RCA cables between the TT and hotel

I don't recommend taking your TT to a hotel, good way to get bed bugs in your setup. 
Title: Re: Rotel Amplifier Help Needed
Post by: Buffalo Budd on March 11, 2017, 08:44:04 PM
Yeah from what you are saying it sounds like the amp's power supply is the issue. 

If you know a good stereo repair guy it might be salvageable, otherwise you'll probably need a new amp.

I'm leaning towards this. Testing out an old Technics receiver I had kicking around to see how it compares.
Title: Re: Rotel Amplifier Help Needed
Post by: Buffalo Budd on March 11, 2017, 11:00:20 PM
Since I know everyone's on pins and needles, I tried out the Technics and no high pitch hum/hiss.
Just a shittier sound quality.  :|