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Hearing radio even with no tuner connected, Yamaha Ca810

Semanon said:
what happens when you change the cartridge load impedance? Use another phono input?

It means that your cable from your turn table are of a certain length and couple with an impedance that creates a tuned circuit. Because of the amplification of the phono circuit, the minimal sound of the ad hoc circuit is amplified enough for you to hear.

Make sure all the grounds are well made and the input caps are in good shape. Experiment with different placement of the TT and routing of the cable.

if everything is disconnected and you get no radio, it’s the interface created by the TT and the amp that creates a primitive radio receiver.
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I tried a longer cable and that.... Maybe... Helped. I can't hear it from the couch anymore, I think. I can't go any shorter than the cable I initially had, it was the width of the TT to the amp. Zig zagging the cable so it's not straight seems to help. Changing impedence doesn't make any difference.
 
cademan said:
It is what's called stray RF. Some equipment is prone more than others and a lot of times caused by grounding issues.
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I tried grounding the amp (from the gnd post) to the earth prong on the AC outlet. Didn't seem to make a difference, though I'm not sure if it made contact inside the outlet
 
Sometimes it is a grounding issue but not always. Unfortunately, you will just have to troubleshoot and also take into consideration any previous comments about using ferrite beads and different types of cables.
 
cademan said:
Sometimes it is a grounding issue but not always. Unfortunately, you will just have to troubleshoot and also take into consideration any previous comments about using ferrite beads and different types of cables.
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Yep my brother has some ferrites I'm going to grab tomorrow
 
A stereo system I had years ago would pick up the neighbor's ham or CB broadcasts...LOUD. It ended as suddenly as it began.
 
I unplugged everything aside from the amp aside from the speakers. No fm noise was discernable above some light static. Any cable being plugged in, regardless of length, introduced FM noise. Touching the cable or the RCA jack seemed to remove the majority of the noise.

I tried covering the amp in tin foil but it didn't make a difference. Including connecting the foil to the ground pin or not.
 
Semanon said:
When I was a kid, the wire mesh fence at the back of our yard was very close to another metal fence. Sometimes I could stand at the corner of the fences and hear a local AM station quietly but clearly. My Dad thought I was nuts until I showed him.
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My Dad loaded down a chainlink fence with and linear amplifier just to see what kind of QSL he could achieve. Guarantee you didn't want to be touching that fence while transmitting..
 
avionic said:
My Dad loaded down a chainlink fence with and linear amplifier just to see what kind of QSL he could achieve. Guarantee you didn't want to be touching that fence while transmitting..
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My Dad was not a tech guy: I’m sure he could not spell QSL (but he did have many other redeeming qualities).

BTW, the station was WXYZ, Detroit, 50,000 watts. It is the best radio call sign.
 
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Splatter Pak said:
A stereo system I had years ago would pick up the neighbor's ham or CB broadcasts...LOUD. It ended as suddenly as it began.
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When I was a teen, my neighbor was a ham extra…1x2 (IIRC). When he transmitted, my stereo sounded like the X-Wing fighters from Star Wars entering the Death Star’s magnetic field. He taught me to use an oscilloscope, helped reduce interference with my stereo, and sparked my interest in electronics. Grilled me on Morse Code for my FCC license (when that was a thing).
 
equalizeme said:
I unplugged everything aside from the amp aside from the speakers. No fm noise was discernable above some light static. Any cable being plugged in, regardless of length, introduced FM noise. Touching the cable or the RCA jack seemed to remove the majority of the noise.

I tried covering the amp in tin foil but it didn't make a difference. Including connecting the foil to the ground pin or not.
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Ferrite beads.
 
wonder if this thing is supposed to have a line to chassis cap for RFI purposes. If thats bad it may contribute to this as well. I can't check the schematic from here.
 
Reminds me of my band playing days.I was the bass player and my my Marshall 100w amp,or some part of my rig, used to pick up local taxi comms,clear as a bell,expletives included,and broadcast them to an unsuspecting crowd at full volume.A sure show-stopper.Oh how we laughed.But it was only my amp,never anyone elses.
 
So I tried shortening the speaker wires to just a foot or so. Same issue. Ferrite beads (clamp on) same issue.

Anyone have any feedback on what this guy did to try and curb FM interference https://www.diyaudio.com/community/...ickup-in-a-yamaha-ca-810.390569/#post-7130128

Edit: I also got some shielded cables. Seemed to help when plugged in to the Bluetooth receiver but no help when plugged in to the phono (heard the noise even before the tt was connected.... And it didn't improve after it was connected)
 
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gadget73 said:
wonder if this thing is supposed to have a line to chassis cap for RFI purposes. If thats bad it may contribute to this as well. I can't check the schematic from here.
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I'm going to pop the lid tomorrow. What should I look for? Ill post some pics obviously as well
 
dug up the service manual, per that it does not have a line to chassis cap on any model. Aussie models have a grounded cord though.
 
Took it upstairs and opened it up, as well as another interference test. I didn't see anything obviously wrong. Yamaha ac810 insides https://imgur.com/a/1DRiswv

That said. Nice and quiet upstairs. So that's annoying...I tried a different outlet downstairs, as well as using my old transformer and ground him removed. No effect as far as I can tell
 
I set my old avr70 up again. Not a lick of interference. I guess I should be happy but I really liked the sound of the 810 when it was actually playing music. I've got some deoxit coming tomorrow. Maybe it will improve the sound... Also considering a tripplite power conditioner as well. Even if I do stick with the avr70 I'm hoping it will lower the noise floor...
 
I saw there is a capacitor on the shielded section grounded to the chassis.... Is the capacitor normal? It's a ceramic capacitor - maybe I should put a film capacitor on it?.... OR maybe it's bad....
 
So I placed the TT directly on top of the amp..
. And.... It got really quiet. Regardless of cable length, the 2.5ft and the 6ft, both got quiet. What uh.... What gives?

I then went to hook my eq up, I put it off to the side. The noise came back. I hadn't even hooked it up to anything! When I put it back on the floor/away, noise went away.

I found that letting the input cable get anywhere near the power source (conduit running along the wall), noise is quite prevalent.

I also found out where transmitter is. It's about 1.5mi from me.

I'm going to try shielding all input cables and power cables. But I'm still really perplexed about the tt.
 
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