Project Preamp picking up Radio noise?

mantis

Hello everyone,
got a strange one, never seen this happen before but yet here It is. A Project Phono box Plus DS+ just started picking up a radio station. I don't know how this happened, I have not dug into this issue but I was curious since many of you have turntables and external Preamps, have you ever had an issue?

jdjohn

Radio Frequency Interference (RFI) - you must have a pretty strong radio tower fairly close by...and by close by, I mean within a few miles. I've experienced RFI before with certain external phonostages since there is a tower a few miles away from my house. Best I could ever tell, the interference is due to inadequate shielding in the power supply.

Did it just now start with that phonostage, or was it operating quietly before?

newbie308

I'm not familiar with the project phono box. Is it a plastic case or metal? If it is metal, you might have a poor ground connection from the case to Earth. Shielding against RFI and EMI typically requires a good Earth ground to function properly.

engie490

Check your interconnects. Make sure you are using shielded interconnects or they can act an an antenna for RFI into the system.

mantis

Thanks guys, this preamp is a customer of mine and he has had it for years. He recently called me and told me radio sounds where playing when he switches to the Phono input on his Rouge Intergraded Tube amp. It's background sounding he said and it's never been there before. He has all Audioquest Mackenzie RCA cables from the table which is a Project to the Preamp and from the preamp to the Intergraded. I recently replaced his Subwoofer amp he has a passive subwoofer in a cabinet with a vent tube, it's custom and this issue started after that install. I didn't notice it when I was there but it came about several weeks later. I also put a Spade connector on the grounding wire to the preamp as my guys installed the ground wire bare wire wrapped around the grounding post. I don't like that as it's slopping looking and the wires tend to fray so a nice spade connector there is really clean.

halo71

I had a M&K subwoofer years ago that would pick up CB radio talk from time to time. lol Never did figure out why. I eventually moved and never had the issue again.

treitz3

Dan, he might want to start experimenting with these - https://resources.pcb.cadence.com/blog/2022-selecting-ferrite-chokes-and-clamps-to-minimize-rfi-and-resistance

They are cheap and can be moved around from cable to cable along the path from the TT to the phono pre and from there to the pre-amp (if he has this type of configuration). Here is a link to 27 of them in varying sizes for $16 - https://www.amazon.com/Taigoehua-Suppressor-Diameter-40X24X16mm-Ferrite/dp/B07ZNL5CDH/ref=sxin_16_pa_sp_search_thematic_sspa?content-id=amzn1.sym.ea7393e3-de5f-4d19-84a5-8c5fb5c68d5f:amzn1.sym.ea7393e3-de5f-4d19-84a5-8c5fb5c68d5f&crid=2X8IPG56AU8O8&cv_ct_cx=ferrite+chokes&keywords=ferrite+chokes&pd_rd_i=B07ZNL5CDH&pd_rd_r=0084ea17-1bb1-40d0-a601-3ff27e7f32e7&pd_rd_w=6Q7R5&pd_rd_wg=onea1&pf_rd_p=ea7393e3-de5f-4d19-84a5-8c5fb5c68d5f&pf_rd_r=KVQPTGH51BCA4MSJYCAH&qid=1682683051&sbo=RZvfv//HxDF+O5021pAnSA==&sprefix=ferrite+chokes,aps,108&sr=1-5-2b34d040-5c83-4b7f-ba01-15975dfb8828-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExUFdDNkE4SDRLNEk0JmVuY3J5cHRlZElkPUEwMDA3ODk4MlM3UzFYS1VINVgzJmVuY3J5cHRlZEFkSWQ9QTA0NDg0NjMzR0ZEVDRTMjVORDBCJndpZGdldE5hbWU9c3Bfc2VhcmNoX3RoZW1hdGljJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

There effectiveness is usually best right before it enters a component and can be further enhanced by moving them between 1 to 4" away from the connection to where the signal enters the component.

I am not saying that this will eliminate the radio signal completely (Although it might), but it might shed some light on which cable/gear may be the culprit, using basic troubleshooting skills. There are cheaper ferrite kits out there but for a whopping cost of $16 and a little bit of his time? The issue may easily be solved.

BTW, they are removable and will not damage the cable, if installed correctly.

Tom

mantis

treitz3 wrote: »

Dan, he might want to start experimenting with these - https://resources.pcb.cadence.com/blog/2022-selecting-ferrite-chokes-and-clamps-to-minimize-rfi-and-resistance

They are cheap and can be moved around from cable to cable along the path from the TT to the phono pre and from there to the pre-amp (if he has this type of configuration). Here is a link to 27 of them in varying sizes for $16 - https://www.amazon.com/Taigoehua-Suppressor-Diameter-40X24X16mm-Ferrite/dp/B07ZNL5CDH/ref=sxin_16_pa_sp_search_thematic_sspa?content-id=amzn1.sym.ea7393e3-de5f-4d19-84a5-8c5fb5c68d5f:amzn1.sym.ea7393e3-de5f-4d19-84a5-8c5fb5c68d5f&crid=2X8IPG56AU8O8&cv_ct_cx=ferrite+chokes&keywords=ferrite+chokes&pd_rd_i=B07ZNL5CDH&pd_rd_r=0084ea17-1bb1-40d0-a601-3ff27e7f32e7&pd_rd_w=6Q7R5&pd_rd_wg=onea1&pf_rd_p=ea7393e3-de5f-4d19-84a5-8c5fb5c68d5f&pf_rd_r=KVQPTGH51BCA4MSJYCAH&qid=1682683051&sbo=RZvfv//HxDF+O5021pAnSA==&sprefix=ferrite+chokes,aps,108&sr=1-5-2b34d040-5c83-4b7f-ba01-15975dfb8828-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExUFdDNkE4SDRLNEk0JmVuY3J5cHRlZElkPUEwMDA3ODk4MlM3UzFYS1VINVgzJmVuY3J5cHRlZEFkSWQ9QTA0NDg0NjMzR0ZEVDRTMjVORDBCJndpZGdldE5hbWU9c3Bfc2VhcmNoX3RoZW1hdGljJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

There effectiveness is usually best right before it enters a component and can be further enhanced by moving them between 1 to 4" away from the connection to where the signal enters the component.

I am not saying that this will eliminate the radio signal completely (Although it might), but it might shed some light on which cable/gear may be the culprit, using basic troubleshooting skills. There are cheaper ferrite kits out there but for a whopping cost of $16 and a little bit of his time? The issue may easily be solved.

BTW, they are removable and will not damage the cable, if installed correctly.

Tom

Years ago they use to come with Plasma TV's for the power cords. That's not a bad idea to try. I might have some laying around somewhere.

Thanks Tom

jdjohn

mantis wrote: »

Phono input on his Rouge Intergraded Tube amp. It's background sounding he said and it's never been there before. He has all Audioquest Mackenzie RCA cables from the table which is a Project to the Preamp and from the preamp to the Intergraded.

Surely he's not running his external phono preamp into the phono input on the 'Rogue Integrated'...is he? One of the Aux inputs would be the proper connection.

I've used ferrite chokes for helping reduce RFI, but that's about all it did...reduce it. The chokes should be put on the phono cables from the turntable, AND on the phono preamp power supply cable. I recommend creating a small coil/loop with the cables, and then clamping around that. It increases the effectiveness.

Also, if he's using a MC cartridge, bump-up the capacitance setting to the max on the Pro-Ject Phono Box DS+. This is NOT, however, recommended for a MM/MI cart.

SeleniumFalcon

Sometimes just moving a sensitive component's position can solve this kind of problem. Similar to de-tuning a radio's antenna, in this case adjusting the connecting cables and the component itself and then seeing which position reduces the RF. If possible, shift everything 90 degrees and see if that helps. He may need quad-shielded interconnects. Sometimes small ferrite beads can be installed on the leads of individual components to get rid of RF. Also, small sized sheets (6" x 6") of Mumetal can be placed on top of a component and then connected to a ground point.
I used to live next door to a ham radio operator and on Okinawa there were no limiting rules for amateur radio's transmitting power. He would peg the VU meters of my Teac open reel, I mean bury them in the red. I politely asked him if there was anything he could do (he way out ranked me). He scoffed at me and said I should buy better equipment. I had a crazy friend who was in the Navy and at night he sneaked into this guy's yard and using a safety pin punctured his transmitting cable so the outgoing signal ended up grounded to the shield. Then he snipped off any excess of the pin so nothing was visible. When the guy warmed up his mega-watt transmitter and hit the transmit key he blew out his 5,000 watt amplifier.

treitz3

LOL....apparently your crazy friend had an issue with RFI as well. Too funny.

Not to the outranking officer of course but....

Tom

billbillw

Check the phono box for bad caps or bad ground connections. If this is something that was not there before and now it is, then I would bet some component inside is marginal or completely bad. If the phono box uses a wall wart, that could have gone bad too.

I saw that it has a bunch of relays inside. Its possible any one of those might be making a bad connection that is causing RF to be amplified.

mantis

jdjohn wrote: »

mantis wrote: »

Phono input on his Rouge Intergraded Tube amp. It's background sounding he said and it's never been there before. He has all Audioquest Mackenzie RCA cables from the table which is a Project to the Preamp and from the preamp to the Intergraded.

Surely he's not running his external phono preamp into the phono input on the 'Rogue Integrated'...is he? One of the Aux inputs would be the proper connection.

I've used ferrite chokes for helping reduce RFI, but that's about all it did...reduce it. The chokes should be put on the phono cables from the turntable, AND on the phono preamp power supply cable. I recommend creating a small coil/loop with the cables, and then clamping around that. It increases the effectiveness.

Also, if he's using a MC cartridge, bump-up the capacitance setting to the max on the Pro-Ject Phono Box DS+. This is NOT, however, recommended for a MM/MI cart.

The Rouge doesn't have a Phono input, yes he is using AUX that why he has an external preamp.

mantis

SeleniumFalcon wrote: »

Sometimes just moving a sensitive component's position can solve this kind of problem. Similar to de-tuning a radio's antenna, in this case adjusting the connecting cables and the component itself and then seeing which position reduces the RF. If possible, shift everything 90 degrees and see if that helps. He may need quad-shielded interconnects. Sometimes small ferrite beads can be installed on the leads of individual components to get rid of RF. Also, small sized sheets (6" x 6") of Mumetal can be placed on top of a component and then connected to a ground point.
I used to live next door to a ham radio operator and on Okinawa there were no limiting rules for amateur radio's transmitting power. He would peg the VU meters of my Teac open reel, I mean bury them in the red. I politely asked him if there was anything he could do (he way out ranked me). He scoffed at me and said I should buy better equipment. I had a crazy friend who was in the Navy and at night he sneaked into this guy's yard and using a safety pin punctured his transmitting cable so the outgoing signal ended up grounded to the shield. Then he snipped off any excess of the pin so nothing was visible. When the guy warmed up his mega-watt transmitter and hit the transmit key he blew out his 5,000 watt amplifier.

I thought about that as it did get moved when I installed the Sub amp. It actually sits on top. His cabinet has limited space.

heiney9

After I installed my L600's there was a one sided ham radio conversation coming over my speakers. Completely random and nothing was powered on. At first it scared the crap out of me because I wasn't expecting my speakers to start talking. This went on for about 1/2 hour, then he signed off and I've never heard it again.

Something similar may have happened years ago, can't remember if it was at this house or before this house.

Weird stuff

jbreezy5

Continuation of @SeleniumFalcon comment:

https://youtu.be/DC0s6KqQz3g

Although this video could’ve been 5 minutes or less, thought it gives a nice visual of what he described.

treitz3

heiney9 wrote: »

After I installed my L600's there was a one sided ham radio conversation coming over my speakers. Completely random and nothing was powered on. At first it scared the crap out of me because I wasn't expecting my speakers to start talking. This went on for about 1/2 hour, then he signed off and I've never heard it again.

Something similar may have happened years ago, can't remember if it was at this house or before this house.

Are these voices in the room with us right now?

Tom

mantis

treitz3 wrote: »

LOL....apparently your crazy friend had an issue with RFI as well. Too funny.

Not to the outranking officer of course but....

Tom

He lives in a high rise in Phila Pa and maybe the radio stations upped their output or changed frequencies and now his gear is picking it up. I'm gonna find time to get over there and figure it out.

mantis

heiney9 wrote: »

After I installed my L600's there was a one sided ham radio conversation coming over my speakers. Completely random and nothing was powered on. At first it scared the crap out of me because I wasn't expecting my speakers to start talking. This went on for about 1/2 hour, then he signed off and I've never heard it again.

Something similar may have happened years ago, can't remember if it was at this house or before this house.

Weird stuff

Ghosts