Hi everyone! I'm building a record player, I have connected the + and - from the cartridge to 2 RCA plugs and plugged those directly into the Preamp (Behringer PP400) and when I connect the output to anything: non amplified speakers, amplified 2.1 sound system, headphones etc. it hums hard/buzzes hard; I haven't had a chance to connect it to an amp that does have a phono input with a ground screw but not sure that would solve the problem.
A RCA ground loop isolator doesn't do the job also if I connect the RCA cables to the preamp and leave the cartridge unplugged doesn't change the story.
My questions are:
A turntable does need an internal grounding? Mine is mostly made of plastic so not sure where that would go.
Are my connections wrong?
Do I miss something?
Thanks to everyone for the help!
A RCA ground loop isolator doesn't do the job also if I connect the RCA cables to the preamp and leave the cartridge unplugged doesn't change the story.
My questions are:
A turntable does need an internal grounding? Mine is mostly made of plastic so not sure where that would go.
Are my connections wrong?
Do I miss something?
Thanks to everyone for the help!
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Ensure the metalwork of the deck and arm are connected to a separate wire that connects, alongside the phono cables, to the preamp chassis.
as I mentioned above my turntable is made of plastic and has no metal parts except for a central rod, even the tonearm has no metal, where would that wire go otherwise? Cheers
sure I forgot to mention that I removed the motor to avoid any interference to try to understand where the problem is coming from. Do you reckon I need the motor hooked up and wire going from the motor ground to the preamp ground screw?
Here some photos for you, any wiring is to be intended temporary, for test purpose as I had previously soldered the wires to the full metal connectors without any improvement and are hard to remove, like this it's easier to swap things around in case I need to, also the plugs are not the ones I intend to use on the final product.
The only thing that comes to my mind is the cartridge, could that be faulty?
If I wire the cartridge on the table away from anything and I plug it in the Preamp without any load I still hear the buzzing big time.
Not sure what is happening here 😕
You must short the input of the preamp. then you should not have humm.
Tone arm cables as short as possible. use pure copper or silver cable.Then use shielded cable from player to preamp.
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ok, thanks for the extreme useful information, by shorting the inputs you mean only the negatives, only the postives or both?
I'm sorry to bother you guys a lot but would you happen to have a link for both type of cables, tonearm and shielded RCA's?
Thank you so so much to everyone contributing!
Good idea to twist the cables inside your arm from the cartridge to the point where you hook up onto the shielded cable that goes from your T/T to your pre.
Short positive to negative on each of the two channels at the headshell end.
For the tonearm wiring using the thinnest, lightest insulated copper wire you can find.
For the connection to the preamp you need twin screened audio cable.
Any good quality, metal barrelled RCA (phono) plug will do.
For the tonearm wiring using the thinnest, lightest insulated copper wire you can find.
For the connection to the preamp you need twin screened audio cable.
Any good quality, metal barrelled RCA (phono) plug will do.
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shorthing the input is connect signal to the ground. Then there is no input of humm possible the output of the preamp should be humm free.
It is unlikely that the cartridge itself is faulty.
Look at the 'Audio Technica Cartridge Pins' diagram in the link below.
Audio Technica Headshell and Cartridge Wiring
To test your wiring, short L+ to LG and R+ to RG.
When connecting to the screened cable, make sure L+ goes to the inner conductor and LG goes to the screen (shield) conductor on one side of the cable. Similarly for the right hand channel.
Perhaps I should emphasise that shorting the cartridge wiring is only a temporary measure used to test your wiring.
If your wiring is good then there should be little or no hum when the the wires are shorted at the headshell end..
After testing, of course, the shorts are removed.
Make sure that L+ and R+ go to the centre pins of the RCA plugs and that LG and RG go to the bodies (barrels) of the plugs.
If your wiring is good then there should be little or no hum when the the wires are shorted at the headshell end..
After testing, of course, the shorts are removed.
Make sure that L+ and R+ go to the centre pins of the RCA plugs and that LG and RG go to the bodies (barrels) of the plugs.
Ok so I did a quick test, is night now so I don't have access to shops and I have to play with the wires I have at home, I connected together the white to blue pin and the red to the green pin it did the job, the humming is gone but it doesn't play any sound now, have I missed any step or I need a shielded RCA to make it work properly?
My cartridge happens to be an Audio Technica and it is wired the same way as the top one
😀
the shorted input is only a test to determen if the preamp is the course of the humm.
Now you know it is good.
The problem is in your wiring to the input.
At picture sample of wiring
Now you know it is good.
The problem is in your wiring to the input.
At picture sample of wiring
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As Koifarm says, you have eliminated the pre-amp as the source of the hum. You may now remove the shorts and concentrate on wiring the tone arm properly. Thin, twisted wires from cartridge to a tag strip near the base of the tonearm and twin screened cable from the tag strip to the RCA plugs, following the wiring instructions I gave you earlier.
If you just run untwisted and unscreened lengths of wire all the way to the RCA plugs then they will pick up hum from nearby power cables etc..
Ok so tomorrow I'll buy a proper cable for the Tonearm and I'll use this for the RCA, it's from the store I have down the road.
I have to thank you guys so much! Now I'm even more excited, I'm definitely looking forward to update you guys and to hear it sounding properly!
That's good screened cable.
It even carries an earthing wire down the middle that you can use to ground all metalwork on your turntable to the pre-amp.
Keep us posted and show us some photos of your handywork.
I hope you guys are not going to laugh at me but I wanted to make something open source,
inexpensive, easy to print and accessible to everyone. It's fully 3D printed except the center rod and bearings.
Here the renderings: this is what is supposed to become like.
This is where I am now (pre beta version, a sort of Frankenstein lol).
inexpensive, easy to print and accessible to everyone. It's fully 3D printed except the center rod and bearings.
Here the renderings: this is what is supposed to become like.
This is where I am now (pre beta version, a sort of Frankenstein lol).
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