• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Tonearm Help! Left Channel Fine, Right Channel No Sound and Hum

Isaac C.

Isaac C.

Cat Hoarder
Hello everyone, I just completed my first tonearm rewire on a Syntec S-220 with KABUSA supeflex and Cardas solder and have run into a bit of a problem. The left channel works fine and sounds fine, however the right channel has no sound and a ground hum. What is weird however, is that if I loosen the headshell socket screws and fiddle with it I can get it to comeback sometimes, but then my azimuth is horrible. Here is what I know and have tried:

Turntable is a Kenwood KD 500 and has a chassis ground.
Amplifier is a Hitachi HA-610 and has a two prong power plug.

What I know:
  1. The hum is present with or without the headshell and cartridge. (this combo works perfectly fine on my other turntable).
  2. It is not the RCA to DIN tonearm cable, I have another one that works perfectly fine that I tried, it still hums on the arm though.
  3. It is not the phono section of the amp or the amp at all (again my other turntable works fine)
  4. The left channel works and sounds fantastic.
  5. Sometimes fiddling with the headshell socket makes the right channel come back, but my azimuth is way off.
  6. Hum is present sitting on arm rest.
  7. Hum is not as loud when I touch the tonearm.
What I have tried:
  1. Measured continuity of ground with one probe on the arm tube and one probe on the ground spade connector at the amp-end of the cable. Continuity is fine, I get a low reading of .0x something.
  2. Measured the continuity of all four wires from the DIN plug in the tonearm base to where they are soldered to the headshell socket. All have continuity.
  3. Measured the continuity of all four wires from the DIN plug end and the headshell end to various points along the arm tube. That is, one probe on one end of the tonearm wire, another probe on the arm tube. None have continuity so no grounding from exposed wire I don't suppose.
  4. If I measure the continuity for the green wire contact pin on the inside of the headshell socket to the DIN plug I do not get continuity, but I do if I measure the solder joint on headshell socket.
  5. Reflowed solder joints.
Any suggestions and help is appreciated! Its just weird that loosening the headshell socket screws and titling it can make the sound come back sometimes. Also the solder joints have rubber insulators over them made from earbud cable tubing.

Also the two headshell socket screws keep coming loose.

When I was able to get it working for a bit it sounded great, no hum or noise, just super crisp sound.
 
Last edited:
Register to hide this ad
Just tried adding a chassis ground didn't help. This is frustrating. Tried a different headshell as well. I messed with those headshell collars screws got it to stop humming for a second then it came back. What in the world does the right channel working/not working have to do with the headshell collars screws and me fiddling with them??
 
Are the pins in the end of the tonearm nice and "springy" and clean? They can get stuck and or tarnished. That could give a flaky connection. The fact that it comes back when you fiddle with it is a strong indicator. You could also have a bad solder joint inside the arm but that would be both unusual and a bit harder to fix.
 
I did notice that the green right channel ground pin is somewhat stuck and the others are springy. How do I get it unstuck? Could that cause a ground hum if the right channel signal (red wire) is making contact but doesn't have a return so to speak?

I didn't think to check that earlier. When I removed the headshell and connected the chassis ground to the amp the hum was a lot less and in both speakers. But when I put the headshell on, its louder and just the right channel. And when I touch the headshell as it's buzzing it is not as loud.
 
Poke them, perhaps after a squirt of contact cleaner, with a mini screwdriver. They might loosen up and pop out more readily.
 
I would recheck your tone arm wiring - sounds like a wire has shorted. You have kind of answered where you need to look - cartridge/ headshell isn’t the problem, RCA’s and amp aren't either - that leaves the project you just completed - bad solder, bad conductor, bad pin - it’s in there somewhere! How do you connect the tonearm wires to the rca cables - you may want to look there.
 
Montycat said:
Poke them, perhaps after a squirt of contact cleaner, with a mini screwdriver. They might loosen up and pop out more readily.
Click to expand...
Okay, I'll give that a try. I noticed the pin for the green wire was basically flush with the nylon insert while the others were pushed out.

visman said:
I would recheck your tone arm wiring - sounds like a wire has shorted. You have kind of answered where you need to look - cartridge/ headshell isn’t the problem, RCA’s and amp aren't either - that leaves the project you just completed - bad solder, bad conductor, bad pin - it’s in there somewhere! How do you connect the tonearm wires to the rca cables - you may want to look there.
Click to expand...
I'll check again, but I've checked the wiring multiple times and have continuity from the rca cable to the headshell collar. And I've inspected the wires where they are visible and look fine.
 
Even headshell pins are not always consistent in how much they protrude. Have a look there too.
 
It's not unusual. My KD-650 has separate ground wires as does my Sony PS-2400. They were both non metallic plinths with stock tonearms but are designs that lend themselves to tonearm swaps. Generally speaking you are more likely to need only the tonearm grounded but others might have different experiences . Try either or both and use what you find has the least noise
 
Well maybe the hum and the lack of signal are two unrelated issues. Even though this was my first rewire I was extremely careful when threading the new wires through the tonearm. Plus these KAB wires are extremely slippery because of the insulation they are made of, so I don't think they snagged on anything to expose the wire somewhere in the tonearm.
 
How about a couple of close up pics of where the tonearm wires connect - at the head shell and at the rca’s?
 
Good idea, maybe I'm overlooking something. I'll take some pictures later of the solder joints when I try to get the pin unstuck.
 
I understand these are not the prettiest soldering joints, but given my limited ability to see very small things up close, the appear to do the job. Again the left channel works. Also the green pin was not making contact with the headshell pins. There was the smallest of gaps between the contacts that I could feel when I moved it.
20200415_124526.jpg 20200415_124543.jpg 20200415_124555.jpg 20200415_124613.jpg 20200415_124619.jpg 20200415_124625.jpg
 
The pin might be sticky due to the soldering melting the plastic a bit. Concentrate on working it to loosen it.
 
I think I got it fixed for the time being thank you so much @Montycat and @visman! I sprayed a little deoxit on the back side of the pins then used my needle nose pliers to work the stuck pin back and forth until it became springy again. Then before reassembling everything I laid the tonearm on the platter and plugged the DIN cable in and used a very fine paint brush to simulate the record playing and got sound from both channels. Then reinstalled the two collar screws and secured the DIN plug. Next I mounted it back on the armboard. Now I had a very feint hum in both channels, which is better then in one channel. So I added the chassis ground and it was gone. So I hope it will work from now on. The green pin still isnt the springiest of the four but at least it makes contacts. Dumb question, should my crappy solder joints be fine? I tried tidying them up but my bad close up vision keeps me from doing a better job.
 
Another question, does my armtube look straight? The way it attaches is two set screws, there are no holes, so I have to eyeball it. If it is off barely, will it hurt anything if the azimuth is correct when playing a record? I know the s-shape has to do with the offset angle so it worries me its not straight.
20200415_193217.jpg 20200415_193224.jpg 20200415_193232.jpg 20200415_193237.jpg 20200415_193245.jpg 20200415_193309.jpg
 
You must log in or register to reply here.
Back
Top Bottom