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My turntable signal has a channel drop-out from time to time. I'll be listening in stereo and, suddenly, one channel will just go silent. It is often the right channel, but I am not certain the left one hasn't also gone bye-bye.
The other day, the right channel went out. I switched the leads going into the preamp and the left channel was on and the right one silent. I assume from that that my preamp is not at fault, but that there is nothing getting into it on the dead channel.
I have a little RS multi-meter, so I can check continuity from one place to another where I can get the probes on.
How ought I to precede to try and run down this problem?
Tonearm is an SME 3012 Mk II with Shure V15 Vx MR cartridge. I have a spare headshell and cartridges I could swap out if necessary.
Thanks,
George
Follow Ups:
Later Gator,
Dave
One of the spring loaded pins in my 3012 Improved that makes contact with the head shell pins sticks in the in position when the head shell is removed and when the head shell is reinserted the connection on that channel doesn't always work. I don't know for sure but I'm thinking that different manufacturer head shells may have slightly different pin lengths and if shorter, that could make the situation worse if the pin is stuck in the in position.
Thanks. This was certainly one potential cause I considered but I wasn't sure how to address it. Have you found a way to pull those pins out so they make good contact?
If I remember correctly I thought the problem might require a tonearm rewire with a new set of spring loaded pins so I just went for the risky and pulled on it with a slender nose pair of needle nose pliers.
The initial problem was that pushing the pin didn't free it up but since being pulled out, if it sticks again it will snap back out when pushed with a Qtip. Probably just got lucky with that.
With a good narrow beam of light shining into the area it was obvious that one pin was not out as far as the other three.
I also went in with Qtips and Deoxit to clean all the pin ends in the arm and the pins on the back of the head shell.
If all the pins look to be out the same distance I wouldn't try what I did with the needle nose but cleaning shouldn't hurt.
"The other day, the right channel went out. I switched the leads going into the preamp and the left channel was on and the right one silent. I assume from that that my preamp is not at fault, but that there is nothing getting into it on the dead channel."
So you're saying you swapped the channels going into the preamp, and the silent channel stayed on the right side...... This means that the problem is likely at or beyond the preamp......
Several questions.....
1. Is your phono the only source of the system? Or do you use other sources? (CD/DAC, tuner, etc.)
2. If you do have more than one source, is the problem ever occur with other sources?
3. Does your preamp have the phono stage built in or are you running a phono stage ahead of it? (If the latter, the phono stage is likely not the problem.)
4. If your preamp has a built-in phono stage, is the phono stage on a separate card that is connected to the main circuit board of your preamp? (As opposed to being just part of the main circuit board.) Do you know if your phono stage uses integrated circuit chips?
5. When one of the channels goes silent, do you still hear noise out the speaker of the "silent" channel? Does the noise change with volume setting? When a channel does go silent, and you then cue up the cartridge off the LP, does the noise sound the same on both channels or stronger on one channel?
6. Does the sound tend to return when a loud passage is played?
It's hard to speculate the problem, answers to these questions will really narrow it down.
Thank you, Todd, for asking these questions. I should add that I have two preamps. A GAS Thalia II for solid state and an ARC SP-8, which is a tube preamp.
This phenomenon occurs with both of these preamps.
I apologize because my original description was mistaken. I'll try again. I start out with the R ch phono lead in the right ch preamp phono input and the left ch phono lead in the L ch preamp phono input. The right ch sound drops out--R ch speaker is silent. I switched the L ch phono lead to the R ch preamp phono input and the R Ch phono lead into the L ch preamp phono input. Now the left speaker is silent and the R ch speaker is playing. In other words, the L ch phono lead played music through the L or R preamp phono input and the R ch phono lead would not play through either preamp phono input.
I do have other sources. The CD player works fine. Streaming files from computer to DAC to preamp work fine. FM Tuner works fine.
Both of these preamps have an in-circuit, built-in phono stage. (They're old components!)
Question 5--no
Question 6--no
When you switched leads going into your phono preamp and the right channel was still dead, it indicates the problem is NOT in your turntable. It's either in your phono preamp itself or further downstream toward your speakers.
Is your phono preamp a separate component from your line-stage. If so, check the interconnects between your phono preamp and your line-stage.
Try another source like your CD player and see if the right channel is still dead. If it is, then the problem is either in your line-stage or further downstream toward your speakers. On the other hand, if both channels play just fine from your CD player, then the problem is either in your phono preamp or else the interconnects connecting your phono preamp to your line stage assuming they're separate components.
Good luck!
John Elison
Thank you, John. Please see my attempt to clarify my unintentionally misleading first post in my reply to Todd's questions. It's hard for me to describe this. Sorry.
The problem is either in your turntable wiring or in your phono cartridge. You can find out where by switching cartridge leads at the cartridge pins. In other words, switch the RED lead with the WHITE lead and switch the GREEN lead with the BLUE lead. Now, if the left channel goes out instead of the right channel, the problem is in your phono cartridge, but if the right channel continues to go out, the problem is in the wiring between your cartridge and your phono preamp.
Make sure you reconnect all your other interconnects correctly before conducting this test.
Good luck!
John Elison
John,
Thank you for this advice on how to test the cartridge leads! This is one area where I really didn't know how to proceed.
I'm with John! If the problem is in the turntable, when you swap pre-amp inputs the problem should switch channels so it points to the pre-amp (or further down the chain). If you swap pre-amp inputs and pre-amp outputs you will still have the left channel in the left speaker - if the problem is in the turntable it will stay in the same channel. If the problem swaps channels then it is not the turntable.
" I have a little RS multi-meter, so I can check continuity from one place to another where I can get the probes on."
Please do not do this without removing your cartridge. Meters work by sending a voltage though the circuit ( why they are powered by a battery). If you let it do this through a cartridge it will be fried.
"We need less, but better" - Dieter Rams
Thanks for this tip! I do NOT want to fry my cartridge!!
But still, there is no need to do it in this case since swapping leads will eventually reveal the location of the problem.
Hi, George,
If you switched leads into the preamp and the right channel was still dead, wouldn't that indicate the preamp was at fault? Or did I miss something??
Tom
I would start with checking the connectors under the SME at the back of the arm. These are silver plated and prone to corrosion.
When silver corrodes, it oxidizes to silver oxide, which is still an excellent conductor. Maybe the silver plating wears off over time. I wouldn't know.To the OP, now that you have exonerated your preamplifier, which I assume contains the phono stage, keep working back up the chain toward the cartridge until you find out where switching R to L and L to R does make a difference. OR, you could check the cartridge pins for a loose connection of the R hot lead and maybe save yourself some time and trouble. Just a guess.
Edits: 11/19/21
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