Dual 1245 - one channel sounds thin & not loud

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yazkazoo
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Dual 1245 - one channel sounds thin & not loud

Post by yazkazoo » 29 Dec 2018 20:24

So, this was my uncle's turntable and hasn't been used in years.
It has the original cartridge - a Shure V15 III - DU, which means it was made for this turntable as the cartridge and mounting unit are one piece. There are no bolts & nuts to swap out the cartridge, it has plastic lugs attached to the unit.
Anyway, the needle was broken, so picked up a Pfanstiehl 4764-DE and it fits perfectly.
Here's the issue. When I play an album, the left channel sounds fine, but the right channel is much softer and thinner sounding. I swapped the RCA plugs on my receiver and the issue switched sides, so not the receiver. I also tried different albums and had the same result. When I swapped my Toshiba turntable back in and played the same albums, they sounded fine.
I read threads on this forum regarding corroded contacts, so cleaned up the ones on the mounting unit as well as the tonearm with a pencil eraser.
I verified the lead wires were connected and snug, and even wiggled them a little. Wiggling the RCA's did not do anything either.
Could this be a bad cartridge, or could it be a bad stylus?
Any help would be much appreciated!

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Re: Dual 1245 - one channel sounds thin & not loud

Post by mrow2 » 30 Dec 2018 00:07

Hi It sounds to me like a stylus or cartridge issue but this is only a guess. I'd be looking at the stylus, any irregularities, a tiny bead of glue on the post of the stylus or a bent cantilever, maybe stylus not aligned properly or really bent. The magnet in the stylus assembly might be wrong somehow. Maybe the vendor would allow an exchange, you could try another. Trying another might help eliminate some possibilities. In a cartridge, functional parts to be centered for it to work evenly because it is generating electrical energy from the undulations in the record grooves. If the elastomer (suspension) in the stylus assembly was positioned incorrectly, it conceivably could cause this. Be sure the stylus unit is inserted all the way into the cartridge, too. If it was hanging away from the body just a little, it could affect the sound. Having extras of these things (like cartridge, stylus, headshell etc) makes it easier to diagnose but you can still do some checking.

Measure the resistance using an ohm meter on the 2000 Ω scale to get readings of L and R channels of the cartridge. You can do this with the cart installed, and take the readings from the cable ends. Don't put any current into the cartridge. Ω check should not harm it. I forget Shure V15 range but the two sides should be reasonably close maybe within 20-50Ω or something like that. A reading might be 1450 on one side and 1432 on the other, for instance.
Two similar numbers either in xxx or x,xxx range would be ok. This test can also identify tarnish problems, connection problems. This can even be a really lousy continuity of one of the tiny leads in the headshell, but it's less likely since you're describing a condition which sounds pretty constant. This is a simplified view of a magnetic cartridge; if the parts were not centered the sound could be thin on one side; I have heard this before. This view differs quite a bit from the various manufacturers; they all have their special solution for making more accurate sound but the principles are the same. The trouble may not be in any of the areas I've mentioned but this is what comes to mind. -- Don
Simple Schematic MM cart.JPG
(24.5 KiB) Downloaded 157 times

yazkazoo
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Re: Dual 1245 - one channel sounds thin & not loud

Post by yazkazoo » 30 Dec 2018 03:45

mrow2, thanks for the reply. So, I did measure resistance on the cartridge and here is what I found:
I first connected the ohmmeter leads to the white pin and the blue pin. I don't remember the exact reading, but it did register a value.
I then connected the ohmmeter leads to the red pin and the green pin. The meter did not register a reading, so it appears the cartridge is bad. Big old bummer.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by mrow2 » 30 Dec 2018 05:43

It's quite possible; I have a V15 type III which is similarly dead on one side. But It doesn't explain why you hear diminished sound (softer and thinner). There should be no sound on one side in that circumstance where you connect R & G to Rt channel and Wh & Blu to L channel What you describe could also be out of phase stereo (channels connected incorrectly). Verify:
Left signal = white wire
Left Ground = blue wire
Right signal = red wire
Right Ground = green wire

Should be like this all the way to the input jacks in the turntable. Check continuity of each line from connector clip through to the turntable terminal. Also check Ω again on the right channel resistance... As for the cartridge I guess you could do this first. The connection to the pins needs to be good or you get unstable readings. It may have been connected out of phase, but the R channel may possibly still be dead. If connected correctly, there should be no sound from that side if that cartridge channel is really dead. Worth checking again, and verifying correct phase if nothing else. I'd like to know what resistance the good channel registers.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by yazkazoo » 31 Dec 2018 21:47

Don-
On the left channel (white & blue lugs), I get 1342 with my meter set to 2k.
I did also verify the leads were all connected to the correct lugs.
I reached out to the vendor, and they are sending me another stylus free of charge.
Will let you know what happens.
Thanks again,
Mark

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Re: Dual 1245 - one channel sounds thin & not loud

Post by mrow2 » 01 Jan 2019 06:12

But you're saying the R channel (red and green) gives no reading? Hang on to the stylus, maybe it will be useful at some point. The mystery to me is the observation that there is some sound in the R channel, just not good sound. There should not be any, at least that has been my experience. Regardless, if the R channel is dead, so is the cartridge. I have one or two dead Shures, a dead Stanton, and 2 dead Grado carts. Each of them has one dead channel, with no sound output on those channels.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by DSJR » 01 Jan 2019 12:36

When Shures die on one channel, that's usually it for the body I'm afraid. Bodies less-the-stylus do come up from time to time, but to be honest, an AT520 for around a hundred quid (dollars) these days (or even the naked-diamond VM95-EN) would probably out-perform it, despite the less fine stylus tip in the 520. Tracking at 1.8 - 2g is actually better for records, according to research, the aim of sub-1g tracking in the early 70's was more of a marketing thing I think now, looking back and something of a blind alley.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by yazkazoo » 02 Jan 2019 16:02

Don-
Correct - red and green give no reading. I tried many times to get a reading, making sure my meter leads were touching the pins correctly. And that being said, I'm plenty confused as to why I am getting some sound from that channel.
I'll definitely know more soon, as the replacement stylus will arrive on Friday.
Any idea why a cartridge dies? As there is not much inside other that wire and magnets, can the wire become frail as it ages and simply break? This turntable sat in my Uncle's apartment since new, and traveled to my house a little while back.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by yazkazoo » 08 Jan 2019 13:37

New stylus received yesterday, same result.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by yazkazoo » 08 Jan 2019 14:55

Is there any way to test continuity from where the headshell locks in to the tonearm all the way to to the RCA output connectors? This would at least tell me if it is definitely a cartridge issue or if there is an internal problem.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by vanakaru » 08 Jan 2019 15:01

You need to try another cartridge. Actually the mounting sled allows you to use 1/2'' mount cartridges. The special clip on mount is easier 'cos not need for alignment but will not interfere with ordinary mounting. eBay has some Dual mount carts listed sometimes and you can replace the plastic of 1/2'' with your Dual if needed. It takes some courage or desperation getting the Shure body out but is doable. I had just the opposite problem - I needed to use cart with Dual mount on 1/2'' shell.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by dualcan » 08 Jan 2019 17:17

yazkazoo wrote:
08 Jan 2019 14:55
Is there any way to test continuity from where the headshell locks in to the tonearm all the way to to the RCA output connectors? This would at least tell me if it is definitely a cartridge issue or if there is an internal problem.
Hi,
Simply slip the cartridge with TK 24 (or 14) holder back into the arm.
Place one multimeter (on Ohms setting...) probe directly on the red cart clip /wire, the other on the tip of the black or red RCA connector (right hot) and measure.
Repeat with:
green / same RCA plug as above, but on the ground skirt (right ground),
white / white or yellow RCA tip (left hot),
blue / same plug as above, but on the ground skirt (left ground),
If you have the DIN connector, then the green and blue cart wires end up on Din pin 2,
Red wire to DIN pin 5,
White wire to DIN pin 3.

By measuring this way, you will measure all the junction points and the complete audio tract from cart to RCA connecting tip.

Regards,
k

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Re: Dual 1245 - one channel sounds thin & not loud

Post by Tittah » 10 Jan 2019 22:59

Hi,

It's not my intention to hijack this thread but I had the exact same problem as the TS. The left channel of my BSR810 sounded very thin. I had to play my records in mono to get an acceptable sound.

I followed the advice of dualcan and found that there was a problem with the cable between the cartridge and DIN connector. I don't know why I started checking from the cartridge to the muting switch al the way to the DIN connector, only to find there was a broken solder in the DIN connector :-)

Happily enjoying stereo again. Thank you for the advice.

Geert.

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Re: Dual 1245 - one channel sounds thin & not loud

Post by yazkazoo » 11 Jan 2019 01:21

Klaus-
I did as you suggested - with cartridge mounted and locked into the tonearm,
red cart clip /wire, the other to the tip of the black (right hot).
green / same RCA plug as above, but on the ground skirt (right ground),
white / white RCA tip (left hot),
blue / same plug as above, but on the ground skirt (left ground).
I got measurements on all - they were bouncing around a bit, but I did get readings.
Does this test confirm that from the cartridge to the RCA's, it is a cartridge issue and not anywhere else in between?
I also read about another test where I tested ohms just on the RCA's. White had a reading (my good left channel), and black did not show a reading (soft & fuzzy right channel).
Thanks...Mark

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Re: Dual 1245 - one channel sounds thin & not loud

Post by DSJR » 11 Jan 2019 12:33

This is where you need a back-up cartridge in your drawer for 'emergencies.' For me, it'd be an AT91/Rega Carbon as they're cheap, actually sound more than ok at 2g or slightly less and work a treat in Duals... The old AT3600 used to be even cheaper, but I remember them as sounding muffled back in the day and I don't think AT-UK list them now, although I reckon millions have been made in various 'colours' for different manufacturers...

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