To whom it may concern ...

the thin end of the wedge
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georgesgiralt
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To whom it may concern ...

Post by georgesgiralt » 09 Oct 2019 10:54

Hello,
I own a Technics SL-150 fitted with an SME 3009 SII (early version non improved). I'm currently fighting an intermittent so played with my cartridges and cables to check resistance.
Once done, I measured the wires and cable characteristics. HEre are the result for the original SME tonearm wire and RCA cable :
Measure of the internal tonearm cable :
Between grounds : 31 pF
Between "hot" : 51 pF
Between one Hot and one Ground : 31 pF (same on other combination)
Measurement on the RCA plugs :
Right side : 134 pF
Left side : 129 pF
With the Grado GTE+1 installed :
RCA Left : 811.8 Ohm, 54.8 mH
RCA Right : 803.2 Ohm, 54.8 mH
With the Audio Technica AT-VM95E installed :
RCA Right : 496.5 Ohm, 444 mH
RCA Left : 499.1 Ohm, 442 mH
With the Audio Technica AT-VM95C installed
RCA Right : 487.4 Ohm, 443 mH
RCA Left : 485.0 Ohm, 440 mH
The two Audio Technica are different carts (bought at a couple of month interval to the same reputable Audio Technica seller ) and both bear the "Made in China" sticker. Both bodies show very same characteristics. Fine quality control....
The construction of the Grado is very different as measurements shows...

I also measured the AT-VM95E right at the tonearm (before the RCA cable, on the 4+1 plastic plug)
Right : 496.8 Ohm, 444 mH
Left : 494.4 Ohm, 442 mH
Now, enjoy ....
P.S. : The turntable part is fine. Still have the intermittent .... So still searching ;-)

Alec124c41
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Re: To whom it may concern ...

Post by Alec124c41 » 09 Oct 2019 13:25

Those cartridges are all well matched between channels.
You say you have an intermittent ...
Not sure exactly what is intermittent, but ...
Check that the RCA plugs are a tight fit on the connectors. If they go on easily, the skirts might not make good contact with the outer surface. Pinch the skirts of the plugs to make them tight.

Cheers,
Alec

BMRR
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Re: To whom it may concern ...

Post by BMRR » 09 Oct 2019 16:51

georgesgiralt wrote:
09 Oct 2019 10:54
I'm currently fighting an intermittent so played with my cartridges and cables to check resistance....

P.S. : The turntable part is fine. Still have the intermittent .... So still searching ;-)
Intermittent what?

lenjack
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Re: To whom it may concern ...

Post by lenjack » 09 Oct 2019 17:01

Problem could be downstream, in the electronics (phono section).

georgesgiralt
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Re: To whom it may concern ...

Post by georgesgiralt » 09 Oct 2019 18:17

Hello
to explain myself :
I use an Apt Holman pre-amp. Sometimes the left channel loudness on record playing is very low. Sometimes it it normal. It did not appear when I used the Luxman L-2 amplifier with it's phono input.
I checked all I could on the turntable side and for all 3 carts I use on this table. Everything is correct. The Holman is fine when playing a Tuner or set top box in high level inputs. So I'll have to check everything in the phono preamp switching and amplification....
Hope this clarify things ;-)

JoeE SP9
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Re: To whom it may concern ...

Post by JoeE SP9 » 09 Oct 2019 20:19

It would seem that liberal use of De-Oxit will be helpful. Spray it in all the switches and controls. Work them a dozen or so times and carry one.

lenjack
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Re: To whom it may concern ...

Post by lenjack » 09 Oct 2019 21:26

I agree with the previous post. This confirms my suspicion that the problem lies in your Apt preamp, which is about 40 years old. Has it ever been serviced? As great a unit as it was, and I freely admit it was, it would not be unusual for such a problem to rear it's head.

georgesgiralt
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Re: To whom it may concern ...

Post by georgesgiralt » 09 Oct 2019 22:23

Been there, done that. I bet that something is amiss in the phono preamp.
Will investigate further.

lenjack
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Re: To whom it may concern ...

Post by lenjack » 09 Oct 2019 22:38

Almost overlooked this. #-o You've got 2 phono inputs on your preamp. Simply connect to, and select the other one. If the problem is solved, then you can sit back and decide if you want to get the first phono input repaired.

Collux
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Re: To whom it may concern ...

Post by Collux » 09 Oct 2019 23:12

Swapping the left and right channels from the deck to the pre-amp, should also help to confirm if it is a phono problem or a pre-amp problem.

dahoo
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Re: To whom it may concern ...

Post by dahoo » 10 Oct 2019 22:26

sometimes, a relay could also be oxidized and cause such issue. you may have to open up the relay's cover and spray the contacts as well.

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