SME 3009II Improved old style cable connector

[iso]

Does anyone know how to open old style male SME cable connector. I try to attach longer RCA leads to original cable connector. Connector is old and I did not dare to use the first idea of using screwdriver to pry connector open. I did not find any help from original SME service and user manuals either.

Best Regards

Kimmo

 

[kevinkr]

I just used a couple of small screw drivers, I'm assuming it is the long narrow 4 pin connector you are talking about. I've done it this way to several of them without any issues.

 

[iso]

Thank you for advice, it is long narrow 4 pin + ground tag... but where I should place screwdrivers. Does long side clips pop open when I pry from earth connector tag... or should I try some other way?

Best Regards

Kimmo

 

[nigel pearson]

It's very good as it is pure silver as far as I know, made by Bulgin I think and said not to be plated. Don't buy the " upgrade RCA ". It will unclip as said . Othen the plastic brakes as it is old. Even so super glue will fix it well enough if unlucky. I dare say heated in the steam of a kettle would help, a heat gun being too strong.

 

[stoN_Cold]

Thank you for advice, it is long narrow 4 pin + ground tag... but where I should place screwdrivers. Does long side clips pop open when I pry from earth connector tag... or should I try some other way?

Just pull.

 

[nigel pearson]

I seem to remember it will slide if wires are broken anyway. Take the earth off first , then unclip it. Make sure when using to think about clamping it. 90% of ones I have seen are loose ,that must be a bad idea.

The old SME often has a very loose bottom bearing. Like a motorcycle the bearing can be adjusted just like it were the steering head. Too much and the arm will stick and too loose to have loose bass. SME got this wrong. I supect as it was a safe choice. When too tight it will not blow across the record at 0 grames ( stylus gaurd on ). The adjustment is an allen head set screw in the round collar at the arm bottom. If unsure best not to.

 

[iso]

I got 4-pin inline connector open with help of oven heat and rewired it. I used 4 conductor shielded cable for rewire and connected 2 wires in parallel to reduce resistance. I ran balanced feed from cartridge to output RCA:s without connecting them to shield. I connected shields of both channels and tonearm ground lead to 4-pin connector tonearm ground lug. This way I can ground tonearm and conductor shields to preamp chassis ground or turntable chassis, whichever proves to be better alternative.

However separating audio ground from signal ground created situation where capacitance between signal conductors is 220pF... but capacitance between ea signal conductor and chassis ground is 300pF. When using MC:s this should not be any problem... but if MM cartridge will see both capacitance´s in parallel... 520pF may be problem.

I really do not understand does cartridge only see capacitance between signal conductors or do capacitance against chassis ground also load cartridge.

Any good advice about this issue?

Best Regards

Kimmo

 

[kevinkr]

Might want to consider lower capacitance cable if using MM, how much of this is just the arm?

 

[nigel pearson]

I think TV coax is about 70 pF per meter if that helps? Audio cable usually more than double. Inside some SME there will be ceramic caps. I am sure they would have been seen. Also unseen inside the older SME arms they used fibre plugs we called Rawlplugs if my childhood memory correct? The sort of things used when shelves were screwed to walls . Some say when the 12 inch SME this accounts for a sound quality being above what the looks suggest. Later arms not filled. Having never got that far I only say what I was told. The one who told me said it made rewiring a no-no. I was also told Mr Akeman's sister when in her 90's was still the best at doing the hanging weights. Her dressmaking skills to tie knots.

 

[iso]

Thank you all for advice. Cable I used is 110 pF/1m one... as I paralleled 2 conductors to archive lower resistance, it seems that this increased capacitance to two other paralleled conductors and common screen. Now I measured capacitance from positive feed to negative feed tied to common screen and capacitance was 330p. I suppose that this is the figure that cartridge will see in parallel to phono input. This is still a bit high as recommendations for MM capacitive loading do vary from 150-300 pF Ortofon, 275pF Stanton, 200-500pF Shure V15....

Internal wiring of SME was less than 20pF but DCR was 1 ohms/conductor... this figure did not scare me too much... it is not ideal for Ortofon MC30 Super requiring 10 ohm load, but is shall be OK now.

I will prefer now this "balanced" wiring with ability to separate signal ground from chassis (screen) ground as I am building now vintage test bed to try the following up the date and vintage cartridges I have. Benz Glider, Denon DL-103S, Stanton 881S, Entre EC1, Acutex M320-III, Ortofon MC30Super. Some of them are quite low output ones as you can see, so noiseless input is needed. So low capacitance coax is not for me now... it may be possible cut 1,2m leads slightly shorter... but not too much.

If capacitance proves to be problem, I try find slightly lower capacitance balanced cable. If I will get my Ariston RD11S/SME3009 test bed ready to roll´within this weekend, I will report how it will play.

Best Regards

Kimmo

 

[AndrewT]

For either 50ohm or 75ohm coax, the bigger the screen diameter the lower the core to screen capacitance.

To fit a pair of coax inside the arm tube, one must use small diameter cable and this will have higher capacitance.

If you want lower capacitance, then you must shorten the small diameter "in arm" cable to be as short as possible and then complete the route in larger diameter cable.
This is what SME do as standard. They fit a connector at the base of the arm making the "in arm" length of small diameter cable as short as possible.

 

[iso]

Please, accept my sincerest apologize. My description about rewiring has not been crystal clear. I will try to make things clear now.

Internal wiring from SME 3009 head shell to 4-pin connector has been stock and it seems that I will not rewire it, unless some valid reason to do rewire appears. Capacitance in internal wiring harness is less than 20pF and DCR is 1 ohm in ea conductor.

Original wiring from 4-pin connector to output RCA connectors was done using coax and leads were only 20 cm long. As I needed longer tonearm cables and I wanted also separate audio ground from chassis ground (screen/shield) in this part of wiring similar way as it was done in tonearms internal wiring, ordinary 2 conductor + shield microphone cable was minimum needed. However, I used 2 pcs 1,2 m long midi cables with 4 conductors + shield, as I happened to have it, to connect 4-pin tonearm connector to 2 output RCA-connectors. So... coax (1 conductor + shield) is not practical way to rewire this way...

Best Regards

Kimmo

 

[iso]

I did cut 30 cm off the cables and capacitance seems now be perfect, when Stanton 881S is used with Harman-Kardon Citation 17/12 combo. This seemed to be best match with this front end. I tried also ARC SP6C/D76A and Quad 34/405 combos, but did not like the results. 220 pF input capacitance was obvious reason for dullness of Quad set. I must return to Audio Research combo as it has been my favorite with CD player.

Now I like to try also my other vintage cartridges, and need some extra headshells. As SME3009/S2 specs specify 4-9g cartridge weights to be acceptable with std counterweight and original SME headshell weight is about 5 g... this means that 9 g headshell would be OK for 5 g lower compliance cartridges. So... light 5 g original, or original style headshells are needed anyway for higher compliance cartridges. Heavier 1902/MWR counterweight would of course be ultimate solution to this problem, but at cost.

Something like Audio Technica AT-HS1 Headshell seems to be fine for lower compliance cartridges, it will not cost arm and leg... but it is too heavy tipping the scales at 10,2g. So... do anyone here have any widely available good 5 - 9 g weigh headshells to recommend.

Best Regards

kimmo

 

[iso]

Hunt for decent headshell is not over... but arm lift is not working properly. Arm seems to drop like stone. Most obvious cause for this is that silicone fluid in the dashpot has dried. SME seems to specify now discontiuned 1610 part number as correct fluid. This part is 1,75 ml. vial with 1.000.000 c/s viscosity silicone fluid.

As original part is no longer available, I have tried to figure decent replacement and I found CRC 30724 as one possible substitute. CRC do specify viscosity to be as follows "Dynamic viscosity active product basic oil 350 mPa.s (@ 20°C)". I have also attached complete dataseet of this product. I am not too familiar with different viscosity units... so I am now asking help for conversion or other recommendations... is CRC viscosity 350 mPa.s close enough to original 1.000.000 c/s to be useful replacement? Or... is there better alternative available widely, as postal regulation seems forbid sending fluids overseas very often?

Best Regards

kimmo