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Strain Gauge catridges

Pio1980 said:
You will want on-the-fly VTA adjustment to get the most out of this cart and the KAB/1200 has no automute to disable. I'm using a ca 6 gram spacer plate with my cart to make weight and get some reaction mass on it, an addl ca 1/16"-1/8" spacing for the cart couldn't hurt as well. Do not discard the original stylus, it may eventually be rebuildable.
The JVC looks like a shoo-in for a conventional cart 2nd TT.
Click to expand...

Dr Win recommended 1.2g originally but later decided 1.6 is better but who knows how old suspensions age...yes I did try the On-The-Fly VTA on the Sony Biotracer PX-800 with it, and used that for my other TT even though the resonant f of the PX-3's arm is 12.5Hz.

Yes I have a 5g spacer plate too. Think somebody might have wired the cart or the external module out of phase; have to find a record that I really know I can identify a right/left signal...
 
Qilin, keep us posted on this project and let us know if parts need finding.
One guy recommended 2.5g for the Panasonic SG carts and generally I've found this valid. Susurus, have you found a source for replacement stylii for the Win? As you no doubt have found, the stylus packet that came with your cart was not for the Win stylus but a Shure N-44E replacement.
 
I don't know if I am the only guy who has recommended 2.5 grams VTF for the Panasonic cartridges but I am one of them.

I base my recommendation on the cartridges' performance with CD-4.

At 2.0 grams, there are times (although rare) when there is CD-4 breakup or sounding like it is on the verge of breakup.

At 2.5 grams, performance is very consistent and clean sounding.

Since CD-4 provides the stringest test of stylus/groove interface, it is assured that the same VTF is the best for regular two channel performance too.

It may be that you could get away with less force for two channel but I feel it is best to play it safe. The difference isn't that great anyway and, considering the increased area contact of the Shibata stylus, the equivalent elliptical force is about 1.5 grams.

Doug
 
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Pio1980 said:
Qilin, keep us posted on this project and let us know if parts need finding.
One guy recommended 2.5g for the Panasonic SG carts and generally I've found this valid. Susurus, have you found a source for replacement stylii for the Win? As you no doubt have found, the stylus packet that came with your cart was not for the Win stylus but a Shure N-44E replacement.
Click to expand...

Hello Pio1980,
New developments...
The new shibata Jico replacement stylus EPS46QD for my EPC-451c cartridge arrived today. It is the red plastic one labelled '4 channel'. I did a quick install & played a Passport LP...WOW! It sounds fantastic! It exceeded my expectations. I used the Technics SL1200-Mk2.
I was playing it through a Panasonic SE-405 preamp, stereo mode. The only problem is that the preamp's left channel is low relative to the right channel. It needs some restoration. I will tackle the restoration after the DIY preamp project.
I have ordered the stereo stylus you recommended. The OPA preamp kit is also on its way.
Best regards, DM
 
Pio1980 said:
You should adjust the VTA pillar higth collar while playing for the clearest sound, it may dial in between 3 and 4 on the collar. With the spacers I used mine comes in around 3.5 .
If you have contact cleaner spray you can try this; http://www.audiokarma.org/forums/showpost.php?p=4461484&postcount=34
Click to expand...

Hello again Pio1980,
Perfect reference! Thanks!
It sounds like it's exactly spot-on my issue with the SE-405. Will probably get to it later this weekend.
You are the expert!
Best regards, DM
 
I've sort of had to crash-course myself into these things with the knowing/unknowing help of others and some lucky web search hits.
BTW, if you would, take a resistance measurement of each side of that cart please.
 
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Pio1980 said:
I've sort of had to crash-course myself into these things with the knowing/unknowing help of others and some lucky web search hits.
BTW, if you would, take a resistance measurement of each side of that cart please.
Click to expand...

OK, will do the resistance check later. How many ohms should it be?
DM
 
They seem to fall in between 600^ and 1200^. My EPC-450C-II is ca 1200^ per channel and the EPC-451C ca 750^ per. For your custom pre we will want to choose the value of the current limiting loading resistors to keep the current at ca 4 ma per channel.
 
About that stylus, yes, it was the box, not the contents...looked at it on a microscope and couldn't tell what the stylus actually was, but it didn't seem damaged (yay). Looked pretty new.

Since the condition of storage has been different for everybody's cart, the state of the suspension will not be the same. For elastomers on conventional carts some get brittle and some get looser--consequently the best-sounding tracking force may be different for each cart.

Now the strain gauge is a different animal. Do they hold up better?

Seems to me the 'sweet spot' is a smaller target. 1.6g does not sound like 1.85. When it clicks in and the stars align, wow.

There were some pics of the PNW event where I demoed my Win on the PX-3, Parasound P/LD 1100 & Yamaha PC-2002 through Hales Revelation 3's.
 
Thnx Susurus for the update and response. The Panasonic carts don't seem to age at all from what I've been told. One thing I like with these carts is that I have 4 different type stylii that I can snap in and out without removing the headshell or changing settings for different recordings and situations.

Here's some pix of the prototype e-Bay board SG conversion in the test mule chassis, the bottom view shows the exact placement of the added current limiting loading resistors. I used the provided terminals as test points, you won't be mounting them on the board instead soldering the input/output and transformer power directly to the board pads.
 

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Pio1980 said:
They seem to fall in between 600^ and 1200^. My EPC-450C-II is ca 1200^ per channel and the EPC-451C ca 750^ per. For your custom pre we will want to choose the value of the current limiting loading resistors to keep the current at ca 4 ma per channel.
Click to expand...

Hello Pio1980,
Here are my measured resistances:
Left Channel: 711 ohms
Right Channel: 774 ohms
I treated the SE-405 with De-oxit last night, in the SC/MM switch, and the mode selector switch, as outlined in the other thread. The left channel level is still about 6-8 dB down from the right channel. Is the different resistance in the cartridge causing the channel imbalance? Is the difference in the cartridge resistance 'normal' or is something wrong?
Sound quality is great!
Best regards, DM
 
I honestly don't believe the cart's the problem, they all measure somewhat asymmetrically from perfectly balanced resistance.
Someone else in the ref'ed thread has run into this problem with this decoder, it has an asymmetrical signal path between channels with the addition of a unity gain inverter stage in the strain gauge section's left channel that I don't care for, the problem may or may not lie there as it's a rather busy signal path. The circuit I use is fully symmetrical, short, and simple. Thanks goes to Flavio Egoavil of Lima Peru for introducing me to the topology I've adapted for the convenient and very economical e-Bay board kit.
Your cart is essentially identical to my EPC-451C, we'll go with ca 3000^ 1/4W metal film loading resistors.

The only problem I have with my SG set-up is that I've pretty much lost interest in listening to vinyl thru anything else, including my MC carts.
 
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Pio1980 said:
I honestly don't believe the cart's the problem, they all measure somewhat asymmetrically from perfectly balanced resistance.
Someone else in the ref'ed thread has run into this problem with this decoder, it has an asymmetrical signal path between channels with the addition of a unity gain inverter stage in the strain gauge section's left channel that I don't care for, the problem may or may not lie there. The circuit I use is fully symmetrical, short, and simple. Thanks goes to Flavio Egoavil of Lima Peru for introducing me to the topology I've adapted for the convenient and very economical e-Bay board kit.
Your cart is essentially identical to my EPC-451C, we'll go with ca 5200^ 1/4W metal film loading resistors.

The only problem I have with my SG set-up is that I've pretty much lost interest in listening to vinyl thru anything else, including my MC carts.
Click to expand...

OK, so I'm understanding that the different measured resistances in my cartridge is probably not the cause of the channel imbalance...root cause is more likely to be within the SE-405.
Since it might be some time before the pre-amp kits arrive, I will set up the circuit board that I harvested from the SL-721 CD4 turntable. Maybe it will not have the channel imbalance.
Best regards, DM
 
Just finished running an experiment. I played the 451C through the circuit board that I harvested from the CD4 turntable. A couple of quick impressions:
- The left channel level is lower than the right by about 4dB; better than the SE-405 but still imbalanced.
- The sound quality is not anywhere near the SE-405.
Bottom line...really looking forward to getting on with the DIY preamp kit project!
Best regards, DM
 
Good plan for now, it's a much simpler unit than the 405 and could be worth recapping as a stand-alone 4-channel decoder for this specific SG cart since it was 'tuned' for that one example. The homebrew will still be better for stereo playback. If the imbalance persists as an artifact of the cart we'll deal with that in the pre, so no worries.
 
Hello Pio1980,
Do you think a transformer from a computer PSU will do the trick? ATX PSU's have -12v and +12v pins. It would be far heftier than the 150ma you specified! Or should I keep looking?
Best regards, DM
 
These things have pulse power supplies, not really usable. It seems the plastic printers nobody wants also use pulse power supplies. I got one 30VAC CT floor brick transformer from a box of wall-warts at a thrift that I use for the 2nd SG pre in my secondary system.
 
Pio1980 said:
These things have pulse power supplies, not really usable. It seems the plastic printers nobody wants also use pulse power supplies. I got one 30VAC CT floor brick transformer from a box of wall-warts at a thrift that I use for the 2nd SG pre in my secondary system.
Click to expand...

Ohhh...so I should be looking for 25-30VAC, not VDC!?
 
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