Hi, here is ccs that I use. I bought 100 J111, 10 J112 from Mouser for not much and that will keep me going for the rest of my life.
Note that source resistor on J111 is adjust on test (AOT) to get desired current. The cascode jfet ccs has smaller parts count than (say) a ring of 2, and better performance. But setting exact current is awkward. I finished up with 10//82 ohm and this got me close enough to 10mA. The circuit can handlevariations +/ 10% without any real change in performance.
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Doesn't really matter because you need to AOT in any case, but 8 ohm source resistor in that circuit, with my devices, is actually for 20mA not 10mA as shown. Standard disclaimer applies. Never trust my calculations or my schematics.
From memory, CCS was originally set at 10mA, and source resistor was 82 ohm. I changed to 20mA by adding 10 ohm in parallel with 82 ohm (8.9 ohm). Close enough.
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1 watt will be fine. The voltage across the source resistor is around 0.1 to 0.2V, at 20mA thats only a few mW.
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Thank you all for the very interesting informations about strain gauge cartridges and systems! Some weeks ago I heard a sao win lab strain gauge system (on a sao turntable!) ... to be honest, I was shocked about the plus of informations and the quality of reproduction. I heard something like informations about the room situation, what I never heard before on this record!
Some days later I found a Sao Win System at Audiogon (SDT-10 cartridge+"Semiconductor Disc Transducer") ... and bought it.
I am very interested which turntable and tonearm you used with your strain gauge systems (sao win, technics, panasonic) ...
Thank you,
Norbert
Some days later I found a Sao Win System at Audiogon (SDT-10 cartridge+"Semiconductor Disc Transducer") ... and bought it.
I am very interested which turntable and tonearm you used with your strain gauge systems (sao win, technics, panasonic) ...
Thank you,
Norbert
Hi Norbert, congratulations on your purchase, The WIN cartridge is brilliant, I prefer it to Panansonic, and it can easily compete with expensive m-c cartridges. I have a Lyra, and a zYX cartridge, and I prefer the WIN. to get the best out of it, I would suggest that you junk the WIN amplifier, which is just a cheap op amp gain stage. It will be improved by any of the jfet circuits in this thread IMHO.
In answer to your question - my turntable is based on a Lenco L75 motor/bearing system, mounted in a custom corian plinth. Tonearm is a MG-1 air-bearing arm. I am very happy with this combination and after nearly 40 years in the audio hobby I am finally happy with my set up and don't feel need for any more upgrades.
Cheers, Hazard
Hi Paul
No idea how I missed your post, but thank you for the heads-up on the circuits' gain.
I've collected a number of Panasonic EPC-451C's but I have no idea if there is a family sound consistently through the line. However, I believe the 460 is the lowest compliance of the lot, so maybe that stiff suspension isn't the best match for your low moving mass MG-1, causing it to fall a bit short compared to the Win.
I want to send at least one SG to Dave Slagle for a new boron cantilever, in the hope of squeezing out another performance improvement.
Its cool that you also like the Lenco. I'm building a mold for an epoxy granite base for my L-75. This combined w/ a PTP top plate, an upgraded bearing with torlon bushes and thrust pad and silicon nitride bearing ball, a Ladegaard type air bearing arm, the SG w/ your clean phono stage, and I think I'm also pretty much done.
Cheers, Peter
Hi Hazard,
yes, I will try to make my own SG-preamp. Unfortunately my electronic skills are not that good than all of yours in that thread. I try hard to understand everything what are you posting about strain gauge here. Which circuit would you recommend? I don't use an symmetric amp, so I prefer the capacitator version instead of your lundahl-trandformer. I am not sure about equalization or exclude, like you did.
Funny that you all use Lencos! I also use one "corian-lenco" (PTP solid) and one heavy-wood-plinth-lenco, made by Jean Nantais.
Tonearm is also a difficult question. All my tonearms are quite heavy, and I guess the WIN-cartridge needs a very light tonearm. I bid for a Grace 707 at ebay, what is – I guess – one of the light "candidates" for the WIN.
Cheers, Norbert
yes, I will try to make my own SG-preamp. Unfortunately my electronic skills are not that good than all of yours in that thread. I try hard to understand everything what are you posting about strain gauge here. Which circuit would you recommend? I don't use an symmetric amp, so I prefer the capacitator version instead of your lundahl-trandformer. I am not sure about equalization or exclude, like you did.
Funny that you all use Lencos! I also use one "corian-lenco" (PTP solid) and one heavy-wood-plinth-lenco, made by Jean Nantais.
Tonearm is also a difficult question. All my tonearms are quite heavy, and I guess the WIN-cartridge needs a very light tonearm. I bid for a Grace 707 at ebay, what is – I guess – one of the light "candidates" for the WIN.
Cheers, Norbert
Hi Hazard,
finally I found a light tonearme for my SDT-10, an Infinity Black Widow. So I could start to listen to my strain gauge cartridge (up to now with the original Win labs preamp).
Wow!!!!! This is an absolute game changer! I heard so many records with the strain gauge the last two weeks. It's so much better then all my MC's! I will never go back to them! Sell them all!
But I need more strain gauge! More SDT-10 will be hard to find. So I am looking for Panasonic EPC 450, 451 or 460. Which one do you prefer?
I will also try to rebuild your preamp circuit, even if my electronic skills are very poor. Or find someone who will help me!
Strain Gauge is so exciting!
Norbert
finally I found a light tonearme for my SDT-10, an Infinity Black Widow. So I could start to listen to my strain gauge cartridge (up to now with the original Win labs preamp).
Wow!!!!! This is an absolute game changer! I heard so many records with the strain gauge the last two weeks. It's so much better then all my MC's! I will never go back to them! Sell them all!
But I need more strain gauge! More SDT-10 will be hard to find. So I am looking for Panasonic EPC 450, 451 or 460. Which one do you prefer?
I will also try to rebuild your preamp circuit, even if my electronic skills are very poor. Or find someone who will help me!
Strain Gauge is so exciting!
Norbert
You don,t want a light tonearm with a low compliance SG or evem MC,s
I would add some Mortite to the top of the headshell to give it some mass
You are more than likely pushing that combination above the ideal range of 7-12 hz
Easy to remove if it doesnt improve on your stellar impression already.
Regards
David
I would add some Mortite to the top of the headshell to give it some mass
You are more than likely pushing that combination above the ideal range of 7-12 hz
Easy to remove if it doesnt improve on your stellar impression already.
Regards
David
Ok, I should be finally building this phono and powering it up in the next few weeks. I will be ordering parts for the final build soon. Just wondering, as I will be combining the schematics from Hazards' page #2 and Polyphase page #4 circuits, will I need to retain the 4.5k resistors between voltages and SG cart? Thanks!
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