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In Reply to: RE: High compliance ceramic cartridges posted by maxhifi on March 08, 2016 at 07:57:27
There were so called HIFI ceramic carts. by Decca and some others. The 1 I have (not a Decca) will track at 2 g. and produces 200 mV., which is very low by piezoelectric standards. Rochelle salt crystal carts. produce O/Ps measured in (sic) volts.
"HIFI" ceramic carts. employ the same 1/2 inch mounting that mag. carts. use. A spec. I recall being provided is up to 17 KHz., but I have a scheme that may produce even better HF extension. As was pointed out by another poster, piezoelectric carts. are high impedance devices, which are very vulnerable to cable capacitance induced HF losses. My idea is to mount a low noise JFET source follower at or very close to the arm pillar. Between elimination of cable capacitance and a 10 Mohm cart. load, I hope to gain some additional HF extension.
The better ceramic carts. may need some preamp EQ. That will be dictated by what frequency sweeps reveal. In any event, 20 dB. of preamp gain are needed to raise 200 mV. to the 2 V. level associated with digital sources.
Eli D.
Follow Ups:
Hi Eli,My plan is to use a 6J7 with a DC filament, and a 1-2M grid reaistor. I will use my turntable's existing SME tonearm wiring, I like your idea of close coupling but don't want to mess with what already exists. Plus I have EV T35 tweeters, so thinking about what exists above 17kHz makes little sense.
What model of cartridge do you have ? It sound exactly like what I am after.
What got my on this as I said in my post to coffee Phil, was a desire to use a pentode tube as the first Stage without getting overwhelmed by tube hiss, I don't plan on making a one tube record player out of my thorens so 2V is not required, but 200mv pushes hiss way into the background rather than front and centre as it would be if I used the same tube for a mag cartridge
Best regards
Max
Edits: 03/08/16
I bought my cart. from Garage-A-Records, as they were permanently closing shop. The lady in charge was retiring.
Eli D.
What's the brand/model ?
The cart. is not handy, at this time. When I can get through to the Wayback Machine, I'll try to find a decent link.
Eli D.
Oh awesome thank you
I checked out the Decca you referred to - looks amazing for a ceramic and they're still around too.
Sorry, I'm not having any luck with WayBack. :> (
Garage-A-Records reroutes to TurntableNeedles. Contact them to see if you can still look at the old scans of a ceramic cart. catalog. IIRC, the 1/2 inch mount cart. I acquired has a "D" as its initial code character.
Eli D.
I got it to work - lots of interesting things in their old catalogue - I remembered right away what you were talking about, I used to check out their website from time to time when it was active
One of the EV models stands out as interesting, but I wonder which one you went for
see link below
The cart. I acquired is an Arista 1490D. It's figure D4 on chart 4.
Eli D.
That is cool ! Kind of in a class of its own, I totally overlooked it browsing their catalogue. Some company in the Netherlands is selling them for 29'euros, I have to check the exchange rate.
I couldn't find any specs on it. Do you have a link? Replacement needles seem readily available. That says to me that there must be a lot of cartridges out there too. If you get one, post your results. I am restoring a Garrard Type A turntable, and it might be fun to try one on some of my "less than perfect" records, although the main cartridge will be a Sure SC35C (unless I can track down an M3D).
Dave
Found this on another forum:
Decca Deram Ceramic: Stereo / Mono cartridge.
White shell: transcription quality. Playing weight 2 gm; Tip mass 0.6gm
Compliance: 9 x 10-6 lateral, 5 x 10-6 vertical.
Frequency Response 18Hz - 18kHz =+/- 3dB.
Separation better than -20dB at 1kHz
Output 200mV at 5cm/sec, Recommended load 2MegOhms
Stylus; diamond 0,7 thou diamond; Mono version stylus 1 thou diamond.
NOTE:
Deram heads are suitable for all amplifiers having a sensitivity of 100mV.
Diamond styli for all Deram pick up heads, including 78s, and elliptical styli are available
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