ortofon sl15 output

cressy · Post by **cressy** » Fri Oct 09, 2009 1:17 pm

hi guys, im buying colins sl15 cart to go on the garrard.
will has very kindly found the specs for the output of the cart.

originally it seems these came with an 88:1 step up that ive been advised isnt the best in the world, and that the output of the cart is 0.067mv so rather low.

the o/e transformer would have bumped the output up to 5.896 mv to be used with an mm phono stage.

will recommended a set of cinemags he uses that are highly recommended for all sorts of other carts too so should be a good bet.

question is, i have a pair of sowter 10:1s and possibly a set of nondescript mic transformers that are also 10:1. if i feed the sl into the sowters i'll get 0.67mv, and then into the other ones i'll get 6.7mv so a gain of 100 ish. the benz i use at the moment puts out 0.5mv so 5 using the sowters.

is this a recipe for disaster?? is there a reason why it wont work? the loading for the cart would probably be way off by doing this so i thought id ask before buggering about.

cheers ant

Post by **Nick** » Fri Oct 09, 2009 1:55 pm

It would work, but likely to have a lot of losses I suspect, but give it a try.

cressy · Post by **cressy** » Fri Oct 09, 2009 2:32 pm

cheers nick, i just spoke to sowter and they reckoned it was a non starter due to the load that would be put on the primary of the second transformer squashing the hf output, they said that the best they could offer would be a 20:1 step up. that would give a 1.34mv output to the phono stage. not sure how your phono would cope with 3 times less input voltage, though i suspect it wouldnt really make a difference to it

this the best way to go about it?

can anyone direct me towards the cinemags? i havent looked into that yet

Will · Post by **Will** » Fri Oct 09, 2009 2:36 pm

Had another look at the output, I lost the specs Colin might have them.

Cartridge Database give

SL15 1964 0.125ma
SL15E 0.025ma
SL15 Mk2 0.015ma
SL15ELL O.125ma this is the what I was using at Owston and the output is correct.
The SL15 from 1964 I think must have a conical stylus.
The SL15E is the other one I have with "Elliptical" on the body and the output allot less than the ELL this has SL15ELL impressed on the underside of the body.

http://www.cinemag.biz/mic_input/mic_input.html

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Mike H · Post by **Mike H** » Fri Oct 09, 2009 4:53 pm

Trouble is the biggest step-up available there is still only X5. So that's still only 0.625mV.

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Mike H · Post by **Mike H** » Fri Oct 09, 2009 4:58 pm

To get it up to 5mV say, the turns ratio needs to be 1:40.

Looks like another amplifier stage is the simplest option

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Post by **Nick** » Fri Oct 09, 2009 5:18 pm

Then the sig/noise ratio becomes a problem. You could try the jfet input circuit, and possibly a 1:10 step up as well. you should get 64dB or so from the jfet phono, so that might be enough.

Mike H · Post by **Mike H** » Fri Oct 09, 2009 5:35 pm

Yes I was thinking it would have to be a transistor stage of some sort.

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cressy · Post by **cressy** » Fri Oct 09, 2009 5:59 pm

thanks for the replies guys, turns out i was whittling about nothing! your phonos fine with it nick, it appears its one of the 0.125mv output models.

yep i have to crank the amp up about a third of a turn more for the same volume but even so theres still plenty left on the dial

ive only had a cursory listen so far, but its immediately obvious that the benz is rather outclassed.i was too impatient to wait to try it with the garrard so its on the yamaha. i'll give it a thoroughly anal setup later.

but my jaw hit the floor after listening to side 2 off floyds the wall. very very very good. i see why will likes his so much and the spu has such a following

thanks for selling it to me colin!

Toppsy · Post by **Toppsy** » Fri Oct 09, 2009 6:12 pm

Glad you are enjoying it Anthony. It does have a certain charm if a bugger to drive.

I am still very pleased with my Rondo Bronze and it would have been a bit of a challenge to modify my phono stage to use both the SL15 and Rondo. And I needed the cash.

cressy · Post by **cressy** » Mon Oct 12, 2009 11:23 am

ive had a weekend to listen to the sl15 and i have to say im very impressed thus far. tracking weight has been set to 1.5g, vta is slightly off as the arm wont go up far enough

so it is slightly down at the back.

imaging is brilliant with this thing, better than the benz and the smoothness it has to the presentation is a real plus and gives the cart a relaxed quality. not too relaxed, as a blast of the 1812 overture showed! neighbours didnt take kindly to the canons............(in trouble again

)

only thing im not sure of is the tracking weight. any suggestions? i see it'll go up to 2g but on reluctant to go too high given the perfect stylus. is there a 'sweet spot' for the tracking weight?

Mike H · Post by **Mike H** » Mon Oct 12, 2009 11:31 am

Try it a quarter gram each way?

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Toppsy · Post by **Toppsy** » Mon Oct 12, 2009 3:09 pm

is there a 'sweet spot' for the tracking weight?

Ant,

you could try Henley Designs. They are the official UK importers for Ortofon.

I think I tracked it at 2.3g. Though from memory most the ortofon range of carts are recommended 2 - 2.5g.

Toppsy · Post by **Toppsy** » Mon Oct 12, 2009 3:18 pm

Ant,

Found exactly what you need.

Seems it should be 0.75g - 1.5g.

Check out the document link below page 13 of 14.

http://forums.klipsch.com/forums/storag ... rs-212.pdf

Mike H · Post by **Mike H** » Mon Oct 12, 2009 7:03 pm

See also the bit at the bottom about the transformer?

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