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CuSat or Lautus from TT- Reflex- Amp'

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Post Options Post Options   Thanks (0) Thanks(0)   Quote lfc jon Quote  Post ReplyReply Direct Link To This Post Posted: 08 Sep 2020 at 7:25pm
Hi Jon
I think your right short is best. the HiFi dealers I spoken to have said the same and the online cable dealer on my last cable up grade also said go for the shortest you can get away with . But as with anything it all depends how and where you have your HiFi they also said the same for speaker cables too
 
Pro-j tt,Ortofon 2m Bronze cart,Audiolab 8300CD,GS Reflex M. Solo headphone amp both with PSU1,MF M2si amp,Monitor audio silver 100 speakers, Atlas cables
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pushpaw Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep 2020 at 3:39am
thanks for the links. 

I read these posts by Graham as well, which have helped me understand a bit better. 

What I’ve taken from it all (I might easily have gotten this wrong) I want capacitance of the cart wire + interconnect + phono stage (Reflex M) to fall somewhere between 150-250pf for an MM cart. I have Goldring 1042 by the way. So cable from TT to Reflex should be about 25 to 125pf to fall in that range, assuming 25pf cart cabling. 

Which I think means 2ish meter CuSat50 or Lautus. Am I missing anything?


Edited by Pushpaw - 09 Sep 2020 at 3:43am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BAK Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep 2020 at 1:10pm
Nutshell; 20pf (+/-5pf) tonearm + 90pf cable + 10pf total all RCA plugs + 100pf phono stage input = 220pf.
If you have a cable with 70pf, that is OK giving 200pf total...
Capacitive cartridge loading is allowed +/- 10% tolerance.

Below is the best explanation of capacitive cartridge loading I have ever seen.

Graham Slee stated all of the following ... Posted: 09 Mar 2008 at 1:15am
Either it's me or you but there's some confusion here.

The usual tonearm wiring capacitance (measured) for most tonearms I've ever encountered is around 20-25pf.

Usually tonearms come complete with fixed interconnect or a detachable by means of a 5 pin arm base connector. In the case of the P******t it looks as if the tonearm is terminated in the turntable with phono sockets.

The usual 100pf or thereabouts (90pf in this case) should refer to the tonearm internal wiring with the usual interconnect hopefully supplied with the turntable.

If the tonearm itself was to be 90pf we would have an impossible situation where (with the exception of ultra short and often impractical ultra low capacity cables as you mention here) by adding the usual length of arm interconnect cable, we would have already used up all the load capacitance before considering that of the phono stage.

The result would be a terrific loss of HF information.

So I'll repeat what I know (about 40 years experience)...

The tonearm itself contributes about 20-25pf. The cable connecting it to the phono input contributes about 70-80pf, and the total arm plus cable capacitance is 100pf plus or minus a bit.

If I have this wrong then I'd better retire now.

Now add the phono stage input capacitance which in reality will be a tad more than the 100pf cap stuck across its input because phono sockets contribute 3-5pf, and you're very close to 200pf.

If you're out by a good percentage in either direction the sound will deteriorate de-facto.

The resonant frequency if things are matched properly will be...

using

Fr = 1/ 2pi x square root of (L x C) 

(best I can do here to represent the equation because of this software's limitations - devil in the detail again!)

Fr = resonant frequency, pi = 22/7 (close), L = 500mH on average for a MM, C = 200pf

Fr = 1 / (44/7) x square root of (0.5 x 0.0000000002) = 16kHz (as near as damn it)

Why 16kHz?

because rearranging XL =  2pi x F x L to make F (frequency) the subject

F = XL / 2 x pi x L, where XL is the 47k load and L is the inductance 500mH

F = 47,000 / (44/7) x 0.5 = 15kHz (as near as damn it)

so the approximation for capacitor value is close (within 1kHz)

Therefore the loading is OK. 

(Edit: actually 220pf total loading capacitance gives an almost ideal match and therefore 90pf of actual interconnect cable looks like the ideal situation and 1.1 metres of Belden 9907 Coax - Coaxial Cable - Thinnet 10Base2 Ethernet looks tempting. I shall have to try it.)

Now try running it with different capacitances (and even different resistive loads). Too low capacity and it would peak at a higher frequency causing upper midrange losses. Too high capacity and it would peak in the upper midrange causing high frequency losses.

(Edit: And now it can be seen that some phono stage designers talk twaddle when they talk about finding better load impedances for MM cartridges - mentioning no names, and no names of reviewers who support them through their combined ignorance, in one case contradicting the meaning of his very own name...)

As for the phono stage output cable, capacitance still matters but it is not a matching capacitance as in matching a MM cartridge.

The 0.5 - 3 metre lengths of satellite cable I quoted would give 30 - 160 pf. Any more and you run into high frequency attenuation which displaces nth order harmonics, defeating the object of buying the Reflex. 

Edited by Graham Slee - 09 Mar 2008 at 3:46am


Edited by BAK - 09 Sep 2020 at 1:16pm
Bruce
AT-14SA, Pickering XV-15/625, Technics SL-1600MK2, Reflex M, Lautus, Technics SH-8066, Dynaco ST120a, Eminence Beta 8A in custom cabs;; Using Majestic DAC
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pushpaw Quote  Post ReplyReply Direct Link To This Post Posted: 09 Sep 2020 at 1:32pm
thanks, yes that post is exactly where I drew my info. It is indeed a great post. I also happen to have the make of turntable mentioned. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pushpaw Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 2020 at 3:25am
Anyone know if GS will do a custom CuSat50 Y-cable? Need it to run from Reflex M to solo ULDE and my integrated amp. If I’m going to upgrade the cables it seems kinda counterproductive to then plug them into a y-adapter that is not of the same quality. 




Edited by Pushpaw - 24 Sep 2020 at 3:26am
P******t Debut Carbon, Goldring 1042, GS Reflex M w/Enigma, GS Solo ULDE w/PSU1, Sennheiser HD6XX, Technics SU-800 IA, Castle Knight 1, PS Audio Ultimate Outlet
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ICL1P Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 2020 at 4:39pm
Send a private message to John C.
Ifor
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Reflex M, CuSat50, Majestic DAC, a Proprius pair.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pushpaw Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 2020 at 7:47pm
Thanks - actually I just realized that the Accession has 2 outputs so when I upgrade from Reflex I will not need the Y-cable. So maybe I don't need it and can deal with switching cables for a while until I upgrade.
P******t Debut Carbon, Goldring 1042, GS Reflex M w/Enigma, GS Solo ULDE w/PSU1, Sennheiser HD6XX, Technics SU-800 IA, Castle Knight 1, PS Audio Ultimate Outlet
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