Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Simplistic NJFET RIAA
Simplistic NJFET RIAA
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th October 2011, 04:56 PM   #6891
merlin el mago is offline merlin el mago
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by nicoch46 View Post
HI Andrew

you are welcome to help us on load difference active vs passive
That's confusing, doesn't exist active or passive load because step-up are also passive like resistors.
  Reply With Quote
Old 13th October 2011, 05:07 PM   #6892
nicoch58 is offline nicoch58  Europe
diyAudio Member
 
Join Date: Oct 2004
Dear friends I thinks the word step-up is confusing.....

Fact are :

the cinemag load the denon at 40 ohm and lot on web with different trafo are at 100ohm , (no commercial one)

jfet Salas at 400 to 1k

this is a big difference ...why ?
  Reply With Quote
Old 13th October 2011, 05:14 PM   #6893
merlin el mago is offline merlin el mago
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Step-up confusing because of the nonlinearity of the impedance transformation, as said before the impedance differs by the square of the turns ratio.

The difference is passive (step-up) vs active pre-amplification for MC cartridge, is other history.

Last edited by merlin el mago; 13th October 2011 at 05:18 PM.
  Reply With Quote
Old 13th October 2011, 05:20 PM   #6894
pieter t is offline pieter t  Netherlands
Account disabled at member's request
 
Join Date: Apr 2009
Quote:
Originally Posted by merlin el mago View Post
Step-up confusing because of the nonlinearity of the impedance transformation, as said before the impedance differs by the square of the turns ratio.
What is nonlinear about that?
  Reply With Quote
Old 13th October 2011, 05:22 PM   #6895
merlin el mago is offline merlin el mago
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Impedance transformation.
  Reply With Quote
Old 13th October 2011, 05:24 PM   #6896
nicoch58 is offline nicoch58  Europe
diyAudio Member
 
Join Date: Oct 2004
Ony induttance vary with the frequency ,the turn ratio is fix ie primary/secondary turn coils ratio

this turn ratio reflect the Rinput of the active phono , End of story....
  Reply With Quote
Old 13th October 2011, 08:17 PM   #6897
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Simplistic NJFET RIAA
Quote:
Originally Posted by nicoch46 View Post
wrong:

DL-103 with a Cinemag CMQEE-3440A 36.5 turns ratio ,47Kohms / 36.5^2= 35.3 ohm
Please read the info about the Denon AU340 SUT.

The 1:10 winding works best with the DL103 and has a primary winding inductance of 40ohm. That does not mean that the cart is loaded at 40ohm because you now know it depends on the input impedance of the Riaa amp.

1:10 means 470ohm load for 47k riaa input impedance.

This Denon SUT also has another setting, in this case with a 1:33 ratio and presenting a 3ohm primary impedance. (I did not like this setting with the Denon DL103)

For a perfect explanation look for "Step-Ups and MC Cartridges | The Secrets of a Successful Marriage | Vinyl Engine." where it is stated:

<<Now, on a step-up you’ll find internal impedances indicated: for instance, take a look at a DENON AU320, two positions are possible: 3 ohms and 40 ohms. So this step-up should be good with cartridges of internal impedance of 3 ohms and 40 ohms. Now the problem is, that for the moment, the load impedance used in that step-up is not known (but we’ll soon know this very important information!). We’re only sure that this load impedance is superior to the internal impedance. And secondly, the load impedance given by a manufacturer for its cartridge is the one you should use on active devices; the one you should use on passive devices is not generally the same and is superior to the load impedance given by the manufacturer.

But, why are only internal impedances indicated on a step-up?
The main reason is certainly the fact that, as I already indicate, natural impedances are not constant: they are a function of the impedance of your MM input. For instance, if your MM input has a 10 Kohms impedance, with a 1:10 amplification>>

Enjoy
Attached Files
File Type: pdf http___www.audioinvest.no_denon_products_tr_340.pdf (127.3 KB, 44 views)
__________________
RC
  Reply With Quote
Old 13th October 2011, 08:54 PM   #6898
pieter t is offline pieter t  Netherlands
Account disabled at member's request
 
Join Date: Apr 2009
Quote:
Originally Posted by RCruz View Post
Please read the info about the Denon AU340 SUT.
The 1:10 winding works best with the DL103 and has a primary winding inductance of 40ohm. That does not mean that the cart is loaded at 40ohm because you now know it depends on the input impedance of the Riaa amp.
"primary winding inductance of 40 ohm" is a typo I guess; inductance is expressed in henries.

Looking at that specification card of the Denon AU340 SUT all I can say that they should have specified 3 resp. 40 ohms as source impedance of the particular cartridge (better still source resistance) instead of "primary impedance".
In general 3 ohm MC carts have low output, therefore need much gain (by using the higher step up ratio which should be the 1:33 option of the AU340).
At the same time the 3 ohm source impedance will need less inductance of the transformer primary; a higher impedance cartridge like the DL103 connected to the 1:33 will be very bass shy because there is not enough induction, and should therefore use the 1:10 connection. I guess that the 1:33 connection was for the low impedance DL301 series of cartridges.

Finally, the winding ratio of the step-up transformer reflects the secondary load back to the cartridge: 47k resistor as secondary load will be seen as a 470 ohms load by the cartridge in case of 1:10. This is said already, and so it is.
  Reply With Quote
Old 13th October 2011, 09:02 PM   #6899
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic NJFET RIAA
*In general don't pay much attention to specs given for such audiophile products. Most are presented in a way to serve the consumer's intuition. Many times by stating the primary with a number they just mean good for carts with this and that output impedance.
  Reply With Quote
Old 13th October 2011, 09:10 PM   #6900
RCruz is offline RCruz  Switzerland
nhinstruments
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Simplistic NJFET RIAA
Consensus at last....
__________________
RC
  Reply With Quote

Reply


Simplistic NJFET RIAAHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


New To Site? Need Help?

All times are GMT. The time now is 10:48 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki