+ Reply to Thread
Page 3 of 12 FirstFirst 12345 ... LastLast
Results 21 to 30 of 113

Thread: Moving Coil Cartridge loading

  1. #21
    RothwellAudio Guest

    Default

    Quote Originally Posted by Firebottle View Post
    Andrew I'm familiar with the build and circuit (not exact details) and I am sure it would be a straight swap out of surface mount resistors.
    Sorry, no offence intended - I just baulk at the thought of hand-working surface mount resistors. I avoid it if possible

  2. #22
    Join Date: May 2013

    Location: Rotherham

    Posts: 693
    I'm steve.

    Default

    I opened up the Mani for a look inside, the components on the circuit board are really tiny so I don’t think removing and replacing the input resistors is really a viable possibility. I’ve sent a message to Audio Technica UK to query the use of the ATF2 or ATF7 into a impedance of 47ohms, as yet I’ve not had any response.


    Sent from my iPad using Tapatalk

  3. #23
    RothwellAudio Guest

    Default

    Quote Originally Posted by steve-z View Post
    I’ve sent a message to Audio Technica UK to query the use of the ATF2 or ATF7 into a impedance of 47ohms...
    With a 47 ohm load there will be a 2dB reduction in signal amplitude compared to the open circuit voltage and a 1dB reduction in signal amplitude compared to the signal amplitude into a 100 ohm load, ie not a lot to worry about.
    As for any change to the frequency response, I doubt there will be any (because the source impedance, particularly inductance, is so low). No doubt others on the forum will disagree and swear that small changes in load impedance produce audible results. In my experience the load impedance isn't that significant.

  4. #24
    Join Date: May 2013

    Location: Rotherham

    Posts: 693
    I'm steve.

    Default Moving Coil Cartridge loading



    Is this graph rubbish then ?
    I certainly wouldn’t be happy with either of the lower 2 response curves

    Sent from my iPad using Tapatalk

  5. #25
    RothwellAudio Guest

    Default

    Quote Originally Posted by steve-z View Post


    Is this graph rubbish then ?
    Not necessarily complete rubbish, but maybe not applicable to the AT cartridges the OP is considering.
    The graph shows in general terms what happens when a source with a resistive and inductive output impedance is fed into different load impedances. However, with a resistance of only 12 ohms and an inductance of only 25uH the curves won't be anything like as bad as the ones in the graph. I'll check the figures and get back to you.

  6. #26
    RothwellAudio Guest

    Default

    This page illustrates what's going on with an MC cartridge and loading:
    http://www.hagtech.com/loading.html
    However, his examples use cartridges with 500mH, 50mH and 5mH inductance. Most LOMCs have much lower inductance. The Audio Technica cartridge has an inductance of only 25 micro Henries which is 200 times less than the lowest inductance in the Hagerman examples.

    Yes, the graph shows the correct form of the frequency response curves but putting in realistic values gives much flatter curves than those.

  7. #27
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 6,089
    I'm Alan.

    Default

    Quote Originally Posted by steve-z View Post
    I opened up the Mani for a look inside, the components on the circuit board are really tiny so I don’t think removing and replacing the input resistors is really a viable possibility.
    It certainly is possible, just fiddly.

    The circuit uses a low noise op-amp as the input stage so the loading will be just in parallel with the input.

    Trying the unit with whatever cartridge you get is the best approach, the resistor change is still on the cards should you wish.

  8. #28
    Join Date: May 2013

    Location: Rotherham

    Posts: 693
    I'm steve.

    Default

    Quote Originally Posted by RothwellAudio View Post
    This page illustrates what's going on with an MC cartridge and loading:
    http://www.hagtech.com/loading.html
    However, his examples use cartridges with 500mH, 50mH and 5mH inductance. Most LOMCs have much lower inductance. The Audio Technica cartridge has an inductance of only 25 micro Henries which is 200 times less than the lowest inductance in the Hagerman examples.

    Yes, the graph shows the correct form of the frequency response curves but putting in realistic values gives much flatter curves than those.
    With all the variables it looks as though it’s almost impossible to predict the outcome with any particular MC cartridge. The Youtube video I saw when a MC was tried with the Mani was with a Dynavector xx2 cartridge, this is a £1k cartridge, it also has a low coil impedance of 6ohms, so should work better into the Mani’s 47ohms input impedance, unfortunately the reviewer did not consider the combination to be optimal.


    Sent from my iPad using Tapatalk

  9. #29
    Join Date: May 2013

    Location: Rotherham

    Posts: 693
    I'm steve.

    Default

    Quote Originally Posted by Firebottle View Post
    Trying the unit with whatever cartridge you get is the best approach, the resistor change is still on the cards should you wish.
    Yes it is if money was no object, but making a purchase that doesn’t work out can be a costly mistake, that’s what I’m trying to avoid, unfortunately you can’t “try before you buy” with cartridges.


    Sent from my iPad using Tapatalk

  10. #30
    RothwellAudio Guest

    Default

    Quote Originally Posted by steve-z View Post
    With all the variables it looks as though it’s almost impossible to predict the outcome with any particular MC cartridge.
    Not at all. The only variables are the source resistance, source inductance and load resistance. 12 ohms and 25 uH is feck all and will give you a flat frequency response to within 1dB well over 20kHz. This is mathematical and factual, not youtube-generated rumour.

+ Reply to Thread
Page 3 of 12 FirstFirst 12345 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •