Question about phono preamp loading plugs...

Hello,

I currently have a Musical Fidelity LX LPS on loan. It's a nice little phono preamp with MM/MC inputs. As an added feature, it has extra inputs for (1 pair each for MM and MC) for impedance matching. Here are the specs:

MM

• Input Impedance: 47 KΩ
• Input Sensitivity: 3.0mV
• Total Harmonic Distortion: 0.01%
• Signal to Noise Ratio: >80dB
• Input Overload Margin: 15dB

MC

• Input Impedance: 100 Ω
• Input Sensitivity: 300μV
• Total Harmonic Distortion: 0.01%
• Signal to Noise Ratio: >70dB
• Input Overload Margin: 22dB

Included Accessories

• Power Supply
• 2 x 100 ohm RCA Plugs (Green for MC loading)
• 2 x 47pF RCA Plugs (Blue for MM loading)

So my question is, what effect would these loading plugs have if i used them? The cartridge in use is a Denon Dl110. Also, if ever i opt for a low output MC (like the Denon 103), would the input impedance of 100 ohms be enough? Furthermore, the manual says that these loading plugs could be modified in order to accommodate most cartridges. I hope someone can explain this in simpler terms. Thanks in advance!

 

Basically you solder in a capacitor.
The value being what you requires
You can buy additional plugs. You can mute your pre, and quickly change plug and carry on listening ASAP.
This way you can determine the best value.
Pink noise is the best to get this right .

 

100 ohms is perfect for the DL-103.

Some people will load the DL-110 differently than the "standard" 47 K, but I have no experience with this.

Here's some info & calculator from Mr Hagerman. Hagerman Technology LLC: Cartridge Loading

Here's a calculator for parallel resistance if you solder up your own RCA loading plugs. Parallel Resistor Calculator R1 + R2 = equivalent resistor R resistance circuit equiv total resistor finder made easy piggyback = parallel - sengpielaudio Sengpiel Berlin

Making up your own RCA loading plugs can be tedious, but it allows you to really dial in the sound of your cartridge.


I've made up a lot of RCA resistor plugs for moving coils, but haven't made any cap plugs for MM's yet.

 

Thanks a lot for your replies guys!

 

BTW, I tried this and the sound quality was noticeably reduced so I went with my preset loadings. Could have been bad solder since I suck at that. But keep ears open