2. analog
  3. 1323961908

Einstein TTC phono - Making Loading Plugs Help

My Turntable's Choice Unbalanced phono comes with 40, 85, 150 and 300 ohm loading RCA plugs. I need to make a "100ohm" loading plug. Measuring the true resistance of the plugs yields:

40 - 40ohm
85 - Not measured
150 ~ 220ohm
300 ~ 820ohm

So obviously I cannot use a 100hm resistor in this case. Any gurus can advise what resistor value I should use for an actual 100ohm loading for my Lyra Helikon SL cart?

Many thanks in advance!
shsohis
intactaudio
301 posts
 
To me your results suggest an unloaded input impedance of 470 ohms (By chance does it use a 1:10 SUT?)

In any case the numbers work out close enough and you just need ot find the resistor to use in parallel with 470 ohms to get your desired load. To get 100 ohms you need a 127 ohm loading plug.

dave

Measured R__Actual Load=(R*470)/R+470)
40__________37
85__________72
220_________150
820_________299
127_________100
Ag insider logo xs@2x
tdaudio
201 posts
 
I had the balanced Einstein and made a couple loading plugs. IIRC the balanced unit had an imput impedence of 940 ohms (or something close to that) with no loading plugs inserted. The number was found in the owners manual. I calculated the resistors used to be in parallel with the 940 ohms.

Dave has the formula above and you can use google to get more info.

TD
shsohis OP
119 posts
 
Incredible! I'm off to get the resistor....! Thanks everyone....!
shsohis OP
119 posts
 
This is strange - Marpe is right. With the 100 ohm, the soundstage collapses and everything else becomes bloated and much less airy than with the 150 ohm. Cannot understand....
Ag insider logo xs@2x
tdaudio
201 posts
 
I run 100 or 200 ohms with my cart. There is slight but distinct difference but both work fine. If I drop down to 50 the life is gone. At some point a cartdrige is just loaded down too much. Its not the same but its kinda like having too much VTF.

More to discover