Electron Engine ™
Printed Circuit Boards by Emissionlabs

Last Update:

EE20-LT Gold Plated Board. Version 1.0

For Moving Coil or Audio Input.

Use with LL1544(A), 1544(A), 1550, 1636, 1678, 1926, 9206, 9226(XL)

Description:

E20-LT is a 'Light' version of the more complex EE20 Board. It is made for the SMALL footprint transformers. Gain is set with the solder bridges, and most typical gain options are possible. Termination is with a Load resistor, which is optional. This is explained at the end of this text. Input is for RCA or XLR. Output is for RCA.

Set gain to "High" by closing the two "High" bridges. Set gain to "Low" by closing only the "Low" bridge.

Close the Gnd bridge, connects In- to Ground. If left open, In+ and In- can be used for an XLR connector. This can be done for Line input Applications.

For Moving Coil, XLR inputs is generally not recommended. Though you can try it on your own risk, and it makes only sense with LL1636. All other MC transformer for this board need RCA.

EE20 Board

Order Nr: 310-120-38

MC Applications:

  1. Moving Coil, 1:10, 1:16, 1:20, 1:32
  2. RCA input for Moving coil.

Audio Applications (line input):

  1. Audio 1:1, 1:2, 1;4, 1:8
  2. Balanced or unbalanced input possible.
  3. Step up transformer or 1:1 Isolation

EE20-LT Dimensions:

Moving Coil
 
Low
High
Termination
Gnd
LL1678, Amorph
Data sheet
1:16
1:32
Closed
LL9226-XL, Mu-Metal
Data sheet
1:10
1:20
Closed
LL1636, Amorph
Data sheet
1:10
1:20
Open or closed

 

Audio Input
 
Low
High
Termination
Gnd
LL1544A, Amorph
Data sheet
1:1
1:2
3k9
Closed
LL1545A, Mu-Metal
Data sheet
1:1
1:2
3k9
Closed
LL1550, Amorph
Data sheet
1:4
1:8
6k8
Closed
LL1926, Mu-Metal
Data sheet
1:4
1:8
6k8
Open or closed

 

Mounting

Hint: For stereo you could stack two Boards on each other, with long space holders.

Solder Bridges

The solder bridges are simply closed by a drop of solder. No need to use wire pieces. This drop can easily be removed with a solder iron, no desoldering tool is needed. The PCB is high quality, and the bridges can be closed and opened multiple times.

Grounding

The ground plane is shielded on both sides. In this way, also closing the small openings at the bottom of the transformer by static shielding. The PCB ground is connected to the transformer case, and to transformer inner the static shield (if the transformer has one). The primary side has a floating ground, which by he user's choice can be connected to the Signal Ground, by closing the solder bridge "Gnd" or can be left floating for XLR or floating RCA connectors or for other reasons. This system makes the board universal.

Termination for Moving Coil

Initially Moving Coil applications will work well without termination. The termination is done, by adding a termination resistor. This will give additional needle damping. It may be required if the needle jumps out of the groove with loud recordings, or in buildings with a wooden floor.

In some cases, if the sound is harsh at high signal, this means the needle is not following the groove correctly, due to not enough damping. If such problems do not occur, sufficient damping is already given by the RIAA amplifier, and no termination is needed.

If additional damping is needed, it can be found by experiment. Begin with 220k, and use a smaller value until the problem is resolved. Best is probably connect a potentiometer of appr 220k, and slowly decrease the value. If a good value was found, measure the potentiometer, and then mount a resistor of this value. Generally, If the high tones begin to disappear, there is too much damping, and a good setting must be found somewhere in between.

Termination for normal Audio signal (not moving coil)

Values are not very critical. The values in the table are recommended by Lundahl. This improves square wave response, expands the high frequency range, far into the ultra sound.