Electron Engine ™
Printed Circuit Boards by Emissionlabs
EE21-LT Board. Version 1.0
For Moving Coil only
For LL1681,LL1931, LL1933, LL1941, LL1943, LL1961, LL1963, LL1971
Description:
E21-LT is a 'Light' version of the more complex EE21 Board. It is made for the LARGE footprint transformers. It is intended for a typical Moving Coil application. Gain is set with the solder bridges. Termination is with a Load resistor, which is optional. This is explained at the end of this text. Input and output are for RCA connectors.
Set gain to "High" by closing the two "High" bridges. Set gain to "Low" by closing only the "Low" bridge.
Order Nr: 310-121-62
Dimensions:
- Outside Dimensions: 70 x 46mm
- Mounting holes 3.5mm. Distance 62.3 x 38.1mm
| Transformer | Board | Gain Low |
Gain High |
Core | Characteristic |
| LL1681 | EE21 | 13x |
26x |
Amorphous mu-Metal |
Studio Favorite. What goes in, ist what comes out. Only version of this series, with FARADAY Shield, for extremely low hum. |
| LL1931 | EE21 | 8x |
16x |
Amorphous Cobalt |
Best Sound of Amorphous, 6N 'Cardas' wire. |
| LL1933 | EE21 | 8x |
16x |
Amorphous Nickel |
Amorphous, Low Distortion. With 6N 'Cardas' wire. |
| LL1961 | EE21 | 3.2x |
6.4x |
Amorphous Cobalt |
Best Sound of Amorphous, 6N 'Cardas' wire. |
| LL1963 | EE21 | 3.1x |
3.2x |
Amorphous mu-Metal |
Neutral sound, Low Distortion, 6N 'Cardas' wire. |
| LL1971 | EE21 | 12x |
24x |
Amorphous Cobalt |
Best Sound of Amorphous, 6N 'Cardas' wire. |
| LL1941 | EE21 | 1:16 |
1:32 |
Amorphous Cobalt |
Best Sound of Amorphous, 6N 'Cardas' wire. |
| LL1943 | EE21 | 16x |
32x |
Nickel |
Clean sound, Low Distortion, 6N 'Cardas' wire. |
Mounting
Hint: For stereo you could stack two Boards on each other, with long space holders.
Solder Bridges
The solder jumpers are simply closed by a drop of solder. No need to use wires for this. This drop can easily be removed with a solder iron, no desoldering tool is needed. The PCB is high quality, and the jumpers can be closed and opened multiple times.
Grounding
The ground plane is shielded on both sides. In this way, also shielding the openings at the bottom of the transformer. The PCB ground is connected to the transformer case, and to transformer inner the static shield (if the transformer has one).
Termination for Moving Coil
Initially MC applications will work well without termination. In this case the cartridge will be damped very soft, by the internal impedance of the Phono amplifier. For additional damping, add a termination resistor, where it said "Load" on the PCB. This 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, enough damping is already given by the RIAA amplifier, and no additional load is needed. Generally, If the high tones begin to disappear, there is too much damping, and the resistor must be changed to a higher value, or even leave it away, .
The value of the damping resistor can only be found by experiment. Begin with 220k, and use a smaller value until the problem is resolved. Alternatively, 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.