Electron Engine ™
Printed Circuit Boards by Emissionlabs.

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EE50 and EE51 Moving Coil Boards

 
LL1636, LL1678, LL1681, LL1931, LL1933, LL1941, LL1943, LL1961, LL1963, LL1971, L9206, LL9226(XL)
LL1636, LL1678, LL9226 or LL9226XL

EE50 for large and small transformers
Kit or ready build

EE51 Compact size, only for small transformers
Only ready build

Bare PCB without connectors: 104 x 67mm
Height with transformers mounted: 30mm.

Bare PCB without connectors: 94 x 60mm
Height with transformers mounted: 25mm
Order Numbers:
310-050-09. Kit.
310-150-52. Kit wihout RCA connectors.
310-250-93. Ready Build

Order Number:
310-051-09. Ready Build
Transformers must be ordered separately. Housing not included

 

Introduction

EE50 can work with most Lundahl small and large size transformers. EE51 is a compact size version, it can work only with small size transformers. Electrically their function is the same.

Features:

Pictures: EE51: With LL1636, With LL1678, With LL9226XL

Gain Settings with Jumpers H1, H2, L

Line
PCB
Input
H1+H2
L
Core
Characteristic
Ground Lift
Frequency
01

EE50,
EE51
1:20
1:10
Amorphous Cobalt
 Lundahl's only MC transformer with internal Faraday shield. Best product for environment with a lot of mains hum. Closed or open. If open, shield is activated. 10 Hz--25 kHz @1dB
02
EE50,
EE51
1:32
1:16
Amorphous Cobalt
 High Gain recommended Closed 10 Hz--35 kHz @1dB
03
EE50
 LL1931
1:16
1:8
Amorphous Cobalt
 Wound with 6N 'Cardas' wire. Best Sound of Amorphous. Recommended Closed 10Hz--100kHz @1dB
04
EE50
 LL1933
1:16
1:8
Amorphous Nickel
 Wound with 6N 'Cardas' wire. Also amorphous sound, but cleaner as cobalt. Recommended Closed 8Hz--100kHz @1dB
05
EE50
 LL1681
1:26
1:13
Mu Metal
 Much preferred product by professional users. Has internal shield, for very low hum. Neutral sound. Closed or open. If open, shield is activated.
7Hz--55kHz @ 1dB
06
EE50
 LL1941
1:32
1:16
Amorphous Cobalt
 Wound with 6N 'Cardas' wire. Best Sound of Amorphous. Recommended Closed 10Hz--100kHz @1dB
07
EE50
 LL1943
1:32
1:16
Amorphous Nickel
 Wound with 6N 'Cardas' wire. Best Sound of Amorphous. Recommended Closed 8Hz--100kHz @1dB
08
EE50
 LL1961
1:6.4
1:3.2
Amorphous Cobalt
 Wound with 6N 'Cardas' wire. Best Sound of Amorphous. Has internal shield, for very low hum. Closed or open. If open, shield is activated. 12Hz--100kHz @1dB
09
EE50
 LL1963
1:6.2
1:3.1
Mu Metal
 Wound with 6N 'Cardas' wire. Neutral sound Closed or open. If open, shield is activated. 20Hz--100kHz @1dB
10
EE50
 LL1971
1:24
1:12
Amorphous Cobalt
 Wound with 6N 'Cardas' wire. Best Sound of Amorphous. Has internal shield, for very low hum. Recommended Closed 10Hz--100kHz @1dB
11
EE50,
EE51
1:20
1:10
Amorphous Cobalt
 Just an older type, but very good transformer. You can use it with EE50 when you have a pair around. recommended Closed 10Hz--90 kHz @ 1.5B
12
EE50,
EE51
1:20
1:10
Amorphous Cobalt
 One of the best transformers. recommended Closed 5Hz--100kHz @ 1.5dB
13
EE50,
EE51
1:20
1:10
Amorphous Cobalt
 Top model version of LL9226, with less loss, and less distortion. recommended Closed 4Hz--90kHz @1.5dB

.

Explanation page: To choose between MOVING COIL transformers

 

Damping Settings with Jumpers A, B, C, D

This is for EE50 and EE51

 

Damping

 
Cartridge Load at 1:10
Cartridge Load at 1:16
Cartridge Load at 1:20
Cartridge Load at 1:32
A
B
C
D
Gnd
Very soft
-
-
-
-
X
470Ohms
184Ohms
118Ohms
46Ohms
Soft
X
-
-
-
X
390Ohms
152Ohms
98Ohms
38Ohms
Medium
X
X
-
-
X
320Ohms
125Ohms
80Ohms
32Ohms
Hard
X
X
-
X
X
280Ohms
109Ohms
70Ohms
27Ohms
Very Hard
X
X
X
-
X
190Ohms
74Ohms
48Ohms
19Ohms

Ground Lift Option with Jumpers Gnd

Function of the Gnd Jumpers:

If Gnd Jumpers are inserted, Input Ground and Output Ground become connected to each other, which is the normal use.

If Gnd Jumpers are removed, the primary and secondary becomes isolated from each other, which is only needed for for failure finding, or for using the special LL1636 transformer, which has a Faraday shield. LL1636 is used for very difficult environment.

There are two Gnd jumpers, these either must be BOTH inserted or BOTH be removed.

Needle damping Setting

Too much damping gives loss of high frequency, and loss of stereo information, which is embedded mainly in the high frequency range. That is because faster needle movements (as needed for high frequency) get damped a lot more. The stereo information is coded in the vertical needle movement, which get damped just as well.

Not enough damping leads to reduced groove contact during loud sound parts, which is a form of distortion. Because of the V-shape of the groove, the needle will be forced a little bit higher up in the groove, which is not where it should be. In severe cases it can even cause the needle to skip a groove with very loud music parts. This is mistakenly judged sometimes as a bad adjustment of the tone arm. Though increasing the needle pressure may also help, you would be curing it at the wrong place.

This is why we recommend to take as much as possible damping, but not exceed the point where you begin to loose high frequency. If that happens, you would also loose stereo information. The only good way is simply try it out. Here is some more information about needle damping.


Note: The Jumper A is used for the settings as you can see. But in fact, it switches the damping of the EE51 on or off. When off, this leaves only the damping of the RIAA amplifier, which is always a "Very Soft" damping. For instance, when set for "Hard", with jumpers A-B+D, just by removing Jumper A, you go from "Hard" to "Very soft". Like this you can quickly compare the effect, while playing music. This works for the other settings as well.

Settings for some cartridges

EE50 and EE51 boards work with most cartridges needing a gain from 3x to 32x.

Complete table here

 


PART2. Building information:

The smalller size EE51 fits exactly into Hammond case, type 1590B3 (116x77x38mm). This nice box, you can order it in five colors. Or, take any other box you like. The slightly larger EE50 fits in Hammond case 1590BBS (120x94x42). This is blank metal. It can be ordered in color too, for instance for green, add GR, and the Hammond Numver is 1590BBSGR.

 

NEVER test an MC transformer with an Ohms meter. This will magnetize the core permanently, and sound will be distorted. For this reason, buying second hand MC transformers, we strongly recommend against it. For testing, connect a small AC signal to one of the coils, and the windings ratio must appear on the other coils.

Grounding:

The PCB is has a ground plane on each side, which are both connected to the "Gnd" connection of the PCB. This "Gnd" connnection of the PCB should be connected with a wire, to the ground plug of the metal case. If the chassis is colored or surface treated (such as passivated aluminum), remember to clean the metal beneath the screw

In addition to the four RCA Connectors, the metal case needs also a ground screw at the outside, which connects to the record player, with a simple single wire. Since Dec 2023, this ground screw is also provided, a nice gold plated version.

Fault finding hints

This MC unit designed to work right away. If there is hum however, the EE51 board has a some modes for fault finding

Fault finding methods.


 

A project by Bratislav S. from Serbia, Belgrade.

Please note, we only sell the EE51 unit at the inside. Our customer send us these nice, inspiring pictures of his EE51 build.

ss

Thank you Bratislav!

More Projects

Drilling holes for the connectors

Above each connector is a dummy hole in the PCB. This can be used as template for the drilling holes. Here is a hint you may like: When drilling holes in Aluminum, use alcohol as a lubricant, and then drill at low speed. This gives a much nicer drill hole. You won't believe this if you have never tried it.

 

After drilling, the result should look like this. This is for EE51.