Electron Engine ™
Printed Circuit Boards by Emissionlabs.

Last Update:

EE51 Moving Coil Board

Can be used with LL1636, LL1678, LL9226 or LL9226XL

Introduction

EE51 is a compact size version, made for LL1636, LL1678, LL9226 or LL9226XL. For the larger housing transformers, EE50 should be used, which has identical functioning. EE51 is available as ready build version, but without the transformers on it. These can be ordered with the board separate.

EE51

EE51 Order Number: 310-051-09. EE51 is partially build, as you see here. This is what you receive. Transformers must be ordered separate.

Features:

Picture of EE51 with LL1636

Picture of EE51 with LL1678

Picture of EE51 with LL9226XL

Dimensions:

Gain settings

LINE
P/N
Low
High
 High Gain: Set jumpers H1, H2, remove Jumper L.
Low Gain: Set Jumper L only, remove Jumpers H1 and H2.
Ground Lift
All of the below types, have the BEST cores ever made. These have am Amorphous, COBALT core transformer, double C-Type, with fully symmetrical windings. Meaning the windings package is used twice, there is a complete transformer on each C-half. These two are either connected parallel or in series, to get the low or high ratio.
01
1:10
1:20
Just an older type, but very good transformer. You can use it with EE51 when you have a pair around. recommended Closed
02
1:10
1:20
Medium gain.recommended Closed
03
1:10
1:20
Top model version of LL9226, with less loss, and less distortion. recommended Closed
04
1:10
1:20
Lundahl's only MC transformer with internal Faraday shield. Best product for environment with a lot of mains hum. Amorphous COBALT core transformer. Closed or open. If open, shield is activated.
05
1:16
1:32
High Gain recommended Closed
.
Explanation page: To choose between MOVING COIL transformers

Ground Lift Option (GND jumpers)

Ground lift is only used for failure finding, or for using the specially shielded LL1636 transformer, which can handle extreme hum situations. For normal use, Ground Lift it is not needed. This means, the GND Links are normally permanently inserted, giving primary and secondary a common ground.

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.

 

 

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


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

The EE51 board works with most cartridges needing a gain from 10x to 32x.

The table which is linked here, will quickly assist with the choice.

If a box is green, this is the recommended setting.

If a box is black, so no number is visible, the output signal is much too high or too low.

Special Situation, blue boxes. This may be useful for noisy pre amplifiers. A blue box generates an output signal above normal, thus improving signal to noise ratio. However it gives higher load to the cartridge, and needle damping becomes higher. This may be compensated by choosing the lowest possible damping. In case you want to go this way, ideally you can choose a green and a blue box. So in case the blue box generates too much damping, you can still go for the green box.

Here are some examples, considering the choices.

  1. Denon DL103. One of the most popular cartridges ever. LL1678 would be possible to use 1:16, it gives 3.9mV. Using 1:32 setting would give a theoretical 8.8mV, but it doesn't work well, otherwise this box would have been blue. The 8.8mV will not appear, because load on the cartridge is very high. Also it will give high frequency loss. So LL1678 makes only sense for DL103 when you already have a pair, and you want to try if it works perhaps. A better choice is the LL9226-XL transformer and set it for 1:20. This gives a nice 4.4mV, which is very good, and cartridge load is optimized, as with all green boxes.
  2. Fidelity Research FR-1 Mk3F. In the table, it has a blue box with LL1678 and 1:16. If your pre amplifier is too noisy, this by itself is the real problem. It may be solved however by choosing this blue box, and get 7.4mV signal. However there is some risk, because when it appears wrong, there is no green box setting. The official, recommended use for this cartridge is 1:10 with the transformer LL9226-XL This gives even 4.8mV which is even a very good value. So here, the recommended choice is LL9226-XL. Or, use LL1678 which has higher needle damping as intended for the cartridge.
  3. Benz Wood M2. It has only a blue box, and it is the only option anyway for this curious cartridge. Using a blue box means the damping may be higher as expected. From our side, we can only say it is a little bit risky to have only a blue box. Ask at Benz company if they advise this.
  4. Benz Micro Reference S Copper. This is a nice one for noisy pre amplifiers. In that case use the LL1678, and try it for 1:32. Though 32x gain is quite a load for the cartridge, it can take this because impedance is an incredible low 5Ohms. Even so, minimum load is low, with 40 Ohms. This is why the blue box is highlighted. In case some high frequency is lost, you can still go for the green box and get 4mV, which is a nice value. Some other brand cartridges give only 3.2mV and these are also good.

PART2. Building instructions:

 

These PCBs fit exactly into Hammond case, type 1590B3. This nice box, you can order it in five colors. Or, take any other box you like.

In Germany, this Hammond Box can be bought at Conrad. Here is a direct link to the 1590B3 in their shop.

Never test an MC transformer with an Ohms meter. This will magnetize the core permanently, sound will be distorted. For this reason, buying second hand MC transformers, is generally not a good idea.

 

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.

 

Grounding:

The PCB is double sided grounded, and the two mounting screws are also the ground connections. In general, screws of PCB's tend to get somewhat loose over the years. To prevent a bad ground connection by this, there is also a soldered ground connection. This 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.

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

Video of this system. Thank you Bratislav!

A project by Francois Bergeret from France.

Please note, we only sell the EE51 unit at the inside. The case was custom engraved very nice.

Click on this link for the company who sells the case nr 1GX140N.

sss

Thank you very much Francois!

A project by Gyula S. from Hungary

The used cartridge is here Denon DL 103R. This cartridge needs normally 1:20 step up, and the damping set to "very soft" for most tone arms. It is an ideal candidate for the LL9226 Cobalt Core transformer. The box gas engraved lettering, and a treated surface.

ss

Thank you very much Gyula!

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.