Electron Engine ™
Printed Circuit Boards by Emissionlabs

EE20 Gold Plated Multi Purpose Board. Version 2.9

Read the introduction text below here, or read about MC or Audio applications.




Introduction EE20 Board

For use with LL1544, 1544A, 1545, 1545A, 1550, 1636, 1678, 9206, 9226, 9226XL.

EE20 BoardThe connections of the popular input transformer LL1544A, LL9206, etc, and many other transformers are the same.

This series transformers has six coils. The advantage of this is the very many applications, making this concept one of the best existing. For good reason these products are very popular with HiFi studios, private users, and many OEM users.

Yet the disadvantage for DIY builders are many. The user needs to do the the wiring himself, which is difficult, because the footprint is for Printed Circuit Board. Also, having to understand the technical details of the necessary connections is only useless trouble for users who only want to get a pair of transformers working. There is a also risk for grounding concept mistakes, and wiring errors. Then, all in the end, the only way to mount the transformer is by glueing it on the chassis. Not fully realized is also, the wiring method initially chosen, may not be the best, but when "it works" nobody takes it apart any more, just to try something else. All these issues are solved with the EE20 board. In addition, the board offers some NEW connections schemes, which can be quickly tested, simply with the Piano Switch.

EE20 Board

The EE20 Board, can be used stand alone, or without the external switch board EE22. This can also be attached at a later time.

Using the external switch board, all options stay working, but the gain can be changed by a factor 2, with the external switch.

All these applications are simply done with the Piano switch, just select the settings from the table, and it already works.

Note, with a PHASE SPLITTER Application, the external Switch Board EE22 can not be used. .

Ordering examples for LL1544:

Order number What is received

LL1544
Order Number:
218-059-69

  1. Only LL1544 transformer

LL1544-Option1
Order Number:
218-392-60

  1. LL1544 transformer
  2. Board EE20, Piano Switch, Mounting hardware

LL1544-Option2
Order Number:
218-393-84

  1. LL1544 transformer.
  2. Board EE20 Piano Switch. Mounting hardware
  3. External Switch Board EE22 +Switch

 

EE20 Dimensions:

EE22 Dimensions:


Gain + tuning Options

The gain options + tuning option for the EE20 Board are many, but don't feel confused by this. It is possible to make just ONE configuration quickly, without tuning, no external components, and no measurement is needed. Initially it will always work, which takes less than than 10 minutes. Actually this is then the same as the data sheet.

From here, with the Piano switch, other applications can be selected quickly, and the best sounding gain or impedance can be found, without risk on problems or mistakes.


Mounting

There is always a small space where the EE20 board will fit in. Just a small hint, for stereo you could stack two of them on each other with longer space holders.


Grounding

The ground plane of the PCB is double sided, and via the mounting screws connected to the chassis ground. It is recommended to use an additional wire for the chassis ground, soldered to one of the 'G' connections. The advantage of this is, the board works normal, also if not attached to the chassis.


Tuning of the EE20 Board

Why is this sometimes needed?

 

Please do not see Tuning as "something difficult", the E20 board "seems to need".

The board works without tuning, just as in the data sheet. The tuning option can be activated by inserting the solder bridge J2. If not wanted, the tuning parts can be left in, just open the bridge J2 again. However tuning is elementary for good sound MC transformers for record players. For all other applications, tuning extends the linear frequency range up to 100...200kHz, or higher even, depending on the application. Below 20kHz, tuning is not needed. Yet, when you see on the oscilloscope, how a transformer works perfectly linear up to 200 kHz, by adding only a simple resistor, or a small RC combination, you would not want to leave it away. In case where Lundahl already recommends these parts, they can be added on the positions X1...X3 (See picture above).

For more info about tuning, check depending on what the application: Audio Board tuning, or Moving Coil tuning.


Changes of V2.10 vs previous versions

Board dimensions are increased, appr 5mm from each side. No other changes.
Dimensions 76x49mm
Mounting Hole distance 68.6mm and 40.6mm,

Changes of V2.9 vs previous versions
  1. More space for LL9226-XL
  2. Gold Plated PCBs