Electron Engine ™
Printed Circuit Boards by Emissionlabs
EE20 Multi Purpose Board
Please read introduction before selecting Moving Coil or Audio - Moving Coil, Applications
- Moving Coil, Tuning
- Audio Board, Applications
- Audio Board, Tuning
Introduction EE20 Board
For use with LL1544, 1544A, 1545, 1545A, 1550, 1636, 1678, 9206, 9226, 9226XL.
This series transformers has six coils. Resulting in 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 OEM users.
Yet these transformers are not intended for soldering wires directly on it. Though this is possible, and people do it, this causes sometimes damage. Also hand wiring is difficult, because the pin distance is very small, same as standard IC's. Having to understand the technical details of the necessary connections is difficult for users who only want to get the transformers working quickly. There is a also risk for grounding mistakes, and wiring errors. Often there is more than one way to connect everything, and the user begins of course with the most obvious. Once this works, nobody takes it apart any more, just to try another wiring. Besides, the pins are made for one time soldering only. At repeated soldering they can become loose, breaking off the internal wires. Finally, the only way to mount the transformer is by glueing it on the chassis.
All these issues are solved with the EE20 board.
In addition, this board offers several NEW connections schemes, which are not in the data sheet. We list those in the selection tables, together with the classic schemes. All of these can be quickly tested, simply with the Piano Switch.
The EE20 Board, can be used stand alone, or without the external switch board EE22. This EE22 board can also be attached at a later time.
Using the external switch board EE22, all options stay working, but in addition the gain can be changed by a factor 2, with the external switch.
All these applications are selected with the Piano switch, just select the settings from the table, and it works immediately.
Note, with a PHASE SPLITTER Application, the external Switch Board EE22 can not be used.
EE20 Dimensions
- 70x40mm. Mounting holes 3.5mm. Hole distance 63mm x 32mm.
- Vertical space needed: Depending on transformer: appr 28mm
EE22 Dimensions
- PCB: 30 x 35mm. Drill hole for switch: 6mm
Gain + tuning Options
It is possible to make a configuration quickly, without tuning. No external components, and no measurement is needed. Initially it will always work. Actually this is then the same as the data sheet. If you want, in addition you can do some tuning, but wait with that until it works initially. With the Piano switch, all applications can be selected quickly, and the best sounding gain or impedance can be found, without risk on problems or mistakes.
Mounting 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: 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 which E20 needs, or otherwise it doesn't work.
The board works without tuning, just as in the data sheet. Tuning is only an option. 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 can be helpful for MC applications, when the needle jumps out of the groove. For all other applications, tuning extends the linear frequency range up to 200kHz, depending on the transformer application. If you are satisfied with a flat 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 probably. 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.