Electron Engine ™
Printed Circuit Boards by Emissionlabs ®

For LL1620, LL1623, LL1627, LL1679, LL9202
The boards work on all Versions, SE, PP and Parafeed (PPZ)

EE16 + EE17 Board + Switch. Order nr: 310-022-29
EE18 + EE19 Board + Switch. Order nr: 310-024-89
EE32 + EE17 Board + Switch. Order nr. 310-032-00

These boards eliminate the need to understand this difficult situation with ALT-B, ALT-C, etc. Just look in the table, and make your choice.

Headroom with Lundahl Transformers.

There is some reserved output power for head room, included in the specifications. The intention of this is, to make the specification and transformer choice easier. So head room is ALREADY added by Lundahl. When they say 25 Watt, that means 25Wattt + headroom. In this way, the output power is guaranteed at the combination of maximum output power and maximum DC current for Single ended, with the specified maximum distortion. In a practical situation, you may not use the full output power and /or not use the full DC current. If so, the distortion will be less than the guaranteed maximum. How much better, is very difficult to say of course, but the surprise will always be in your advantage.

These Boards allows following impedances:
Trans-former
Input Impedance
Output Power SE
Output Power PP
Set the switch to 'Low' Position
Set the switch to 'High' Position
Board + Switch Combination
650Ω
50W
100W*
EE16-EE17
1k2Ω
25W
100W*
EE16-EE17
1k2Ω
25W
100W*
16Ω
EE18-EE19
1k6Ω
50W
100W*
EE18-EE19
3kΩ
25W
100W*
EE16-EE17
3kΩ
25W
100W*
16Ω
EE18-EE19
3k3Ω
50W
100W*
EE18-EE19
4k5Ω
20W
100W*
EE32-EE17
5k6Ω
13W
62W
16Ω
EE16-EE17
6kΩ
25W
100W*
EE16-EE17
6kΩ
25W
100W*
16Ω
EE18-EE19
6k5Ω
50W
100W*
EE18-EE19
9k7Ω
9W
45W
16Ω
EE32-EE17
11kΩ
25W
100W*
EE16-EE17
11kΩ
25W
100W*
16Ω
EE18-EE19
11k5Ω
13W
62W
16Ω
EE16-EE17
23kΩ
13W
62W
16Ω
EE16-EE17
* Output power is limited at 100 Watt at 4Ω. Switch may only be used with the amplifier off.

 

This combination will switch from the low to the high impedance in the above table.

Switch Board EE17 or EE19.

All transformer boards are is supplied together with the special switch, and are connected to the EE16, EE18, or EE32 board.

With EE16, the speaker can only be attached to the switch board. With the EE18 and EE32 board, the speaker can be either attached to the transformer board, or to the switch board, whatever is more convenient.

This switch can be mounted from each side of the board, whatever is more convenient for the wiring. This is a special switch, for high current application.


These boards fit on LUNDAHL Transformers LL1620, LL1623, LL1627, LL1679, LL9202
This transformer is mounted with the metal plate down. Note, '1' is on the left.

Now, the transformer has the metal plate up, but the text on the board is still readable. For this, the board EE16 or EE18 is just flipped over, and the printing will be reversed.


EE32 board for LL1679. Order Number: 310-032-00

AVAILABLE DEC 2020

The special lay out of the LL1679 transformer resulted in a dedicated board as well. This board can be used stand alone, or with the switch board EE17. If stand alone, use the solder bridges. The speaker can be connected to the switch board, or to the EE32 board. On the EE32 Board the speaker can be soldered with wires. Or use your own PCB Screw Terminal (not supplied with the board). Low impedance: Bridges E + J +O. High Impedance: Bridges B + D + N. Open all bridges in case the external switch board is connected.


DIMENSIONS for all Boards:

SALES: We have a copyright on this design.

Dual Output Impedance Solution

With Lundahl output transformers, people do not like to wire those by hand. No matter how good you can solder, it looks often not nice in the end. Another issue is wiring errors. Some errors will cause a malfunction, an you will notice. Some errors can be unclear, and the transformer still works, but performance is lower. I can tell, because I had that myself.

So, with PCB's the wiring is less, and mistakes are harder to make. Most of all it enables to switch between two output impedances. Please note, it may seem, you know the ideal impedance already, but I always recommend my customers to try out the next lower impedance too. Though this stays often theory, because people avoid the re-wiring of course. With the switched solution, it is not theory any more.

A very useful application is also when the speaker system is extremely high efficiency, like it can easily happen with the AVANTGARDE Systems, or similar horn drivers. Read also this article. The amplifier has in fact too much output power, and the remaining hum will become too loud. In that case, switching to a lower impedance will reduce the hum by 50%. Just try it out, and you will see!

Mounting of the transformer board.

The board can be mounted from either side, which reverses the printing text too. So one way or another the printing will never be upside down.

What is not possible: Do NOT rotate the board. So there is this white U-Shape marking on the board. When this is oriented the same as the transformer, the board is always mounted correct.

Lundahl Housings: The transformer board will fit nicely inside those LUNDAHL covers

Mounting of the switch board.

This little board of 4 x 4 cm only, is mounted just by the switch itself. To optimize the wiring inside the amplifier, the switch on the EE17 board may be mounted from each side. Interestingly, the board still works the same.

The switch is not a very common type, and is supplied with the board.

Preliminary Picture. Final boards are black color

For safety, the speaker connector (BLACK TERMINAL) must be grounded to the chassis.

Speaker Output transformers are always inter sectioned. So there is a primary layer, a secondary layer, a primary layer, etc. This will improve the high frequency performance. The disadvantage of this is, any isolation failure between primary and secondary, would lead to the DC high voltage on the output circuit. To prevent this, the "cold" side of the speaker output (the "Black" terminal) must always be connected to the chassis, and the chassis to safety ground. This is the connection NOT marked with a star (*) symbol. The "hot" side is marked with a star (*) symbol, and is connected to the "Red" speaker terminal. The switch should be grounded as well, so mounted at a metal part of the chassis.