Siemens - Klangfilm

Introduction / Overview

Klangfilm History

Moving Coil MC preamps

KLV Eurodyn Rack Amps

KLV Preamps

Output Transformers
Siemens 2000 Amps

6SELA Preamps

6SELA Power Amps

6SELA Tuners

Spare Parts

Typical Tubes




Eugen Bauer

Siemens / Klangfilm 714102 Output Transformer  


 a1 - a2: secondary 200 Ohms

 a4 - a6: feedback winding #1

 a8 - c8: feedback winding #2

 c4 - c2 - c6: plate #1 - B+ plate #2

  Originally the output impedance is 200 Ohms with two secondary windings in series.

Wired in parallel the output impedance will be 50 Ohms (Maintaining the same primary impedance).


How to lower the output impedance:

1. Take the (green isolated) centre tap of the secondary winding off the gap between the coil and the core.

2. Dissolder the two leads.

3. Use an Ohm meter to find out which one of the leads is not connected to a1. This is necessary to get the windings well phased.

4. Connect this wire to a1.

5. Solder the other wire to a2.


  As the secondary impedance can be lowered by using the OPT with an application that requires a lower impedance on the primary side than EL34s, this OPT will work well enough on 16-32 Ohms speakers.  Keep in mind that such a design will not allow to get the full output power from this transformer.

 These changes are NOT recommended for use in the original 6SELA 2754, 6SELA 2735 or KLV 551 design.