Siemens - Klangfilm
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Output Transformers
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| Siemens / Haufe Input Transformers - Tech Site | |||||||||
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This page will give technical advice how to use Siemens / Haufe input transformers as step up transformers for Moving Coil pick up cartridges. |
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| 1. Determine the input and output winding(s) | |||||||||
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Before thinking of using them as input transformers, be sure you really have a pair. Similar looking units can be pretty different!
For step up input
transformers (as T41, T42, T110 a.s.o) goes:
3 and 500 Ohms 1.5k and 8.5k. Even transformers coming from the same preamp can be different. T41s i.e. range between 350 and 450 Ohms on the primary and 7.5k and 8.5k on the secondary windings.
Many transformers have a pair of twisted leads which represent the
input winding. Caution! Many windings are defective. Connecting higher output or active units to the input transformers many input windings have been killed. If you do not find a pair of working winding this may be your case. |
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Matching is recommended if possible... |
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| 2. Built the trannies into a case or into your amp | |||||||||
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I recommend using different input transformers for different cartridges (as T41 for Denon DL-103 or T110 for the EMT Tondose), so that impedance matching (adaption with resistors) is not necessary. | ||||||||
| I wire as seen left. The (twisted) primary winding to the input jack, a jumper connecting the ground connectors of the RCA jacks and then the ground cables and the secondary winding to the output jack. | |||||||||
| It is very important to properly phase the windings (never trust the colors of the leads). Using a scope this is pretty easy. | |||||||||
| Out of phase | Properly phased | ||||||||
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| inside the transformers | |||||||||
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Under the yellow or orange tape the mu metal shielding cans can be seperated to look inside the transformer. |
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In many cases the PU foam has dried out and does not keep the winding in its correct position. This is not audible, but the thin cables can be cut when the transformer is shaken. |
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Another way of matching is to measure the impedance curve of the transformers (left).
Residual magnetism
(dtsch. Remanenz): Using a digital ohm meter I could never measure
any negative effects.
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