JTM45 Style Output Transformer
784-103

 

This transformer is a copy of the one used in JTM45 amps from
1965 to 1967. It is hand wound on a paper form and uses paper
insulation between the windings just like the old ones.

The original had secondary taps for 8, 16 and 100V. I have made
this one with an added 4 ohm tap. The 100V tap is buried and not
used. The first reason I did this is because most ohm selector switches
only have 4, 8 and 16 ohm selections on them. The second reason is the
100V tap is not used today but does effect the tone of the transformer.
So by winding the transformer in this way you gain an extra output tap
and retain the original tone of the output transformer.

 

Specifications on the 103 transformer:

Primary Impedance: 8K (KT66)
 
Secondary Taps: 4, 8, 16 Ohms W/ Buried 100V winding
 
Output Rating: 30W Conservative

 

Wiring diagrams for all Marstran transformers

Sound clip of the 103 in action.
(Thanks Eric)

All transformers are sold with hammertone covers.

 

 

 

 

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