Just thought it was pretty obvious, that connecting 91 volts DC to a coil that is directly coupled to ground would be as good as a short
And indeed, this particular Tamura is ungapped and generally unremarkable (not permalloy).
Luckily, even if you short the cap out it will still not blow
Draw you badly the schematic?
What's the purpose of OPT having the output coupling capacitor?
To stop dc flowing through the transformer.
What's the purpose of OPT having the output coupling capacitor?
Hi Merlin,
If the capacitor wasn't there, the plate voltage of the tube would be very low and performance wouldn't be good. Also, the core of the transformer would have a large DC component which would shove the operating point up into a very non-linear portion of the B-H curve.
analog_sa gave you the answer to this question.
-Chris
If the capacitor wasn't there, the plate voltage of the tube would be very low and performance wouldn't be good. Also, the core of the transformer would have a large DC component which would shove the operating point up into a very non-linear portion of the B-H curve.
analog_sa gave you the answer to this question.
-Chris
Apart from a few resistors used for the LED supplies there are none in the audio path or inductor's (excluding transformers). The small transformers in the preamp are used for balanced input and output and do not feature if just rca input and outputs are used.Hi merlin,
I would believe that if I could see a resistor in the ground return to generate that bias voltage. It's probably there and is simply missing as an error in the schematic.
A corrected schematic would be nice so we don't have to guess at things.
-Chris
The amp is currently all back together but I have a NOS Tung-sol JTL5687 to fit some time soon so I'll remeasure any voltages people are interested in.
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