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Transformer ratio??

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Posted on March 10, 2017 at 05:59:37
Tubenstein
Audiophile

Posts: 159
Joined: August 5, 2011
My friend sent me this circuit and looks very simple.

200v B+ seems a bit low, right?

What is the transformer ratio would work for this circuit??

 

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the circuit, posted on March 10, 2017 at 06:00:24
Tubenstein
Audiophile

Posts: 159
Joined: August 5, 2011



Here you go

 

RE: Transformer ratio??, posted on March 10, 2017 at 10:30:19
6AS7_6SN7
Audiophile

Posts: 678
Joined: September 10, 2009
It depends on the load impedance (an earphone I suppose).
If both triodes have a nominal bias close to @15 mA/@ -2V and the earphone nominal impedance is 32 Ohm than I would guess something close to 1:4/1:5 voltage ratio.



ecc230

 

RE: Transformer ratio??, posted on March 10, 2017 at 20:59:21
Tubenstein
Audiophile

Posts: 159
Joined: August 5, 2011
What about the primary impedance of such a line output transformer?

 

RE: Transformer ratio??, posted on March 11, 2017 at 14:08:42
6AS7_6SN7
Audiophile

Posts: 678
Joined: September 10, 2009
IThe primary impedance is equal to load impedance (32 Ohm in the example) times the voltage ratio (1:4 to 1:5 in the example) squared, that is, from 4 X 4 X 32 = 512 to 5 X 5 X 32 = 800 Ohm.



ecc230

 

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