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Audio and Video Talk
Valves / Vacuum Tubes
How to design a Power Transformer for a Push-pull tube amplifier?
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<blockquote data-quote="handsome" data-source="post: 195099" data-attributes="member: 772"><p>hehehe well the 3dB point is at 17kHz which probably rules out all of us ahem older folk. you can try putting the original pot back in and listening for a change around the 1 - 4 o' clock mark i seem to recall hearing a difference a while back using a 250k pot on a 12AU7 preamp.</p><p></p><p>if you are looking to have some fun fiddling....why not try upping the current through your VR tubes? there is a school of thought that holds thus: the signal current is a varying quantity. the more shunt current one dials in the more the signal current becomes a smaller portion of the overall current drawn. in an extreme case if the signal current was 1mA and the shunt current was 100mA the signal current is therefore only 1% of the total current draw thus the entire PSU system is effectively stable with no variation and any perturbations are 'swallowed' by the shunt. in your case however you have a choke in between the shunt and the preamp which presents a very high AC resistance....but give it a go (within reason of course - mind the total current that the VRs can draw) see if there is an improvement/change?</p></blockquote><p></p>
[QUOTE="handsome, post: 195099, member: 772"] hehehe well the 3dB point is at 17kHz which probably rules out all of us ahem older folk. you can try putting the original pot back in and listening for a change around the 1 - 4 o' clock mark i seem to recall hearing a difference a while back using a 250k pot on a 12AU7 preamp. if you are looking to have some fun fiddling....why not try upping the current through your VR tubes? there is a school of thought that holds thus: the signal current is a varying quantity. the more shunt current one dials in the more the signal current becomes a smaller portion of the overall current drawn. in an extreme case if the signal current was 1mA and the shunt current was 100mA the signal current is therefore only 1% of the total current draw thus the entire PSU system is effectively stable with no variation and any perturbations are 'swallowed' by the shunt. in your case however you have a choke in between the shunt and the preamp which presents a very high AC resistance....but give it a go (within reason of course - mind the total current that the VRs can draw) see if there is an improvement/change? [/QUOTE]
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Audio and Video Talk
Valves / Vacuum Tubes
How to design a Power Transformer for a Push-pull tube amplifier?
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