Hello,
I'm building a 2 x EL84 18 - 20 watt box. I will be using an Edcor CXPP25-8K OT. My question is will using the screen taps of the OT be Okay? Or should I have screen resistors off the HT? (PT=550v ON it's taps)
I'm seeing a pretty wide range of of screen resistors and thought maybe just using the OT taps would be best.
Screen Taps for 18 watters?
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- martin manning
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Re: Screen Taps for 18 watters?
No reason you can't try it both ways. Even using the UL taps a small screen resistor can be included. Experiment a bit and see what you like.
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Re: Screen Taps for 18 watters?
Are you running a rectifier tube, or SS?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Screen Taps for 18 watters?
Magnatone had a family of amps in the mid '60s. Output is a pair of 7189 (high voltage EL84) into UL tapped primary. Their transformer is similar to a Dynaco Z565, with larger core & winding than typical 18W. Different preamp and tone controls from the 18W classic. It's a clean amp, warm jazz to country twang.
Video demo provides a good tone sample ---
As Martin suggests, experiment and see if works for you. Easily made switchable.
Best .. Ian
Video demo provides a good tone sample ---
As Martin suggests, experiment and see if works for you. Easily made switchable.
Best .. Ian
Re: Screen Taps for 18 watters?
Thanks for the replies; I think a switch might be in order. I definitely want the amp to be overdriven, sometimes a lot. I've used the preamp in another of my designs, the Harlow, and it's got plenty of guts. So after reading up more on UL screen configs I may want to use it to clean up the tone a bit when needed. But mostly not. In fact, I'll leave the leads long enough to use but not hooked up initially. I'm thinking 470R - 1K screen resistors to be kind to the tubes. Then if it's necessary the UL taps can be hooked up to a switch (I'll leave a space on the front panel).
Anyway, thanks again for the replies and advice. As always, this place rules.
Anyway, thanks again for the replies and advice. As always, this place rules.