Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: DummyLoad on July 07, 2012, 08:57:12 am
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yup. back at it.
ho-hum, another PA amp. a bogen CHA10. this one's been sitting on the back porch for a couple of years. PT was replaced and replacement is junk. the OT tests fine and does not appear to have cooked. slapped a hammond 270CAX i had gathering dust in it - 500VCT @ 70mA. won't quite get me to 320V like bogen plan, but with SSR it'll be close enough.
topology: the geetar pushes the triode, the triode pushes the midget pentode, the midget pentode pushes the big pentode. pushy lot, no? never tried this before. we'll see how it works out.
chassis has been hacked and ready for stuffing, i'll start strapping in parts later today. pics coming too. maybe. if it doesn't draw a strong vacuum...
--DL
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It's no wonder you never got that Dynaco stereo done! :icon_biggrin:
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Another notch on the butt of your gun :thumbsup:
Thanks for sharing !
K
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VERY cool idea! I like it. Looking forward to the tone review.
Thanks for sharing it.
With respect, Tubenit
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I would sure like to hear a clip that shows how the tone cap switch sounds in different positions.
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The three-resistor network could be a dime cheaper:
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The three-resistor network could be a dime cheaper:
who let the bean counters in here? :BangHead:
thanks PRR! :icon_biggrin:
--DL
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finally finished the damn thing. schema attached as what went to press with telemetry... except C2 is a 10uF - i wanted a 4.7uF there, but all i had was a 10u.
not over the top gain as you'd think with the 6AU6 driving the output tube.
nice warm crunch and blues overdrive - cleans up nicely when you back up on the volume. it's very quiet - barely audible hum with all controls up and no instrument plugged in.
--DL