Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: chocopower on December 10, 2013, 05:09:44 pm
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Hi there!
2 questions:
1.- Any way to hardwire the output in the attached transformer for 8 and 16 ohm? I mean, 2 jacks or 1 jack with a switch to choose 8 or 16.
2.- That transformer is working already in a old french amp.
U.L. taps are used and i wanna disconnect them. Any change in secondaries impedance?
thanks in advance!
EDIT: Original attached file deleted due Intelectual Propierty problems.
(http://3.bp.blogspot.com/-PXY1ucj5u0k/UP_TiuXb0rI/AAAAAAAADvo/CrodEzua82s/s1600/AUDAX-TU101-1.jpg)
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attached schema should work... can it be simplified? maybe?
requires a 4PDT switch.
--pete
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attached schema should work... can it be simplified? maybe?
requires a 4PDT switch.
--pete
Thanks a lot!!!
I forget to tell that i had to switch the main outputs when i rewire from the original 16 ohm (as i get the amp) to 8 ohm.
The amp have NFB loop and i got a nice oscillation when i rewire to the 8 ohm combination.
Now, the NFB is disable, so:
Should i have any concern about the phase polarity in a amp without NFB?
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I don't think you are allowed to re-post radiomuseum's images?
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Hi,
Sorry if i did something inappropriate.
I´m a Radiomuseum member, so i though that i can do it.
If it´s a problem, i delete the file.
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Ok, i have that link from another web.
i delete the original one from Radiomuseum.
Sorry for the inconveniences.
(http://3.bp.blogspot.com/-PXY1ucj5u0k/UP_TiuXb0rI/AAAAAAAADvo/CrodEzua82s/s1600/AUDAX-TU101-1.jpg)
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I forget to tell that i had to switch the main outputs when i rewire from the original 16 ohm (as i get the amp) to 8 ohm.
The amp have NFB loop and i got a nice oscillation when i rewire to the 8 ohm combination.
Now, the NFB is disable, so:
Should i have any concern about the phase polarity in a amp without NFB?
IMO , the original NFB desing for a 16 ohms may need some different resistor value for 8 ohms. Copy value on other amp using 8 ohms and same Phase Inverter circuit.
Tu dois parler français pour être membre de Radiomuseum ?
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IMO , the original NFB desing for a 16 ohms may need some different resistor value for 8 ohms. Copy value on other amp using 8 ohms and same Phase Inverter circuit.
Tu dois parler français pour être membre de Radiomuseum ?
Sorry if i explain it wrong. I dont wanna use NFB at all. My question is about if i could have any problem connecting the OT leads in the "wrong" way. That happen when you do it wrong in a amp with NFB, isnt?
I dont speak French, but i dont need it to have my account and use the Radiomuseum archive. :dontknow:
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I dont wanna use NFB at all. My question is about if i could have any problem connecting the OT leads in the "wrong" way.
Sometimes yes , if output transformer did not see the speaker , open circuit.
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ok. i´ll check that to see if DummyLoad schematic can work.
thanks everybody and sorry for the problems i could generate posting the Radiomuseum pic.
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ok. i´ll check that to see if DummyLoad schematic can work.
thanks everybody and sorry for the problems i could generate posting the Radiomuseum pic.
I did not see any problem , you are welcome on the forum and there is not enough picture .