Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jamesedmunda on March 19, 2021, 05:03:05 pm

Title: Inpedance of output transformer
Post by: jamesedmunda on March 19, 2021, 05:03:05 pm

Hi,
 I have a schumacker ot stamped Fender 022889, E18 606 710.
 I want to use in a Silvertone 1474 that uses 4 6l6gc.
 put 22vac into the secondary  and got 1 volt out for a 22 to 1 turns ratio which I squared then multiplied by 4 for
1936 . Does this sound right for a 4 ohm output.
 Thanks in advance, James

Title: Re: Inpedance of output transformer
Post by: 2deaf on March 19, 2021, 05:16:38 pm

022889 is the OT on Twin Reverbs and Dual Showmans, both 4-6L6 into four ohms. 

Title: Re: Inpedance of output transformer
Post by: jamesedmunda on March 19, 2021, 08:48:57 pm

Thank you

Title: Re: Inpedance of output transformer
Post by: tubeswell on March 19, 2021, 10:24:20 pm

Quote from: jamesedmunda on March 19, 2021, 05:03:05 pm

schumacker ot stamped Fender 022889, E18 606 710.
 ...
 got 1 volt out for a 22 to 1 turns ratio which I squared then multiplied by 4 for 1936 . ..

yep. 2k for 4 x 6L6 in PP

Title: Re: Inpedance of output transformer
Post by: Latole on March 20, 2021, 03:53:10 am

Have look at hammond Transformers you'll know right now .
You'll see 4 ohms xfrs have a 2 K impedance for 100 watts outputs

https://www.hammfg.com/fr/electronics/transformers/classic/1750?referer=1101