Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: daveyajd on December 17, 2019, 09:12:34 pm

Title: OT impedance question
Post by: daveyajd on December 17, 2019, 09:12:34 pm

I have an old Fender Bantam Bass that uses 2 6L6 tubes. I upgraded the OT years ago because the original was a little anemic. I went bigger and used a Hammond 1760W (2k primary w/ 4-8-16 secondaries)


Which secondary tap should I use for an 8 ohm speaker so the transformer sees the ideal load? Am I able to run a 4 ohm speaker safely with any of those taps?


Aaron

Title: Re: OT impedance question
Post by: sluckey on December 17, 2019, 09:30:36 pm

Need to double the reflected primary impedance so you must also double the secondary impedance. 4 becomes 8, 8 becomes 16, 16 becomes 32.

IOW put an 8Ω speaker on the 4Ω tap. You no longer have a 4Ω option.

Title: Re: OT impedance question
Post by: daveyajd on December 17, 2019, 09:53:43 pm

Thanks Sluckey.

Aaron

Title: Re: OT impedance question
Post by: Pietro on December 18, 2019, 12:31:53 am

kind a curious what the amp looks like with a 1760Watts OT.  :l2:

Title: Re: OT impedance question
Post by: sluckey on December 18, 2019, 07:04:04 am

Quote from: Pietro on December 18, 2019, 12:31:53 am

kind a curious what the amp looks like with a 1760Watts OT.  :l2:

The Hammond 1760W is a 100 watt OT.

     https://www.hammfg.com/files/parts/pdf/1760W.pdf

Title: Re: OT impedance question
Post by: kagliostro on December 18, 2019, 10:53:56 am

I think Pietro knows that

Probably a joke ?

Franco

Title: Re: OT impedance question
Post by: Ritchie200 on December 18, 2019, 12:56:03 pm

http://ogrforum.ogaugerr.com/fileSendAction/fcType/0/fcOid/23252098522776349/filePointer/23252098522776380/fodoid/23252098522776373/imageType/LARGE/inlineImage/true/Power-Transformer%252004.jpg

Title: Re: OT impedance question
Post by: DummyLoad on December 20, 2019, 11:48:43 pm

(https://media2.giphy.com/media/ahqXZjdmep0Zy/source.gif)

Title: Re: OT impedance question
Post by: daveyajd on December 21, 2019, 12:06:08 am

YESSSSS! 🤘




Aaron

Title: Re: OT impedance question
Post by: DummyLoad on December 21, 2019, 12:12:18 am

what he was actually plugging into... sorta.

Title: Re: OT impedance question
Post by: kagliostro on December 21, 2019, 03:23:46 am

(https://media2.giphy.com/media/ahqXZjdmep0Zy/source.gif)

COOL  :icon_biggrin: :icon_biggrin: :icon_biggrin:

Franco