Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dpm309 on October 11, 2011, 03:22:54 pm

Title: Power Transformer ID
Post by: dpm309 on October 11, 2011, 03:22:54 pm

Have been going through my junk pile of old amp parts and came across this old PT.  I think it came from an old Yamaha bass amp that I gutted and used the chassis for my first build, 5E3, several years ago. Have been all over the internet trying to find what the specs are for this and if it is worth keeping for an amp project but can't find anything.   I see only 2 primary and 2 secondary wires.  See attached picture.

Thanks,

Dan

Title: Re: Power Transformer ID
Post by: stingray_65 on October 11, 2011, 08:51:32 pm

My guess is it is for a solid state amp, no heater wires or CT.

The black wires are likely your primary, but not necessarily, did you take notes when you harvested it?

SS trannys are step down, that means 120V in <120V out, usually in the 25-50V range. Not very useful in tube amps, but they can find their way into other projects like pedal power supplies, bench top variable voltage power supplies, door bell transformer, etc.

You can always power them up with a small AC wall wart if you do not know which end is primary and measure both sides.

Ray

Title: Re: Power Transformer ID
Post by: stratele52 on October 12, 2011, 04:16:27 am

+1 stingray 65

Title: Re: Power Transformer ID
Post by: dpm309 on October 12, 2011, 11:07:46 am

Thanks for the replies.  I guess this PT is headed to the recycle bin since I am not planning on building any solid state amps.

Dan

Title: Re: Power Transformer ID
Post by: spacelabstudio on October 12, 2011, 11:37:12 am

Well a step down transformer is a step up transformer wired the other way around.  If you have some way of generating a 1V-ish sine wave (function generator, variac), you can measure the step up or step down in either direction and decide whether 120V applied on one side will yield something useful on the other side.

Chris

Title: Re: Power Transformer ID
Post by: stingray_65 on October 12, 2011, 10:09:04 pm

Quote from: dpm309 on October 12, 2011, 11:07:46 am

Thanks for the replies.  I guess this PT is headed to the recycle bin since I am not planning on building any solid state amps.

Dan

Hey now!

Good iron is good iron! There are lots of great projects to make besides tube amps!

Measure up the output voltage and see what you got!

LOL take that with the grain of salt, I cry on my yearly shop clean getting rid of all the good junk I collect. Believe me if I didn't have close concerned friends who are more stubborn than me I would keep every scrap.

Ray