Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: bruno on October 23, 2011, 10:38:24 pm

Title: Which Transformers for low voltage/high current operation?
Post by: bruno on October 23, 2011, 10:38:24 pm

I'm trying to design an amp around a pair of 6V6s which would work at what I guess would be similar to class A. I'm using the datasheet values as references for a class A push pull tube amp, which point out to 250 volts on the plates and max current of 80ma.

Where could I get a power transformer that and output transformer that would handle these specifications?

Thanks

Title: Re: Which Transformers for low voltage/high current operation?
Post by: stratele52 on October 24, 2011, 04:07:14 am

Look at Hammond Transformer

Title: Re: Which Transformers for low voltage/high current operation?
Post by: bruno on October 24, 2011, 04:51:22 am

I've looked at hammonds, they'll do for now, but I'd like to know if you guys knowis any company where I can have these custom made?

If not than I guess I'll go with a heyboer ac15 OT and a hammond 369AX power transformer which appears to have 125V unloaded B+ per side and is spec'd up to 115ma.

thanks

Title: Re: Which Transformers for low voltage/high current operation?
Post by: Boots Deville on October 24, 2011, 07:22:31 am

I'd look into Edcor, if you haven't already.  I like their off-the-shelf offerings, and don't have any direct experience with custom orders, but from what I've heard they are pretty easy to work with, at a reasonable cost.

-John

Title: Re: Which Transformers for low voltage/high current operation?
Post by: bruno on October 24, 2011, 07:58:06 am

Thanks man, I just checked edcor... they have loads of options, and reasonable prices too. I'm going to order a set!
Thanks

Title: Re: Which Transformers for low voltage/high current operation?
Post by: stratele52 on October 24, 2011, 03:25:19 pm

Bruno , you want custom made ? ( $$$) ask Mercury Magnetics

Title: Re: Which Transformers for low voltage/high current operation?
Post by: gldtp99 on October 25, 2011, 04:05:59 pm

I also recommend Edcor---- they offer many stock PT's and will custom wind---i had some custom wound PT's done several yrs ago and it was a painless experience.
i used an Edcor PT in a recent 50 watt hi-gain/clean channel switcher build (a local studio has "borrowed" it for several weeks--i may have to take it back by force pretty soon--- they seem to like it)---i also have two Edcor PT's on order that would easily support 100 watt channel switching builds:
http://www.edcorusa.com/products/739-xpwr137_120.aspx (http://www.edcorusa.com/products/739-xpwr137_120.aspx)

I may use one of these Edcor PT's in a KT88 x 2 build with one of the custom wound Heyboer 100 watt OT's i had them make up (Heyboer also does great custom work !!!)---- These Heyboer OT's are a Fender Twin Reverb/Showman-type --- but with 4k primary and 4/8/16 ohm output taps---i just did a Bogen CHA33 gut-and-rebuild with one of these Heyboer OT's and a Mag Comp Twin Reverb/Showman PT--- KT88 x 2--- Fender Brownface Deluxe 6G3 based circuit--- holy crap !!!!--- kind of like putting a Big Block 454 into a Chevette !!! I wasn't sure if KT88 x 2 would give "Big Amp Feel" with this transformer set, so i built up this old Bogen as an experiment------ very powerful and has Big Amp Feel----- i also included a PPIMV (LTP PI in this circuit).
i'm sure that Mercury Magnetics can do great custom transformers------ but Edcor and Heyboer can do great custom work at a much lower price......................gldtp99