Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Curranm on February 27, 2020, 08:56:42 am

Title: wiring up a hammond 1650R for multiple impedance selection
Post by: Curranm on February 27, 2020, 08:56:42 am

I am experimenting with an ultralinear output transformer. the amp is LOOSELY based on a SUNN model T  Phase inverter, and output coupler section, with a very sludgy single input plexu/hot switch plexi preamp, as well as a tube FX loop after the treble control and going into the MV to the PI.

so the question is CAN I/HOW DO I wire up this 1650R(not the A series) for switching between multiple impedance 4/8/16. the primary side makes sense in that I need to attach my B+, my plates AND the two other wires to the screen grid pins of my power tubes(KT88's). but the secondary looks like I can really only wire it for two impedance setting and that's it....... ALSO hammonds use of the little black triangle makes me think those wiring configurations require those taps to go to ground. so any help would be awesome! thank you guys!

http://www.hammondmfg.com/1608.htm

Title: Re: wiring up a hammond 1650R for multiple impedance selection
Post by: sluckey on February 27, 2020, 09:59:38 am

https://www.tubesandmore.com/products/switch-rotary-impedance-selector-hammond-1600-series

Title: Re: wiring up a hammond 1650R for multiple impedance selection
Post by: shooter on February 27, 2020, 10:41:58 am

NICE find!
Hammonds site left my head hurting trying to untangle the mess  :icon_biggrin:

Title: Re: wiring up a hammond 1650R for multiple impedance selection
Post by: sluckey on February 27, 2020, 10:53:05 am

I have one of those OTs in my AC-15. No clue why they have that crazy secondary scheme. They later came out with a 1600-A series that has a more sensible secondary scheme.

Title: Re: wiring up a hammond 1650R for multiple impedance selection
Post by: shooter on February 27, 2020, 12:17:57 pm

 

Quote

No clue why

   
:laugh:
You had to have run into Engineers in your line of work  :icon_biggrin: