"Use first" speaker jack question

S

Swanation45

Active member
Why do some amps like Bogner, have a label above one speaker jack saying, "use first?" I understand if you're only using one jack to just use that one, but why? What if you use the other one instead?


Thanks!
 
If the output jack’s of the OT are in parallel, then there’s no preference. If the outputs of the OT are wired directly to certain jacks, then I can see the need to label what to use first.
 
In the case of old Fenders, the use first jack is a shorting jack that connects the OT secondary (or impedance selector if there was one, which there wasn't) to ground. They figured that in the case of no speaker connected; an infinite load was better than no load at all so they used the shorting jack. The second jack is just paralleled to the Use First jack and is NOT a shorting jack.

My Rivera Hammer power amp is also like that.
 
I've seen the "use first" shorting jack connected to a couple of high power, heat-sinked resistors as well.
 
panhead said:
Im pretty sure on a 101 b I had if you plugged into the second jack you got nothing.
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Yeah, I think the first jack shorts the output to ground in that case if there's nothing plugged in to the "use first" jack.
The 101b or 20th Anni might have been where I saw the big ass power resistors too. Thought it might have been a Bogner thing, but can't remember.
 
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