Speaker Jack Wiring Question

[Lamarrevelous]

Hi everyone,

I'm a noob building a Champ style amp (my first build). I have a quick question about how to wire the output taps to have the option to use a 4 or 8 ohm speaker. I've looked over the site and see a lot of things about adding resistors and switches (the ON/ON switch I understand). What I'm wondering, can I just run the 4ohm tap to one jack, the 8ohm tap to another jack and just bridge the ground between the two. To my way of thinking, the jack only activates if the male is plugged it...no?

Like I said, I'm pretty ignorant, so please advise.

I drew a crappy picture to show what I mean if the words fail to do so.

Thank you for your help.

[martin manning]

can I just run the 4ohm tap to one jack, the 8ohm tap to another jack and just bridge the ground between the two.

Yes, but then both jacks need to be open circuit, and the OT is not protected in the case where no speaker is connected, as it would be with a shorting jack as the "main" speaker out on most amps. You can do it like this: https://ampgarage.com/forum/viewtopic.p ... 23#p267223 Note that if the other end of the speaker cable isn't connected t a load then you still have a problem.

[Stevem]

Make your life easy and place a 250 ohm 5 watt resistor across either jack.

Should a condition of no cable take place then you have the resistor there to keep your OT safe,then when you do have a cable hooked up the OT does not even see that high 250 ohm load.

There are Champ Output transformers that do have a 4 and 8 ohm tap, is that what you have?

[Lamarrevelous]

Thanks for the replies everyone.

I do have the 4 and 8 ohm Champ OT. I looked over the drawing/schematic for wiring and it's for an on/off jack (I think). Mine are mono, so I don't have the third soldering tab. Given that the signal is mono, are the mono jacks fine? Like I tried to illustrate in my drawing, I was just going to bridge the ground across the jacks on the assumption that only the jack that's plugged in will be active. I could also do an ON/ON as I have one of those kicking around. If I do that, again, I'll just be connecting the ground to the switch and from there running them to each respective jack.

Anyway, if I need the open or closed 3 solder tab jacks, let me know...I can grab them and save the monos for another project...

Thanks everyone for your input.

[Lamarrevelous]

Here's what I'm talking about with the switch. This would still require a resistor to protect the OT, as one side is always live. This has me questioning two things.

1. Is the ground to the switch correct?
2. Can I just add the resistor inline from the OT to the switch?

Sorry for all the questions. Like I said, I'm new to circuits. I feel like I understand, but it's one of those I'm 75% sure, so I need you fine folks to tell me I'm right or to set me straight. Thanks.