OT and speaker jacks

[C Moore]

When you have an OT that has a secondary with a Common, 4 Ohm and 8 Ohm tap, and you use a separate jack for each tap; shouldn't both jacks be switching.?
If you are plugged into the 8 Ohm jack, shouldn't the 4 Ohm tap be switching itself to ground.?
Thank You

[paulster]

No, you want the unused tap to be left unconnected or you're shorting out a section of the secondary, which isn't how it's designed to work.

[C Moore]

Yeah , OK I think I follow you. I understand the theory.
So I just run the 4 Ohm tap to the tip of the jack. Do I connect the shaft of the 4 Ohm to the shaft of the 8 Ohm jack, and just not use the switching tabs of the Cliff Jack that is connected to the 4 Ohm.? I just use the switching tabs of the 8 Ohm jack.?
Thanks
Sorry....wish I could draw this out some how. Hope I am being clear.

[paulster]

The common goes to the sleeve connector of both the 4 and 8ohm jacks. It doesn't matter if you go through the switching contact to get from one jack to the other if you use a buss wire, but it's not important so long as you make sure you make a connection to the unswitched side of each jack.

Then the 4 and 8ohm outputs go to the unswitched tip connector on their respective jacks.

I hope that makes sense.

[Super_Reverb]

Another approach is to use an impedance selector switch with one spkr out jack and/or add a 100-220 Ohm resistor from switched lug to ground. When your speaker is plugged in to the jack, the 100-220 Ohm resistor will be switched out of ckt.

This will protect your OT on those rare occasions when you forget to plug speakers into the amp.

cheers,

rob

[C Moore]

Sorry, I don't mean to be dense, but I guess I have never dealt with this situation before.......When you are using a jack for each tap, should either jack use switching that shorts the jack to ground when it is not in use.?
I am using an old chassis and was trying to "avoid" drilling another big hole for an Impedance switch, but they do make things easy.
Thanks

[billyz]

I think if you are going to have different impedance taps on each jack then No, they are not the shorting type jack wiring. But I would use a 180 ohm 20 W resistor from the OT secondary tap to ground to protect the OT.

[C Moore]

10-4
I've got it now.
The amp sounds fine. I wired the 4 ohm tap, and as you can guess, I used the switching contacts and that was causing Hell.
Everything is back to normal now.
Once Again
Thank You All
i try to keep this stuff in my head...the best that i can.