Speaker wiring for multiple ohm taps

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Speaker wiring for multiple ohm taps

Postby nrowell on Fri Mar 29, 2013 3:38 am

hey all

i did a tweed deluxe amp clone and am curious about how to wire up the speaker. the output tranny has a 4ohm and 8ohm tap, both wired to separate jacks. the internal speaker is 8ohm. i want to be able to run the internal speaker and an external 8ohm cab. so here's what i'm thinking......

normally the internal speaker is plugged into the 8 ohm jack via a quarter inch plug that is wired to the speaker. i want to put an "external speaker jack" into the back panel, then wire the jack in parallel with the internal speaker. the thought is that if i plug another 8ohm cab into this jack, it'll be in parallel with the internal 8ohm speaker. i could then take the plug that is wired to the internal speaker and plug it into the 4ohm jack, thus keeping the impedance correct.

if i'm not using the external cab, i'll just leave the internal speaker plugged into the 8ohm jack.

is my logic solid? will this be wired properly?

thanks
nrowell
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Re: Speaker wiring for multiple ohm taps

Postby andomando on Wed Jul 10, 2013 1:07 pm

Have a look online at;Shavano Music Online,
they have loads on speaker wiring etc.good luck.
andomando
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Re: Speaker wiring for multiple ohm taps

Postby madjackhatter on Thu Jul 11, 2013 1:43 am

OK, I just built one and put a selector switch. Use a DP/ST switch and wire a leg to each side and wire the speaker jack like this using the hot leg of the switch.
Image

This is how mine is wired and works perfectly, except the hot wire comes from the switch.
http://site.triodestore.com/5E3DeluxeLa ... 21120V.pdf

Really like how it's as easy as flipping the switch to run an 8 ohm extention cab. There is a primary jack in this wiring so if only one speaker is plugged in it has to be plugged into that jack...
Recordings from Kerosene Highway and Madjackhatter here...
https://soundcloud.com/kerosene-highway
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Re: Speaker wiring for multiple ohm taps

Postby pdf64 on Thu Jul 11, 2013 8:52 pm

My preference is 3 jack sockets; eg 2 x 4 ohm and 1 x 8 ohm.
Wire a 220 ohm ~5W resistor across the 8 ohm output, to prevent the secondary ever being totally open.
The less to go wrong / fail between the voicecoil and the OT secondary, the better.
eg it's dark around the back of amps and no matter how intuitively I think I've arrange a switch, I always end up setting it incorrectly.
Pete
My band:-http://www.youtube.com/user/RedwingBand
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Re: Speaker wiring for multiple ohm taps

Postby madjackhatter on Fri Jul 12, 2013 4:19 pm

I printed a tag for the cabinet and put a reminder sticker folded around the speaker cable to check the setting. Another jack would be the same issue for me as the switch where it would be located behind the upper panel. There is no perfect world for the ohms selection mod in a 5E3 combo.... :wink:
Recordings from Kerosene Highway and Madjackhatter here...
https://soundcloud.com/kerosene-highway
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