Anyone know how to wire a switchable impedence cab

jh45gun · March 27th, 2008, 10:00 PM

OK here is the deal on my amp build I am using a OT out of a Peavey 4 6l6 amp since my amp is going to be 2 6l6's a 5f4 the OT will be seeing things differently. I thought I had it made as a Peavey Tech told me how to wire up the OT but HE GOT IT BACKWARDS! so much for the experts LOL He told me that the OT shifts and they do it all the time and that using only two tubes I would use the 8 ohm tap as the 4 ohm and the 16 ohm tap as the 8 ohm which would have worked perfectly for me. However on a discussion at the gear page they told me when only two tubes are used the primary doubles and then so does the secondary so if your OT is say 4000 ohms for a 4 ohm load using 4 tubes using two tubes would make it 8000 for a 8 ohm load ect. Now do not start picking on the math on the primary I am just picking them numbers out of the air for a description I do not know what the ohms of the primary are on this OT. Peavey did tell me the wire codes so I do know which wire is which tap. So this leaves me with the former 4 ohm tap wanting to see 8 ohms and the 8 ohm tap wanting to see 16 ohms. SO I have a 2x12 cab with a pair of 8 ohm Eminence speakers wired in parallel for a 4 ohm load. If I just used this cab for the 5f4 build I could just wire it series for a 16 ohm load but I also would like to use it 4 ohms for my Deluxe head build as that head has a 4 ohm OT. So is there a way to make a cab that is switchable from 4 ohms to 16 ohms switching from parralell wireing to series for a 4 to 16 ohm cab? Any links for plans for this ect and what type switch to use?

eugenedunn · March 28th, 2008, 12:05 AM

Hey JH45gun,

I have seen rear jack plates sold by Marshall and Line 6 that offer parallel or series wiring for a pair of speakers. You plug into one side for parallel, the other side for series.....

I am having a cabinet built that will have that arrangement. I have a couple of old Jensen C10N's that I want to use for extension speakers for my Princeton Reverb and Champ at 4 ohms, but I also want to use the 8-ohm speakers individually.

jh45gun · March 28th, 2008, 01:11 AM

Did a quick search and found this:

eugenedunn · March 28th, 2008, 01:40 AM

oops, I mistakenly said parallel or series.....I meant mono or stereo...sorry

jh45gun · March 28th, 2008, 01:47 AM

Thats OK I saw that in my search. I think the above drawing should work fine.

March 27th, 2008, 10:00 PM	#1 (permalink)
jh45gun Tele-Afflicted Join Date: Jan 2006 Posts: 1,109	Anyone know how to wire a switchable impedence cab OK here is the deal on my amp build I am using a OT out of a Peavey 4 6l6 amp since my amp is going to be 2 6l6's a 5f4 the OT will be seeing things differently. I thought I had it made as a Peavey Tech told me how to wire up the OT but HE GOT IT BACKWARDS! so much for the experts LOL He told me that the OT shifts and they do it all the time and that using only two tubes I would use the 8 ohm tap as the 4 ohm and the 16 ohm tap as the 8 ohm which would have worked perfectly for me. However on a discussion at the gear page they told me when only two tubes are used the primary doubles and then so does the secondary so if your OT is say 4000 ohms for a 4 ohm load using 4 tubes using two tubes would make it 8000 for a 8 ohm load ect. Now do not start picking on the math on the primary I am just picking them numbers out of the air for a description I do not know what the ohms of the primary are on this OT. Peavey did tell me the wire codes so I do know which wire is which tap. So this leaves me with the former 4 ohm tap wanting to see 8 ohms and the 8 ohm tap wanting to see 16 ohms. SO I have a 2x12 cab with a pair of 8 ohm Eminence speakers wired in parallel for a 4 ohm load. If I just used this cab for the 5f4 build I could just wire it series for a 16 ohm load but I also would like to use it 4 ohms for my Deluxe head build as that head has a 4 ohm OT. So is there a way to make a cab that is switchable from 4 ohms to 16 ohms switching from parralell wireing to series for a 4 to 16 ohm cab? Any links for plans for this ect and what type switch to use?

March 28th, 2008, 12:05 AM	#2 (permalink)
eugenedunn Tele-Holic Join Date: Dec 2006 Location: Sacramento, CA Age: 55 Posts: 839 37 Photos	Hey JH45gun, I have seen rear jack plates sold by Marshall and Line 6 that offer parallel or series wiring for a pair of speakers. You plug into one side for parallel, the other side for series..... I am having a cabinet built that will have that arrangement. I have a couple of old Jensen C10N's that I want to use for extension speakers for my Princeton Reverb and Champ at 4 ohms, but I also want to use the 8-ohm speakers individually.

March 28th, 2008, 01:11 AM	#3 (permalink)
jh45gun Tele-Afflicted Join Date: Jan 2006 Posts: 1,109	Did a quick search and found this:

March 28th, 2008, 01:40 AM	#4 (permalink)
eugenedunn Tele-Holic Join Date: Dec 2006 Location: Sacramento, CA Age: 55 Posts: 839 37 Photos	oops, I mistakenly said parallel or series.....I meant mono or stereo...sorry

March 28th, 2008, 01:47 AM	#5 (permalink)
jh45gun Tele-Afflicted Join Date: Jan 2006 Posts: 1,109	Thats OK I saw that in my search. I think the above drawing should work fine.