1485 Silvertone Dual Output Transformers /Stereo Output Jack?

[plexi50]

I have a 1965 1485 Silvertone with (2) output transformers. Someone has done some wiring that i am questioning on the output speaker jack. It is a Mono jack. Can't i use a stereo output jack seeing as the original speaker cab has a total of (6) 8 ohm speakers. There is one set of (3) speakers that is for one OT and then another set of (3) speakers for another OT. His cabinet is already wired for a stereo jack for each set of speakers. Any ideas for a good stereo output jack and other helpful info. It seems pretty straight forward that i need a stereo out jack.

[sluckey]

If using a 1/4" pone plug I would use a Switchcraft Type 12B jack. However, I highly recommend you look closely at the way that mono jack is wired to the two OT secondaries.

BTW a new 1484 or 1485 had no speaker jacks. They were hard wired between the head and speaker cab with a long zip cord (2 conductor for 1484 and 3 conductor for 1485).

[plexi50]

If using a 1/4" pone plug I would use a Switchcraft Type 12B jack. However, I highly recommend you look closely at the way that mono jack is wired to the two OT secondaries.

BTW a new 1484 or 1485 had no speaker jacks. They were hard wired between the head and speaker cab with a long zip cord (2 conductor for 1484 and 3 conductor for 1485).

Yes mono jack wiring is what i have been trying to decipher. I have not gotten the jack out yet to get a better picture of whats going on. Yes it originally was hard wired. I am making it more complicated in a way because i could just use (2) switch craft mono jacks. But his cab is wired stereo now. It's the little things that mess me up these days. 

[plexi50]

Will this work? Looks a little different but the connection points match the stereo plug.

[plexi50]

Pic's

[plexi50]

I believe the yellow wire is my secondary 8 ohm. But the Red/Yellow CT?  No. I plugged it in and flipped the switches. It is a great sounding amp. Reverb & Trem both unique.

[plexi50]

Mono Jack removed.

[sluckey]

There is no 8Ω tap. Yellow is the 4 ohm tap, and red/yellow is the 2.66 ohm tap. Black is ground.

Watch this video. The part you need to see starts at 3:40 and ends at 5:48. U. Doug shows you everything you need to know about putting a stereo plug in that amp.

&ab_channel=UncleDoug

[plexi50]

There is no 8Ω tap. Yellow is the 4 ohm tap, and red/yellow is the 2.66 ohm tap. Black is ground.

Watch this video. The part you need to see starts at 3:40 and ends at 5:48. U. Doug shows you everything you need to know about putting a stereo plug in that amp.

&ab_channel=UncleDoug

Your a God send Steve! Thankyou much!

[plexi50]

Well i just happen to have a J12B stereo jack. It was new. (was)? I wired it up and while i was tightening down the nut, the entire guts of the center jack shaft pulled itself through the carbon hole. It's going be one of those days i Guess. Ordering a 12B from Studio Sound Electronics here in Clearwater Fl. Too bad they don't have a store front where i could walk in and out with it. Strictly mail order. I wish they still had Radio Shack stores around. But at the end of them going out of business everything they had electronic part wise was junk cheap egg shells. Especially their jacks selection.

[sluckey]

Radio Shack 1/4" jacks and plugs have always been low quality, cheaply made crap. Buy Switchcraft!

[plexi50]

Yes i always buy Switch Craft. It's already shipped and on the way. I should have it in a few days seeing as i am 1 mile away from the place i ordered from. That's if it does not wind up going to Miami and then back up this way. Ive seen that happen on more than one occasion.

[sluckey]

So, tell me about the speaker cab that will be used with this amp. Remember, the OTs in this 1485 were also used in the 1484. The secondary output impedances available are 2.67Ω for the 1485, and 4Ω for the 1484.

[plexi50]

There are a total of (6) 10" 8 ohm speakers. One set of (3) is wired parallel. The other set of (3) speakers are wired parallel with the ground wire sharing all (6) speakers. Each set of (3) speakers have their own red load wire from each output transformer. Each set of speakers will have a 2 ohm impedance to each output transformer.

[sluckey]

There are a total of (6) 10" 8 ohm speakers. One set of (3) is wired parallel. The other set of (3) speakers are wired parallel with the ground wire sharing all (6) speakers. Each set of (3) speakers have their own red load wire from each output transformer. Each set of speakers will have a 2 ohm impedance to each output transformer.

That's not right! Haven't you been listening? Three 8Ω speakers in parallel equals 8/3=2.67 total resistance. Been that way forever. Possibly when Bradey came down, he let some air outta the math. But that only applies to the Tampa Bay area!   

[scstill]

Love U Doug videos and especially this 1485 video. Thanks...
If you recall, an early project that you all helped me with was my 1484 which continues to work great even with original caps, restored original reverb, re-coned original 12 and repaired cab. A favorite of my collection. I'm still on the lookout to get a 1485 so this thread is a nice read.

https://stillampd.com/silvertone-1484-restoration

[plexi50]

There are a total of (6) 10" 8 ohm speakers. One set of (3) is wired parallel. The other set of (3) speakers are wired parallel with the ground wire sharing all (6) speakers. Each set of (3) speakers have their own red load wire from each output transformer. Each set of speakers will have a 2 ohm impedance to each output transformer.

That's not right! Haven't you been listening? Three 8Ω speakers in parallel equals 8/3=2.67 total resistance. Been that way forever. Possibly when Bradey came down, he let some air outta the math. But that only applies to the Tampa Bay area!   

There are (2) yellow wires on each terminal srtip that are just soldered to the tabs but have nothing else connected to them. The red wires were originally connected to a plastic stereo jack along with a ground wire from the transformers. The schematic shows the speakers wired in parallel. What am i missing? Do i need to use the yellow 4 ohm tap wires?

[sluckey]

                    Why are you trying to make this so damned complicated??? It's simple. You've been told exactly what color wires are involved. You've been told exactly how to connect them. JUST DO IT!

[plexi50]

I am using the (2) 2.67 ohm red wires from each OT and connecting them to the stereo jack along with the common ground as shown in the video!

[sluckey]

I am using the (2) 2.67 ohm red wires from each OT and connecting them to the stereo jack along with the common ground as shown in the video!

Got it working yet?

[plexi50]

Yes and it sounds great! I got a 12B stereo jack and used the 2.67 taps to each jack tab. Wired common ground as in the video and speaker cabinet as in the schematic. Waiting on another L12B jack for the back of the cabinet cover. 13:20 is where speaker wiring begins.

[plexi50]

Thanks much for your help. Not something you see everyday but still decipherable with your help.

[sluckey]

Maybe add this pic to your collection...

[plexi50]

Priceless info when you need it. I thrive off of documentation. Thanks Steve!