How to connect my amp to a cab?

Gretscher

Electromatic
Aug 31, 2021
34
Gretschland
Hello everyone. I have a Koch Studiotone with 4, 8 and 16 ohm outputs. I want to connect this to my Brunetti cab. It has 2x12 inch speakers of 16 ohms each. If I use the 8ohm output of my Koch amplifier and I plug that speaker cable into the mono input of 8ohm, it only works with 1 speaker. What's wrong here?
 

stevo

Friend of Fred
May 1, 2012
7,313
Atlanta
I just checked but no loose wire.

I had a feeling you might say that. Maybe a dead speaker? Do you have a multimeter and a soldering iron? You might have to test each speaker separately. But not seeing this, it's hard to be definitive on what to do next.
 

OzzPocket

Synchromatic
Aug 11, 2020
670
NYS
Silly question, but do you know if the non-working speaker is actually functional? Have you got another amp you can try the cab with?
 

swivel

Country Gent
Silver Member
May 13, 2018
2,307
PNW
If the wires are connected together to both speakers and only one is working, then you have a bad speaker. Normally they would be connected + to + and - to -, then off the end to the jack.

However, the use of the word "MONO" throws me off a bit. Maybe that cab is wired for stereo and if you only plug into the "Mono" labeled jack, you only get one speaker? That seems likely.
 

Gretscher

Electromatic
Aug 31, 2021
34
Gretschland
The other speaker is 100 percent good; If I put the speaker cable in the other input of the cab, the other speaker works but the other does not...
 

Gretscher

Electromatic
Aug 31, 2021
34
Gretschland
If the wires are connected together to both speakers and only one is working, then you have a bad speaker. Normally they would be connected + to + and - to -, then off the end to the jack.

However, the use of the word "MONO" throws me off a bit. Maybe that cab is wired for stereo and if you only plug into the "Mono" labeled jack, you only get one speaker? That seems likely.

Yes that's right. But what can I do now?
 

swivel

Country Gent
Silver Member
May 13, 2018
2,307
PNW
Yes that's right. But what can I do now?
On line I see there are two input jacks. Each labeled 16 ohms. We dont know how it's wired, but is it possible that each is just a jack for each speaker? (Are the speakers wired together one speaker to the other not at the jacks?) If so, you need a Y cable or to split the cable from the amp to each of those jacks.

OK, I see your pics now. Hmmm... It appears those two jacks are maybe wired in parallel already, but....... one labeled " MONO 8 ohms" would make sense then and both should be working. But how does it ever work as "two 16 ohm STEREO" then if they are tied together? Those Cliff style jacks are confusing to me, maybe they are wired to separate when you plug into the second jack?

This still doesn't solve why one is not working though.
 
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swivel

Country Gent
Silver Member
May 13, 2018
2,307
PNW
The other speaker is 100 percent good; If I put the speaker cable in the other input of the cab, the other speaker works but the other does not...
So you are saying that each speaker works and only that speaker works if you plug into it's own jack? (right jack makes the right speaker work, left jack makes the left speaker work. That would indicate to me that you need a Y cable or two outputs on your amp. With a Y cable you would use your amps 8 ohm output.
 

wabash slim

I Bleed Orange
Feb 10, 2010
18,855
lafayette in
The other speaker is 100 percent good; If I put the speaker cable in the other input of the cab, the other speaker works but the other does not...
So you are saying that each speaker works and only that speaker works if you plug into it's own jack? (right jack makes the right speaker work, left jack makes the left speaker work. That would indicate to me that you need a Y cable or two outputs on your amp. With a Y cable you would use your amps 8 ohm output.
There's the problem. Two speakers set up independent of each other for stereo use. Use a Y connector, or rewire the speakers in parallel.
 

GlenP

Country Gent
Double Platinum Member
Jul 23, 2019
2,569
WA
You might try searching the web for a user manual for that cabinet, it might have been designed for use with a particular amp head with corresponding outputs. I suspect that those input jacks are switched, (as in ON/OFF type of a switchable jack) which of the poles are active depends on if a plug is inserted in the jack or not. If you can find a manual and the speakers are not working according to those instructions, then maybe you have a dirty connection between the contacts within a switched jack?
 
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Hammerhands

Country Gent
Aug 26, 2011
2,526
Winnipeg
You might try searching the web for a user manual for that cabinet

http://www.brunetti.it/MANUALS/ENG/Dual Cab (16 Ohm) - ENG.pdf

I think that one of the jacks’ switches isn’t working right.

Use a Y connector

That would solve the problem for good. I recall reading Marshall had problems with the switching on jacks like this.

Is there such a thing as a Y speaker cable? It looks like there’s one by EarCandy and one by Horizon Cables. There’s also some adaptors on Amazon for $6, but I’m not sure if they are suitable for a speaker signal. On Reverb there is an even more expensive y-splitter by Pro Cables N Sound. Weber has one that looks…cheap…but probably works fine. https://www.tedweber.com/y-cable/

Which jack switch isn’t working? Looking at the picture, I think on the left mono jack the switch isn’t being used? When nothing is plugged into the right jack, you should have continuity from one side to the other, when the plug is in, it should break the continuity.
 
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