Converting broken amp into cab?

PieterHefer

Hey guys,

Quick background:
Sadly to say I have been playing for quite some time now, but honestly do not have all the technical skills and knowledge that some of you clever oaks have.

I recently bought the MESA TA-15 with a 1x 12 MESA cab and it sounds great. I usually just play in church and do not really gig otherwise. Predomnantly I use
the head for studio purposes while commuting all the gear back and forth to church. Not so much fun to do the studio setup every time.

Hence my plan to leave the cab in studio all mic'd up etc. And only travel with pedals and head.

Plan:
Our church has a 4 x 12 Behringer cab (Still need to find the model number) and an old crate 2 x 12 combo amp.
I am not sure what the impedance of the 4x12 is, because there is no info at the back, or any other place on the cab.
I know this all depends on the wiring of the speakers etc etc.

So I have basically 2 options imo.

1. Check the impedance of the behringer and confirm the impedance is matching that of the TA-15
So how do I go about checking the impedance on the cab? Open it up, chech the wiring and just measure each resistance on each speaker and do the calcualtions?
Or is there another way of doing it?

2. Convert the crate as a cab and bypass all the pre-amps etc.
Can this be done by simply adding a jack socket and connect the speaker cables to the socket? In other words disconnect them for the transformer of the amp and just connect them into the socket?

If some of the gurus can help me with this one I would really appreciate it.

PieterHefer

PieterHefer wrote: Hey guys,

Our church has a 4 x 12 Behringer cab
I am not sure what the impedance of the 4x12 is, because there is no info at the back, or any other place on the cab.
I know this all depends on the wiring of the speakers etc etc.

Ok so after some more investigation the Behringer is a 4x10 bass cab. So not really an option, but for future reference, will the method I described at the bottom still be the same to test the impedance of a cab?

AlanRatcliffe

If you have a multimeter, check the DC resistance of the cab (insert a plug and put the probes on the contacts of the plug). The DC resistance will be approximately 3/4 of the impedance. So if the DC resistance reads around 6 Ohm, you have an 8 Ohm cab, 12 = 16 Ohm, 3 = 4 Ohm, etc..

PieterHefer

Alan Ratcliffe wrote: If you have a multimeter, check the DC resistance of the cab (insert a plug and put the probes on the contacts of the plug). The DC resistance will be approximately 3/4 of the impedance. So if the DC resistance reads around 6 Ohm, you have an 8 Ohm cab, 12 = 16 Ohm, 3 = 4 Ohm, etc..

Ok so this might sound very stupid, but are you to the jack 2 jack input on the amp?

What about converting the crate to a cab?
I know its not the best speakers but it is atleast a start.

AlanRatcliffe

PieterHefer wrote: Ok so this might sound very stupid, but are you to the jack 2 jack input on the amp?

If I understand your question correctly, then, no, the amp should not be connected to the speaker/cab when you take the reading.

What about converting the crate to a cab?
I know its not the best speakers but it is atleast a start.

No problems with that at all.

Nicholas-L

The crate like Alan said not a problem and is quite easy to do... I'm currently converting a Behringer 2x10 combo into a 2 x 10 cab... all you need is a piece of wood to fill the gap where the amp use to be, otherwise just disconnect the amp from the speakers and add a jack socket to the speakers. Voila.

PieterHefer

Nicholas L wrote: The crate like Alan said not a problem and is quite easy to do... I'm currently converting a Behringer 2x10 combo into a 2 x 10 cab... all you need is a piece of wood to fill the gap where the amp use to be, otherwise just disconnect the amp from the speakers and add a jack socket to the speakers. Voila.

Cool thanks, that was my initial thought as well.
Guess I will just have to check the impedance wrt the wiring of the speakers ( depending on series vs parallel)

Thanks all for the input

PieterHefer

Alan Ratcliffe wrote:
PieterHefer wrote: Ok so this might sound very stupid, but are you to the jack 2 jack input on the amp?
If I understand your question correctly, then, no, the amp should not be connected to the speaker/cab when you take the reading.

Haha, crap! Posted via phone, and that doen not even sound like a question :-[
Do I take the reading on the jack socket which comes from the output of the cab.
Not connected to the amp!

Nicholas-L

Yes test is from the con on the cab unconnected to an amp. ?

SvR65

Pieter,

Weet Tops van jou plannetjies?! Hahaha!

Nicholas-L

hahaha pieter jy't my blessing om die crate te convert ? ?

PieterHefer

SvR65 wrote: Pieter,

Weet Tops van jou plannetjies?! Hahaha!

Jip, natuurlik! Plus jy kan ook moontlik daarby baat vind!
Daan hoef jy nie ook altyd jou cab saam op die ossewa te laai nie ?