Looking For Help - SWR Son Of Bertha - Multimeter Speaker Reading

[faulknersj]

Hi all,

My SWR Son of Bertha bass cab stopped producing volume and I am trying to troubleshoot to find the issue.

I am getting a reading of 6.0 on my cheap multimeter. Does this mean the speaker should be good and I should be focusing more on the crossover, loose wire connection, etc?

Thank you!

 

[walterw]

that's one step

the next is to momentarily touch a 9V battery across those terminals, + to +. the speaker should pop forward

if that happens then you know the speaker itself still works

 

[faulknersj]

that's one step

the next is to momentarily touch a 9V battery across those terminals, + to +. the speaker should pop forward

if that happens then you know the speaker itself still works

Thank you so much for your help. The speaker did move forward…

 

[walterw]

Thank you so much for your help. The speaker did move forward…

so your next step is to see where the signal is failing between the lead wires in the cab and the input jack

 

[faulknersj]

I'm guessing this fuse is the problem.

 

[ihixulu]

i believe blowing that fuse would only kill the signal to the tweeter.

 

[faulknersj]

i believe blowing that fuse would only kill the signal to the tweeter.

I was wondering that…I can't find clear info on what fuse this is.

I am not seeing any other obvious issues though…

 

[Wasnex]

6 ohms DC resist is about right for an 8 ohm woofer.

I believe the woofer is run full range. Looks like the black and white wire run from the jack to the woofer.

I believe the fuse is only for the tweeter.

Looks like an 18dB HPF is connected to the jacks...Here is an example of an 18dB HPF.

+ and - are connected to the input jacks; in parallel with the woofer.


Fuse and L-Pad are connected something like this:

The polarity of the tweeter may be reversed.

 

[Wasnex]

Check your speaker wire.

 

[walterw]

I'm guessing this fuse is the problem.

don't guess!

set that same meter one click counterclockwise of where it is in the picture, from "200" to the continuity "beep check" setting. touch the leads together, it should beep when there's a connection

now, use that to check for where there's no connection; try across that fuse, then more importantly, from the + of the input jack to the end of the + wire at the speaker, and the same for the - connection

the place where it doesn't beep is the place where you're not getting signal through

 

[bundavis]

I've been having trouble out of.my Goliath Sr.
It really sucks that you can't buy replacement parts for them since SWR is out of business.

Hope you get your issue solved my friend..

 

[newfuture]

i believe blowing that fuse would only kill the signal to the tweeter.

Yes.

This is how my old Goliath II was wired. With the exception that the fuse was an automotive light bulb so it gave a fun show when blowing.

 

[faulknersj]

Check your speaker wire.

Thanks for chiming in…the connections look good for the speaker wire…anything else I should be looking for?

 

[faulknersj]

don't guess!

set that same meter one click counterclockwise of where it is in the picture, from "200" to the continuity "beep check" setting. touch the leads together, it should beep when there's a connection

now, use that to check for where there's no connection; try across that fuse, then more importantly, from the + of the input jack to the end of the + wire at the speaker, and the same for the - connection

the place where it doesn't beep is the place where you're not getting signal through

Thank you for explaining that…I'll check it out and report back…

 

[40Hz]

I've been having trouble out of.my Goliath Sr.
It really sucks that you can't buy replacement parts for them since SWR is out of business.

Goliath cabs are usually repairable. A faulty crossover can be diagnosed and fixed by a tech. But the real challenge is either locating a P.A.S. 10" speaker since that company is long gone, or finding a speaker with the same specs and characteristics to replace it.

Should you be dealing with a bad speaker you can either talk to a speaker repair service or check eBay and Reverb to see what's available. PAS-10 speakers do show up every now and then. Sometimes even for reasonable prices. Otherwise you'll want to consult with a pro about what makes and models of 10 inch speakers most closely match the original.

 

[bundavis]

Goliath cabs are usually repairable. A faulty crossover can be diagnosed and fixed by a tech. But the real challenge is either locating a P.A.S. 10" speaker since that company is long gone, or finding a speaker with the same specs and characteristics to replace it.

Should you be dealing with a bad speaker you can either talk to a speaker repair service or check eBay and Reverb to see what's available. PAS-10 speakers do show up every now and then. Sometimes even for reasonable prices. Otherwise you'll want to consult with a pro about what makes and models of 10 inch speakers most closely match the original.

Thanks, i made a post a while back and got some good feedback. It in the input jack plate
That cab i bought brand new in 2003 with my first real good income tax return. I sold it in 07, the guy sold it in 09 and i eventually bought it back. Been a great cab.... Definitely a work horse i tey and take very good care of it ..

 

[Wasnex]

Thanks for chiming in…the connections look good for the speaker wire…anything else I should be looking for?

Don't trust your eyes. Use the continuity tester on your multi-meter. First thing is to make sure there is not a short between + and -.

If you use a 1/4" chord, plug it into the cab. Check continuity from the tip to the end of the white woofer wire. Also check continuity from the sleeve to the end of the black woofer wire.

If you use a speakON, make sure the plugs are genuine Neutrik. Fake speakONs can fail to make connection, and they can also damage the jack. Just because a fake speakON works with one cab is no guarantee it will work with another cab.

It can be a bit tricky, but you could also plug in a speakON and check continuity from the end of the black and white woofer wires to the contact in the plug.


This is the best image I could find.

Look inside the barrel (end) and you should see 4 little metallic contacts. You can see 2 of 4 contacts in this image. One visible contact is on the center post and one contact is on the outer ring. The other two contacts are opposite these.

Amps and instrument cabs generally use only 1+ and 1-. I believe one will be on the center post and the other will be on the outer ring>

If you have NL2 plugs there will only be two contacts, and they are equivalent to 1+,1-

 

[40Hz]

Thanks, i made a post a while back and got some good feedback. It in the input jack plate
That cab i bought brand new in 2003 with my first real good income tax return. I sold it in 07, the guy sold it in 09 and i eventually bought it back. Been a great cab.... Definitely a work horse i tey and take very good care of it ..

I hear you. My workhorse is a Goliath II Jr. I originally had two. Sold one because "I really don't need two." Yeah. Right. I'm still kicking myself for doing so.

 

[Eric Ryan]

Thanks, i made a post a while back and got some good feedback. It in the input jack plate
That cab i bought brand new in 2003 with my first real good income tax return. I sold it in 07, the guy sold it in 09 and i eventually bought it back. Been a great cab.... Definitely a work horse i tey and take very good care of it ..

I still have a Goliath II, & I agree. Fantastic cab. I bought a Darkglass 2X12 in 2021 just to lessen the load on the old girl, but I still use it regularly for practices.