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No Signal from Fender Rumble Line Out

SlightlyDeviant

SlightlyDeviant

Apr 1, 2016
13
14
36
Florida
#1
I purchased a new Fender Rumble 500 combo recently, and when I went to use the line out today the PA was not getting any signal from the amp. I'd like to make sure this is not user error before contacting my local Authorized Fender Service Center.

On my prior amp (Fender Bassman 250), I used a balanced XLR to TRS cable to connect the line out to the PA mixer. This method is not working on the new amp. I've used two different XLR to TRS cables, and plugged them into several channels in the mixer, as well as directly into the powered speaker. My prior amp works in all these configurations.

Is there something I am missing on the Rumble to get this to work, or is it likely that the line out is DOA from the retailer? Thanks!
 
#2
Given you've tried two cables already (I assume those two worked for you with your other setup?) Ad the Amp is brand new, I guess you got one with a bad DI out. But...
Double check the cables with an ohmmeter, XLR 1 = TRS shield, XLR 2&3 to to TRS T&R.
Also the DI on the Rumble is post EVERYTHING. Pretty sure GAIN & MASTER both need to be up.

Pop on over to the Fender Rumble Club and see what those guys have to say.
 
#3
From the manual -

LINE OUT
— Balanced output to connect to externaldevices such as PA systems and recording consoles.
The level and tone of the LINE OUT signal are affectedby all preamp controls, including GAIN. Pressing the
GND LIFT button IN may eliminate hum or buzz result-ing from connection to improperly grounded equip-
ment
 
#9
SlightlyDeviant said:
Problem solved: user error on my part. I used an XLR to XLR cable into the mic-level input on the mixer instead of the XLR to TRS cable into the line-level input. Also had to turn up the master more than I had it while testing.

Thanks for the responses everyone!
Click to expand...
Wait! That's it? Barely half a page?
No fights broke out. No name calling. No rage quits? No cat memes?
Gee Mr., next time bring us something good! :banghead:

Hey just pullin' your chain.
Also glad you got it figured out.
We'll make a sound man out of you yet. :wacky:
 
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#10
Old Garage-Bander said:
Wait! That's it? Barely half a page?
No fights broke out. No name calling. No rage quits? No cat memes?
Gee Mr., next time bring us something good! :banghead:
Click to expand...

Oh no! I don't want my first thread to be a flop! ;)

.bp.blogspot.com%2F-MrT1YWmJIxQ%2FTfcNybVLGJI%2FAAAAAAAAAEk%2FsNOsNUOynIA%2Fs1600%2Fdisappointed.jpg
 
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#11
I understand what you are saying, but the manual has conflicting information. The line drawing found on page 10 of manual suggests otherwise. It indicates that one pin is grounded. This to me is not a negative signal, necessary to balance the positive signal in a balanced signal.
 
#12
Old Garage-Bander said:
Line drawings are generally only good for showing signal flow and are not always very useful for diagnostics.
To parse out actual connections and pins you need the schematic.

This is a Rumble V3 XLR schematic.
View attachment 2925793
Click to expand...
If you say GND-O provides the negative signal, ok, but you don't show how GND-O got it's signal. Otherwise, I don't see how a bunch of caps and resistors invert a signal.
 
#13
Drgonzonm said:
If you say GND-O provides the negative signal, ok, but you don't show how GND-O got it's signal. Otherwise, I don't see how a bunch of caps and resistors invert a signal.
Click to expand...
I didn't say any of that. I just provided the XLR Line Out schematic, because I felt it provides more information about the circuit than a line drawing. This was taken directly from a schematic of the Rumble series amplifier. Nothing more, nothing less. I was simply providing the schematic. I didn't offer to explain how it works. Find someone at Fender to tell you what you want to know or bring in someone smarter than me to explain it. (Which shouldn't be to tough to find - BTW).

I'm just a dumb tech, not an engineer. So even if pin 2 and 3 are out of phase or there is some inversion going on (I never claimed any of that) I don't really see how the circuit is even a truly balanced output. But I couldn't afford to go to MIT, so I have to live off the scraps left behind by the EE's. Today I couldn't probably even put a D cell into a flashlight the right way. So until at least midnight Central Time today, you be barkin' up the wrong tree if you want me to figure it out. Gee willikers anyway Mr., sorry to disappoint. :oops: I'll just remove the whole thing.
 
#14
Old Garage-Bander said:
I didn't say any of that. I just provided the XLR Line Out schematic, because I felt it provides more information about the circuit than a line drawing. This was taken directly from a schematic of the Rumble series amplifier. Nothing more, nothing less. I was simply providing the schematic. I didn't offer to explain how it works. Find someone at Fender to tell you what you want to know or bring in someone smarter than me to explain it. (Which shouldn't be to tough to find - BTW).

I'm just a dumb tech, not an engineer. So even if pin 2 and 3 are out of phase or there is some inversion going on (I never claimed any of that) I don't really see how the circuit is even a truly balanced output. But I couldn't afford to go to MIT, so I have to live off the scraps left behind by the EE's. Today I couldn't probably even put a D cell into a flashlight the right way. So until at least midnight Central Time today, you be barkin' up the wrong tree if you want me to figure it The out. Gee willikers anyway Mr., sorry to disappoint. :oops: I'll just remove the whole thing.
Click to expand...
Do not remove. More than one designer has used the chassis ground to carry signals. In fact, I have a schematic of a pp tube amp where the inverted signal is carried through the chassis ground.
If you look at the schematic following pin3, there is a cap in parallel with a resistor, it allows a signal to come from grd-o to feed pin 3. I believe the resistor gives an elevated voltage, so the ac signal, doesn't clip. The second cap removes the dc voltage. So if the line out is balanced, the inverted signal likely originates on the the chassis ground. Without the rest of the schematic, I have no idea where the signal originates. Thanks for the partial schematic.
 
Last edited:
#15
Drgonzonm said:
Do not remove. More than one designer has used the chassis ground to carry signals. In fact, I have a schematic of a pp tube amp where the inverted signal is carried through the chassis ground.
Click to expand...
I'm sorry man, I don't even know why we're having this discussion?
Nothing against you, I just don't want to be here right now.
Catch ya when I'm having a better time if it. Thanks.
 
#16
SlightlyDeviant said:
Problem solved: user error on my part. I used an XLR to XLR cable into the mic-level input on the mixer instead of the XLR to TRS cable into the line-level input. Also had to turn up the master more than I had it while testing.

Thanks for the responses everyone!
Click to expand...

I had this exact same problem last weekend. First time ever trying to run it to a mixer. I usually use my effects unit but I didn't feel like schlepping it to rehearsal. I guess an XLR to TRS adapter would work also?
 
#17
jfh2112 said:
I had this exact same problem last weekend. First time ever trying to run it to a mixer. I usually use my effects unit but I didn't feel like schlepping it to rehearsal. I guess an XLR to TRS adapter would work also?
Click to expand...
Not unless the TRS input is mic level. Just use an XLR-XLR cable like the designers intended.
 

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