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Weird problem with Fishman Platinum Preamp

Kenan

Kenan

Sep 13, 2014
386
700
#1
Hello TB,
I have a Fishman Platinum Pro EQ Analog PreAmp that gets a lot of use on gigs and I'm having a strange problem with it. When I flip the phase switch to the up position, it mutes the XLR DI completely. As in 100% dead. Flip it back down and we're back in business. This happens regardless of whether I'm sending the signal pre or post EQ. The 1/4" amp output does not have this issue, only the XLR out.

With regards to the phase switch, the manual says that "down position = non-inverting." So it's when the polarity IS inverted that the DI cuts out.

Anyone have any insight into this?

Thanks in advance,

Kenan
 
#2
Not familiar with your pre, but is there more than one channel involved? Dry bass and processed?
If that's the case, I wonder if those channels get summed at the D.I.?
Two channels summed together could drop out if one channel were out of phase (reverse polarity actually) from the other.
 
#3
upload_2022-9-5_18-14-43.png


Here's an image. It's just one channel. Thanks for the reply!
 
#4
A couple of common possibilities…

1. the device you are driving has an impedance compensated output and the input is on an XLR jack but is actually unbalanced.

2. The output in impedance compensated and there is a fault in the cable (pin 1 to pin 2 or pin 3 short)

3. You are using an adapter to convert to 1/4” unbalanced and in one position there will be no signal if the output is impedance compensated.
 
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#5
agedhorse said:
A couple of common possibilities…

1. the device you are driving has an impedance compensated output and the input is on an XLR jack but is actually unbalanced.

2. The output in impedance compensated and there is a fault in the cable (pin 1 to pin 2 or pin 3 short)

3. You are using an adapter to convert to 1/4” unbalanced and in one position there will be no signal if the output is impedance compensated.
Click to expand...

Hi agedhorse, I really appreciate you jumping in here. To address points 1 and 2 (if I understand correctly): the issue happens regardless of where I'm sending the signal, and with different cables. It happens when sending to a professional venue 's board, or when sending to my QSC powered speaker. As to point 3, there are no adapters being used.

Is it possible that it's a wiring short in the preamp?

Thanks for your reply.
 
#7
Greetings Kenan,

Just wondering if you ever resolved your issue with the Fishman? I have started having problems with mine on a couple of recent gigs and some of the ‘symptoms’ sound similar…I’d be curious to hear any troubleshooting steps you took and/or what solution you came up with. Thanks,
Laura
 
#8
Hi Laura,
Nothing has changed for me with regards to the Fishman. I'm still having the same issue and I haven't made any effort to resolve it beyond making this post, if I'm being honest. My unit is fully functional otherwise; I just can't flip the phase switch if I'm using the DI. I've actually been experimenting with other preamps, so it hasn't been much on my mind.

Good luck with your Fishman! Please share any info that you discover. Sorry I can't be more help.
 

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