Fender FR-12 preamp mod : The Hissterectomy

WKSmith said:
And I am pretty sure everyone here can do a null test in a DAW and learn that the signal coming from the stock FR is 180° out of phase from the input signal.... Without a bunch of drama.
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Will flip flopping pins 2 & 3 from the XLR input to the preamp board correct the phase? I’m handy with a soldering iron and this seems a fairly simple mod…
 
pydna said:
Will flip flopping pins 2 & 3 from the XLR input to the preamp board correct the phase? I’m handy with a soldering iron and this seems a fairly simple mod…
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You will get a better result reversing the speaker and horn leads.

At some point I am sure F corp will quietly fix the phase. It would be wise to run your own null test comparing the input signal with a recording of the output (through a mic) as two tracks.. and zoom in on the waveforms.
 
How would a person with just voltage ohm meter determine if the leads to the speakers are out of phase. Is making that much of tone or volume difference? Thanks
 
You would have to compare the phase of the whole system compared to the input signal. Unless you have a scope on your meter .. it's not going to help.

The phase is only an issue when running the FR with a real amp, or another FRFR that is in phase. That is where it becomes obvious for several folks here. They will cancel each other out and the low end especially suffers.

But running one FR by itself you won't have an issue with phase.
 
WKSmith said:
You would have to compare the phase of the whole system compared to the input signal. Unless you have a scope on your meter .. it's not going to help.

The phase is only an issue when running the FR with a real amp, or another FRFR that is in phase. That is where it becomes obvious for several folks here. They will cancel each other out and the low end especially suffers.

But running one FR by itself you won't have an issue with phase.
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Actually, phase can make a difference if you're not using headphones. You can get different phase cancelations, different frequency response... the louder you play, the more difference it makes.
 
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So I am doing a thing..
I have proofs ordered for the V3 circuit, but built like the V2 with old school full size PTH components except for the ICs. That way I can hear it with these really nice film caps.

I may move ahead with the smaller V3 SMT proofs to compare too, if the price is reasonable.

V3MOD.png
 
Greg Ferguson said:
Hmm. A "Go Fund Me" might help it be reasonable.
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I am considering the tonal difference and the price per piece between full SMT.. and the old way. If the build price for SMT is a lot higher the pre will cost more and I won't even bother. I am trying to keep the V3 price down for these $500 FRs

I can fund a few hundred of these.

edit: Just got a good quote for proofs of the SMT build. So I will get to compare the two V3s
 
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WKSmith said:
I am considering the tonal difference and the price per piece between full SMT.. and the old way. If the build price for SMT is a lot higher the pre will cost more and I won't even bother. I am trying to keep the V3 price down for these $500 FRs

I can fund a few hundred of these.

edit: Just got a good quote for proofs of the SMT build. So I will get to compare the two V3s
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Please keep us posted. I also need to balance cost with effect. Thank you so much Liam.
 
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