Fender FR-12 preamp mod : The Hissterectomy

Deadpool_25 said:
So Fender replaced 2 of the 3 applicable opamps and did so with versions that are, on paper, quieter than their original choice but still twice as noisy as the ones @Lysander chose.
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More like 25-30%, but we're talking very low noise floors here, so i doubt it would make any substantial difference. 3.3 nV/√Hz for the OPA1664 Fender's using is an excellent figure (vs. 2.5nV/√Hz for the OPA1604 i suggested). For reference, the original TL084s are 18 nV/√Hz.

As far as i can tell, Fender just chose OPA1664 because is one of the cheapest SoundPlus opamps from TI - about half of OPA1604 when purchased in bulk.

That's still a very expensive "fix" for Fender to put out. I just can't believe no one could be bothered to acknowledge this flaw, and work on a MKII preamp board instead.

This makes me curious to hear one of these "fixed" ones alongside an OG (lol) model and a Lysander-modded version.
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Ditto, i'd really like to try one myself. My modded FR-12 is basically noiseless ever since the mod thou.
 
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Lysander said:
More like 25-30%, but we're talking very low noise floors here, so i doubt it would make any substantial difference. 3.3 nV/√Hz for the OPA1664 Fender's using is an excellent figure (vs. 2.5nV/√Hz for the OPA1604 i suggested). For reference, the original TL084s are 18 nV/√Hz.

As far as i can tell, Fender just chose OPA1664 because is one of the cheapest SoundPlus opamps from TI - about half of OPA1604 when purchased in bulk.

That's still a very expensive "fix" for them Fender to put out. I just can't believe no one could be bothered to acknowledge this flaw, and work on a MKII preamp board instead.
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Ah yeah. I was thinking it was one with 5 nV/√Hz.

I also did your mod and it's basically silent now.
 
Lysander said:
That's still a very expensive "fix" for them Fender to put out. I just can't believe no one could be bothered to acknowledge this flaw, and work on a MKII preamp board instead.
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Well, other than the hiss there are basically zero complaints. I'd guess they'll just quietly acknowledge this on one of the forums with a half-hearted mea culpa and then raise prices on these in 6 months or a year.
 
I held off ordering an FR12 for months after discovering this post. I ordered an FR12 on 1/5 after GC was out of stock for at least 2 months hoping they had corrected the issue with this new batch, it arrived 1/11. No hiss whatsoever. I suspect Fender corrected the issue. here's my test.
 
JustCuz said:
I held off ordering an FR12 for months after discovering this post. I ordered an FR12 on 1/5 after GC was out of stock for at least 2 months hoping they had corrected the issue with this new batch, it arrived 1/11. No hiss whatsoever. I suspect Fender corrected the issue. here's my test.
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I just ordered two. I was going back and forth between these and the EVs but I finally landed on these. I do like the amp look better than the floor wedge and it made more sense for me since I'll be putting them up on a shelf. Apparently the ones I'm getting are a new batch dated Jan 2nd and 3rd respectively. I'm hoping the hiss isn't there but if it is I am fully prepared to get my Fluke and Hakko out and replace a few chips. I just have one question though....does it Chug? ;).
 
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WKSmith said:
The test boards came in early 🙂

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