Fender FR-10/FR-12 noise reduction mod

[Famous_Snack]

Well, folks. I just picked up an FR-12 and after reading this thread, I thought I’d pop the hood to see what’s what in prep for maybe doing the op amp swap. Was surprised to see what I found. Thoughts?

 

[jellodog]

Well, folks. I just picked up an FR-12 and after reading this thread, I thought I’d pop the hood to see what’s what in prep for maybe doing the op amp swap. Was surprised to see what I found. Thoughts?

View attachment 16225

WAT? Picked up totally new from a store? Not used?

So it's been modded already. But by Fender or previous owner?

 

[Lysander]

WAT? Picked up totally new from a store? Not used?

Really curious about this myself as well. That looks like a third-party mod to me, but Note how the input opamp was also replaced.

OPA1664 is an interesting opamp choice for the EQ section though. That part is marginally noisier than the OPA1604s i used in my FR-12 (still exceptional at 3.3 nV/√Hz!), but 30-50% cheaper.

 

[jellodog]

OPA1664 is an interesting opamp choice, too. That part is marginally more noisier than the OPA1604s i used in my FR-12 (still exceptional at 3.3 nV/√Hz!), but 30-50% cheaper.

Hmm... Sounds like a very Fendery choice to me. And they didn't replace every opamp, so even cheaper!

 

[Famous_Snack]

Really curious about this myself as well. That looks like a third-party mod to me, but Note how the input opamp was also replaced.

OPA1664 is an interesting opamp choice for the EQ section though. That part is marginally more noisier than the OPA1604s i used in my FR-12 (still exceptional at 3.3 nV/√Hz!), but 30-50% cheaper.

Brand new, purchased direct from Fender!

 

[Lysander]

Hmm... Sounds like a very Fendery choice to me. And they didn't replace every opamp, so even cheaper! View attachment 16226

Cheaper than the top-of-the-line Burr-Brown audio opamps offered by TI... but over 10x (!!!) more expensive than a TL084 when purchased in bulk.

Unless Fender happened to already source this part for something else, i'd be very surprised to find out they started changing ICs on their amps - and very pissed off, too.

 

[jellodog]

Brand new, purchased direct from Fender!

Well I guess this is Fender's most affordable and pragmatic stopgap solution until they get around to manufacturing a new PCB layout.

They've obviously been listening and reading the online discussion. This might explain a couple of posts on other forums in the last week from people that purchased new and mentioned that their cabs were hiss-free.

 

[Lysander]

Brand new, purchased direct from Fender!

Ok, now i'm livid Really classy move, Fender!

 

[Famous_Snack]

Ok, now i'm livid Really classy move, Fender!

… and now I’m sitting on three OPA4227PA chips and sockets with no place to put them. Wonder what Mouser’s restocking fee is?

 

[Lysander]

… and now I’m sitting on three OPA4227PA chips and sockets with no place to put them. Wonder what Mouser’s restocking fee is?

I think you'll only need to pay shipping if the purchase is less than 30 days old.

PS: Can you check which opamps are used on the input and output crossover (the small 8-pins ones)? Just for my curiosity.

 

[Famous_Snack]

I think you'll only need to pay shipping if the purchase is less than 30 days old.

PS: Can you check which opamps are used on the input and output crossover (the small 8-pins ones)? Just for my curiosity.

Yes. I’ll get readable pics tomorrow. Odd thing, just as only 2 of the 14 pin chips have been substituted, only one of the 8 pin chips was swapped out

 

[deadpool_25]

This would be a cool move if they'd just given credit where it's due.

But they didn't.

So it's a dick move.

 

[aflynt]

Yes. I’ll get readable pics tomorrow. Odd thing, just as only 2 of the 14 pin chips have been substituted, only one of the 8 pin chips was swapped out

Just replacing last two 14 pin chips makes total sense. That‘s all that’s needed to reduce the hiss. Replacing the other chips made no noticeable difference in the noise floor when I tested it out. Not sure why they’d replace the first 8 pin IC though unless they were trying to fix the clipping issue that WKSmith noticed on the Fractal forum.

-Aaron

 

[Famous_Snack]

I think you'll only need to pay shipping if the purchase is less than 30 days old.

PS: Can you check which opamps are used on the input and output crossover (the small 8-pins ones)? Just for my curiosity.

 

[Famous_Snack]

I think you'll only need to pay shipping if the purchase is less than 30 days old.

PS: Can you check which opamps are used on the input and output crossover (the small 8-pins ones)? Just for my curiosity.

This one is very difficult to read. I had to crank the contrast to get anything. Interestingly enough, it was originally covered with a sticker.

Pretty sure it’s an TI RC4558P

 

[Famous_Snack]

This one is very difficult to read. I had to crank the contrast to get anything. Interestingly enough, it was originally covered with a sticker.

The sticker

 

[Lysander]

This one is very difficult to read. I had to crank the contrast to get anything. Interestingly enough, it was originally covered with a sticker.

Pretty sure it’s an TI RC4558P

Thanks! Yeah, it looks like a vanilla RC4558 to me. The other one is a OPA1642, the dual version of the OPA1644 used in the EQ section.

So... yeah. This all looks like a "factory mod" to me, down to how cleanly (machine) those solders look on the DIP adapters for the ICs.

 

[Famous_Snack]

…down to how cleanly (machine) those solders look on the DIP adapters for the ICs.

I agree from close inspection that those weren’t done by hand. Way too perfect.

 

[JiveTurkey]

So @stilwel ; what's the process for getting our circuit board swapped for the corrected one if we bought our FR12 before this corrected revision? Is this an option?

 

[Lysander]

So @stilwel ; what's the process for getting our circuit board swapped for the corrected one if we bought our FR12 before this corrected revision? Is this an option?

+100. At the very least, Fender should acknowledge they're shipping boards with a fix on it... and deal with customers who bought units with the original preamp.

And hey, a shoutout would be nice as well. Fender is shipping pretty much exactly the mod i described on the very first post in this thread, almost three months ago.