Swapping preamp tubes on F-50 for lower gain

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pulteney

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Hello there, first post, been lurking for a while :mrgreen:

So, I adore the clean channel of my F-50 but don't need that much gain on channel 2. Read about swapping preamp tubes but I've never done it.

1. That affects channel 1, too, right?
2. Do I need to change all 4 preamp tubes or just V1?
3. Have you tried any of these? https://reverb.com/news/how-to-improve-your-amps-tone-with-preamp-tube-swaps

Thanks for your insight!
 
If the F-50 is like the F-30, then V2A (pins 1, 2 & 3) is the first gain stage for the lead channel. V1A follows the tonestack on the lead channel. You could install a JJ ECC832 in V2 or both V2 and V1 to lower the lead channel's gain without affecting the rhythm channel.

The ECC832 is like an ECC83 (12AX7- gain factor 100) on pins 6, 7 & 8 and an ECC81 (12AU7- gain factor 20) on Pins 1, 2 & 3.

I've used the JJ ECC823 (the opposite of this tube) in Mesa DC and Marshall DSL amps for this purpose and it worked well.
 
Thanks! First time I've ever heard of this tube.

I was thinking of swapping V2 for a 12AY7 and V4 for 12AT7 but I'll definitely give yours a spin. Thanks! :mrgreen:
 

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