Why not try changing the tubes? For the past few years, I've been loving the green and blue channels of my 5150 III 50 watt. The red seemed a bit too over the top... I always wished for a voicing similar to the blue channel that I could set differently for leads.
I contacted the designer, Howard Kaplan, from Fender on what he suggets to tame the red channel.He told me that the red channel, in addition to having more gain, has a sustain character that the blue channel doesn't have. If I wanted to lower the gain, I should try at 12AU7 in V2 and V3... and I did just that. I got a set of JJ's and I tried the amp today.
Holy balls!!! What a world of difference!!!
The gain was diminished quite a bit. I used to have to set the gain around 11 or 12 noon to get a good bit of satchuration. Anything more wasn't really needed. Now, I have to set the gain to 3 or 4 o'clock, but even then, the voicing sounds similar to the blue channel. After messing with the EQ for a bit and driving it with a Bad Monkey to tighten up the lead tones, I found some killer killer tone.
I played and played and played. It sounded huge with a nice bit of teeth, but not buzzy at all.
So now, I have a 4 channel amp!!!!
- Channel 1: Clean
- Channel 2: Clean channel with a Bad Monkey for a bit of dirt
- Channel 3: Blue Channel for Hot Rodded Marshall tones - TC Spark to tighten it up when needed
- Channel 4: Liquid lead tone
I love this amp!!! It just keeps on giving!