Surprising what a simple tube change will do...

mystixboi1

mystixboi1

Kick Henry Jackassowski
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!
 
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i have a Kustom Defender 5 watt. 1~12AX7 and 1~EL84. it would start saturating at around 10 o'clock.....way too early.
so i dumped a 12AU7 in the preamp socket and boom.....cleaned it right up. of course i lost some volume on the top end, but i don't care because i bought it as a living room amp in an apartment, so less loud is a good thing.

messing with the preamp tubes can do wonders for an amp. even to the extent sometimes that you wonder what the hell the designer was thinking.
 
Congrats on finding just the right tube!

I believe it was Pine Apple Slim that mentioned a change to an 12AU7, and that got me thinking. I have a Tube Works solid state head that also uses a tube in the preamp stage to generate the overdrive. It had a 12AX7 in it, and I just never liked the overdriven sound. I changed out the 12AX7 to a 12AU7, and it tamed the overdrive, and warmed it up just a bit. I fell in love with the amp all over again.
 
I have a few vintage GE 5751s that I try out in the V1 slot of tube amps that are a bit too harsh. Dropping the gain in that slot by 30% makes a real difference.
 
I have all the gain I need on the red channel, at about 11:embarrassed:0.

It never gets buzzy/fizzy, but turning it up more really doesn't do anything. So, 60% of the knobs range doesn't add any value.
 
GDSmithTX said:
I have a few vintage GE 5751s that I try out in the V1 slot of tube amps that are a bit too harsh. Dropping the gain in that slot by 30% makes a real difference.
Click to expand...

Try those tubes in the tone circuit. Your tone circuit will be more responsive and some of that harshness may disappear. This will allow you to go back to the original tune in V1
 
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