I played around with it a little and so far I like. The basic tone controls don't have a huge impact from min to max in the sense that it doesn't drastically alter the character. It's more like fine tuning across the entire sweep and not trying to get it just right within a millimeter of travel. The mid boost is also subtle, but still noticeable. It's enough for when you'd want a little bit more to cut in a mix. I think the bright boost has the most influence. Nothing over the top, but it does add a nice "sparkle" to the overall tone.
I also did a little tube rolling with the preamp tube. This is where there were some noticeable observations and I have a question. I went through a 12AX7, 12AT7 and 12AU7.
12AX7:
This obviously has the most gain of the three. With this tube in, there was nearly no headroom. The best it would do was clean-ish down at 1. At 1.5 it was already into breakup, and at 4 it was going into full saturation. With the volume up half way it was just before the point of too much. anything past 7-8 on the dial was unusable. Factor in the gain boost and anything past half way was too much and unusable. I don't think this amp is well suited for a 12AX7 even though that's what it came with
12AT7:
This tube was more useable than across the full volume sweep than the 12AX7, but still a bit much. Breakup started around 2.5 on the dial. It was at a good saturation around half way, and just past the threshold of what I'd consider too much for that style of amp. The gain boost was more useable across the range as well. Overall a 12AT7 would work okay, but not get the most out of the full range.
12AU7:
Of course this has the lowest gain of the tube family and had the most clean headroom. It was able to stay mostly clean on the lower half of the knob's sweep and started breaking up around half volume. Hitting the gain boost here pushed it into some light saturation. With the volume at max and gain boost on it was right before the spot where it became too much. On the other side, it wasn't quite enough for my taste. I would have liked it to have just a little bit more room for adjustment before it capped out. But if I were looking for it to be more on the clean side this would be the tube I'd go with.
For now I've left the 12AT7 in, but I want to get a 12AY7 to try. It sits right between the AT7 & AU7 in terms of gain and I think it would be the perfect balance between the two that fits my wants.
As I said I have a question that came from trying the different tubes. With the 12AX7 anything past 3/4 volume the amp would start to fart and cut out. With the 12AT7 It cut out like this only at max volume with the gain boost on. And with the 12AU7 I didn't experience this at all. I went back and rechecked all my solder joints and double checked the voltages. Solder joints were good and voltages were in range. So I'm thinking the higher gain tubes were overloading the tone stack and causing it to clip. The behavior and sound was similar to my Synergy Pitbull module where the GEQ is after the volume. Pushing too much signal causes the GEQ to clip and fart out.
So the question (and I'll post this in the tech section too). Is my guess that the higher gain tubes are pushing too much signal into the tone stack causing it to overload/clip correct? Or should I be looking for something else that may be out of whack?
