It’s time for a new amp build!
This time I’m teaming up with @guidothepimmp to build ourselves a pair of fire-breathing 1x12 combos. The broad idea at the moment is that I’ll handle the electronics, he’ll handle the wood and metal, and together we’re hoping to make something pretty special.
The first step of course is deciding what type of amp we want to build.
We’ve toyed with a few ideas, but it looks like we’ve settled on a version of the awesome Splawn Quick Rod (… or really the Street Rod since it’ll be a combo). For those of you who aren’t familiar with it, the Quick Rod is a hot-rodded Marshall circuit aiming for an 80s metal sound (think Van Halen). The clean channel is already pretty potent, but the dirty channel is where it all happens. It has three ‘gears’ - 1st gear is a hot Plexi, 2nd gear is a hot 800 and 3rd gear is a hot 800 turned to 11. It also has an OD1/OD2 switch that moves all three of the gears into overdrive and an additional Solo boost on the master… so yeah, pretty crazy stuff.
I’ve found a schematic for the Quick Rod preamp (link at the end) and am looking at putting that into a relatively standard Marshall style phase inverter/power amp with cathode biased tubes and presence control in the feedback loop. I believe that the cathode bias is a departure from the Splawn amps, but it will allow me to use VVR power scaling to keep the beast under control.
Powertube wise, we’ll probably either go with 6V6 or EL84 in AB mode. We’re thinking of putting in 4 and then giving a half power switch to disable two of them. So, it’ll probably end up with a max power of 30W but between the half power mode, power scaling and master volume control I’m hoping you’ll be able to play it at a very manageable level.
We’ll also probably look at building a foot switch while we are at it and giving it an effects loop (it looks like the Splawns don’t use buffered loops, which would make it easier)
… oh, and we won’t be bothering with a reverb tank. 😛
Other than that, we’re also toying with a built-in load box for silent recording and possibly a reactive attenuator, although I don’t think that will be necessary.
So, where to from here?
Well, first step is finalizing the circuit and specifying the components. After that I want to do a proper circuit layout, with this much gain in the amp, poor component layout and lead dressing will just be noise.
Once that is done, we can design the chassis and cabinet.
Then it’s on to ordering components and starting the build.
Lots of work ahead, but I’m pretty excited about this one. 😃