Big Monk
Well-known member
I'm going to use this thread to document my build on the Muffin board.
I'm using the schematic values from Kit Rae's site for the Version 2 Violet Ram's Head 1972 #5 unit:
I have a whole stash of Amperex A115 transistors that I bought from Small Bear in the hopes they actually delivered around the gain bucket Steve showed. I wanted to use them for Axis Face Silicon Fuzz units. Turns out his hFE bucket was low for some reason. Most of them were over 150, with a distinct gathering around 175-200. Not so great for what I bought them for but good for the more traditional Silicon Fuzz Face and, as it turns out, this project. I decided to go with Kit Rae's site again where he singles out 2 exceptional Violet Ram's Head units with all 4 transistors in the 160-200 hFE range:
I ended up picking a fairly matched set of A115 units:
Q1, Q2, Q3 = 171 hFE
Q4 = 164 hFE
I had some 1N456 diodes left over from my Ampeg Scrambler parts so I grabbed 4 of those centered around a Vf of 756 mV. Nothing special other than they look really cool.
The last thing I am working on right now is the tonestack. I'm going for more of a Gilmour thing here and plan on using this by itself but also EQ'd by a Vick Audio Overdriver. My little Single Ended EL84 amp is fantastic for my home playing and the Drive control I installed gives me a broad range from clean to semi-dirty to full out crunch. It has a reasonable amount of mid-range content when driven so I don't want to do anything crazy with the tonestack except to flatten out the mid-scoop a touch.
So, I went to the Duncan TSC:
In the form you see in the schematic, there is a -12.5 dB mid scoop at around 1kHz when the tone control is at 50%. I wanted to bump this up a bit but not quite flatten it out as I have a somewhat mids-forward amp and ways to adjust the mids should I need to. I'm still not certain how I'll end up configuring it, but I'll likely just pick an appropriate value for C9 and call it a day.
Here are the TSC charts for C9 = 6.8 nF and 8.2 nF, respectively:
The mid-scoop at 50% Tone goes up to -8.3 dB and -9.4 dB respectively.
Lastly, here is the mockup with controls and mechanicals attached to the Tayda Ball Silver enclosure:
Should find some time this week to get everything wired up.
I'm using the schematic values from Kit Rae's site for the Version 2 Violet Ram's Head 1972 #5 unit:
I have a whole stash of Amperex A115 transistors that I bought from Small Bear in the hopes they actually delivered around the gain bucket Steve showed. I wanted to use them for Axis Face Silicon Fuzz units. Turns out his hFE bucket was low for some reason. Most of them were over 150, with a distinct gathering around 175-200. Not so great for what I bought them for but good for the more traditional Silicon Fuzz Face and, as it turns out, this project. I decided to go with Kit Rae's site again where he singles out 2 exceptional Violet Ram's Head units with all 4 transistors in the 160-200 hFE range:
I ended up picking a fairly matched set of A115 units:
Q1, Q2, Q3 = 171 hFE
Q4 = 164 hFE
I had some 1N456 diodes left over from my Ampeg Scrambler parts so I grabbed 4 of those centered around a Vf of 756 mV. Nothing special other than they look really cool.
The last thing I am working on right now is the tonestack. I'm going for more of a Gilmour thing here and plan on using this by itself but also EQ'd by a Vick Audio Overdriver. My little Single Ended EL84 amp is fantastic for my home playing and the Drive control I installed gives me a broad range from clean to semi-dirty to full out crunch. It has a reasonable amount of mid-range content when driven so I don't want to do anything crazy with the tonestack except to flatten out the mid-scoop a touch.
So, I went to the Duncan TSC:
In the form you see in the schematic, there is a -12.5 dB mid scoop at around 1kHz when the tone control is at 50%. I wanted to bump this up a bit but not quite flatten it out as I have a somewhat mids-forward amp and ways to adjust the mids should I need to. I'm still not certain how I'll end up configuring it, but I'll likely just pick an appropriate value for C9 and call it a day.
Here are the TSC charts for C9 = 6.8 nF and 8.2 nF, respectively:
The mid-scoop at 50% Tone goes up to -8.3 dB and -9.4 dB respectively.
Lastly, here is the mockup with controls and mechanicals attached to the Tayda Ball Silver enclosure:
Should find some time this week to get everything wired up.
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