Blackhawk Amplifiers Volume IV

 Traced by evilarsen.

Blackhawk Amplifiers One Knob Valhalla Fuzz V1

 

Blackhawk Amplifiers Valkyrie Drive V3

 This one was quite tricky to trace. Got the topology figured out quite quickly but but identifying some of the capacitor values was quite difficult with these Greenies with faded markings. Had to look at several units, all had some minor variations but I think the layout below is pretty much spot on.

It is a heavy fuzzy overdrive with the gain control rolled back, maxed out it is a high gain fuzz. Most units had a 100k gain control with quite a limited range. It was later reworked for V4, using a 500kC potentiometer which gives a much more useful range.

It can be quite noisy with the gain maxed out (probably bcause of the layout itself, not the circuit design...) but short wires and shielded by an enclosure helps.

Blackhawk Amplifiers Gandalf Octave Fuzz

 Traced by evilarsen.

A great sounding octave up fuzz which has an op amp slamming a transformer and two diodes just like in an old Octavia. The transformer listed is 42TL022 but the more recent version has a different unknown part number which is supposed to work even better. A wild guess would be 42TL002?

More info at Blackhawk Amplifiers.

Blackhawk Amplifiers Valhalla Fuzz V1

Here we have a layout for the first (I think!) handwired version of  Blackhawks take on a Fuzz Face. But it has a few interesting and useful extra things going on. 

First, a passive pickup simulator so you can have a buffer upfront or anywhere in the signal chain. Next comes the fuzz circuit itself which are closely related to a Meathead but with larger input and electrolytic "gain" caps. Next there is two quite large value output caps that are connected to the Bass Boost switch. At the end of the circuit there is a simple but very effective notch filter that gives a wide array of tones, from rumbling bass, scooped mids and sizzly high mids.. The notch filter Tone control can be bypassed with the tone bypass switch and will give a big volume boost with a thick grinding middy fuzz. 

Note that the Bass Boost switch only works when the notch filter is engaged. Also note that I couldn't read the marking on C9 but I'm pretty confident that the value is 220nF.

C9 is now confirmed, 220nF it is

 

Blackhawk Amplifiers Azoth Baxandall Boost

 A great sounding and flexible 2-band baxandall eq booster that can get quite gritty depending how you set the internal gain trimpot. The Mid control is not actually an active mid band control, it is a passive variable resistor that changes the overall mid slope.

Note that this seem to be an earlier version, the current version got a small revision with an external gain control and fixed mids. More info on that at Blackhawk Amplifiers.

Blackhawk Amplifiers Morgul Boost

 Here is a heavy dirty booster that will melt your Orange, Green or Sunn amp head. And your one knob fuzz will love it.😈. The gain range goes from a fairly clean boost to a hairy and fuzzy overdrive. "Transparent" it is not...

It is a fairly simple circuit that boost the whole sound spectrum and relies on op amp clipping. The most common chip used seens to be the olde LM741 which works great for this application. LM308 and CA3130EZ is used as well, the former sounding pretty close to LM741 while the latter is more high gain and has more high end distortion qualities. Note that LM308 and CA3130EZ requires an external compensation cap (read the notes below the layout).

It has two internal trimpots, one for Gain and one for Tone. The Tone trimpot is quite subtle while the Gain trimpot is worth having as an external potentiometer IMHO.

This one is traced by evilarsen, thank you!

More info on the circuit at Blackhawk Amplifiers.