Big Monk
Well-known member
So I’ve been down a rabbit hole the past few days looking at diodes for sale at SBE with an eye toward a specific forward voltage range.
I currently have a Muffin build that is modeled on the 1973 #3 Ram’s Head from KR’s site.
In his section on conponents and their effects on the BMP circuit, he talks about and provides measured values from some of his most prized ones. “Exceptional sounding” units to quote him directly.
I went with lower gain (actually matched around 175 hFE) Amperex A104 transistors and now I’m itching to tweak the diodes. The same unit he quoted as a stellar sounding 1973 Ram’s Head had diodes forward voltages of ~0.586-0.626.
I ran some experiments last weekend subbing in some germanium diodes with forward voltages matched at around 0.495 v. These lowered the output too much and sterilized the bigger.
I originally had 1N456 from GI leftover from the ill-fated Scrambler build and those were up near 0.8 v. I ended up with a quad of matched 1N4148 at just around 0.7 v.
I ordered about 20 glass cases silicon diodes from SBE with a forward voltage range of 0.5-0.6 v and I’m going to try those. I think those will smooth out the grrr just enough for it to be perfect.
I’m rebuilding on a new muffin board and rechristening it the Big Monk Pi, Gilmour Monk’s Head edition.
New graphics are already worked up and I’ll post them up Monday.
I currently have a Muffin build that is modeled on the 1973 #3 Ram’s Head from KR’s site.
In his section on conponents and their effects on the BMP circuit, he talks about and provides measured values from some of his most prized ones. “Exceptional sounding” units to quote him directly.
I went with lower gain (actually matched around 175 hFE) Amperex A104 transistors and now I’m itching to tweak the diodes. The same unit he quoted as a stellar sounding 1973 Ram’s Head had diodes forward voltages of ~0.586-0.626.
I ran some experiments last weekend subbing in some germanium diodes with forward voltages matched at around 0.495 v. These lowered the output too much and sterilized the bigger.
I originally had 1N456 from GI leftover from the ill-fated Scrambler build and those were up near 0.8 v. I ended up with a quad of matched 1N4148 at just around 0.7 v.
I ordered about 20 glass cases silicon diodes from SBE with a forward voltage range of 0.5-0.6 v and I’m going to try those. I think those will smooth out the grrr just enough for it to be perfect.
I’m rebuilding on a new muffin board and rechristening it the Big Monk Pi, Gilmour Monk’s Head edition.
New graphics are already worked up and I’ll post them up Monday.
Last edited:
