Verified! Great clean sounds, extremely gnarly drive sounds. Due to the way the tone stack works, it's easier to hear the difference in the EQ knobs by setting them all to 0 and then gradually increasing to dial in a sound.
If I see this right, the 15nF and 4k7 between Gain 2 and 3 are the values for the Bright Switch, so in this vero the switch is always on. They are CX1 and RX1 in the schematic.
The 15nf capacitor and the 4.7k resistor on its left should be changed to a Bright switch. In addition, the circuit is incomplete, and the signal is inverted and output, which will cause problems if it enters some delay or reverb effects.
The layout matches the schematic, as far as I can see. And it's pretty much a straight 1:1 adaptation of the actual Musicman HD130 preamp, including the inverted output (which gets un-inverted in the subsequent power section). No problems as far as Fuzzhead's work. If anytime takes issue with the design of the amp itself, take it up with Leo Fender, I guess?
I realize that 18 pages is a lot of reading, but the rather thorough build guide that Electronic Audio Experiments did for the DIY PCB project of this circuit addresses the bright switch, and a whole bunch of other stuff.
If you click on the link above the drawing, folks, you will see not only Sebastian's statements corroborated, but also a whole bunch of other interesting history/tidbits about this circuit. Seriously - it's quite informative.
"incomplete" refers to the Phase Inverter of the amp, which is not an issue in an amp, but becomes a problem when used in a pedal. If signal into the "RETURN,"it's ok. However, phase inversion from pedals will become an issue when you are trying to blend a dry signal with the effect or when running several pedals in blended parallel loops. Such a design is considered defective in "Modern Stompbox", and as a DIY project, it should be noted. I encounter this issue several times a year with repair orders for pedals like the Bluesbreaker due to similar problems.
Okay, then use this pedal with a blend box that includes a phase reverse switch, like this one: https://tagboardeffects.blogspot.com/2022/12/dylan-159s-blendy-buffoon.html You are also welcome, of course, to make amendments and offer your own schematic and/or layout, as folks in this community are always happy to do!
What is the difference between this and the Musicman HD preamp posted in Feb? https://dirtboxlayouts.blogspot.com/2024/02/electronic-audio-experiments-musicman.html
My hero! I'll build this soon; will let you know the outcome :)
ReplyDeleteVerified! Great clean sounds, extremely gnarly drive sounds. Due to the way the tone stack works, it's easier to hear the difference in the EQ knobs by setting them all to 0 and then gradually increasing to dial in a sound.
DeleteIf I see this right, the 15nF and 4k7 between Gain 2 and 3 are the values for the Bright Switch, so in this vero the switch is always on. They are CX1 and RX1 in the schematic.
ReplyDeleteYep correct; omit these for the "Normal" channel setting or you could place them on a separate switch.
DeleteThe 15nf capacitor and the 4.7k resistor on its left should be changed to a Bright switch. In addition, the circuit is incomplete, and the signal is inverted and output, which will cause problems if it enters some delay or reverb effects.
ReplyDeleteby "incomplete" do you mean that this drawing is missing part or parts of the schematic that is linked just above the drawing?
DeleteThe layout matches the schematic, as far as I can see. And it's pretty much a straight 1:1 adaptation of the actual Musicman HD130 preamp, including the inverted output (which gets un-inverted in the subsequent power section). No problems as far as Fuzzhead's work. If anytime takes issue with the design of the amp itself, take it up with Leo Fender, I guess?
DeleteI realize that 18 pages is a lot of reading, but the rather thorough build guide that Electronic Audio Experiments did for the DIY PCB project of this circuit addresses the bright switch, and a whole bunch of other stuff.
DeleteIf you click on the link above the drawing, folks, you will see not only Sebastian's statements corroborated, but also a whole bunch of other interesting history/tidbits about this circuit. Seriously - it's quite informative.
"incomplete" refers to the Phase Inverter of the amp, which is not an issue in an amp, but becomes a problem when used in a pedal. If signal into the "RETURN,"it's ok. However, phase inversion from pedals will become an issue when you are trying to blend a dry signal with the effect or when running several pedals in blended parallel loops. Such a design is considered defective in "Modern Stompbox", and as a DIY project, it should be noted. I encounter this issue several times a year with repair orders for pedals like the Bluesbreaker due to similar problems.
DeleteOkay, then use this pedal with a blend box that includes a phase reverse switch, like this one:
Deletehttps://tagboardeffects.blogspot.com/2022/12/dylan-159s-blendy-buffoon.html
You are also welcome, of course, to make amendments and offer your own schematic and/or layout, as folks in this community are always happy to do!
Thank you for sharing, Ding. Our community goes stronger.
DeleteWhat is the difference between this and the Musicman HD preamp posted in Feb? https://dirtboxlayouts.blogspot.com/2024/02/electronic-audio-experiments-musicman.html
ReplyDeleteRead last comment in your link. It is a revision.
Delete