Bluesbreaker: Original Diodes and Op-Amp?

[DrRogersA]

Greetings, all.  I have a question for those with more pedal experience than I.  Can anyone confirm what op-amps and clipping diodes were used in the original early 90s Bluesbreaker pedal?  I've looked at lots of schematics - most seem to suggest TL072 as the op-amp and 1N4148 (or occasionally 1N914) for clipping diodes.  Can anyone tell me what was actually used in the early 90s production units?  Did they really use these bog-standard op-amps and diodes, not some unobtainium mojo parts?

The reason I ask is that I want to build a Bluesbreaker as close to stock as possible (with some switchable mods, perhaps), and then build a few variants (Morning Glory, Pantheon, King of Tone - complete with mojo diodes).

Right now I have the basic circuit on my breadboard.  I have tried it with many different clipping combinations, and for soft clipping it seems that 2x2 1N4148s or 1N914s sound pretty good.  For hard clipping, lots of things sound good, but I find I need a small cap across the second op-amp when I have hard clipping configured (certainly not stock).

Thanks much.

[GibsonGM]

Hey Doc, welcome!   "My sources" (probably as much 'net research as you've done) tell me that yes, it is that simple...'72 and 4x1N4148s.   Thing is - if you're mass-producing, you want to stick with OBTANIUM parts, so as to not run out    

Boutique can be a different game...but like a TV manufacturer, the big dogs want CHEAP, easy to source stuff that they can buy 1 million of at a time.  I've never seen a 'real' schematic from them however.

I agree, a small cap really can take some fizz away! 

[Rob Strand]

1N4148
Nice pics.
https://www.thegearpage.net/board/index.php?threads/npd-v1-marshall-blues-breaker.2135073/

[Mark Hammer]

More important will be the actual forward voltage of the diodes used, keeping in mind that the very same numbered part can exhibit a range of values.  Not huge, mind you, but shave off 100mv here and there, and the character of what gets generated at this or that Drive pot setting can be different.  Garden variety Si diodes like 1N914 an 1N4148 are fine in this application but they can range from the low 500mv Vf to mid 600s.

[DrRogersA]

Many thanks to all who responded!  I love this hobby, and thankfully my sainted wife thinks it's good for me (keeps my brain active).

[Mark Hammer]

Marriage is a pretty good lifelong habit as well.  And much like our building and our playing, it's a good habit to keep up and keep in shape. 

[Rob Strand]

Marriage is a pretty good lifelong habit as well.  And much like our building and our playing, it's a good habit to keep up and keep in shape. 

and when the "I" want to buy something there's a stronger "ME" regulating the expenditure.   

[bartimaeus]

The reason I ask is that I want to build a Bluesbreaker as close to stock as possible (with some switchable mods, perhaps), and then build a few variants (Morning Glory, Pantheon, King of Tone - complete with mojo diodes).

Also worth noting that the original used axial ceramic(?) capacitors, probably so the resistors and caps could be machine-populated. But I wouldn't recommend using too many ceramics in the audio path of any build as the possible microphonic issues aren't worth it.