etheory
Well-known member
Hi there!
After reading the inspired stories of many forum members after that elusive DOA-design bliss, I did the clearly stupid thing and started looking into it myself.
I wouldn't call anything here original, even slightly, but I guess copying and pasting concepts is the way you get your start, and then building upon it over time with truly original ideas.
So don't expect anything good or even average, but I have a whole bunch of 550C's, 560C's and 2SK170BL's destined for around 100 Tamas BigFetBlokes, and though, "why not have a crack at it myself!". Not to mention that as good as the BigFetBloke is, I don't necessarily need 100 of them ;-). So with inspiration from pretty much all the main contenders - 2510, 2520, Forssell JFET opamp, and Tamas' BigFetBloke, I present, the horrifically designed eCheekyDOA's.
I expect, and hope that I will get slaughtered for these designed, all in order to learning something. So fire away! And tell me what is good/bad about these! As long as they are not so bad that PRR never posts in one of my topics again, I'll feel relatively happy.
Design requirements:
1.) 24V rails - cause that's what I have
2.) Differential inputs for use in differential input stages and EQ's
3.) I need to get rid of a large number of BD140/BD139/BC550C/BC560C and 2SK170's, so it has to use those
4.) I want something warm sounding and thick - i.e. even with no transformers, I want lots of harmonic "thickness" - hopefully not distortion per-se, but some girth in the lower order harmonics - if I want clean I'll use a VST - I want something that thickens and makes it's presence known
Design 1 is far too simple, and the second JFET current source I think would explode if it were built in real-life, however, it performs OKishly on the simulator in a mic preamp, and is an interesting initial point of discussion:
After reading the inspired stories of many forum members after that elusive DOA-design bliss, I did the clearly stupid thing and started looking into it myself.
I wouldn't call anything here original, even slightly, but I guess copying and pasting concepts is the way you get your start, and then building upon it over time with truly original ideas.
So don't expect anything good or even average, but I have a whole bunch of 550C's, 560C's and 2SK170BL's destined for around 100 Tamas BigFetBlokes, and though, "why not have a crack at it myself!". Not to mention that as good as the BigFetBloke is, I don't necessarily need 100 of them ;-). So with inspiration from pretty much all the main contenders - 2510, 2520, Forssell JFET opamp, and Tamas' BigFetBloke, I present, the horrifically designed eCheekyDOA's.
I expect, and hope that I will get slaughtered for these designed, all in order to learning something. So fire away! And tell me what is good/bad about these! As long as they are not so bad that PRR never posts in one of my topics again, I'll feel relatively happy.
Design requirements:
1.) 24V rails - cause that's what I have
2.) Differential inputs for use in differential input stages and EQ's
3.) I need to get rid of a large number of BD140/BD139/BC550C/BC560C and 2SK170's, so it has to use those
4.) I want something warm sounding and thick - i.e. even with no transformers, I want lots of harmonic "thickness" - hopefully not distortion per-se, but some girth in the lower order harmonics - if I want clean I'll use a VST - I want something that thickens and makes it's presence known
Design 1 is far too simple, and the second JFET current source I think would explode if it were built in real-life, however, it performs OKishly on the simulator in a mic preamp, and is an interesting initial point of discussion: