I have spent many months trying to find enough information to build a discrete preamp. I have come across plenty of information on power amps, but not much at all about preamps. I have found lots of designs, but I lack sufficient basic knowledge to attempt to build any of them. I am currently studying Self’s Audio Power Amplifier Design book (2nd edition). Probably, a lot of what I have found about power amps would also apply to preamps, but I am not in a position to know what the differences would be. My workspace is littered with bits and pieces of stuff that don’t work and I don’t have the savvy to work out where I went wrong. I suck at mathematics and I am not that gifted at electronics (obviously). Can anyone point out some resources where I can get good information – specifically about pre-amp design? (without going too much into EE territory).
You can email nuuk, here is a discrete preamp/active crossover:
dd site
However, the most common preamp around here is probably Nelson's Balanced Zen Line Stage/ bride of son of zen, see passdiy and this article.
A new version with extra "X" circuitry is featured on this thread, maybe you should join in and get a board set when they are made?
dd site
However, the most common preamp around here is probably Nelson's Balanced Zen Line Stage/ bride of son of zen, see passdiy and this article.
A new version with extra "X" circuitry is featured on this thread, maybe you should join in and get a board set when they are made?
Thanks Igreen.
I am familiar with DD - if you look around there(under his buffered gainclone), you will find some feedback from me re transistor combinations in the 3 bjt buffer (which i am currently using single ended with an OPA637 gain stage. It sounds pretty good by most standards and beats the socks off one of Nelson'e pre's that my friend built from a kit, but I am still looking for more "magic". An opamp, however good, is still an opamp and sounds like an opamp[sterile]).
I would like to build with BJT's (or at least mostly BJT's) for now. Perhaps, once I know a bit more about what I am doing, I may get funky and add in a valve VAS (single 5687 probably). My big problem now is that I don't know what I am doing, even with simple circuits like the 3 BJT buffer at Decibel Dungeon. I can drive my active x-over with it (up to about 80%), but I can't drive my power amp with it. I suspect it is an output impedence problem, and including it in the feeedback loop with the OPA637 allowed me to drive my crossover to about 90-95%, but it then sounded really **** (all frequencies present and correct, but about as involving as a transistor radio).
So, my current mission is to learn more - but I only seem to be finding info on power amps.
I am familiar with DD - if you look around there(under his buffered gainclone), you will find some feedback from me re transistor combinations in the 3 bjt buffer (which i am currently using single ended with an OPA637 gain stage. It sounds pretty good by most standards and beats the socks off one of Nelson'e pre's that my friend built from a kit, but I am still looking for more "magic". An opamp, however good, is still an opamp and sounds like an opamp[sterile]).
I would like to build with BJT's (or at least mostly BJT's) for now. Perhaps, once I know a bit more about what I am doing, I may get funky and add in a valve VAS (single 5687 probably). My big problem now is that I don't know what I am doing, even with simple circuits like the 3 BJT buffer at Decibel Dungeon. I can drive my active x-over with it (up to about 80%), but I can't drive my power amp with it. I suspect it is an output impedence problem, and including it in the feeedback loop with the OPA637 allowed me to drive my crossover to about 90-95%, but it then sounded really **** (all frequencies present and correct, but about as involving as a transistor radio).
So, my current mission is to learn more - but I only seem to be finding info on power amps.
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