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Hi, I've got a schematic for a Randall RG80 and I'd really like to build just the pre-amp so I could hear what it soundeds like. I've built a few pedals before so its not like have 0 expierience but very close to that, as building a pedal is more assembly then "building" as you usually have a pcb. My father recommended I try building it on perf board but I'm honestly having trouble understanding how to get whats on the schematic to whats in front of me on the board. Does anyone have any advice as to how I should go about figuring this out? Possibly a book or something I could read that would help me understand how to lay stuff out on a perf board when all you have is a schematic. Thanks...
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I sort of hate to direct you to another forum, but many of the same people post here and there, and the links below are to example of people working on the same idea. The first link a guy actually drew up a pcb for the pre-amp. The second link is older, but also guys working up their own RG80/RG100ES pre-amp.Originally posted by broken flyer View Post
Randall RG100 hybrid
Randall RG100 hybrid
Randall RG80/RG100 Preamp DIY
Randall RG80/RG100 Preamp DIY
To your first question, the schematic is telling you the type of devices used. Everything up to the effects send is the pre-amp. THere are two channels, "RED" is the probably the one you care about. You probably don't care about the reverb send, so you don't need the 4558 opamp or associated circuit. The devices are TIS-58 in the original, but you can get 2n5484 from mouser (which has slightly different pinout). Voltages in the preamp are 24V. There are really only four FETs in the preamp. Making this on perf board, you just need to understand which pins on the 2n5484 are the Drain, Source and Gate (get data sheet at mouser when you research the devices) and then lay out the resistors and caps appropriately. I would try laying it out first on 1/4" square-ruled paper. Making this pre-amp is actually also on my "to-do" list of projects. I have a 1983 RG80, and can probably find a gut shot for you if you don't have one. -
Alright thanks... There isnt any kind of free computer program out there or anything i could download where you could take a schematic redraw the part you want and then use the program to show you where to lay out the parts on a perf board is there?Comment
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There are programs for pcbs, check out express pcb. THis allows you to draw parts to scale and draw pcb traces.
ExpressPCB - Free PCB layout software - Low cost circuit boards - Top quality PCB manufacturingComment
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