An preamp for electric instruments, based on an Opamp.
(pronounced Micro-Pre)
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Got parts in the mail fro the uPre from digikey, took only 4 days! This week I'm going to build one up and test it, just going to wired it up to a breadboard and some 1/4 TRS jacks and run my guitar through it to test. Stay tuned and follow the project to find out how it goes and how it sounds :)
Parts Pic
(I am aware its the same picture as on Audio Blox, parts for the uPre and JFET pre were in the same order lolz)
Hey so I got the PCBs in the mail from OSHPark, but I neglected to order the new components featured in the V2 design that are different from the V1, so its gonna be a few days before a build and test. Here are the PCBs:
I also prepared a bill of materials view-able below and available as open document format in the files section of the project page.
Symbol | Value | Package | Quantity | Digikey Part Number | Manufacturer Part Number | Price | Comment |
C1, C2, C5 | 10uF | 4X6mmCAP | 3 | 493-10354-1-ND | UMW1C100MDD1TP | $0.36 | |
C3, C4 | 0.22uF | 4X6mmCAP | 2 | 493-10373-1-ND | UMW1HR22MDD1TP | $0.36 | |
C6, C7 | 47uF | 5X12.5mmCAP - BLUE | 2 | 493-4653-1-ND | UKA1E470MDD1TD | $0.50 | |
P1, P2 | Header 3 | HDR1X3 | 2 | Header 3 | |||
P3 | Header 4 | HDR1X4 | 1 | Header 4 | |||
R1 | 10K | R0805 | 1 | P10.0KCCT-ND | ERJ-6ENF1002V | $0.10 | |
R2, R4 | 2.2M | R0805 | 2 | 1276-5445-1-ND | RC2012F225CS | $0.10 | |
R3, R7 | 1K | R0805 | 2 | 1276-5272-1-ND | RC2012F102CS | $0.10 | |
R5 | 100K | BOURNS_PTD90SERIES_POT | 1 | PTD901-2015K-B104-ND | PTD901-2015K-B104 | $1.68 | |
R6 | 20K | BOURNS_PTD90SERIES_POT | 1 | PTD901-2015K-B203-ND | PTD901-2015K-B203 | $1.68 | |
R8 | 220r | R0805 | 1 | 1276-5236-1-ND | RC2012F221CS | $0.10 | |
R9 | 100K | R0805 | 1 | P100KCCT-ND | ERJ-6ENF1003V | $0.10 | |
R10 | 220K | R0805 | 1 | 1276-5414-1-ND | RC2012F224CS | $0.10 | |
R11 | 3M | R0805 | 1 | 1276-5448-1-ND | RC2012F305CS | $0.10 | |
U1 | RC4580IDR | SOIC127P600X175-8N | 1 | 296-15367-1-ND | RC4580IDR | $0.85 | |
Total | $6.13 | ||||||
So give it 10 days or so and I'll have parts and be able to build and test, stay tuned folks!
So I cashed in on a OSHPark giftcard I had laying around (thanks little bro) and ordered a PCB for the new uPre! This will serve as a good test build of the new design with PCB mounted potentiometers. It will be good for testing the circuit and how well it performs. The next version depending on the how this one works out will be redesigned to better fit inside instruments and enclosures.
OSHPark Board Render:
Next post should be on assembly and testing, can't wait to get PCBs in the mail :)
Over the last few days I've been making a lot of progress on all my audio themed project, even uPre V2!!! So last night and this morning I redid the schematic and PCB, its not a complex design so it went pretty fast, the last day and a half of finding and making component footprints really helped though lol.
So here is the schematic
And here is the first route of the PCB, I haven't done much audio design so I'm looking for all the feedback I can get on the board layout.
So there's that, stay tuned!!
So I'm doing a few audio based projects theses days , just some simple fun stuff. One of those projects will be revising uPre's design to include PCB mounted potentiometers for tone and level control. Two versions will be produced, one with a pot that contains an integrated on/off switch for turning on the preamp by increasing the level and a version without this switch that can be packaged in a hammond box as an electric instrument effect. Expect more to come on how the existing design works and updates on the new one!
BTW V2 Schematic:
Soldered up a second prototype for the traveling hackerbox, I hope whoever gets it reports back here with their experience with it, Its untested, I'm gonna include the potentiometers so only wire,headers, battery, and jacks will be needed.
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