Discrete semiconductors.
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(or just search for the part number, J201 shows a few results)
Invalid Link Removed
(or just search for the part number, J201 shows a few results)
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Build your own onboard preamp
- Thread starter rojo412
- Start date
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I'd start with a plain old J201. Do you know how a FET works? It may be worthwhile doing a little reading up if you want to try something a bit different.
I'd start with a plain old J201. Do you know how a FET works? It may be worthwhile doing a little reading up if you want to try something a bit different.
- Aug 5, 2005
- 7,243
- 92
- Disclosures
- Endorsing Artist: J.C. Basses
I wish I had the time to devote to these things. I'm a physics minor, but even then, I work in the realm of theoretical and quantum physics. Circuits were never my strong suit.
Bleh, I'm glad I don't have to do that stuff any more!
My MSc was full of quantum physics, now it's allll experimental
AFAIK, the NTE parts are a line of replacement semiconductors intended primarily for repair work. NTE maintains cross reference data to help make substitutions. This might explain the relatively higher price.
JFETs should be in the $.39 ballpark in small quantities, even for high performance devices.
- Aug 5, 2005
- 7,243
- 92
- Disclosures
- Endorsing Artist: J.C. Basses
Bleh, I'm glad I don't have to do that stuff any more!
My MSc was full of quantum physics, now it's allll experimental
Ah, well, I'm a theoretical kind of guy. I love dabbling in the theoretical maths (I'm getting my masters in topology) and theoretical physics as well.
Labs are actually my least favorite parts of the class....until I get to go work at CERN or something.
I would get it from Digikey. they don't gouge you on shipping like Mouser Invalid Link Removed
If one were to be attempting to make a shopping list for this project, what would one be needing (with add ons for messing with other values, making additional units, tools, etc)?
Multitester
J201 JFET Transistors
Battery clips
Stereo and mono jack
wire...
Lots of caps of as many values between ____ and ___? I don't know, you tell me!
Multitester
J201 JFET Transistors
Battery clips
Stereo and mono jack
wire...
Lots of caps of as many values between ____ and ___? I don't know, you tell me!
You will need some PCB boards to mount your preamp on when it's finished.
I would strongly suggest you get a prototyping breadboard as well, since you plan to tweak your design a lot before you settle on what your going to put in the bass.
Large ones like the one in the second picture I posted in this thread can get pretty expensive, but you can get a small board that would be perfect for a simple preamp design for maybe $10.
RadioShack usually sells the small ones.
It's hard to say about resistor and capacitor values.
Something useful you might want to note is that you can combine resistors in series for a total resistance of the sum of the individual resistances, or in parallel for: RTotal= 1/[(1/R1)+(1/R2)+...]
For parallel capacitors, the total capacitance is the sum of the individual capacitances, and for series capacitors: CTotal= 1/[(1/C1)+(1/C2)+...]
If you're buying capacitors, also note that there is a difference between polarized and non-polarized capacitors. You may need both in your circuit.
+1 to everything Line6man has said.
At this stage you might be aswell buying a couple packs of capacitors (both polarised and non-polarised) and a pack of resistors.
Most online retailers sell them. You get multiples and quite a wide range of values. Over here they are generally in the £5-£10 region, you'll generally get several hundred parts.
Just makes more sense than buying a bunch of individual caps and resistors.
You also need to get a soldering iron and some solder if you don't already have some.
At this stage you might be aswell buying a couple packs of capacitors (both polarised and non-polarised) and a pack of resistors.
Most online retailers sell them. You get multiples and quite a wide range of values. Over here they are generally in the £5-£10 region, you'll generally get several hundred parts.
Just makes more sense than buying a bunch of individual caps and resistors.
You also need to get a soldering iron and some solder if you don't already have some.
@line6man:
I have some electronics knowledge, but know nothing about oscilloscope readout results to know if they mean that it works. Would the circuit you built be worthwhile to actually put in a Bass?
I have been looking at preamps with much sticker-shock at the prices and figured I could build one from a schematic much cheaper. Would this be what I would need?
I have been looking for awhile for a tried and true DIY preamp. Maybe this is it....
I have some electronics knowledge, but know nothing about oscilloscope readout results to know if they mean that it works. Would the circuit you built be worthwhile to actually put in a Bass?
I have been looking at preamps with much sticker-shock at the prices and figured I could build one from a schematic much cheaper. Would this be what I would need?
I have been looking for awhile for a tried and true DIY preamp. Maybe this is it....
- Aug 5, 2005
- 7,243
- 92
- Disclosures
- Endorsing Artist: J.C. Basses
While it wasn't directed at me, I'll still answer.
What I gathered from the earlier readouts is that the J201 preamp mentioned earlier gives roughly a 3dB signal boost but with very little effect to the sound other than making it louder.
Also, I'd try something like this long before a tube preamp. The worst that could happen with one of these is it doesnt work or you burn yourself with a soldering iron or something. A tube preamp (depending on design) could have enough juice to fry you good and proper!
What I gathered from the earlier readouts is that the J201 preamp mentioned earlier gives roughly a 3dB signal boost but with very little effect to the sound other than making it louder.
Also, I'd try something like this long before a tube preamp. The worst that could happen with one of these is it doesnt work or you burn yourself with a soldering iron or something. A tube preamp (depending on design) could have enough juice to fry you good and proper!
Thank you. That helps a lot. If all goes well, I'll be trying one of these out shortly.
(Don't meant to hijack here, carry on...)
- Aug 5, 2005
- 7,243
- 92
- Disclosures
- Endorsing Artist: J.C. Basses
I just had this amazing idea for a 3-band EQ, where every band is sweepable.
Bass: 31Hz - 125Hz
Mid: 250Hz - 1kHz
Treble: 2kHz - 16kHz
I got the idea from one of the 6-band EQ designs here: [Invalid or Expired Link Removed]
If only I actually had the ability to pull off something like that.
Bass: 31Hz - 125Hz
Mid: 250Hz - 1kHz
Treble: 2kHz - 16kHz
I got the idea from one of the 6-band EQ designs here: [Invalid or Expired Link Removed]
If only I actually had the ability to pull off something like that.
I posted the scope response pictures just as a reference for anyone interested. The scope won't tell you what the circuit is going to sound like, it just gives you a reading of how the circuit affects the waveform you feed it.
If your goal is to save money by building instead of buying, you might want to consider a preamp with a two or three band EQ.
The J201 preamp is meant to lower the impedance of the signal and give a slight gain boost, but it has no EQ.
So the one idea I was kicking around in my head (though it's a few steps ahead of the basics), was a preamp design that reduced external knobbage by substituting big pots for trim pots.
Can you do that?
Can you do that?
