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5 string fretless showcase: Habanero V
- Thread starter adam.beauchene
- Start date
Got my PCBs!
Nice and tiny, like an onboard pre should be. I ordered and paid for 4 of them, received 8!
I hope this topology works, I want to try different gain settings and center frequencies in the tone stack. I might be hooking up some people here that I am grateful to for circuit help, as well. Hope these work!
Soldering tonight!!!!
Nice and tiny, like an onboard pre should be. I ordered and paid for 4 of them, received 8!
I hope this topology works, I want to try different gain settings and center frequencies in the tone stack. I might be hooking up some people here that I am grateful to for circuit help, as well. Hope these work!
Soldering tonight!!!!
Reconfigured my mess for soldering:
Check every component value before placing:
Don't be stingy with the flux:
Can't solder and take pics, but after you're done, clip the leads:
And after about an hour of lovely rosin fumes, you get:
I'm still waiting on 2 electrolytic caps and 1 polyprop cap that are backordered from mouser, digikey has them so I might order them tonight. Also found that the potentiometer files I used in Eagle has holes that are too small for regular pin headers. I don't think drilling them out will work, the solder pads are already very tiny and a few of them need the through-plating. I may just have to commit to wiring the pots directly to the board, or put the male and female connectors in the middle of the wire. I need to make my own custom library if I'm going to keep playing with Eagle.
Check every component value before placing:
Don't be stingy with the flux:
Can't solder and take pics, but after you're done, clip the leads:
And after about an hour of lovely rosin fumes, you get:
I'm still waiting on 2 electrolytic caps and 1 polyprop cap that are backordered from mouser, digikey has them so I might order them tonight. Also found that the potentiometer files I used in Eagle has holes that are too small for regular pin headers. I don't think drilling them out will work, the solder pads are already very tiny and a few of them need the through-plating. I may just have to commit to wiring the pots directly to the board, or put the male and female connectors in the middle of the wire. I need to make my own custom library if I'm going to keep playing with Eagle.
Hey guys, sorry for the lack of updates. Busy couple of weeks.
I dropped in the preamp, did some tests...nothin'. Decided to get a little tool to help me troubleshoot:
I checked out used, full-size oscilloscopes on eBay, but I didn't want to take a chance for the prices that are out there. I decided to get this little toy oscilloscope from Seeed Studios, the DSO Nano v2. Bought it from sparkfun: [Invalid or Expired Link Removed]. Less than a hundred bucks, single channel, 1Mhz. I don't need anymore than that for the basic stuff I am doing. Here it is, connected directly to the pickup, 'A' string plucked. I probed around my preamp and found that signal is getting to the input pin of the buffer opamp when the power is disconnected. When the power is on, I see Vref at the pin, but no more signal. I couldn't figure that out with multimeter alone- I saw the DC, but couldn't tell if there was the signal component there. So I need to play with this some more. Hoping to make the deadline- Worse comes to worst, I'll wire it up passive. It works that way now.
I dropped in the preamp, did some tests...nothin'. Decided to get a little tool to help me troubleshoot:
I checked out used, full-size oscilloscopes on eBay, but I didn't want to take a chance for the prices that are out there. I decided to get this little toy oscilloscope from Seeed Studios, the DSO Nano v2. Bought it from sparkfun: [Invalid or Expired Link Removed]. Less than a hundred bucks, single channel, 1Mhz. I don't need anymore than that for the basic stuff I am doing. Here it is, connected directly to the pickup, 'A' string plucked. I probed around my preamp and found that signal is getting to the input pin of the buffer opamp when the power is disconnected. When the power is on, I see Vref at the pin, but no more signal. I couldn't figure that out with multimeter alone- I saw the DC, but couldn't tell if there was the signal component there. So I need to play with this some more. Hoping to make the deadline- Worse comes to worst, I'll wire it up passive. It works that way now.
I bet you guys are sick of hearing about the preamp, and seeing my messy desk instead of wood chips a-flyin'....well, I'm done, it works!!!!
For both people on earth that care though, here's what happened:
I was getting absolutely no sound at all. Nothing. I thought maybe it was a soldering problem, or a manufaturing defect in the boards. Checked every node, built a second pre, nothing. Decided to go back to the drawing board- I built the first gain stage on plugboard, to see if I could get it to work:
I set up my laptop to play a sweeping sine wave, 20Hz-20kHz on loop, adjusted the volume so that the signal was approx. 100mV peak to peak, to simulate what my Red Baron pickup puts out. Ran that into the opamp (used a TL062 for this) and read it with my new oscilloscope. Nothing. Tried inverting the stage, different resistor settings, all kinds of things. This went on last night for 4 hours.
Long story short, I started getting desperate and just tried random stuff. I realized that if I pulled R2 completely out, I would get signal. It was dirty, and swung well into clipping the opamp, but it worked! (The TL062, as a side note, seemed to work fine like this. OPA2134s and AD822s, however, did not seem to enjoy the abuse, and did not respond. I have a newfound respect for the lowly TL062, the thing is a tank.)
I tried a few different resistor values for R2, thinking it was a stability problem. Everything I tried caused the opamp to flatline. Then it occured to me, to try and decouple R2 from ground with a cap. I grabbed the first electrolytic on my bench, a 10uF, and plugged it in. It worked! The opamp was swinging a nice sine wave! I tried a few different cap values, 22uF seemed to allow the lowest lows through, once I was brave enough to plug headphones into the plugboard for a listen. Apparently, having the negative input pin of the opmp connected to ground without a decoupling cap causes the opamp to stop working. Maybe someone smarter 'round here can explain why? So I made this mod to the circuit:
So tonight, I modified to the preamp, and decoupled R2 and R8 from the ground plane with caps:
Set up a test rig:
Plugged everything in...no signal!!!
:scowl:
Oh wait, would help if there were an opamp in the socket
Booya.
The preamp takes a 100mV sine, swept from 20Hz to 20kHz, and amplifies it to up to 3V peak to peak, with the bass, treble, and volume maxed out. Yes!!!!
So I put it all together:
Plugged it in and it sounds great. I really like the baxendall tone control- there are no unuseable settings- to me. I won't rave about it too much, mamas love their babies even if they are ugly... but I think the preamp sounds good. Very, very clean. The low B is very well defined. I'll get some samples up ASAP.
Here's some pics of the whole bass. I still need to love on the finish, but this is now a fully-functioning instrument:
I need to figure out what to do about knobs.
Time to celebrate!
For both people on earth that care though, here's what happened:
I was getting absolutely no sound at all. Nothing. I thought maybe it was a soldering problem, or a manufaturing defect in the boards. Checked every node, built a second pre, nothing. Decided to go back to the drawing board- I built the first gain stage on plugboard, to see if I could get it to work:
I set up my laptop to play a sweeping sine wave, 20Hz-20kHz on loop, adjusted the volume so that the signal was approx. 100mV peak to peak, to simulate what my Red Baron pickup puts out. Ran that into the opamp (used a TL062 for this) and read it with my new oscilloscope. Nothing. Tried inverting the stage, different resistor settings, all kinds of things. This went on last night for 4 hours.
Long story short, I started getting desperate and just tried random stuff. I realized that if I pulled R2 completely out, I would get signal. It was dirty, and swung well into clipping the opamp, but it worked! (The TL062, as a side note, seemed to work fine like this. OPA2134s and AD822s, however, did not seem to enjoy the abuse, and did not respond. I have a newfound respect for the lowly TL062, the thing is a tank.)
I tried a few different resistor values for R2, thinking it was a stability problem. Everything I tried caused the opamp to flatline. Then it occured to me, to try and decouple R2 from ground with a cap. I grabbed the first electrolytic on my bench, a 10uF, and plugged it in. It worked! The opamp was swinging a nice sine wave! I tried a few different cap values, 22uF seemed to allow the lowest lows through, once I was brave enough to plug headphones into the plugboard for a listen. Apparently, having the negative input pin of the opmp connected to ground without a decoupling cap causes the opamp to stop working. Maybe someone smarter 'round here can explain why? So I made this mod to the circuit:
So tonight, I modified to the preamp, and decoupled R2 and R8 from the ground plane with caps:
Set up a test rig:
Plugged everything in...no signal!!!
:scowl:Oh wait, would help if there were an opamp in the socket
Booya.
The preamp takes a 100mV sine, swept from 20Hz to 20kHz, and amplifies it to up to 3V peak to peak, with the bass, treble, and volume maxed out. Yes!!!!
So I put it all together:
Plugged it in and it sounds great. I really like the baxendall tone control- there are no unuseable settings- to me. I won't rave about it too much, mamas love their babies even if they are ugly... but I think the preamp sounds good. Very, very clean. The low B is very well defined. I'll get some samples up ASAP.
Here's some pics of the whole bass. I still need to love on the finish, but this is now a fully-functioning instrument:
I need to figure out what to do about knobs.
Time to celebrate!
Musiclogic
Commercial User
- Aug 6, 2005
- 6,505
- 75
- 60
- Disclosures
- Owner/Builder: HJC Customs USA, The Cool Lute, C G O
knobs are simple Adam, you stuff them onto the potentiometer post and screw the set screw down tight(if there is a set screw) and voila' knobs....LMAO
Thanks everyone. I'm going to make some sound samples soon, but I want to finish the setup first. Right now the nut slots aren't deep enough, and I want to polish out the body some more. There are two tiny spots where I blew through the finish...again...:scowl: but I think I'm on track to proficiency with the product. I'm getting decent results with a brush now, can't wait to get a sprayer!
This preamp feels like the biggest accomplishment to me, though. I can't thank you guys enough for the help I received- specifically, Taylor Livingston, MusicLogic, gyancey, and T-34. Without your help, I probably would have given up on this after the first miserable failure of a breadboard version...ok maybe the 6th or 7th one, I'm kinda hardheaded.
I'm rolling the changes into BarnaclePre v1.1, it's even smaller than this one; about 1.5" square. I plan on putting one in my previous habanero, and my old Squire Jazz.
This preamp feels like the biggest accomplishment to me, though. I can't thank you guys enough for the help I received- specifically, Taylor Livingston, MusicLogic, gyancey, and T-34. Without your help, I probably would have given up on this after the first miserable failure of a breadboard version...ok maybe the 6th or 7th one, I'm kinda hardheaded.
I'm rolling the changes into BarnaclePre v1.1, it's even smaller than this one; about 1.5" square. I plan on putting one in my previous habanero, and my old Squire Jazz.
Thanks, Beej. This build kinda took on a life of its own from when I started.
For those that like this stuff, I rolled the changes I made to the pre into the Eagle file, and will be ordering some more of these. I may play with the tone stack component values to drive the midpoint frequency a little lower, but the topology works. I also replaced the two voltage splitter resistors and the 47uF cap with one TLE2426 chip, it takes up less space. I used it in the plugboard version, it worked well.
I also made the board a lot smaller, that's a .1" grid.
For those that like this stuff, I rolled the changes I made to the pre into the Eagle file, and will be ordering some more of these. I may play with the tone stack component values to drive the midpoint frequency a little lower, but the topology works. I also replaced the two voltage splitter resistors and the 47uF cap with one TLE2426 chip, it takes up less space. I used it in the plugboard version, it worked well.
I also made the board a lot smaller, that's a .1" grid.
I would make small 5/8 x 5/8 inch Ebony knobs and inlay the top with the same MOP you have used as markers. They would nicely complement both markers and the exposed p-up poles. (Plastic knobs with MOP top should be also available on the market - hard to find maybe and not as classy).
Well, that's what I would do.
Anyway, that's a truly gorgeous bass, Adam! And you have outdone yourself with the electronics!
You're welcome- it was cool hearing it through your 5x10 stack! I'm looking forward to the next GTG.
I would make small 5/8 x 5/8 inch Ebony knobs and inlay the top with the same MOP you have used as markers. They would nicely complement both markers and the exposed p-up poles. (Plastic knobs with MOP top should be also available on the market - hard to find maybe and not as classy).
Well, that's what I would do.
Thanks- I stoked about the electronics, too. My next project is to see how it works with a piezo, on my first build!
The concept of tiny knobs with big MOP caps came up earlier in the thread, I agree that they would look good. I'm planning to do that, probably in ziricote though- since I'm fresh outta ebony
SDB Guitars
Commercial User
I'd worry that ziricote might be a bit brittle for knobs, but I've never tried turning it, so I really have no idea... Bet they'd look pretty awesome, though. Kudos on this, looks great!
Musiclogic
Commercial User
- Aug 6, 2005
- 6,505
- 75
- 60
- Disclosures
- Owner/Builder: HJC Customs USA, The Cool Lute, C G O
just a possibility for ya Adam...9/16" ebony knobs, inexpensive, and this guy is great to deal with.
Real Wood - MINI Guitar Knob - EBONY Wood - 9/16" Dia. | eBay
just a note
Real Wood - MINI Guitar Knob - EBONY Wood - 9/16" Dia. | eBay
just a note
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