L5 Preamp - New Version

chongmagic

chongmagic

Well-known member
Just finished up this project. It was a lot of fun to build, for some reason I love the projects with tons of components. This is the new DC version, I build the legacy version years ago. This thing rocks just like the legacy version.

I was able to calibrate the compressor, per the build guide.

The distortion trimmer is still giving me issues, the build guide seems to still reference the legacy build. I Just know that I am barely getting 1v on pin12 of IC 10.

Otherwise, a great project, I highly recommend.


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Nice work! Looking forward to finishing mine as well….some day. It looks like the drill template ended up working out?
 
If I recall, on mine I tried really hard to follow the setup guide and ended up just tweaking it by ear. I have the real thing so was able to get it in the same ballpark just by feel. Plus it really depends on if you want to push a power amp or use this as an effect. Labs have a pretty wide swath of headroom.
 
chongmagic said:
I have my signal generator setup with the positive and negative of the probe are going to their respective test hole on the mainboard. Then I have my multimeter measuring the voltage at pin 12 of IC10.
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Did you ever get this worked out? This is on my short list of pedals to build in the next year.
 
chongmagic said:
I have my signal generator setup with the positive and negative of the probe are going to their respective test hole on the mainboard. Then I have my multimeter measuring the voltage at pin 12 of IC10.
Click to expand...
I was able to get the compression dialed in to 1.1v, but for my distortion (Pin 12), the best I can do is 2.4v.

I guess I'll just need to get it all hooked up to see how she sounds and go from there.
 
chongmagic said:
I have my signal generator setup with the positive and negative of the probe are going to their respective test hole on the mainboard. Then I have my multimeter measuring the voltage at pin 12 of IC10.
Click to expand...
It has been a little while, I think I did it by ear in the end, I know not preferred, I will have to break it out again. I have this little problem of having to many pedals on hand, that I never get to try them all out properly. I can't imagine anyone else here has that problem. :)
 
chongmagic said:
It has been a little while, I think I did it by ear in the end, I know not preferred, I will have to break it out again. I have this little problem of having to many pedals on hand, that I never get to try them all out properly. I can't imagine anyone else here has that problem. :)
Click to expand...
Perish the thought… 🤣
 
chongmagic said:
It has been a little while, I think I did it by ear in the end, I know not preferred, I will have to break it out again. I have this little problem of having to many pedals on hand, that I never get to try them all out properly. I can't imagine anyone else here has that problem. :)
Click to expand...
Nothing wrong by doing it by ear, and set things the way you like it to sound. Being able to add some subjectivity to projects like this is what makes it so lovely a hobby. :)
 
chongmagic said:
I have this little problem of having to many pedals on hand, that I never get to try them all out properly. I can't imagine anyone else here has that problem. :)
Click to expand...

That and I have a box of completed boards that I started not knowing whether I'd like the circuits. I've put them on the test bed, spent five minutes with them, and concluded that they don't merit an enclosure. I'd probably like at least a couple of them if I spent more time with them.

But I also have a hoard of uncompleted boards, and putting together a new one always seems like more fun.
 
Absolutely fantastic build! Thank you for sharing!

I have a question about it if you don't mind. I'm creating a UV layout for this and I just want to be sure I get all the labels right. This is in the docs about the Channel 2 controls, and it says the same in both versions of the document:

Channel 2
• Bright (toggle switch) adds a treble-bleed capacitor to the volume control, which preserves some of
the treble at lower volume levels to keep it from getting dull.
• Volume controls the amount of gain in the first stage, before the EQ and drive section.
• Treble and Bass form a standard 2-band Baxandall control. Each band is flat at the 12:00 position,
and can either cut (CCW) or boost (CW).
• Mid boosts (CCW) or cuts (CW) the midrange frequency selected by the Frequency control.
• Frequency selects the frequency that will be boosted or cut by the Mid control, from 100 Hz at full
CCW to 6.4kHz at full CW.
Click to expand...

I found it odd that the Mid knob works backwards (CCW boosts) compared to the Treble and Bass knob (CW boosts). Can you confirm that is the case on your build? Thank you!
 
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