Equilux Mini Low-ish Output

[C Taylor]

I just completed my Equilux Mini build. It sounds as it should, however with no EQ boosting or cutting, the level control needs to be maxed in order to achieve unity, and even then there is an extremely slight volume drop. Once I'm boosting frequencies I have some room to work with but I'm pretty sure I should be able to achieve unity with the level knob closer to noon (based on demos I've seen of the OG Spaceman Equinox).

I'm not new to soldering or wiring, but I'm still learning to troubleshoot circuits. I have checked voltages at the charge pump and all is well. Of course there is the possibility that I have missed a component value somewhere but I really take my time on my builds and double check the values I'm putting in before soldering.

Curious if anyone else can speak into wether or not this is the appropriate volume level for this build or if everyone else has more output on tap. Any advice or suggestions would be helpful!

Pics of the build below for reference:

 

[dutycycle]

I am curious about this as well. I built the large ver of this last year and have the same issue- very low output. I also got this kit bc of the Spaceman demos I saw. I have the mini ver of this as well that I will probably finish in a few weeks and wonder if it will have the same issue or not... Will see.. err, hear.

 

[armedstew]

I just completed my Equilux Mini build. It sounds as it should, however with no EQ boosting or cutting, the level control needs to be maxed in order to achieve unity, and even then there is an extremely slight volume drop. Once I'm boosting frequencies I have some geometry dash lite to work with but I'm pretty sure I should be able to achieve unity with the level knob closer to noon (based on demos I've seen of the OG Spaceman Equinox).

I'm not new to soldering or wiring, but I'm still learning to troubleshoot circuits. I have checked voltages at the charge pump and all is well. Of course there is the possibility that I have missed a component value somewhere but I really take my time on my builds and double check the values I'm putting in before soldering.

Curious if anyone else can speak into wether or not this is the appropriate volume level for this build or if everyone else has more output on tap. Any advice or suggestions would be helpful!

Since you’ve already confirmed the charge pump voltages, I’d next look at

Resistor values in the output gain stage (even a single swapped value can cause this)
Op-amp choice vs. original spec (some have lower output swing headroom)
Pot taper/value for the level control itself

 

[punchy712]

Interesting timing to see this thread. I have the same issue with my build that I completed a year or two ago and the low output volume was always bothering me. I was just about to start searching the forum to see if it's a known issue so I'll be following this thread.

 

[C Taylor]

Since you’ve already confirmed the charge pump voltages, I’d next look at

Resistor values in the output gain stage (even a single swapped value can cause this)
Op-amp choice vs. original spec (some have lower output swing headroom)
Pot taper/value for the level control itself

When I have the time to dig into it I'm going to double check all of these things. If I remember correctly I sourced the exact op-amp the build called for but of course there are often so many variations/brands it's possible that it isn't exactly right.

One thing that makes it extra difficult for me to troubleshoot post-build is that I am colorblind and reading resistors is REALLY difficult, which is why I am so careful when putting them in the first time (triple checking I have the right bin, measuring their resistance before putting them int the circuit, etc.) I'm jealous of the people who can look at a populated board and see what values are in there.

It sounds like a couple of others have this same issue which makes me feel a little better, but I'd love to know if this is by design or if we have all mixed up some resistors or pots. Or maybe we've all source our op-amps from the same wrong place!

Thanks for the replies, everyone.

 

[jwin615]

This is just the design of the circuit
Mosfet buffets don't provide much gain. And passive filters are going to decrease overall signal level.
Quick calculation says a gain of 0.9 for the input and 1.1 for the output.(Grain of salt with the exact numbers).
Remember, Robert doesn't design it, he just traces and replicates.
Maybe the output stage could be replaced with a jfet or BJT to add some output gain.
Otherwise, cram a jfet buffer or Muffin crumb in there.

 

[jwin615]

I would amplify at the input, not the output, for better noise specs.