Caesar Chorus Volume

[ElReverendoRyan]

Hey gang, just fired up this build, everything is working fine, waveform works albeit a percivable clicking when internal leds are engaged, read that a TL071 could fix this.

But my question is concerning a volume drop, everything i'm reading is saying that it should compensate, but i'm hearing a drop when engaged, even with the blend on dry. I've checked component values, they check out for me, switched out op amps, but still experiencing the problem. It's not horrible, but perceivable loss in low frequences and volume. Is this normal?

 

[Alan W]

Are you testing it all on its own, just guitar in and pedal to amp? If not, give that a shot. It could be an impedance issue with another pedal that’s affecting the output on Ceasar.

Try dressing the lead on the side near the LEDs further away from them, that may help with the LFO ticking. (Actually, just play around with the lead some. I think the ticking is coming from the op amp. A small but of distance can make a difference.)

Nice looking build! Welcome!

 

[ElReverendoRyan]

Hey! Thanks for your response!

I gave it a shot, ticking went away after moving the wiring.

Still having volume drop tho. I decided to plug it into my daw to get a visual, and it’s not far from being a 50% drop. It’s odd because it sound great

 

[Alan W]

Hey! Thanks for your response!

I gave it a shot, ticking went away after moving the wiring.

Still having volume drop tho. I decided to plug it into my daw to get a visual, and it’s not far from being a 50% drop. It’s odd because it sound great

That’s definitely not how it should be. I’m not sure if bogus chips in the pair that do the modulation (which have proven to be popular candidates for faking) could account for the reduced output. And, as you say, it sounds great. But—do you have any other of those that you can sub in, as a test?

 

[ElReverendoRyan]

That’s definitely not how it should be. I’m not sure if bogus chips in the pair that do the modulation (which have proven to be popular candidates for faking) could account for the reduced output. And, as you say, it sounds great. But—do you have any other of those that you can sub in, as a test?

I think so, I’ll try that

 

[ElReverendoRyan]

That’s definitely not how it should be. I’m not sure if bogus chips in the pair that do the modulation (which have proven to be popular candidates for faking) could account for the reduced output. And, as you say, it sounds great. But—do you have any other of those that you can sub in, as a test?

Had a go switching out the bbd, still having the issue. I have a hard time with modulation schematics, could you point me in the direction of the part of the circuit that takes care of make up gain?

 

[zgrav]

check your resistor values around the 4558, particularly R14.

 

[ElReverendoRyan]

check your resistor values around the 4558, particularly R14.

just finished checking everything, everything seems ok. this one is really leaving my head scratching

 

[Cybercow]

Chorus circuits are almost always a perceived volume drop. It's their nature. At best they are a unity gain circuit. If you need/want more volume out of it, you try changing R38 from 47K to 100K or higher. I usually apply a 250K trimpot there and tweak to my liking. (Too high a value there may contribute to OD.)

 

[ElReverendoRyan]

Chorus circuits are almost always a perceived volume drop. It's their nature. At best they are a unity gain circuit. If you need/want more volume out of it, you try changing R38 from 47K to 100K or higher. I usually apply a 250K trimpot there and tweak to my liking. (Too high a value there may contribute to OD.)

i'll try that then! thanks

 

[benny_profane]

but i'm hearing a drop when engaged, even with the blend on dry

Verify all the the parts associated with the input and output. So, up to and including the first op amp stage (IC2.1), the blend network, and everything from IC2.2 on. With the blend completely dry, there’s no BBD circuitry in effect.

If this is not an extreme volume loss, then I’d say it’s normal. With the blended signal, there’s an additive effect than can go a bit loud. It’s tough trying to balance those dynamics and psychoacoustics.

 

[ElReverendoRyan]

Verify all the the parts associated with the input and output. So, up to and including the first op amp stage (IC2.1), the blend network, and everything from IC2.2 on. With the blend completely dry, there’s no BBD circuitry in effect.

If this is not an extreme volume loss, then I’d say it’s normal. With the blended signal, there’s an additive effect than can go a bit loud. It’s tough trying to balance those dynamics and psychoacoustics.

I went over everything, nothing's out of place and eveything works. But its definitely audible even in dry that there's a volume drop, and checking levels in my daw definitely confirmed it, it's about half as loud. What's weird is that's the ONLY issue. I might just chalk this up to "meh, that's how it is" and just use it when recording, or have it in a boosted loop if i decide to use it live

 

[swyse]

What is the value of this resistor? I can't really figure out the band colors in a way that makes sense.

 

[benny_profane]

What is the value of this resistor

Looks like a 470k instead of a 470R.

 

[ElReverendoRyan]

That it is, good catch

 

[ElReverendoRyan]

Looks like a 470k instead of a 470R.

Ok, you’ve got better eyes than I do, that totally nailed it

 

[zgrav]

that certainly accounts for the volume drop through the pedal

 

[benny_profane]

waveform works albeit a percivable clicking when internal leds are engaged, read that a TL071 could fix this.

By the way, both op amps here are dual and cannot be replaced with a TL071. If you’re getting ticking, route all wires (especially the input, output, and GND wires) as far from the LFO block as possible (i.e., the TL022 and the SHAPE switch).

 

[ElReverendoRyan]

By the way, both op amps here are dual and cannot be replaced with a TL071. If you’re getting ticking, route all wires (especially the input, output, and GND wires) as far from the LFO block as possible (i.e., the TL022 and the SHAPE switch).

TL071 was a typo, was thinking 072. In any case that’s sorted!

 

[cgreenCRNA]

Gurus,

Please help me wrap my head around the logic of increasing the resistance at R38 and decreasing the resistance at R40, both resulting in a louder output. My guess is that R38 is part of a negative feedback loop so more resistance causes a greater difference between the opamp inputs and therefore higher output. Meanwhile, R40 simply reduces flow along the path to the output jack. Is this anywhere close to correct?

Thanks,
Chris