Seabed Delay - signal above unity

[Coach_McGuirk]

I built a Seabed Delay, which I like a lot, but I noticed that my guitar is bit louder when the pedal is engaged versus not. I'm a circuits noob, so I'm not sure which resistor I could try replacing to see if I can get the volume to unity. I've attached a picture of the schematic.

Is it R22 that I should be looking to substitute? Would decreasing the value of this resistor increase the amount of signal going to ground and decrease the amount going to output?

 

[Feral Feline]

So the dry signal's too hot, and the repeats "LEVEL" isn't doing it for you?

Here's a few things I would try (use only 1):
- You could add a volume pot at the output (between the board and your 3PDT).

- R3 could be changed to a 500k pot. Or a smaller value pot with a resistor in series.

- R5 try 10k resistor (or switch it to a pot)

- increase R6 by replacing it with a pot, adjust to taste, measure the resistance of the pot, then put in the closest resistor value to what the measure pot's resistance was.

 

[phi1]

All above are good ideas, I'd personally adjust R5 first.

Although I am a little surprised, I've built this circuit a few times and never had a volume level increase. And mathmatically, it seems lik it should be very near unity. Did you make any value subs in your build?

 

[DailyDovetails]

All above are good ideas, I'd personally adjust R5 first.

Although I am a little surprised, I've built this circuit a few times and never had a volume level increase. And mathmatically, it seems lik it should be very near unity. Did you make any value subs in your build?

I tried mine and I actually also thought it got slightly louder when turned on but not enough to bother me.

It does seem like adjusting R5 if there is a difference might be an easy fix tho. I think you could try putting values in there in parallel until you find one that works. https://www.digikey.com/en/resource...rsion-calculator-parallel-and-series-resistor

 

[Coach_McGuirk]

So the dry signal's too hot, and the repeats "LEVEL" isn't doing it for you?

Here's a few things I would try (use only 1):
- You could add a volume pot at the output (between the board and your 3PDT).

- R3 could be changed to a 500k pot. Or a smaller value pot with a resistor in series.

- R5 try 10k resistor (or switch it to a pot)

- increase R6 by replacing it with a pot, adjust to taste, measure the resistance of the pot, then put in the closest resistor value to what the measure pot's resistance was.

The level knob only controls the level of the repeats. There are no controls for the dry signal, which is what is boosted a few dB when the pedal is engaged.

I'll try your suggestions when I get a chance. Thanks!

 

[Coach_McGuirk]

All above are good ideas, I'd personally adjust R5 first.

Although I am a little surprised, I've built this circuit a few times and never had a volume level increase. And mathmatically, it seems lik it should be very near unity. Did you make any value subs in your build?

I'm pretty sure I used all the recommended values, although I have a bad habit of not checking resistor values with the multimeter before installing. I just sort of assume they are accurate and within a 1% margin. It's possible I grabbed the wrong resistor or something at some point, but I'm usually pretty careful with that stuff. It's also possible that R5 or another resistor is wildly out of spec.

The volume increase is not that bad, but it's definitely noticeable to me when I'm playing. It makes the pedal a bit problematic to use.

 

[Coach_McGuirk]

I tried mine and I actually also thought it got slightly louder when turned on but not enough to bother me.

It does seem like adjusting R5 if there is a difference might be an easy fix tho. I think you could try putting values in there in parallel until you find one that works. https://www.digikey.com/en/resource...rsion-calculator-parallel-and-series-resistor

Thanks for the link. Maybe I'll try this. Would you recommend just opening the back of the pedal and touching various resistors across R5 while I have a loop pedal playing something and switching the pedal on/off? Or is there a better way to do this?

 

[phi1]

Sounds like other people have had volume increase so maybe it’s common within part tolerance.

I don’t personally measure resistors when building either. Couldn’t hurt. I do usually look at the stripe code though I guess, it’s good practice learning the color code

 

[DailyDovetails]

Thanks for the link. Maybe I'll try this. Would you recommend just opening the back of the pedal and touching various resistors across R5 while I have a loop pedal playing something and switching the pedal on/off? Or is there a better way to do this?

That would work. You could use a trimmer also. Then just enter the 2 values into the link and it should give you a good idea of the resistor value to put there.