Cave Dweller Brightening

[pryde]

My Cave dweller was a bit dark and muddied up my overall tone when on. Brian suggested lowering C3 to brighten up the tone. Stock value is 4n7. I experimented with 2n2 and found this worked well. I also went down to a 1n5 which made it even more clean/bright but the echo function became less effective.

So for my rig C3 change to 2n2 seemed to be a good balance of function and brightness.

[G.G.]

Just did this mod to mine, works great with a 2n2!! Thanks! 

[timbo_93631]

My Cave dweller was a bit dark and muddied up my overall tone when on. Brian suggested lowering C3 to brighten up the tone. Stock value is 4n7. I experimented with 2n2 and found this worked well. I also went down to a 1n5 which made it even more clean/bright but the echo function became less effective.

So for my rig C3 change to 2n2 seemed to be a good balance of function and brightness.

Did it become less effective because it got too noisy on the single repeat or because the repeat was less prominent?

[pryde]

It was like the repeats were less prominent. There just wan not much change in the repeat level from 3 oclock on up. I am not sure why this was the case with the lower values in C3?

[midwayfair]

I'd venture a guess that brightening the signal by changing C3 means that you're not increasing the overall volume (both "audio volume" and actual "volume of signal passing through the circuit") of high frequencies but rather decreasing the amount of low-end signal going to the Pt2399, resulting in less total signal available. What's leftover is brighter but only because it's lost bass, not because you've increased the treble (there's no gain stage in this pedal, remember). The leftover signal has to go somewhere - and the only place for it to go at that point in the circuit, if it's not passing as easily at C3, is the path from pin 14 to the "Out." Less signal going into the chip means less echo volume.

[pryde]

Thanks for the insight. that makes sense to me. So a strong echo signal requires a good amount of bass, and low mids behind it to give it some "umph" and volume.

[midwayfair]

Thanks for the insight. that makes sense to me. So a strong echo signal requires a good amount of bass, and low mids behind it to give it some "umph" and volume.

Well, sort of. I just mean that it's possible that the cause is that there's only a certain amount of signal for the pedal to work with as a whole, and if you change the balance between what gets to the chip and what goes to the output, you're changing the overall mix. But like I said, it's just a guess.

[timbo_93631]

I ended up using 1n5 and 680k instead of 750k on the input to balance out the volume on mine.  Everything seems really groovy.  I also put a 39k resistor across the two outside lugs of my time pot for a value of right over 20k and am really happy with it now.

[Rethfing]

Hello everyone, I would like to apologise for bringing this topic to life, but my problem is exactly what this topic is about, so it would be foolish to start new one.

I've built Cave Dweller, its awesome, I even managed to put it in 1590A with my own etched PCB (that was the first and the last time of putting anything to 1590A ). I have a problem though. I made mods as suggested in other topics: I've put 510k for R1, and 47nF for C1. The tone is now very dull and full of bass + it added A LOT of volume.
I started to lower the value of C3, Im stuck now with 1nF. It sounds almost ok, there is still volume boost which I want to get rid off, because I really want for my effects to have the same output as input. Also, it still adds some bass to the sound, I would like brighten it up some more. I dont know if I should proceed with lowering C3 or maybe there is something else I could do?

Thanks in advance
Maciek

[midwayfair]

Hello everyone, I would like to apologise for bringing this topic to life, but my problem is exactly what this topic is about, so it would be foolish to start new one.

I've built Cave Dweller, its awesome, I even managed to put it in 1590A with my own etched PCB (that was the first and the last time of putting anything to 1590A ). I have a problem though. I made mods as suggested in other topics: I've put 510k for R1, and 47nF for C1. The tone is now very dull and full of bass + it added A LOT of volume.
I started to lower the value of C3, Im stuck now with 1nF. It sounds almost ok, there is still volume boost which I want to get rid off, because I really want for my effects to have the same output as input. Also, it still adds some bass to the sound, I would like brighten it up some more. I dont know if I should proceed with lowering C3 or maybe there is something else I could do?

Thanks in advance
Maciek

Lowering the size of R1 and C1 should not increase the bass and dull the tone -- this is the opposite of what these changes do tonally (think about it -- they are a high pass filter on the input, how could you raise the lower frequency limit and get MORE bass?), and the volume increase should be mainly because there are more highs. Did you double check all your parts values? Most importantly: Did it sound right before you made the mods?

To just lower the volume, decrease R9. This forms a voltage divider with R10 at the output, just like a volume control. Resolving the "too much bass" problem is another matter.

[Rethfing]

Well I dont know how it sounded before these changes because I didn't have bypass built in, so its really hard to tell. I was just happy that it worked and started to work on another effect (I was making like 9 at once). Im going to check all the values

Edit: Whoaaaaaaaaa, it appears I have 100uf instead of 10uf in place of C13. Replacing now!

[Rethfing]

After replacing C13 to correct value there was a slight treble boost/bass decrease, but not enough. So I replaced C3 with 560pF - it now sounds OK I guess, maybe little bass boost. There was still volume increase problem so I placed 56k in place of R9. There is also little volume boost but I dont think thats gonna matter on high volumes during rehearsals. Im going to check how it all sounds on sunday Thanks for your help midwayfair!

[midwayfair]

After replacing C13 to correct value there was a slight treble boost/bass decrease, but not enough. So I replaced C3 with 560pF - it now sounds OK I guess, maybe little bass boost. There was still volume increase problem so I placed 56k in place of R9. There is also little volume boost but I dont think thats gonna matter on high volumes during rehearsals. Im going to check how it all sounds on sunday Thanks for your help midwayfair!

I think there must still be something else that's the wrong value. 560pF should make for incredibly noisy repeats in C3. There's a demo of two versions of the cave dweller on my youtube channel, one with the stock values and one with R1, C1, and C3 slightly reduced.

[Rethfing]

Yea I think something is still wrong because I have still volume and bass boost I think the best thing I can do right now is make a new PCB. Not to mention that this one already lost 2 solder pads because of solder pump I think ill do it today or tomorrow and see what happens