Wanted to post this in the Tech Help area but decided not to pollute the area with non-MB content.
SO, a couple of us had been really content with the Wicked Switches switching system by Tone God, but I noticed a weird problem going on recently. It involves using the WS with overdrives.
With my build, The Marble Dilemma 3-in-1, I included a Zendrive, Phase 90, Digital Delay with tails. While the modulations work fantastic, I get a strange problem with the Zendrive, if, and only if, I turn the Volume control past 1 oclock. The problem is manifesting itself as light screatching, crackle, on fatter strings, on A and E string [so yeah, the ones that generate even more voltage] while on the lighter strings everything is fine.
As I keep turning the volume past 1 o clock the noise becomes so pronounced that by the end of the dial you cannot even hear what you are playing, even on the light strings :(
Looks like the switching system has some sort of limit, voltage-wise, that overdrives seem to go beyond.
My friend used WS with his RC Booster build - same problem.
I never noticed this before since I wasn't in a position to turn the dial that far [strange how I never tried it just to see that everything works, but hey..] but I had the chance of playing really loud the other day, and in the meantime my friend got the same problems with his build so I would expect others too, so beware if you're considering using this system with overdrives.
Any ideas whatsoever, how to remedy this?
I replied in the other thread, but I'll write it here too.. I haven't noticed something like this. But maybe it's exactly what you said. I'll check the datasheet. If the problem is because of limits of the chip, maybe there isn't a way to remedy this.. Still I don't know yet...
Hector
Thanks man. It is strange, I would hate it if this switching would fall because I really like it.
Quote from: Cortexturizer on October 11, 2013, 10:01:56 AM
Thanks man. It is strange, I would hate it if this switching would fall because I really like it.
Indeed, I didn't expect that. But neither have I checked the datasheet values.. I found something but we have to decide where we should continue posting about this.. I tink it's better here, where the whole problem is stated, right? ;)
Hector
yes!
So here's what I found. From voltage point of view, input voltage can vary from -500mV to 9.5V on a 9VDC supply. So there, we may not have a problem. Then again, current-wise, the input current should vary from -10mA to +10mA. A overdrive/distortion circuit offers a lot of gain, and maybe, the signal is too big on the output, so the chip clips in some way..
That's a start, but I'm not sure for what I'm talking about, because I don't know how big is the signal on the output.
Hector
Yeah, great. Ok, I'm gonna open mine today and measure the voltage on the output to see where we're at.
Hm, seem so noob to me now but I've never measured current in a pedal, how should I do this in order to know that the maximum hasn't been exceeded on the chip?
In order to take right and stable measurements, I think it's best to use a function generator, if you have one on your testing rig. Unforunately, I haven't built one yet.
And in order to measure current in the output, you should have your multimeter is series with the circuit in the output. This can be done if you remove the cable from VOLUME lug 1 and put the MM leads in VOL lug 1 and GND.
Hope I helped a little.
Hector
alright, will do as soon as I get home from work.
BTW, I searched a little more and there is another chip, the 74HC4066, which seems to have bigger input current ranges. If you find any in a store near you, try it...
Hector
Just to add a bit of perhaps useless info:
The circuit has no problem with the Rat build I did, even on the highest gain settings. I had problems with the APIS Klon klone, were I would get high pitched oscillation as I turned up the gain. It was extreme. But I chalked it up to a grounding issue, or some knuckle-headed mistake of my own making. So for whatever it's worth.
By the way if anyone makes a batch of PCBs for these let me know if you'd be willing to part with a few (for a price of course. 8))
I don't have a problem with gain, just with volume. My friend had it to on his RC booster, volume was the problem. Maybe tone god was a bassist who designed this and tried to force people not to be too loud on rehearsals?
we'll never know...
Quote from: Cortexturizer on October 11, 2013, 03:10:49 PM
I don't have a problem with gain, just with volume. My friend had it to on his RC booster, volume was the problem. Maybe tone god was a bassist who designed this and tried to force people not to be too loud on rehearsals?
we'll never know...
Hahaha! Nice one... ;D
Quote from: spaceboss on October 11, 2013, 02:52:25 PM
Just to add a bit of perhaps useless info:
The circuit has no problem with the Rat build I did, even on the highest gain settings. I had problems with the APIS Klon klone, were I would get high pitched oscillation as I turned up the gain. It was extreme. But I chalked it up to a grounding issue, or some knuckle-headed mistake of my own making. So for whatever it's worth.
By the way if anyone makes a batch of PCBs for these let me know if you'd be willing to part with a few (for a price of course. 8))
I'm happy there's someone with no problem on a high-gain build!
Hector
I'll give it a try tomorrow with a Tube Screamer and report here too.
Quote from: spaceboss on October 11, 2013, 02:52:25 PM
Just to add a bit of perhaps useless info:
The circuit has no problem with the Rat build I did, even on the highest gain settings. I had problems with the APIS Klon klone, were I would get high pitched oscillation as I turned up the gain. It was extreme. But I chalked it up to a grounding issue, or some knuckle-headed mistake of my own making. So for whatever it's worth.
By the way if anyone makes a batch of PCBs for these let me know if you'd be willing to part with a few (for a price of course. 8))
What charge pump do you have in the Apis? That can cause the squealing..
George