Wah output bufer

[dthurstan]

A while back I posted in a topic about wah buffers, I came up with the idea of using the darlington i/p buffer as an o/p buffer. Genius, I know  !
http://www.diystompboxes.com/smfforum/index.php?topic=94775

So I wired it up like this;


a = input (switch)
b = output from circuit (pot)
c= to 1uF cap to output (switch)

There are trace cuts between input jack & b and between a & c.

So I thought this would give be an output that would work with the input of a fuzz face. But it doesn't sound right. To start of with I get popping from the switch, I guess I need a pulldown resistor on the output. I get a lot of hum when I connect it to a ff, I get more sweep than without a buffer but I'm not sure it's quite right. I also plugged it into my Formula No.5 clone and that sounds crap too. I assumed this buffer would have a high i/p Z and a low o/p Z to work with fuzzes etc.

Doing a bit of searching I found these topicson the subject;
http://www.diystompboxes.com/smfforum/index.php?topic=97466.0
http://www.diystompboxes.com/smfforum/index.php?topic=97899.0
So I may just go with the 50k pot solution. I just don't understand why different buffers wouldn't work, I would of thought so long as you have high Z in & low Z out your laughing. I guess not. Is it because the darlington buffer has a high output current?

[dthurstan]

I realise wah output buffers may have been done to death here but has anyone tried this before?
I can't find anything about how a ff circuit sounds with a standard crybaby in front of it. That is with the input buffer in the bypassed signal chain. Did people have issues with it before an ff other than the reduced interact with the guitar?

[pinkjimiphoton]

i tried every single buffer suggested on this board and others to use in my wah before a fuzz, and every single one sounded like poo.
the 50k pot trick works, every time. you can dial up just enough resistance to make it work well with distortions and overdrives. but...fuzzes have to go first, or they simply don't work well. any buffer between guitar and fuzz completely destroys the interaction of the guitar and the fuzz.

my suggestion...add the 50k pot, put your fuzz first before wah, and drives/distortions after. use the knobs on your guitar, and you'll be able to get the same tones you'd get with wah into fuzz anyways, and can make it scream going into the dirt afterwards.

[dthurstan]

Cheers Jimi

Yeah I've seen your post on the subject as I searched the forum. Thats a good point about fuzz before wah and roll off the guitar volume.

I think I'm gonna do a bit of investigating using my ears. Ill put a boss pedal in a TB loop after the wah and switch it in and out to see how it changes the reaction with fuzz/other pedals. I've also got a passive 250k volume & tone pedal I use with an acoustic pickup (quite a handy little module to have). I could use this to see how a pot after the wah changes things. Will this work similar to a 50k pot? I know it's not quite the same and the fact that there is a tone control there also but I'm hoping it's close enough.

I remember testing the boss buffer before a fuzz previously and yeah it removes that interaction between the guitar and pedal. I'm just surprised that relocating the darlington input buffer from the crybaby to it's output doesn't yield better results.

There is a PGS demo of the MXR fuzz which shows how the buffer toggle changes the interaction between the fuzz and a wah, recovering the sweep range etc.

This is nothing new, but I was hoping to come up with an efficient way of dealing with poor wah - fuzz interaction. Just a couple of trace cuts, some wire and a new cap, but it seems its not that easy.

Dave

[dthurstan]

Ok so I've carried out my investigations. 

So with a buffer (a boss dd-7, opamp based buffer I'm assuming) in between the wah & fuzz I get hum & buzz like I do with the darlington buffer and it does improve the sweep range like the darlington buffer does.

I'm sure the last time I did tests with a buffered pedal in front of a fuzz I didn't get the hum and buzz. I'm wondering if this is because last time I used a silicon fuzz face and now Im using a Ge FF with bipolar supply (MAX1044 chip) to get the -9 volts.

I also tried using my passive volume & tone pedal inbetween the wah and fuzz. It kinda works, I can heard more of the sweep but it's not quite there. I'm guessing a 50k pot works better here.

So I think I need to get my silicon FF back up and running again and try this again, as the bipolar supply is probably giving me the hum & buzz (Im daisy chaining everything).

[pinkjimiphoton]

hi dave,
yah, the buffers thing really messes with fuzz, but if ya have the fuzz first it becomes negligible.
the buffers do help with "normal" kinda boss style pedals tho.

yes, putting a volume pedal between won't work, you get enough loss because of cable length etc where...you guessed it...you'll need a buffer.

the 50k pot wired between the output of the wah board and input to the output part of the switch will work fine. i added a switch to mine, so i can have it in or out as needed. some pedals want to see that extra resistance (which i guess works by changing the voltage to a current or vice versa) some don't. usually a quick tweak of the pot will work.

OR, of course, remove the input/output buffers of the wah, but then if you TB it, expect a volume loss. i like the buffers there, myself. ymmv.