2 questions about Bazz Fuss: linking two circuits in series, and diode switching

[Widows]

Hi folks, I've been having a mess around with the Bazz Fuss circuit and have a couple of questions I'd like to ask before I go any further with it and fry my brain.

1) I've built a double bazz fuss; two Bazz Fusses in series - essentially a Buzz Box but without the octave up - and I intend to include the controls for the delux model. I've breadboarded the design as per the buzz box design on http://www.home-wrecker.com/bazz.html, but substituted the caps for 10uF and 100k resistors for 10k as per the Beavis Audio design for a single Bazz Fuzz (http://www.beavisaudio.com/bboard/projects/bbp_BazzFuss.pdf). I've also used a 1N4001 and 1N914 diode pair in the clipping stages of both circuits - this combo gets a really filthy sound even with just the one Bazz Fuss, try it! Even better, run a russian big muff pi in front of the Bazz Fuss - ridiculous!

Firstly, I breadboarded a single bazz fuss circuit and then added a second bazz fuss circuit on the other side of my breadboard, linking the two with a jumper between the  -ve of the 1st stage output cap to the clipping stage in the 2nd bazz fuss circuit as per the design on home wrecker.com above. Leaving the output wire connected to the -ve of the output cap in the first Bazz Fuss circuit  I don't notice any difference in sound between the two set ups when including/isolating the second stage. I thought this may be because the output wire was still connected to the output cap in the first stage but upon moving it to the equivalent position at the output of the second Bazz Fuss circuit there was a huge loss of volume. I would've thought that if anything, there would have been an increase in volume due to the extra gain etc from the second circuit.
---> Can anyone please enlighten me on both the volume drop and the lack of difference between sounds when connecting the second circuit? Am I missing something really obvious here? I must be....

2) I'm also building a second design on vero board (just your regular delux version this time, none of this double stage nonsense) but I would like to include a switching option for diodes to allow me to select between one of two individual diodes or use both at once. I have a DPDT on-on-on switch that I'd like to use. My question is can I use it like a pickup selector switch on a Gibson guitar, i.e with the switch to one side it engages one diode, and to the other side it engages a different diode, and in the central position both diodes are engaged? Or would I have to connect two further diodes to the central position of the switch?

The design that "inspired" me to try this option was featured in this thread: http://www.diystompboxes.com/smfforum/index.php?topic=96630.0 from Nocentelli, it's about halfway down the page.
I'm looking to use a similar method of construction to include diode switching in my design.

Sorry if any of this is unclear, I'm still learning and getting used to the terminology etc. If you need me to clarify anything, please ask

Cheers

[Pollinator95]

Re: the second question, I found this:

http://music-electronics-forum.com/t17281/

It looks like generally, in DPDT toggle switches the middle setting combines both of the other ones.
I was going to attack one of my ON-ON-ON switches with a multimeter to make sure, but it looks like I don't have any. 

[Widows]

Cheers Pollinator, I'll check that out. Just out of interest, how would I go about checking this with a multimeter myself? It'd be interesting to learn so I can check out other switches in a similar manner.

Cheers

[Earthscum]

It's actually pretty simple to check the switches. Just set your DMM to "Ohm" and flip the switch. Lugs that are connected will measure nearly zero Ohms, while lugs that aren't connected will measure nearly infinity. Now, if you had a SPDT ON-ON switch, if you flip the lever one way, the lugs at the opposite side of the casing will be connected. Picture the toggle going inside as a straight line and pointing at the pair of lugs that are connected.

[Widows]

ok, so I've got an update for you. the switch I have is 3 way centre on (or on-on-on) as I mentioned before.  Pos 1 = up / Pos 2 = centre / Pos 3 = down
After checking a bunch of posts - which I'll link below - it would seem that when this type of switch is in the centre position (2), it will act as though the other two positions (1 and 3) are engaged simultaneously. - like a gibson style pickup selector switch.

I breadboarded a basic Bazz Fuss circuit again as per the layout on Beavis Audio (http://www.beavisaudio.com/bboard/projects/bbp_BazzFuss.pdf), but where the diode is supposed to go, I took the switch and wired it up like this:

                               D1
                           1N4001
                         +ve  -ve (banded)
                         __l___l__
                         ¦  1   4 ¦
  collector --->   ¦  2   5 ¦  <------------  base
                         ¦  3   6 ¦
                         ^----------
                            l     l
                         +ve  -ve (banded)
                           1N914
                              D2

Hopefully my diagram makes sense, but just in case:
D1 = 1N4001, D2 = 1N914

• +ve end of D1 is connected to lug 1, -ve (banded end) of D1 connected to lug 4
• +ve end of D2 is connected to lug 3, -ve (banded end) of D2 connected to lug 6
• Lug 2 connected to collector leg of 2N5088 transistor
• Lug 5 connected to base leg of 2N5088 transistor

When the switch is set the switch to either up or down it engages whichever diode is connected to it successfully, however when the switch is in the middle (centre on) position it creates a really odd, patchy effect that sounds like a really extreme voltage starve - totally different from the sound I was getting when I breadboarded the circuit with D1 + D2 running together in a loop which created a heavyweight fuzz.

I wondered if the switch in the centre position could be lifting/bypassing the diodes completely and effectively removing them from the circuit altogether so I pulled the switch out of the breadboard and hey presto, exactly the same nasty, spluttery effect as when the switch was connected and set in the central position.

I really like the idea of having a 3 way clipping selection switch where I can use one or other of the diodes, or both at once and whilst I could just take the easy way out and connect 2 diodes to one end of the switch and a single diode at the other, that would still leave me with the central position bypassing the diodes and frankly it sounds a bit crap so it's not an option I'd like to include in the design if I'm honest.

Is there a way I can make both the diodes work together with the switch in the centre position, with everything connected as shown above?
Or do I just accept that this kind of design is going to be a little heavier on parts than I was hoping, and simply solder two more diodes between lugs 2+5 along with the wires going to the collector and base?

Thanks

[Widows]

Here's the posts/pages I read to get info before posting above:

Bazz Fuss layout with diode switch: http://www.diystompboxes.com/smfforum/index.php?topic=96630.0  <--- scroll about halfway down
Post about diode/LED switching on Harmony Central: http://acapella.harmony-central.com/showthread.php?2109272-Wiring-diodes-on-a-DPDT-on-on-toggle-switch
Post about DPDT diode switching on Harmony Central: http://acapella.harmony-central.com/showthread.php?2219452-dpdt-as-a-diode-switch-help
Beavis Audio switches advice page: http://www.beavisaudio.com/techpages/Switches/
Post about SPST switching of two diodes on DIYStompboxes: http://www.diystompboxes.com/smfforum/index.php?topic=87942.0
Website about guitar pickup wiring: http://www.1728.org/guitar.htm

[RandomGlitch]

it seems to me that the switch you have is not ON-ON-ON, rather it is ON-OFF-ON.  I don't think you can do what you want with that switch. Have you checked the central position with a multimeter?

What you want is an ON-ON-ON that connects both sides in the central position. There are different kinds of these switches, that do different things in the central position, so you need to check I think.

I built a bazz fuss a little while ago, experimenting just like you with different diodes, putting 2 fusses in series, all sorts of switching options and so on. Lots of fun!

I was optimizing it for bass, guitar might be different, but what I found was the diodes didn't make a big enough difference for me.  Rather, I added a pot in place of the collector resistor, makes it more or less gated, depending on the transistor.  For bass I liked the 2n2222 best.  The MPSA13 seems like a favorite amongst guitarist though. Also I found the 2 fusses in series option fun but a bit too much mayhem for a band-useful effect. For guitar I think it would be awesome. Using different transistors for the two stages was interesting - the order can make a big difference, thin and wirey or thick and meaty just by flipping the order.

Anyway, maybe you could achieve what you want with a normal DPDT switching between your 2 diodes, with an additional switch (you could use a SPST) to switch a 3rd diode in and out. More switches I know.

Or, get a rotary switch. you should be able to get 6 positions then. But you'd need to have more diodes in there.

[Widows]

Thanks for the reply man, sounds like you've been busy on the building side of things :-)

Thing is with this switch, I specifically selected one from the supplier listed as on-on-on, and it even states that it is on-on-on when you look at the casing so I'm a bit confused. I'll try wiring another diode to the middle lugs n see what happens with that. If I get some fuzz then I know I'm on the right track, if I get that crappy spluttery effect then I'll have to rethink, or simply buy a different switch haha.

[Widows]

I wound up just wiring 2 diodes in series on the middle lugs, (+ve of one diode and -ve of the other on lug 2, and vice versa on lug5). This seems to work well enough. just a shame I had to use 4 diodes really, would've been nice to minimize parts. It looks pretty ghetto, but it works, that's the main thing ;-)

I now want the option to switch between two different transistors using a 3pdt stomp switch as well, I've got some questions on that but I'm going to whack those in a new topic.
Thanks for your help folks

[RandomGlitch]

There's a diagram for transistor switching with a 3PDT on Beavis Audio site, again it's not hard to do.

Don't worry too much about being ghetto - everyone starts off like that.  My ghetto builds still work, just don't look inside!    You learn so much building your first pedals.

[Pollinator95]

Just wondering, I think I recently read that putting two diodes in series means the threashold (or whatever it's called, forward voltage?) is added up, so two .3V diodes in series make a .6V one. Could it be that when you put the switch in the middle it actually works as it's meant to, but the combined forward voltage means it sounds almost like they're not there? Just thinking aloud, really.

[Widows]

could be man, I don't really know about their relative operating levels etc as I'm still starting out really. I've just been putting one diode in and going "yeah, sounds ok, let's try a different one....ooooh much better" etc haha. I noticed that some of the pedals whose sounds I prefer have 2 or more diodes linked up in their clipping stages in a loop, so I tried that out on the breaboard too and it gave it a slightly different character so I thought I'd whack in the option to use both. As I said, now those two diodes are running into each other on the middle lugs it sounds fine when the switch is central. Am gonna do a bit more testing at volume tomorrow as the differences were quite subtle at low volumes when I was playing through it earlier.