My distortion box

[Goodrat]

After a lot of reading, tweaking and annoying the house and neighbors for months, here is what I ended up with.
(until I change my mind again).
I have these SP3T switches and pots are a pain.
They are an interesting way to get 3 progressive levels of something.
Sounds great. I'll get around to recording a clip soon.
http://www.rickviola.com/images/Scooch012211.jpg

[petemoore]

  Snazzy lookin' !
   I like seeing worked up schematics of distorters like this.
  Input cap selection makes flexible as does the split-level output [stage bypass].
  And the inductor coil in there...where'd you get that?, interesting, inasmuchs I've heard that other electronics can do 'that', it certainly does look simple on a schematic.
  I'm still not exactly sure I understand the switch type, they look like DPDT.
      
 

[Goodrat]

I have toroids that can fit about 100 turns and give me 100mH.
46 to 50mH in series with a 1uf gives a nice simple notch at 750 Hz that I can't seem to get witch caps.
Maybe it is the way the core saturates. I suppose using the coil of a small audio xfmr with similar value will work too.
I discovered three throw switches when researching another project. The contacts are in opposite states in the middle position. (see the example on my drawing where the red lines are).
If a DPDT was used with 3 caps, the capacitance would switch from the lowest value in the center position, then some higher value in the other 2 positions as they are put in parallel. With the SP3T you can arrange to get a low, medium, high value for positions 1, 2, 3. The way I have it in this example is all 3 caps in series in the left position, middle is just one cap, right is all 3 in parallel. Low, medium, high.  More user friendly. There are other possibilities also like no cap, one cap, two caps in parallel as I did on the output filter and coil.
I have Mouser part # 612-100-L1111 and it is a toggle described as DPDT ON-ON-ON.
(Some of the description says Slider but that is an error.)
Some manuf call it DP3T, SP3T. But always ON-ON-ON.
The usual intention of the switch is to have one input and 3 outputs.

[Goodrat]

I still want to tweak a few things. Update will follow.

[Goodrat]

Here is the latest rev:
http://www.rickviola.com/images/Scooch012711.jpg

[Goodrat]

Here is where I am now with caps and gains tweaked.
That coil connected where it is, gives an odd but pleasing notch that when seen on a scope, looks like it doubles the frequency of the signal at the resonant frequency. Some kind of phase distortion I assume. I'll record soon.

[deadastronaut]

looks good, look forward to hearing it!....cool.

[Maik]

Cool. Waiting for the clips (and the pbc  )

[Goodrat]

I made a few minor changes today.
I also noticed I forgot the link to the last rev.
http://www.rickviola.com/images/Scooch020711.jpg

[Quackzed]

I discovered three throw switches when researching another project. The contacts are in opposite states in the middle position. (see the example on my drawing where the red lines are).
I have Mouser part # 612-100-L1111 and it is a toggle described as DPDT ON-ON-ON.
(Some of the description says Slider but that is an error.)
Some manuf call it DP3T, SP3T. But always ON-ON-ON.
The usual intention of the switch is to have one input and 3 outputs.

Thats some good thinking. I can totally see this type of cap switching( ie low med high orientation) becoming a popular option in designing effects...
You should write up a separate post on how to use these switches in the manner you described, with some examples. or just link to your schem as an example... i see for the input cap you get .11 .33 and .99, low-med-high. thats the first time i've seen that. nice.
Works with resistors as well, if the 3 caps in your schem were each say 10k youd get 30k 10k and 3.3k in the same fashion.
Brilliant!

[Maik]

You should write up a separate post on how to use these switches in the manner you described, with some examples. or just link to your schem as an example... i see for the input cap you get .11 .33 and .99, low-med-high. thats the first time i've seen that. nice.
Works with resistors as well, if the 3 caps in your schem were each say 10k youd get 30k 10k and 3.3k in the same fashion.
Brilliant!

Bump! Would be great for a noob like me...´cause that´s what I want in a lot of boxes but don´t know how to do it 

[Goodrat]

Thanks.
I used to manufacture headphones for metal detecting and I was going to use resistors this way in place of expensive higher current capable volume controls.
There are a lot of possibilities with a SP3T switch. The usual intended use is one input switched to 3 outputs.
You can switch caps in parallel with a DPDT, but you have to settle for the lowest capacitance in the middle position.
I will write something up on my website by this weekend.

[askwho69]

this is very interesting hope to hear on this:D

[Goodrat]

I decided to put the first high pass switch after the first stage instead of before, so I am making another change.
The thump on muted power chords sounds better that way. Why? Not sure.
So don't anyone go and build this yet until I'm done tweaking.
I will have a PC board layout using a small DIP proto board.

[Goodrat]

Getting closer....
I did all I can not to go as low as 100 ohms on the 2nd stage input (R9) but is just sounds too good.
Also, setting the 2nd stage lower roll off to as high as 1500Hz rather than the usual 300Hz sounds good too.
Hmmm.

[arawn]

great work looks like a first class design, I look forward to some clips>

[Goodrat]

I've been doing a lot of work on this and came up with a new ideas also.
A lot of decisions to be made.
In any case, as promised, here is some info on switches and capacitors:
http://rickviola.com/electronics.htm

[Goodrat]

Update:
I'm still making decisions about switching, gain, filters etc. so this is going to take a while.
I may go to a better op amp to get the bandwidth I need at high gain.
I'm trying to squeeze to much from a TLO82.
So I may delete previous schematic versions for now.

[Goodrat]

OK, I'm going to go with this. Build time.
I decided to use a pot for the final high control.
http://www.rickviola.com/images/Scooch030111.jpg
C13 seems to even out the lower frequencies and give me an overall better bandwidth up to 18KHz.
I don't know why.
An accidental improvement.

[Goodrat]

Something is not right.
Calculations are not matching the prototype.
Drawings on hold.