Original Dallas Rangemaster Master

[myonus666]

Recently I posted a request for a original layout for the Rangemaster,  which I quickly adapted to my pedal.  Thank you Travis!!!!!!!  

Now I have an extra toggle switch that was a unnecessary drill in the stompbox.  Since id rather not have a hole;   I mounted a SPDT toggle hoping to find a use for it.  

I was thinking of maybe a feedback switch,  or something that I could flip to make this thing sound nasty (just for fun)

As I already made the board,  this would be some kind of secondary circuit soldered directly to the switch,  or mini daughterboard I can sneak in a unused corner space of the enclosure.

I was hoping that someone may have a idea what I could use this toggle switch for that would add to the original layout of this D. Rangemaster.  

I used a very small enclosure,  so my space is extremely limited,  but if anyone had any ideas,  maybe a mod of some sort to put a little green Vulcan blood in the mix.

Thanks for any ideas,

Kind regards

[Travis]

I'd switch the input cap which can be done with the same board like this

[Neil mcNasty]

Try a 2.2uf cap (or similar big size) where Travis put the 22nf cap on the layout with the cap switch.
The Rangemaster distorts in a very lovely way when you let low frequencies enter the circuit.
A highly recommended mod!
(If you then also blast the input with a boost up front, you can make it scream like a overdrive pedal)

Another nice mod is to replace the 3.9K resistor with a 10K pot for Bias adjustment.
Then you can tune it from a loose and clean/open dynamic respons, to a tight compressed and fat sound.
If you go bigger on the value of the pot (like 25K or 50K) you can also reach the point where it starts to gate and crap out. (not always recommended for those of you who are like me, and use low output pickups)

[myonus666]

This looks great!!  Thank you so much Travis & Neil for this.

Kind regards

[myonus666]

Well, got the whole board made, everything acording to design. But i got nothing.  Im guessing its the positive ground i missed.  I dont think i have enough room in the enclosure for a voltage converter since ive incorporated the dual switching and a step ladder design.

Ooops

[Travis]

What do you mean by dual switching and step ladder design?

If you have this in the same box with a “negative ground” circuit it won’t work unless you use a voltage converter

[myonus666]

Ok, pulled it all apart again. Starting over with the rangemaster only. Let me get that working first....

If i follow Travis layout,  do i need to have a special circuit to convert the -9v  and +ground so i can use it with another pedal..?  Or is that only if you are powering 2 or more pedals from the same power source?

Reason i ask, is because the step ladder is completely passive. No power needed.  Maybe i just messed up when trying to use the dual wiring with 3pdt and leds.... hmmm

[myonus666]

I got the dual offboard wiring here:

http://tagboardeffects.blogspot.fr/2012/02/offboard-wiring.html

And the step ladder here:

https://www.modkitsdiy.com/pedal/step_ladder

Im going to start with the rangemaster first. Get that working.  Then see if i can make it work with the ladder.  May have to change the design.  Will cross that bridge later.

Also going to build a converter, just so i have one in case i need it.

And get a larger enclosure.  Haha, should have started there.


Kind regards

[Travis]

The Rangemaster won’t work unless you remove it from the enclosure or change the wiring of the pedal to positive ground (including any other circuit within the enclosure)

The dual effect wiring is not designed for positive ground. You can change it to positive ground, but if you install a positive ground circuit in a negative ground enclosure you short out the power supply

If you don’t understand, I can draw a complete layout for you this weekend, just let me know all of the mods and additions that you want to include in the enclosure

[myonus666]

Thanks for the help on this Travis- Negative Voltage Inverter

http://tagboardeffects.blogspot.com/2012/05/negative-voltage-inverter.html


I made a few of these to keep on hand for future projects.

Kind regards,

[Travis]

Cool beans man

Did that get everything working? How’s the Rangemaster

I’m about to finish up a little Rangemaster myself!

[myonus666]

well.  I'm not sure.  I'm getting odd results from the voltage inverter.  putting this on a breadboard.  cant seem to get correct voltage out :(.

what are you getting from the inverter as output?

[myonus666]

I don't think +9v should be going to pin 1 on the 7660S.....just pin 8??

looking at the datasheet......

[rocket88]

You should be getting -9V output from the invertee.

[myonus666]

[myonus666]

with the original values on caps, I get    -.36v

I tried a 100uf cap in place of the 47uf

I got .96

I tried all of the 7660s I have.  and get different results.

I thing this lot of chips are bad

going to try the 555 version

[Travis]

It is correct to connect both pins 1 and 8 of the 7660S to +9V. This engages the frequency boost function which sets the oscillator frequency above the human hearing range so that the charge pump does not introduce high pitched noise into your signal

It could be a problem with the charge pump build or the IC. Many of us have received faulty 7660S including myself.

The 555 inverter seems like a fair idea either way

[myonus666]

Researching the datasheet,  if input voltage is over 5v; a schotky diode is required to prevent latching and damage.  Also,  it appears there are a couple other things in the datasheet that are not addressed in this circuit. We should read this before attempting to build.

This circuit should clearly be researched a little more.  Ive melted 5:  ICL7660S ; This should not be that difficult.

I talked to someone off this forum,  and they have never had any luck with this circuit as well.  

At least a warning on this circuit should be explained as a courtesy.

I ordered 10 new ICL7660s from mouser.  I'm determined to make something that works.

[myonus666]

I found this matches the datasheet closer.  But still the diode should be in place....  im wondering if the 47u cap in the layout is a typo.  Everything in the datasheet says they should be the same.  Also. It does say that the caps are not critical.

[myonus666]

Added the diode to pin 5 > 4 ,  both 10uf caps. And  +9v only to pin 8.  I now have a solid - 5.65v   this may be due to the diode i used. Need to find a smaller one. 1n914.  Or 1n4148......

Found the 4148. Holy crap.  I have -9v!!!!!!!!!  

So now we have the fix. Can someone do the new layout??

+9v only to pin 8
In4148  pin 5 to pin 4 (cathode)
10uf caps for c1 and c2  , i used 25v