Rangemaster questions

[stefcuypers]

Hellow!

I'm building an Dallas Rangemaster clone and have some questions, I want to put a 12 way selector switch like the DIrty Boy Germanium boy, on the site they say:

A multi-frequency booster with a 12 position frequency selector and a gain function. It allows you to choose which frequency you choose to boost.

Witch 12 caps should i use? Suggestions?

Maybe i want to add a bias arranger switch like the throbak strangemaster, but don't really understand it cause i thought you need to set the collector to -7V and leave it so biased ...

on the throbak site : As far as we can tell we are the only company offering a Dallas Range Master clone with a bias adjustment. This  allows you to change the character of boost from flabby to tight. Switchable range allows treble and full boost germanium distortion. Recreate the Clapton Beano tone or the singing overdrive of Brian May with this pedal, its all in there. ( http://gundrymedia.typepad.com/throbak_electronics/2005/02/strange_master.html )

Thanks for reading this, greets from Belgium, Stef

[jlullo]

on mine, i used .0056uf and .01uf input caps.  The .0056uf was the stock "treble" boost, and the .01uf was a nice midrange boost.  a twelve way selector seems a little overkill, but if you want to do it i'd start at the bottom with .0056 and work your way up.  I hear .1uf is around a full range boost... you most likely woudn't want to go much higher than that.

as for the gain function, you could just switch out some clipping diodes and see how that sounds.  i've been meaning to try that one myself!

to add a bias pot, just replace the 68k resistor with a 100k pot.

good luck and let us know how it turns out

[foxfire]

i added some clipping diodes to a lpb2 pedal that i made up. sounds really good(for how easy it is/low part count) if you ask me. the only thing is that the output gets cut big time with the diodes on. i ended up adding another lpb2 to make up the difference.

[mac]

mine has a direct 5.6nf at the input, and in parallel a 5.6nf and a 250k pot. when pot is at min the caps are in parallel and the total capacity is near 10nf. when the pot is at max most of the signal goes to the 5.6nf. this makes a 5nf to 10nf input control.

mac

[soulsonic]

For switching a bunch of input caps, I'd go with .0015 or .0022 as my absolute minimum value, and maybe .1 as the highest. The overall gain will go up as well as the low end as you switch to higher and higher caps.

[stefcuypers]

Thanks a lot for all the info! Helped a lot! Is it possible to hear a diffrence between a 5.6nf, 4.7nf, 6.8nf input cap? Or should i make bigger steps? Would be nice to have the first 6 position on the rotaryswitch subtitle changes, that it stil sounds like a treble booster ...

[nooneknows]

If you have a prototype board I think it's better to try every single cap.
I've tried this trick for a FFace type circuit for a friend and the values I've found he like were different from what I thought, for example some had no audible differerence between them so we changed the values a bit to make it work.
I can't tell you what we decided to use, lost the circuit...

[petemoore]

  Id tack one on the switch, another in a socket, find one I liked in the socket position, install that value to the switch, then find/choose another value to leave in the socket.
  If you can avoid 'cap falls from socket', yes, it makes a permanent 'enough, easily moddable setup.
  I like to wire it so when the switch falls apart there is a default value signal path route.

[JHS]

The BIAS pot on the Throbak is complete crap. Any Ge-style boost needs a perfect BIAS setting for the trannie to sound good and to clean up if the git-vol is rolled back. All of my Ge-boosts have an internal trimpot for the BIAS-adj. and if you shift the perfect BIAS-setting a bit up or down, all of them sound like crap and won't cleanup anymore. All in all it's a good idea, there's no need for Throbak to set a correct BIAS-point for the trannie , saving time and money.

A 12-pos- switch is complete crap, too. It's a treble booster and a 6,8n and 5,6n selectable via switch is all you need, 10n or more as I-cap will not deliver a good fullrange boost but something like middy fuzz.

Set the voltage on the collector by ear, until it sounds right for you, I bet it's in the -6 - -7V range if you measure the voltage afterwards.
And don't use a pulldown R at the input, even a 10M sucks tone...

JHS

[vanessa]

A 12-pos- switch is complete crap, too. It's a treble booster and a 6,8n and 5,6n selectable via switch is all you need, 10n or more as I-cap will not deliver a good fullrange boost but something like middy fuzz.


JHS

+1

I would look into a Java Boost build from the layout section. Like JHS says the bigger cap just turns it into a mild fuzz effect. I pretty much only use the middle setting on mine.

[mordechai]

to add a bias pot, just replace the 68k resistor with a 100k pot.

good luck and let us know how it turns out

What about using a 5KB pot instead of the 3.9K fixed resistor?  Is there a practical benefit to having the 68K resistor be variable instead of the smaller one?