rangemaster clone help please

[dansamp]

i have built several rangemaster boosters using transistors i purchased from small bear along with the recommended resistor values but it doesn't seem to bias correctly. i only get about -1.5 (approx) volts on the collector. i ended up changing to a NTE158 transistor on the first one
they don't seem to have the right amount of boost.
the boost pot must be set to about 12:00 position to get the same amount of volume between the on and off settings so i end up only using half of the pot range
reading the info on the analogman rangemaster clone unity gain is about
9:00 position on the pot

any help would be greatly appreciated  :roll:  :roll:

[bwanasonic]

I never found those recommended resistor values to work. I ended up using a 100k trimpot for  the 68k (stock value). Have you read RG Keen's www.geofex.com article on the Rangemaster? It details biasing the transistor by changing the 68k and 3.9k (stock). I now use a trimpot for both  "Rb1" and "Re" (as RG calls them). Unity gain on mine is about 9 o'clock, but I find the "sweet spot" around 1-2 o'clock.

Kerry M

[dansamp]

which resistor should i start with first
68k or 3.9k ?
i agree with you on the "sweet spot"
that too is about 1-2:00 for me also
i am just worried that perhaps i am missing out on some of the tone? :cry:

[arfy]

I agree with all of the above, I just finally got my attempt at a Rangemaster to sound good this weekend, I had to lower the 3.9k resistor and increase the 68k quite a bit to bring the collector voltage to around -7.0 volts that the GEOfex article recommends.   With the Small Bear values I had over -8.2 and it was kind of blatty sounding, not at all what I wanted.
If you read the manual on Keeley's website, he uses trimpots for both resistors as bwana recommended.
Now if I can arrive at an input cap value or two that I like...
Another must for tweaking your Rangemaster is using those little sockets for cap and resistor leads so you can try a lot of values.
If you test your Rangemaster with the amp on 2 it'll sound just plain boring, at home I turn the preamp up at least halfway even if that means turning the master way, way down and it's a pretty satisfying sound.

[dansamp]

yeah i used sockets for the input cap and both of the biasing resistors
i used the fuzz central lay out

[dansamp]

another question though,
if the "sweet spot" is still in the same position around 2:00
should i even bother with messing around with it some more or
should i leave well enough alone
i am using the beginers boost project then kicking in the rangemaster

[bwanasonic]

another question though,
if the "sweet spot" is still in the same position around 2:00
should i even bother with messing around with it some more or
should i leave well enough alone

What you want to be able to achieve is right around -7v on the collector. I'd start with the 68k.

Kerry M

[brian wenz]

Hello Hello--
  With the Rangemaster circuit [or any similar booster...]  you can use the "-7 v"  as a reference point, but anything betwen 4 - 7V can sound great depending on the tranny [as well as the guitar and amp you're using].
Brian.

[birt]

i've got -6,8 with the stock values