Too much boost from my Rangemaster kit.

Started by Guitarist1983, November 14, 2018, 08:02:51 PM

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Guitarist1983

How do you reduce the distortion in a Rangemaster?  I'm using a CEN 2N3904 in the GGG kit.  I've tried input caps from 0.0047uF to 0.1 uF and the distortion is somewhat unpleasant/harsh to my ears.  I'm using a Les Paul into the normal channel of an AC30 (my choice cap is 0.0047uF).  With a Tele the RM is thin and buh-right with the 0.0047 uF; a 0.01 uF is better.   Anyway, the distortion kicks in with the vol control at 10 o'clock.  Any advice to tame the boost?

BetterOffShred

Well all that stuff you have put together is pretty bright.  The rangemaster is a treble booster..  they get pretty bright.  I would suggest trying a 220n or something ridiculously huge on the input to see if it's even noticeable in your rig.  It very well may not be. I've only built Germanium Rangemasters, but I find I end up using at least the 47n and 5n in parallel if not the 100n for just this reason.  YMMV..  I used the darkest sounding AC128 I could find in one, and then built an NPN version with a rather hot (80s) MP38.. that was a little "darker" even yet. 

Guitarist1983

Quote from: BetterOffShred on November 14, 2018, 09:31:22 PM
Well all that stuff you have put together is pretty bright.  The rangemaster is a treble booster..  they get pretty bright.  I would suggest trying a 220n or something ridiculously huge on the input to see if it's even noticeable in your rig.  It very well may not be. I've only built Germanium Rangemasters, but I find I end up using at least the 47n and 5n in parallel if not the 100n for just this reason.  YMMV..  I used the darkest sounding AC128 I could find in one, and then built an NPN version with a rather hot (80s) MP38.. that was a little "darker" even yet.
Thanks for the tips.  On the "bright" side (pun) I'm learning a lot from building the rangemaster--its only my second kit. Biasing transistors and swapping input caps, oh my!

antonis

IMHO, you have first to decide what bothers you..

If it's an issue of total gain/boost, leave capacitors as they are and place a trimpot (1k say) in series with Emitter & by-pass cap..
When you're OK with the total amount of distortion, measure trimpot's value and replace it with the closer value resistor..

If it's more an issue of specific frequency band gain, try different Emitter by-pass cap values..
(the lower the cap value the higher the specific frequency gain...)
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

pinkjimiphoton

remember too the only dif between a treble booster and a fuzz pretty much is the input cap. its supposed to be too bright n kinda distorted ;)
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Guitarist1983

Quote from: pinkjimiphoton on November 15, 2018, 06:21:26 PM
remember too the only dif between a treble booster and a fuzz pretty much is the input cap. its supposed to be too bright n kinda distorted ;)
Didn't know that.  The base circuit looks like a nice one to learn from.

Guitarist1983

Now I figured out what I don't like about the Rangemaster--it doesn't play well with others who buffer their outputs.   The guitar --> RangeMaster -->  Amp sounds fine.  But add another pedal--a buffered pedal--in the path and the RangeMaster becomes brighter and thinner.  Not a sound I like.  Is there a mod to reduce the effect of other pedals' buffers?

BetterOffShred


antonis

Quote from: Guitarist1983 on November 18, 2018, 06:05:25 PM
Is there a mod to reduce the effect of other pedals' buffers?
Just "load" Rangemaster input..  :icon_wink:
(I'm kidding, of course, but that's exactly what you need..)

Buffers in front of fuzz-like circuits "vanish" their relatively low input impedance thus altering their characteristic frequency responce..
(a buffer is considered very low output impedance source so it doesn't form any voltage divider with whatever it drives..)

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..

Guitarist1983

Quote from: BetterOffShred on November 18, 2018, 06:43:55 PM
It has a buffer?  :icon_question:
Sorry, my bad English.   I'll try again.
guitar-->RangeMaster-->AC30 sounds good   
guitar-->buffered-bypass pedal-->RangeMaster-->AC30 sounds thin and tinny.

samhay

We usually reserve the first place in our signal chain for fussy pedals like the rangemaster or fuzz face.
If you can't or won't do that, try adding a variable resistor to the input of the rangemaster similar to the 'Fuller' fuzz face mods here:
http://www.geofex.com/Article_Folders/fuzzface/fffram.htm
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Guitarist1983

Quote from: samhay on November 19, 2018, 07:58:31 AM
We usually reserve the first place in our signal chain for fussy pedals like the rangemaster or fuzz face.
If you can't or won't do that, try adding a variable resistor to the input of the rangemaster similar to the 'Fuller' fuzz face mods here:
http://www.geofex.com/Article_Folders/fuzzface/fffram.htm
Yes, I will reserve a place at the head of my signal chain for diva pedals.

BetterOffShred

As pointed out above I think you can put a 500k pot in front of it to load that input back up.  I've never done it myself but input gain pots are pretty common.  Let us know what you find  :icon_cool:

antonis

And place a SPST switch to short input resistor when used unbuffered..
"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..