Author Topic: NPN Boost Range Control (Read 17146 times)

vanhansen · « **on:** September 08, 2004, 01:21:52 PM »

I've looked all over here and have read discussions about Doug's range control and what's needed. Unfortunately the links to his site don't work anymore and I'm looking for a drawing of how it is all wired up, what value pots to use (I think I saw 5K being used for it, maybe 10K). Does anyone have diagrams of this added to the NPN boost? Thanks.

Erik

aron · « **Reply #1 on:** September 08, 2004, 04:12:30 PM »

Here you go....

vanhansen · « **Reply #2 on:** September 08, 2004, 04:20:31 PM »

Sweet! Thanks, Aron. I'll do this when I wire up the switch and box it. I'll post my results/thoughts here. I'm assuming that the .68uF cap on the drive pot is not electrolytic? Would axial lead caps be better here (for space)?

aron · « **Reply #3 on:** September 08, 2004, 05:32:11 PM »

Yes, the .68uF is film. Doesn't really matter about type. Just go out and get a film .68uF if possible.

Let us know how it goes.

GOOD LUCK! :wink:

Voodoo Blues · « **Reply #4 on:** July 27, 2009, 09:39:09 PM »

Aron, in the diagram above what so you mean by "1uF to 22uF electroltic cap"? Do you mean to get a cap with a value between 1uF and 22uF? What is the difference between chosing 1uF vs 22uF, does one offer more range then the other?

aron · « **Reply #5 on:** July 27, 2009, 10:04:48 PM »

The larger value, the more bass that gets blended in. Note that this is not adding bass, just adding back whatever bass you currently have to the treble signal. .68uF is a treble booster - then you blend in bass to get the bass back. I would use a 22uF (easily found) or 10uF.

Even the range pot isn't critical - 5K, 10K, 25K will be ok.

Voodoo Blues · « **Reply #6 on:** July 31, 2009, 03:57:35 PM »

Quote from: aron on September 08, 2004, 05:32:11 PM

Yes, the .68uF is film. Doesn't really matter about type. Just go out and get a film .68uF if possible.

Will tantalum do? If so, does the negative side go to the outside lug?

slacker · « **Reply #7 on:** August 01, 2009, 07:56:12 AM »

Yes and yes

Voodoo Blues · « **Reply #8 on:** August 01, 2009, 10:52:20 AM »

Thanks Slacker, after not getting any replies I went ahead and put it in and aside for two small problems she works nicely. Now I can't decide if I a fuzz type sound or crunch. Decisions, decisions, decisions.

luko-man · « **Reply #9 on:** August 02, 2009, 02:23:34 PM »

what does this doe exactly does it make the boost more powerful or make it more of a drive?

also when you say emmiter of transistor is it dierectly at the emitter or is it wired the same as here on the first picture?

http://www.diystompboxes.com/smfforum/index.php?topic=941.0

neuman · « **Reply #10 on:** September 14, 2009, 09:54:28 PM »

Just digging around and found this thread; are the 5 K pots audio or linear?

curious.

thanks

aron · « **Reply #11 on:** September 14, 2009, 10:04:31 PM »

Linear is fine.

neuman · « **Reply #12 on:** September 15, 2009, 01:56:08 PM »

Thanks for the advice on linear pots; now, I might be suffering brain-lock, but does this 2 pot mod take the place of the 5 K pot in the original circuit or....

I'm just not seeing it. Is there a diagram of the whole NPN boost circuit with this mod in it?

Sorry for being dense.

aron · « **Reply #13 on:** September 15, 2009, 05:30:40 PM »

The .68uF cap replaces the original 47uF cap. Then the 5K range pot and the 22uF is an add-on. Now that I think about it, you could probably use the original 47uF cap instead of the 22uF in the "Range" addition.

pazuzu · « **Reply #14 on:** November 12, 2009, 10:00:18 AM »

is there a way to cut treble with this set up? i was thinking of running 2 caps with a spdt center off, and it would be nice to have a treble cut and a bass cut.

<edit>
nevermind. i made that post right after i woke up.

1tczx · « **Reply #15 on:** December 11, 2009, 09:54:06 AM »

must it be a .68uf? can a .47uf work? my range knob dun seem like its doing anything/....

.Mike · « **Reply #16 on:** December 11, 2009, 01:39:05 PM »

Quote from: 1tczx on December 11, 2009, 09:54:06 AM

must it be a .68uf? can a .47uf work? my range knob dun seem like its doing anything/....

When I built my NPN Boost, I added the range control. I find the control to be very subtle, barely having any impact on the tone. I found that there was a minor change if the gain control was up all the way, and found that it did pretty much nothing when the gain was all the way down. If I were to build it again, I would leave it out.

I ended up adding a switch that selects a different input capacitor to cut the bass a bit. Works like a charm.

Mike

MBackus · « **Reply #17 on:** July 14, 2010, 02:04:31 PM »

Quote from: .Mike on December 11, 2009, 01:39:05 PM

Quote from: 1tczx on December 11, 2009, 09:54:06 AM
must it be a .68uf? can a .47uf work? my range knob dun seem like its doing anything/....

When I built my NPN Boost, I added the range control. I find the control to be very subtle, barely having any impact on the tone. I found that there was a minor change if the gain control was up all the way, and found that it did pretty much nothing when the gain was all the way down. If I were to build it again, I would leave it out.

I ended up adding a switch that selects a different input capacitor to cut the bass a bit. Works like a charm.

Mike

How did you wire that switch? And what different capacitor did you add? I was thinking 1.0uf?

.Mike · « **Reply #18 on:** July 14, 2010, 08:09:12 PM »

This is how I wired it. I choose 0.0047uF as the alternate value because it is what is used in the Rangemaster treble booster.

I hope that helps!

Mike

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Author Topic: NPN Boost Range Control (Read 17146 times)