Anyone build the Vox Treble Booster?

[80k]

Just saw the Vox Treble Booster layout on Dragonfly's vero page.  I then did a search expecting a bunch of threads on this circuit, and found that there is very little information on it!  I also couldn't find much on the web.

Can someone tell me a little more about it?  I notice the original schematic had no volume pot.  Also, the volume pot mod on the vero layout has the pot in the input of the circuit instead of the output like i would have expected.  

Just a little curious as to what to expect from it, and what else can be done with the circuit?

Thanks

[petemoore]

I believe that's a Rangemaster derivitave'.
 Volume pot is easy enough to add, I haven't looked at the schematic lately, I built and messed with that, sounded very good, similar to Rangemaster, I think I even preferred it in some sense.
 Some biasing adjustments may be necessary/transistor dependant, I'd socket at least the transistor and the input cap, and use Pos Gnd.

[80k]

cool thanks for the information.  i will socket the transistor and cap as you suggest.

the transistors called out on dragonfly's layout calls for NPN transistors, and the schematic i found on the web matched dragonfly's layout exactly (minus the volume control).  Why do you suggest positive ground?

thanks again.

[brian wenz]

Hello Hello--
      I've built a few of them and they seem to match up with humbucking [Gibson style] pickups pretty well.  I messed with the values of the base-to-9v and the base-to-ground resistors [depending on the transistors used] and also raised the value of the input cap to .0068 uf.
Brian.

[80k]

Hello Hello--
      I've built a few of them and they seem to match up with humbucking [Gibson style] pickups pretty well.  I messed with the values of the base-to-9v and the base-to-ground resistors [depending on the transistors used] and also raised the value of the input cap to .0068 uf.
Brian.

cool, thanks for the info!

i was really considering a treble booster, because my muffmaster doesn't really boost the treble much for me.  not sure why... i do really like the sound of it going into my Hellhound in UK-mode, but when i switch it to US-mode (fender-like), it doesn't seem to work too well. and it definitely is more of a full-range boost that gives my sound a lot of body... not a very trebly sound.

i hope the Vox will be a nice boost to add to my collection

[petemoore]

Have you tried an input cap mod [smaller value] on the Muffmaster?.

[80k]

Have you tried an input cap mod [smaller value] on the Muffmaster?.

not yet, but i think i'm going to try it this weekend  i actually like the sound of it at the moment, even if it is not what i expected.  i think i will put in some sockets so i can change caps more easily.

[80k]

ok, i just breadboarded it.  man, it sounded like an ice pick to the head!  that is a serious treble booster

i will definitely have to play around with it before i box it up

[petemoore]

Caps can be calculated like resistors but opposite...
 Two equal value caps in parallel = 1/2 the value...you can parallel or series cap values to get 'sum' values...

[Khas Evets]

80k - I had the same reaction when I first built mine. It's way too bright. As Brian Wenz said, experiement with the input cap. I like it between .005 - .01 uf.

[brian wenz]

Hello Hello--
    A treble booster must be fine-tuned to work with whatever amp you're using........sometimes they can sound like CRAP.  I use mine to drive an already distorted amp into much higher gain and  increase midrange "honk"  [think Rory Gallagher,  and sometimes Brian May....].
 By increasing the input cap [ from, say .oo5 to .01]  you have taken all the "honk" out of the circuit .   It really depends on what type of boost you're after.
A cool mod to the Vox is to replace the  two 2.2K resistors coming off of the collector with a 10K pot [collector goes to one outside lug, output goes out of the middle lug, and the other outside lug goes to the 9v.  This makes it the same as a Rangemaster [sort of.....]
Brian.

[80k]

thanks for all of the tips.  i still have it on my breadboard, so i will be sure to play around with it some more later on, when i have the time.  


edit: just tried it with a .001 input cab (as opposed to the 510 pf i had) and it sounds much better!  tried a .01 and it worked ok, but i like the .001 better.  also, the 2n3904 just doesn't have enough gain.  The 2n5089 and 2n5088 both sounded good, with a very slight preference for the 5088.

[80k]

Have you tried an input cap mod [smaller value] on the Muffmaster?.

haha, i just opened up my muffmaster to start playing with the input cap.  I took one look and immediately thought "hmmm, i don't have any blue 0.01 uF caps?  what gives?"

haha, i had a 0.1 uF cap in there the whole time.  No wonder why it wasn't a treble booster!  i changed it to a 0.01 uF cap as specified by Jack's schematic, and now it's totally a treble booster  (now i'm wondering how many times this has happened in my other pedals, LOL ).

[MartyMart]

Caps can be calculated like resistors but opposite...
 Two equal value caps in parallel = 1/2 the value...you can parallel or series cap values to get 'sum' values...

Pete !
I'm sure you mean "two equal resistors is parallel = half the value" !!
Two "caps" in parallel add together .......  :shock:  :oops:

tut tut tut !!!!  

Marty.