New Piggybacked treble booster

[will]

Hi,

I came up with this great sounding treble booster playing around with the piggy backed transistors. I read R.G. Keen’s article regarding the Dallas Rangemaster and the excellent discussion about piggybacking transistors for lower gain.  I did some surgery on Gus Smalley’s NPN boost. I changed the biasing so it will be easy to adjust with a simple trim pot.  I piggybacked two 2N5210 NPN transistors that had a hfe around 330. I used a 10K emitter resistor so there is still reasonable amount of gain. I didn’t measure it but based on my tinkering with piggybacking fuzz circuits it seemed to sound better around 10k for me.

This has a mild boost that really makes my strat single coils sound very clean, punchy, effortless and bright, in a good way, at all volume gains on my guitar. With my guitar volume at full you get a mild nice melodic sounding distortion with a bit of raspy bite.  I have no idea what is the frequency response. I set the input cap c1 and the r2 resistor by ear as the values I had originally set seemed totally wrong.

I set the biasing so that the collector of the transistor is near cutoff around 7 volts. It never does the gating full cutoff. It is amazingly quiet very little added noise, for a unit that is usually a hiss booster. It’s cheap and simple to build.

I have no idea how it compares to a Rangemaster or how it sounds in a good tube amp. My Peavey Mace has a solid state pre-amp which has lousy distortion so I run it clean. Any suggestions for improvement are welcome.

Regards,
Will

[Marcos - Munky]

Cool, thanks for share the schematic.

[Gringo]

Aren't the transistors bases suposed to be connected? It seems to me that in the schem, q2 base is left hanging open :?

When i finish my rangemaster clone i'll give this one a try, thanks for the schem

[will]

Hi Gringo & Marcos,


Your welcome for the schematic. I really appreciate this forum as I have built at least 20 effects from contributers to this forum and have learned alot.  

Aren't the transistors bases suposed to be connected? It seems to me that in the schem, q2 base is left hanging open  

Yes they are connected, however the gif seems to be distorted, not the good kind of distortion. I created the diagram in a free copy of circuitmaker student and didnt know how to make it into a jpg or gif as it only save as ckt. So I inserted it into a word document and saved it as html which created a distorted gif.

http://www.geocities.com/cobcastle/piggybacktrebleboost.gif

When i finish my rangemaster clone i'll give this one a try, thanks for the schem

I would be very interested in how they compare.

Regards,
Will

[brian wenz]

Hello Will--
  The schematic won't appear on my computer.....I'd really like to build one of those!
Thanks-
Brian.

[Marcos - Munky]

This is what I do: just open the file in Circuitmaker or any schematic software and put the entire schematic in the screen. If the schematic is bigger than the screen, put a part of it. Then hit the Print Screen key in your keyboard. Now open the MS Paint and resize the image for something bigger than the screen if the schematic is smaller than the screen, or something really big, if the schematic is bigger than the screen. Paste the image. Return to the schematic if you didn't captured the entire schematic and go to another part of it. Do another Print Screen and paste in ANY place of the image with part of the schematic that you did this. Then copy the "new" part without all the things that aren't part of the schematic (for example a rollbar). Then do a Ctrl+Z to erase the last action (paste the last image with all the non-schematic things). Paste the image (the one without the non-schematic things) and connect it to the image that is in the file (the first one that you did all this work). Do this until all the schematic is in your MS Paint image. Now "clean" the image (remove the non-schematic things of the first image, write something, resize the image) and save. Hope this helps.

[brian wenz]

Hullo Marcos--
   Are you going to put the schematic on your site??
Thanks-
Brian.

[Marcos - Munky]

If Will wants, I will put in my site. Try to copy the link and paste in another window.

www.geocities.com/cobcastle/piggybacktrebleboost.gif

[brett]

Very nice work.  THanks for that schematic.  Can't wait to build one.

[will]

Opps!

I went to clean up the schematic and realized the drive pot should be 5K.

I'm sending the much improved copy of the schematic to Marcos for his site.  

Regards,
Will