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More drive on Barber Small Fry

Started by gerryblue, March 23, 2016, 05:32:35 PM

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gerryblue

Hi

I'm new here, looking for help, I have a barber Smallfry, which I love, out of production for a while now, it sounds warm and creamy, ala Robben Ford. Thing is, I'd like to have more drive, it is basically and overdrive, which sounds great with humbuckers but quite thin with single coils, would anyone happen to know what components to change in order to up the drive. This clips in 3 different ways, and ha a swtich for that, according to the manual: Stock, simulated assymetric and assymetric.

Thanks for the help!


Blitz Krieg


gerryblue

Quote from: Blitz Krieg on March 24, 2016, 01:41:28 AM
put a booster in front of it?

Thanks, I'd like more distortion from the actual pedal, I'm sure changing something would achieve this?

Ice-9

From your picture it looks quite a simple circuit so if no one can show you a schematic for modding it then you may need to trace it yourself to identify how the circuit is working. As a quick check on adding overdrive you could have a look at the value of  the gain/drive pot. If it is in the feedback loop of the op amp then you might get the extra drive you want just by increasing the value of the pot but without a schematic I cannot say for sure.
www.stanleyfx.co.uk

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gerryblue

#4
Thanks for the reply, I do have a diagram form another website, where I was told that the gain pot could be wired to give me more gain, if I wasnt able to find a higher value pot, but I did not understand how to do that.

http://postimg.org/image/4kdck68yj/


Quote from: Ice-9 on April 12, 2016, 05:53:34 PM
From your picture it looks quite a simple circuit so if no one can show you a schematic for modding it then you may need to trace it yourself to identify how the circuit is working. As a quick check on adding overdrive you could have a look at the value of  the gain/drive pot. If it is in the feedback loop of the op amp then you might get the extra drive you want just by increasing the value of the pot but without a schematic I cannot say for sure.

slacker

#5
You could replace some or all of the diodes in the feedback loop of the opamp with LEDs, thats the diodes above the first opamp in the schematic.That would boost the output of the opamp stage leading to more distortion from the "dynamics" section.

midwayfair

Quote from: gerryblue on April 12, 2016, 07:15:52 PM
Thanks for the reply, I do have a diagram form another website, where I was told that the gain pot could be wired to give me more gain, if I wasnt able to find a higher value pot, but I did not understand how to do that.

Smallbear sells a 2M linear pot. This will double the gain factor. That's ... not as much more gain as it sounds like.

Mouser sells pots up to probably 10M that will still fit in the enclosure, but this is all beside the point.

Just changing the pot value does more than just add distortion. It also changes the EQ curve of the pedal, because there is a filter in parallel with the gain pot, whose frequency depends on the setting. So you get more gain, but you lose more and more high frequencies as it goes up. There comes a point where it stops even sounding like you're adding much gain at all. The other ways to increase the gain in the system also change the frequency response. You can't change the other resistors that affect the drive because they're part of the EQ controls.

The pedal is a single gain stage. (The second half of the op amp is a tone control and buffer for the output, not more distortion.)

The diodes are already switched, and it's soft clipping, so there's a limited amount of utility that can be gotten out of them. However, you can short (solder a wire across) one each of the two diodes in series, which will change the clipping. In the schematic, the diodes pairs below the gain pot are the ones in question.

Despite your desire to just get "more distortion out of the pedal," the best solution really is to either add a booster in front (which will increase the gain factor by a LOT) or use a second distortion pedal, or a distortion pedal that is designed to have higher gain. I'd go so far as to say that if the Small Fry doesn't have enough gain for what you need, then you need a pedal designed from the ground up to be higher gain. Not everything can be "exactly the same but more and different" unfortunately.
My band, Midway Fair: www.midwayfair.org. Myself's music and things I make: www.jonpattonmusic.com. DIY pedal demos: www.youtube.com/jonspatton. PCBs of my Bearhug Compressor and Cardinal Harmonic Tremolo are available from http://www.1776effects.com!

gerryblue

Quote from: midwayfair on April 13, 2016, 01:06:24 PM
Not everything can be "exactly the same but more and different" unfortunately.

Loved this quote, that's exactly was I was looking for, :p 

Thank you all for the time and your great responses, I will try to change the pot, all I really need is a little more gain, so that might do the trick.

Peace

midwayfair

Quote from: gerryblue on April 13, 2016, 01:39:45 PM
Quote from: midwayfair on April 13, 2016, 01:06:24 PM
Not everything can be "exactly the same but more and different" unfortunately.

Loved this quote, that's exactly was I was looking for, :p 

Thank you all for the time and your great responses, I will try to change the pot, all I really need is a little more gain, so that might do the trick.

Peace

In that case, there's a cheaper way if you have resistors sitting around. What's the LOWEST gain setting you use? (Like, where on the dial.
My band, Midway Fair: www.midwayfair.org. Myself's music and things I make: www.jonpattonmusic.com. DIY pedal demos: www.youtube.com/jonspatton. PCBs of my Bearhug Compressor and Cardinal Harmonic Tremolo are available from http://www.1776effects.com!

gerryblue

Quote from: midwayfair on April 13, 2016, 02:58:08 PM
In that case, there's a cheaper way if you have resistors sitting around. What's the LOWEST gain setting you use? (Like, where on the dial.

Actually, I always use it to full drive, I play mostly classic and hard rock but don't like the scooped sound of other pedals, so I loved the creamy tone of this one, but it is mostly and OD, so what I get in tone I lose in punch.

midwayfair

Get a few resistors:

100K
220K
470K
1M

You're going to disconnect lug 1 of the gain pot. In your photo lug 1 is on the right hand side of each pot.

DISCONNECT IT FROM THE POT, NOT THE PCB. It's easy to lift a trace if you're a novice at soldering, so do it on the pot itself.

Now solder, say, the 220K to the pot and the little piece of wire that used to be connected to the pot, using the resistor like a wire between the two. Got enough gain at max? If you don't, try the 470K instead. You'll lose the entire bottom half of the pot, but you can go higher now. If you have too much, you can use the 100K instead.

It's reversible in the future, and a little easier than replacing the pot. It's still probably a better idea to get a 2M or even 5M pot instead, but this is easy and cheap.
My band, Midway Fair: www.midwayfair.org. Myself's music and things I make: www.jonpattonmusic.com. DIY pedal demos: www.youtube.com/jonspatton. PCBs of my Bearhug Compressor and Cardinal Harmonic Tremolo are available from http://www.1776effects.com!

gerryblue

Quote from: midwayfair on April 13, 2016, 04:11:10 PM
Get a few resistors:

Thanks a lot!! I can solder pretty well, built some pedals myself, but cant read diagrams to save my life, this was very useful, I'll do that, see how the dirt changes and in the meantime get the pot

Cheers!!

gerryblue

Quote from: midwayfair on April 13, 2016, 04:11:10 PM
Get a few resistors:
100K 220K 470K 1M

So I've done the mod and it sounds killer, almost like a JCM 800, ended up using a 500k resistor, although will look for the pot, since now it does not roll off distortion, but amazing, nonetheless, thanks for your help!