# Distortion 250 Problems



## jojofogarty (Dec 21, 2020)

I just finished a Distortion 250 build and I have problems with the level and gain. I have to turn the volume pot all the way up to get close to unity gain and the gain pot has basically no response until the last 10%. When you get to that point there is a giant leap in gain. When I first put this one together I accidentally ran the 9v DC jack in reverse and put power through it. Could I have fried some of the components? I also tried two different MC1741CP IC's from a batch that I got from pedalhackerelectronics, and I got the same result
.


----------



## Nostradoomus (Dec 21, 2020)

I always use a C taper for these in the Gain spot, you get a much better range of gain (and it rolls down to clean unity volume, very handy).

The only thing that may have fried would be your 1n5817, that’s what it’s there for. I’d replace it regardless but it won’t solve your volume issue. You may want to try using LEDs for clipping diodes instead, they let more current through thus more volume comes out.


----------



## Mcknib (Dec 22, 2020)

Are your diodes Russian? With the band on the anode side


----------



## jojofogarty (Dec 23, 2020)

Nostradoomus said:


> I always use a C taper for these in the Gain spot, you get a much better range of gain (and it rolls down to clean unity volume, very handy).
> 
> The only thing that may have fried would be your 1n5817, that’s what it’s there for. I’d replace it regardless but it won’t solve your volume issue. You may want to try using LEDs for clipping diodes instead, they let more current through thus more volume comes out.


Thanks! I'll give those suggestions a try.


Mcknib said:


> Are your diodes Russian? With the band on the anode side


I'm not quite sure. I'll switch them around to see if that is the case. Thanks for the heads up!


----------



## Nostradoomus (Dec 23, 2020)

They look like the Tayda 1n34a


----------



## Gordo (Dec 23, 2020)

What are you using for the LED?  I notice the 4k7 is jumped so I assume the LED is internally compensated?  Builds don't get much cleaner than yours (love the graphics too), any chance you have the pots swapped?

I've built a ton of Dist+/250's, and although it's an easy circuit, most of the troubleshooting I've done has involved them.


----------



## jojofogarty (Dec 23, 2020)

Nostradoomus said:


> They look like the Tayda 1n34a


Yep that’s where I got them. So I’m guessing they’re orientated correctly here? 


Gordo said:


> What are you using for the LED?  I notice the 4k7 is jumped so I assume the LED is internally compensated?  Builds don't get much cleaner than yours (love the graphics too), any chance you have the pots swapped?
> 
> I've built a ton of Dist+/250's, and although it's an easy circuit, most of the troubleshooting I've done has involved them.


Thank you! I’m using a prewired led from lovemyswitches.com . They already have a resistor included in them, so that’s why I jumped the 4.7k on the PCB. I don’t think I switched the pots but it’s worth a look in to.


----------



## Chas Grant (Dec 28, 2020)

Just an observation, could be an optical illusion due to the small PCB in the 125B. Your PCB seems to be real low in the enclosure, if it truly is, you may have a short to the enclosure.
     I built one of these and it sounds great, just used a C500K pot for gain. Due to the germanium clipping diodes the output is lower than a lot of pedals, I have to turn the volume up to greater than 12 o’clock to get unity. That’s the nature of the pedal. Btw the way that is a real clean build and it looks good.


----------



## Chuck D. Bones (Dec 29, 2020)

No need to flip D1 & D2 around.  As long as they're facing opposite directions, you're good.  Chas is right, this is not a very loud pedal.  B10K might be a better choice for VOLUME since you won't be setting it below noon.


----------

