MXR Distortion II build

[dthurstan]

Hi Tom

Thanks I pretty happy with that build. Your build looks nice and neat, I can't see any bridges on the solder side. I guess you have done this already but have good look to see if you can spot any yourself. The voltages look good also, all ins & outs are at roughly 1/2 the supply. What pot values did you use? Did you use the correct cap values? Also what type of guitar are you using does it have active pickups? (I'm not sure if that matters)

Btw - My vero layout will work if you use 10k for R26 & R27, I should update the layout. But Mikes layout should work I went over it when mine wasn't working and looked at pics of his builds.

Hope you find the problem.

Cheers
Dave

[tommycataus]

Thanks Dave, I've been working on a couple of builds since this one so cutting the copper strips looks a little neater (not just scratching it off with a utility blade!).

I used the specified pot sizes: Drive & Resonance 50K linear; Volume and Filter 100K log/audio. I also tried a 10K linear for the drive but it made little difference. I've swapped out both the IC's in case there was a bad one, but no luck there. There is one solder bridge towards the bottom right of the picture, but that is intentional due to bad planning... I soldered the IC socket in before realising it needed a jumper underneath 

Also the cap on the far right was originally meant to be 330nf but I swapped it out for a 220nf as that's all I had in the way of non-polarised caps. However for that reason it is socketed and so I tested out a 470nf electro in there... same story. I'm not really sure where to go with this as it *kinda* works, but it's not gig worthy...

Thanks for your input dude, I really appreciate it. I'll just have to try something else - I'll keep exploring.

Tom

[dthurstan]

Sorry I couldn't be more helpful. Mike changed some values to improve the range of the filter & res controls. He also changed the output for more volume. He used to post on here I'm not sure if he does anymore, you could try pm'ing him.

Using caps in the same range should be fine, what I meant was if you read the code on the cap incorrectly and you put 470p instead of 470n. My thinking was if you are getting strange am tuning noises that if a cap is way off your center freq will be way off too.

An audio file may help identify the problem.

Dave

[goldenmonkeycolor]

Sorry to bring up an old topic but I believe there used to be a Post on the Distortion II that contained some information and experience on a couple more modifications.  Esp, modifying the resonance control.  I cannot find it on the web for the life of me!  anyone got any info?

[ironman28]

I searched the site and couldn't find any posts about the resonance mods. Check the fsb site for more posts about this pedal.
Here are some things to try around the resonance control and to reduce the low end:

• Reduce the value of C2 to reduce the low end
• Raise the value of R16 to 100k to 150k
• Lower the values of C12 and C13 to raise the center frequency of the resonance band-pass

check my blog below for some more mods to this pedal.

[FUNCTOR]

I removed the switching network, the output buffer and the Vref buffer. Something is pulling down the Vref and I'm not sure what it could be. Here is a stripped down clearer version of the schematic;

I am new to building pedals.  I want to build an MXR Distortion II.  I am curious as to why you would want to remove the switching network, the output buffer and the vref buffer?