My MXR Dist+ sounds bad =/

[SuperGeo]

hi guys

so, i've built my dist+ and it sounds like an overdrive, something like that,,, it's tottaly diferent compared to some samples that i've heard in runofgroove, etc...
i'm using 1n4148 diodes

here is

http://www.sdragonballz.hpg.com.br/MxrDistPlus.jpg

(just rename to zip, and inside this zip will be the mp3) or

http://www.sragonballz.hpg.com.br/mxrdistplus.mpeg3

(just rename to mp3)

ok? that's it...

[Fret Wire]

I couldn't get your links to work. What schematic did you use? Did you make any parts substitutions to the schematic?

[SuperGeo]

i used that one in tonepad.com...

Did you make any parts substitutions to the schematic?

no :/

[Fret Wire]

Sounds clips are only representitive of the pedal's basic character. They won't necessarily sound the same for you because their equipment and rig is different than yours. Also, recording techniques vary. The fact that your pedal doesn't sound the same doesn't mean it isn't correct.

Assuming you've soldered and wired up correctly, You can try different clipping diodes. The original used germanium 1N270 diodes, sometimes pricey and hard to find. An good substitute for the 1N270's is the germanium 1N34a, which are plentiful and cheap. They will give slightly less output volume than the silicon's, but have a much better distortion sound IMHO. They will have a more of the original MXR sound than the 1N4148's. You can also try different diode combo's with the above, and LED's as diodes.

BTW, Tonepad has two layouts for the Dist.+, one uses the 741 op amp, like the original MXR did, and the other is a dual layout for the Dist.+/MicroAmp, which uses the  4558 op amp. For the 741 version, you can try the NE5534 op amp which will be quieter (less noise) and smoother. It won't sound like the original, however. If your using the 4558 version, you can try the NE5532, which will also be quieter (less noise) and smoother. Both are cheap and easy to find. Just don't confuse the two.

[SuperGeo]

there's any problem if i invert the pots conectors?

==== pot    

1 \  
2 -    :arrow:
3 /          

or
3 \              
2 -   :arrow:
1 /            

the sound will be diferent?

sorry if my english was bad or if i was rude... i'm brazillian and my english is not so good  :oops:

[petemoore]

To get the pot to twist the right way, reverse the connections of the outside lugs till they work right [or left if you like].
 Try the AMZ warp control, I did the one with the 'twangy bite' reference.
 I found it really helped out, and allows different tunings as to the clipping level.
 I socket the diodes to ground and parallel capacitor, try two seriesed in one direction, two seriesed in the other [Silicon diodes] or three one way two the other, and mess around with that parallel cap value, try different settings and diode configurations.
 The other thing I did was add a Jfet booster to the front end of it...Fetzer Valve or Odie [Runoff Groove] come to mind, all it takes is one extra transistor boost of you're choosing.
 Describ the tones you're not liking.
 What kind of amp are you driving with it?

[jimbob]

I think it is more of just an overdrive versus a distortion effect. I would use it with another effect/distortion ect..i dont like it by its self though.

[Fret Wire]

What value and taper are your pots? The original MXR used a few different values (sometimes 10k) for the output pot, but the factory spec was 50k log for the output (volume) and 500k rev log for the distortion. Maximum distortion is at 0-k, so increasing the value of the distortion pot doesn't get you more distortion. Increasing the value of the output pot does raise output. Try 100k log if you want to push your amp more.

I've always been curious why everbody posts schematics with the same 10k value for the output pot. Even the reissue uses a 47k pot. It just doesn't have enough push, especially if you go for the original sound, and use 1N270 diodes.

Like Pete said, switch the lugs around if you like the way it works. If you used linear, then you probably got the crowding at the end of the pot's rotation.

[Mark Hammer]

With 1N4148 diodes it *will* sound like more of an overdrive.  ALL diode-based clippers of this type depend on:
a) the clipping threshold set by the diodes
b) the amount of gain the circuit provides
c) the signal you feed it

Feed a modest signal (e.g., vintage SC pickups) to a circuit with modest gain, and set the clipping threshold higher by using either Si diodes or more diodes, and the degree of distortion will be mild and sporadic.

[Hairston]

I agree. It sounds pretty good with 1N4148 diodes in it. I also agree with Fret Wire that the NE5532 is a good match for this project too.

The AMZ Warp Control is a kick-ass mod too. I'd highly recommend throwing that in if you have the time (or space).

Good luck with the debugging!
-HB

[john1056]

I build one a few weeks ago.  I think it was harsh, with a brittle high end.  I wouldn't say it was completely different than the clip, but the nuances of my gear seem to bring out some negative qualities.  Try substituting the diodes with LEDs or germanium diodes.  The LEDs will give a less-distorted "open" sound that sound very nice compressed (plus it's pretty cool to see them going on and off as you play  Germaniums are also less-disordered but a little warmer.  If you use germaniums I think you're suppose to use 2 in series to equal one of the silicon (see the mods section of this site).  I'm using one silicon 1N4148, and one germanium (forget the number but I got it on Jameco - I think it's the only germanium diode they carry).  I think it sound pretty nice, but I'm going to try two one of these days.  It's a pretty educational experience to hear how much one component can alter the entire sound.  If you decide to experiment, it's a good idea to socket the diodes.

If you search on my user name (john1056) there is a thread concerning the pots in the Tonepad schematic.  Basically you get a more usable gain if you put a 100K resistor in parallel to you gain pot (just solder it to the lugs).

Best of luck,
John

[Gringo]

I like to use 2 100k pots for the D+, as well as sockets for the diodes. So far, i've sticked with 2 1n4001's or 2 1n60's, depending on guitar/amp combo.

[SuperGeo]

sorry i have no computer for some days

so, i'm trying to put the sound samples in somewhere.

but my mxr+... do not have gain enought i think

i cant even use some palm mute or hammer ons pulloffs, theres almost no sound when i use this...

i want to know if that problem is another than IC or diodes

here in my city is praticaly impossible to find IC's like 4558  

that's it

[Fret Wire]

You could have fried your diodes soldering. Check them, and their orientation. Did you use a socket for the IC? If not, IC's can be heat damaged if soldered on too long. You also had some questions about wiring your pots. Double check, and refer back to the tonepad wiring. They now have an off board wiring section.

http://www.tonepad.com/getFile.asp?id=76

Regardless of the diode combination, it should have far more output than you describe. Give all your solder joints and wiring a good check. Don't forget to check the battery too. Sometimes it happens.

[petemoore]

When it gets like 'that', I like to take pin voltages from the OA pins to ground.
 OFten times this can tell what's up or down, as can the probing and signal injection to various points in the circtuit.
 I find just by tracking where the buzz' sound [of my thumb connection to various points in the circuit] is lost and using pin voltages as a guide, I can get through the debugging pretty quick sometimes.
 Sometimes I hit it with everything I've got though, applying the DMM in every concievable way, including computing multiple routes of current paths and related resistance, and comparing that with the actual readings. Last resort stuff really [tho I found a 'dead 10k once] just re- reading color coldes sometimes finds the problem. I have trouble using 470k's instead of 470.

[brett]

Hi.  To get maximum drive out of a D+ you MUST use the standard resistors.  R8 = 1M (or more, not less) and R6 = 4.7k (or less, not more).  1N4148 diodes work great, as do 741, TL071 and NE5534 chips.

Turned to 3 o'clock or further, you'll get some serious distortion out of the circuit.  Good luck.