as flat as the earth

Here’s a simple guide to modding the Distortion + / OD250 / YJM308 / Ross Distortion…

This is generally a great circuit but has its drawbacks (especially in reissues). It can be muddy at low gain settings yet fizzy at high gain settings. It also tends to cut a lot of low end with low tuned/baritone/bass guitars.

All of this is from my own trial and error experimentation and not any sort of formal electronics knowledge/training…

Let’s start at the beginning:

C1 (absent from the DOD 250) filters out some highs and is partly responsible for low gain muddieness. I like to take it right out. This increases clarity and helps balance things once more low end is added in the rest of the circuit. Removing just this capacitor and leaving everything else alone gives better low gain tones. If it’s too bright at this point it’s easy to remove some treble at the end of the circuit.

C2 is the input cap and definitely filters out too much low end for my liking. My current favorite value here is .47uf but 1uf could work for some. The risk in going too high here is mud even at higher gain settings. If you’re a chronic bridge pickup user a larger cap could work but neck pickups could definitely get somewhat muddy.

C4 is a pre clipping output/coupling cap. A larger cap allows more low end clipping. The Ross distortion uses a 10uf cap here and that sounds best to me. Big thick low end crunch instead of just fizzy treble clipping. You could go even higher which could be a good thing if you plan to use it with a bass.

If you’re using a polarized cap make sure the negative side faces away from the op amp towards the diodes.

D1/D2 clipping diodes The vintage MXR and Ross distortions both use germanium diodes which tend to sound warm and sort of fuzzy but are fairly quiet. DOD uses silicon diodes which are louder, crunchier, and brighter. I really like one germanium and one silicon. This preserves some of the fuzziness of the original d+ but opens it up a bit and gives a pretty good volume bump. The Kowloon Walled Bunny uses 1 germanium and 1 led which also sounds great but isn’t really my thing. I really really want to try mosfet clipping in here. Socket the diodes and swap them until you’re happy.

C5 filters out some highs post clipping. This is the best place to get rid of any fizziness. I increase this to .0022 or .0033uf. Another great option (especially if you’re building your own) is to remove this cap and add a tone control. My favorite is mark hammers “stupidly wonderful tone control” which is basically a modified rat style filter. http://www.muzique.com/lab/swtc.htm I’ve also tried a big muff tone circuit here which sounds great but you lose quite a bit of volume unless you’re using 2 LEDs for clipping.

Some versions of this circuit use a small cap in parallel with R4. REMOVE IT unless your circuit oscillates without it. If you’ve done any/all of this and still aren’t happy there’s one last place to tinker. I only recommend this if you use your pedal mainly for higher gain tones. Low gain/boost tones will most likely get muddy.

R2/C3 form a filter that works with the gain pot. You’ll notice as you turn the gain up you get less and less bass response. Increasing C3 while decreasing R2 proportionately will simply increase gain. Increasing C3 alone will give you more bass at high gain but risk muddy low gain. Reducing just R2 will increase gain and give you more bass roll off. I recommend .1 to .47uf for C3 and a slight decrease in R2. These are definitely worth socketing because they are highly interactive with eachother and the gain pot.

Lastly if you have a version that uses a 4558 op amp but want the classic 741… The 1458 op amp is a drop in replacement with the same pinout and is essentially a dual 741. Be careful not to damage the 4558 when removing it so you can sell it to a tube screamer snob for way more than it’s worth. ($0)

Happy Modding

Required reading: http://benadrianaudio.wordpress.com/2009/11/27/the-kowloon-walled-bunny/

http://www.premierguitar.com/articles/mxr-distortion-plus-mods-1

How to Tour in a Band or Whatever by Thor Harris

1-Don’t Complain. Bitching, moaning, whining is tour cancer. If something is wrong fix it or shut the fuck up you fucking dick. goddamn.

2-If you fart, claim it.

3-Don’t Lose shit. Everybody loses shit. Don’t fucking do it. Asshole.

4-Don’t fuck anyone in the band. There are tons of people to fuck who are not in this band. Dumbass.

5-If you feel like shit all the time, drink less beer at the gig. You will play better & feel better. What are you… a child? Some have the endurance for self abuse. Most don’t.

6-Remember the soundman’s name. He will do a better job.

7- Eat oranges. Cures constipation & prevents colds.

8-Masturbate. Duh… Where & when? Be creative. You’re an artist right?

9-If YOU can’t carry your suitcase 3 blocks, it’s too goddamn big.

10-Respect public space in the van. Don’t clutter, you Fuck.

11-If you borrow something, return it. Not Fucked Up.

12-Do not let the promoter dick you or talk you out of the guarantee. If there were not enuf people there, it’s their fault.

13- Driver picks the music.

14-One navigator only (usually sitting shotgun). Everyone else shut the fuck up.

15-Soundcheck is for checking sounds. Shut the fuck up while everyone else is checking.

16-Don’t wander off. Let someone know where you are.

17-Clean up after yourself. What are you… a goddamn toddler?

18-Touring makes everyone bi-polar. Ride the waves as best you can and remember, moods pass. So don’t make any snap decisions or declarations when you are drunk or insane.

19-Fast food is Poison.

20-The guestlist is for friends, family & people you might want to fuck. Everyone else can pay. They have day jobs.

21- Don’t evaluate your whole life while you’re sitting in a janitor closet waiting to go on. You think you’re above having shitty days at work? Shut up & do your goddamn job.

This list was written under the influence of lots of esspresso & anti-depressants while on tour w/ such greats as Shearwater, Swans, Smog, Lisa Germano, Angels of Light, Bill Callahan & many more. I hope this list will help you get along w/ your co-workers whatever your job is. Contributions to the list by Jordan Geiger, Kimberly Burke, Brian Orloff, Brian Phillips Celebrity Gang Bang, Kevin Schneider, Jonathan Meiburg, Michael Gira and some other folks.

I dug into my Vox distortion booster again determined to make something good out of it. In theory it should be a good sounding pedal because the circuit is actually a brilliant bastardization of classic pedals.

Basically it’s a tube screamer clipping stage fed into a distortion plus. The drive pot is a dual pot and controls the gain of both stages at the same time. Then it’s fed into another dual op amp driving and recovering a big muff style tone stack.

The problem with this pedal is all the capacitors are way too small and filter out every trace of bass and low mids. The values chosen for the tone stack are ridiculously small making it barely usable. This thing in stock form is a fizzy trebly mess.

I’ve been trying to learn about actual circuit design so I didn’t want to just add a bunch of toggle switches or extra pots.

What I’ve done is enlarge most of the caps to let more bass in/through the circuit which also increases saturation. The tube screamer circuit got a common bass boost mod so it doesn’t sound so utterly congested. I changed the values in the distortion plus part of the circuit to stock d+ values with a bit more low pass filtering. Then I fixed the tone stack with correct values for a big muff tone stack.

Now it can get nasal mid range ts style crunch on one end of the tone knob with the gain dialed back and big wooly saturation on the other end with the gain cranked.

Sorry my blog has turned into a pedal blog but this one relates directly to actual baritone guitars and their love/hate relationship with big muffs.

So I spent the last few days tweaking my russian muff. I’ve been determined to love big muffs but there’s always something about them that doesn’t work for me. I play baritone guitar (obviously) in a two piece and use my neck pickup almost exclusively. My guitars and amps all have massive low end but when I’d turn on a big muff I’d lose anything even close to clarity. Bar chords would always work and sound massive but any chord even a little bit more complex would turn to mush. To top it off this thing was always ridiculously loud and would drive my amps into insanity. Not in a good way either.

Here’s what I’ve done to “fix” it.

1. Flatten mids in the tone stack. Previously one of the toggles was a tone bypass and that came close but the treble was always a bit too fizzy. Now the mids are flat and I can still use the tone pot to control the bass and treble. 2. Dark toggle. This adds a larger cap to the low pass filter and let’s the tone control filter more highs when an amp needs it. 3. Diode toggle. Swaps symmetrical silicon diodes for asymmetrical germanium. Just a different flavor but very usable especially with the dark switch. 4. Volume pot Swapped 100k linear pot for 50k audio. This tames the excessive volume just enough. Now unity gain is around 1:00 instead of 9:00. 5. Input mods. Input capacitor has been changed to .0047uF to limit the amount of bass getting into the circuit. To put this in perspective most stock big muffs have a .1uf input cap. Some vintage versions used 1uf. The focus control on a musket blends the input cap from 1uf to .01uf so .0047 is pretty tiny. I socketed the input cap with some other values taped inside the enclosure if I feel the need to tweak it on the go. I also increased the input impedance to get even less gain. Yes. Less.

It seems most of this stuff is backwards to what most people are doing to their muffs but it turned out really well and is finally extremely usable and flexible with a baritone into a pair of huge amps. Chords have clarity, pick attack isn’t completely lost, and the low end is just big enough without overpowering everything else.

These are the best links if you feel the need to dive in to a big muff…