Melanhead "M.O.D. Lite" Overdrive .... Tweaked and sounding great!

Melanhead · January 30, 2006, 08:47:08 AM

Well, a while back I posted the M.O.D. experimental overdrive/distortion and I haven't had time to tweak the distortion side of things but have played around with the oevrdrive and a friend of mine has been giging with it. I took it out on the gig this weekend and I'm very happy with it! ... just wanted to share.

It's basically a TS style circuit but has 2 interesting tone controls called Fat and Bite ... as well as a ton of gain! no input buffer but the second op-amp stage is wired as an output buffer. I wanted to use as little part wise as possible.

"Fat" controls the amount of lows in the clipping section, and also the more Fat the less gain, and "Bite" controls the amount of high the sneak through the low pass filter after the output of the op-amp.

Basically with both controls set to minimum you get close to the tubescreamer frequency response ( with a lot more gain ) and as you turn 'em up, frequencies ( low and high ) that we're being cut are allowed to pass variably... This allows for the mid hump of the standard TS to assentially be removed to taste. Pretty cool! ... and not mushy either. I AB'd it with my DYI TS808 .... WOW! ...

anyways the shematic is here:

http://aronnelson.com/gallery/melanhead/M_O_D_Lite

layout is here:

http://aronnelson.com/gallery/melanhead/MOD_Lite_with_Brite_layout

give it a try ....

Mark Hammer · January 30, 2006, 09:14:05 AM

Simple. Smart and tactical. Good on you, fella. Sum jeezley good rockin' ahead!

Xavier · January 30, 2006, 09:23:38 AM

Sigh........ too many veros populated and waiting to be boxed..........

I have a populated board for a Tube Reamer, but frankly speaking your MOD seems to be the TS tweak for the gigging rock player (that's me

) . Do you plan to post sound samples?

Mark Hammer · January 30, 2006, 09:34:40 AM

Incidentally, someone was asking on another thread recently about pre and post EQ. This schematic is about as simple an implementation of pre and post EQ as you can get. The choice to stick the bass content as part of the pre-EQ is smart becaue it can change the quality of clip achieved.

Melanhead · January 30, 2006, 10:25:20 AM

Quote from: Mark Hammer on January 30, 2006, 09:14:05 AM
Simple. Smart and tactical. Good on you, fella. Sum jeezley good rockin' ahead!

Cool! ... thanks Mark that means a lot! ... Simple and great sounding is the plan 'cause as soon as I build one for myself it seems I have three or 4 friends that have to have one

... and of course they have friends too ... it's the snowball affect, or effect!

Melanhead · January 30, 2006, 10:32:37 AM

Quote from: Xavier on January 30, 2006, 09:23:38 AM
Sigh........ too many veros populated and waiting to be boxed..........

I have a populated board for a Tube Reamer, but frankly speaking your MOD seems to be the TS tweak for the gigging rock player (that's me ) . Do you plan to post sound samples?

They are very similar. The idea came about from the "Son Of A Screamer" ... nice simple TS ... I then tweaked the crap out of it

There is actually a soundclip before I added the "bite" control ... it's just able to get more treble now ...

It's here: ( from my other post ... ) just ignore the 3rd sound- bite as it has the extra gain stage that was removed ...

http://users.eastlink.ca/~melanhead/MP3/MOD.mp3

The diode config is slightly different then the schematic ( it's 1N4001/1N34/1N4001 on 1 side in series and 1N4001/1N34 ion series on the other )

It's definitely great for tweaking just that right amount of gain/bass/treble ... that's why I called it the M.O.D ( Melanhead Over Drive ) ...

Melanhead · January 30, 2006, 10:35:35 AM

Quote from: Mark Hammer on January 30, 2006, 09:34:40 AM
Incidentally, someone was asking on another thread recently about pre and post EQ. This schematic is about as simple an implementation of pre and post EQ as you can get. The choice to stick the bass content as part of the pre-EQ is smart becaue it can change the quality of clip achieved.

Never thought of it that way, but you're right

Steben · January 30, 2006, 11:04:08 AM

Quote from: Melanhead on January 30, 2006, 10:35:35 AM
Quote from: Mark Hammer on January 30, 2006, 09:34:40 AM
Incidentally, someone was asking on another thread recently about pre and post EQ. This schematic is about as simple an implementation of pre and post EQ as you can get. The choice to stick the bass content as part of the pre-EQ is smart becaue it can change the quality of clip achieved.

Never thought of it that way, but you're right

hey Mark, poitning at me?

No, really that's indeed true. You could even put in another pot in series with a small cap in the feedback loop for instant pre-treble cut.
But you cannot deny this works well for a non-inverting opamp. What with a Fuzz Face etc...?

vanhansen · January 30, 2006, 12:30:03 PM

That's a neat circuit there. Nice usage of the other half of the op-amp. I like the idea of Fat and Bite controls. Are they really picky about which values are there? Reason I'm asking is because I have some 5kB pots laying around getting no use.

Mark Hammer · January 30, 2006, 04:57:08 PM

A 5k will work fine for the bite control, except you'l need to reduce the value of the cap to get the same degree ofcontrol (5k with .22uf will take too much treble out). Try .047 to .1uf. Alternatively, just stick a 1.5k fixed resistor in parallel with it to mimic a 1k pot.

It will also work for the Fat control. Keep in mind the 10k+470R in parallel with 4k7 will only get you a max resistance of about 3k2. You can easily mimic that by using a 5k in series with the 470R (as shown) and put that in parallel with a 6k8 to 7k5 fixed resistor. The pot may have a different taper than the original but it will work.

vanhansen · January 30, 2006, 05:42:42 PM

Thanks, Mark. I had a feeling some values would need to be tweaked a little. For the life of me, I cannot figure that stuff out, especially on how to mimic a lower value pot using a higher value pot plus resistor in series or parallel. I can do the math for series or parallel resistors OK, just not when pots are involved. Sure, they're just variable resistors, but it still confuses me.

Melanhead · January 30, 2006, 11:35:33 PM

Yup, I ditto what Mark said ... I used the 10K pot in the fat control 'cause I have a bunch and had no use for 'em ... the range I wanted was about 1K to 4K but It got close enough ... You could use a pot and resistor in series but it would be hard to get the same range unless maybe a 2K pot ( I don't have any ) and a 1K resistor ... the upper range of the fat gets pretty muddy anyways if the resistor value is too high and you lose a lot of gain...

I used 1K for the Bite control as it was the same value as the resistor that's normally there and I had one kicking around ....

You could go higher but you'd probably end up shave off too much treble unless you change the value of the cap ( as Mark pointed out ... ) .... I was going for close to the TS frequency response with both controls at 0 ...

I learned a lot with this project ( thanks to Mark and others who helped me along with some theory to coincide with my ideas! ) ..It was well worth the time it took to tweak it ... Now I just have to fit 4 controls in a 1590B box! ... I'll post when finished, it's partially drilled, time for bed

Burstbucker · January 31, 2006, 05:58:44 AM

Hi Bob,

Like I've related to you before, I've only ever built Fuzz pedals and Treble Boosters but I think this MOD Lite is an easy enough build for even someone with my limited abilities. It's now on my very long "to do" list.

Do you miss the distortion mode of your MOD OD/DIST version though? I know that that pedal sounded very sweet. But if you don't miss that extra distortion stage, you've effectively cut the parts count in half, which is a very cool thing indeed.

Nice work and thanks for sharing!
8^)

Melanhead · January 31, 2006, 07:51:45 AM

Quote from: Burstbucker on January 31, 2006, 05:58:44 AM
Hi Bob,

Like I've related to you before, I've only ever built Fuzz pedals and Treble Boosters but I think this MOD Lite is an easy enough build for even someone with my limited abilities. It's now on my very long "to do" list.

Do you miss the distortion mode of your MOD OD/DIST version though? I know that that pedal sounded very sweet. But if you don't miss that extra distortion stage, you've effectively cut the parts count in half, which is a very cool thing indeed.

Nice work and thanks for sharing!
8^)

Well, I played around with the distortion mode and didn't quite get it sounding good enough to leave it in. It was an experiment mainly because I had the extra .... I do have some suggestion of how to make it better but have so many other things I wanna build that it's something for a later date

... I'm gonna finished the box for this one and then move on to a distortion I drew out based on a Rat but with a 4558 chip. It's the same idea as the M.O.D but the clippers are to ground after the op-amp stage and has the same filter control as a Rat. Not sure how it's gonna sound but looks good on paper

The extra distortion was pretty over the top and this thing (withoutthe extra stage) is capable of way more gain than a TS circuit .... I had it set to half gain all weekend on the gig! ....

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Melanhead "M.O.D. Lite" Overdrive .... Tweaked and sounding great!