DOD 250 mods with Clips!

BassJunkie730 · #1 08-21-2007, 12:13 AM

So i got a DOD 250 in the mail today and spent the better part of my night modifying it.

I really need to socket my S***.

After some trial and error I made a few mods

I changed the input cap to .1uf (from .01uf)

I also changed the last cap in the chain from .001 to .01uf

AND I changed the .056uf cap to a .047uf (I had a film cap lying around)

I also removed the diodes and replaced them with two LEDs for more output and better OD

I also socketed the IC and replaced it with a JRC4558

I think I got something good going here

P-bass with chromes

The first part of the clip is clean

Next part is vol and gain at noon

next is vol at 1 oclock and gain at 3 oclock

next is volume and gain maxed - i play with the phrase a bit to show the dynamics.

and it's late - so forgive my sloppy playing.

And it retains the bass well most of the way up.

vtwo · #2 08-21-2007, 12:19 AM

1. Precision Bass
2. D'Addario Chromes
3. Killer OD

Nice.

Did you recycle the input cap for the output?

karter2000 · #3 08-21-2007, 12:24 AM

Wow, that's a great clip. Between that and your Muff/Tonebender, you make some great sounding pedals!

I've actually been thinking of building a DOD 250 for some time now....next project?

Lyle

Sir Edward V · #4 08-21-2007, 12:27 AM

I don't think I have heard the original, but I don't really like the sound of your clips

Sorry, just my opinion.

I think why I don't like it is it distorts the low notes more than the high ones. I like a sharp bright OD myself, I turn the tone knob on my TS5 almost all the way up. This is more muffled and dark. Might be the P-Bass too, they have a darker tone than my bass (ibanez w/ humbuckers), the whole active vs passive probably comes into play too.

what kind of sound are you going for with this anyways? and what problems with the original were you trying to fix

BassJunkie730 · #5 08-21-2007, 12:47 AM

I bought it to toy with it.

I don't know if I am wild about IC based effects - I'd really like to try out some of the cool stuff that RunOffGroove has been doing with the "fetzer valve" aka a transistor wired like a valve.

I digress.

I wanted to see if I could solve two problems inherent to the dod 250.

1. Lacks adequate bass in higher gain settings
2. sounds really harsh when it overdrives.

Now i really don't think there is any way with pedal, NOT to distort the lowend as it is a preamp - it's designed to be as clean as possible - unfortunately it was designed in the 70s - so it ain't that clean. So if that is your bag - a clean blend on your favorite grind box always the way to go.

I replaced the stock diodes with LEDs to stave off the grind a bit and make the unit really touch sensitive and pleasing.

Also by changing out the caps (no I didn't make the switcheroo on the caps as I was using all film caps, and the stock are not) I increase the bass response - BUT I also increase the likely hood of distortion down low - it's a trade off.

And I changed out some resistors in the muff to tonight to see if I could make the thing cut - I'm still working on it.

Sir Edward V · #6 08-21-2007, 01:03 AM

Quote:

Originally Posted by BassJunkie730

And I changed out some resistors in the muff to tonight to see if I could make the thing cut - I'm still working on it.

sometime soon I am adding an active mid bump (3 knob parametric style) to my LBM

I just need to work up the motivation to actually do it, I might add a buffer before it as well... I'll do the mid-bump first

TaySte_2000 · #7 08-21-2007, 04:46 AM

I was contemplating an Analogman Modded DOD 250 but I think the input cap mgiht be to high.

I've not checked this clip yet but I will tonight and maybe shoot Analogman an email about modding a Modded Dod250 further.

sonicvi · #8 08-21-2007, 04:59 AM

How did you go about replacing a 741 with a 4558? They have different pinouts.

TaySte_2000 · #9 08-21-2007, 05:11 AM

Quote:

Originally Posted by sonicvi

How did you go about replacing a 741 with a 4558? They have different pinouts.

There is no 741 in the current RI's

sonicvi · #10 08-21-2007, 06:17 AM

They use a dual opamp in the reissue instead of a single? How are people modding them with 741's then?

TaySte_2000 · #11 08-21-2007, 07:01 AM

Quote:

Originally Posted by sonicvi

They use a dual opamp in the reissue instead of a single? How are people modding them with 741's then?

Completely remove chip and socket and replace.

http://www.analogman.com/dodmod.htm this should provide you with some useful information.

Enjoy

sonicvi · #12 08-21-2007, 07:11 AM

Quote:

Originally Posted by TaySte_2000

Completely remove chip and socket and replace.

http://www.analogman.com/dodmod.htm this should provide you with some useful information.

Enjoy

So then they aren't modding them with 741' at all.

TaySte_2000 · #13 08-21-2007, 07:23 AM

Doesn't the Mojo Mod have a 741 in it?

BassJunkie730 · #14 08-21-2007, 08:00 AM

They are modding them with 741's but it takes a bit more time on the modders part as you need to change the pin outs.

and note on the input cap. the stock was .01 and I bumped it up to .1u For the record I also tried a .047u that worked well too.

EDIT: ACK! does anyone know of a better free file hosting service? thanks.

Charm Bracelet · #15 08-21-2007, 08:00 AM

The 1458 is two 741's in the same IC.

A great mod I came up with once was:
* 1uF input and output caps
* 3K3 and 1uF on the gain pot
* 1 red LED and 1 silicon diode

Ravens · #16 08-21-2007, 09:35 AM

Quote:

Originally Posted by BassJunkie730

Now i really don't think there is any way with pedal, NOT to distort the lowend as it is a preamp - it's designed to be as clean as possible - unfortunately it was designed in the 70s - so it ain't that clean. So if that is your bag - a clean blend on your favorite grind box always the way to go.

This cant be right. If its designed to be as clean as possible why is there a clipping section in it?

The DOD 250 is almost the same Circuit as the MXR distiortion+ and the both are distortion/overdrive pedals. The knowledge how to design clean preamps was known even in the seventies.

ex: MXR Microamp and EHX LPB

Ravens · #17 08-21-2007, 09:43 AM

Quote:

Originally Posted by sonicvi

So then they aren't modding them with 741' at all.

I havent seen anyone mod it with 741, but its seems quite common to build them with LM741. Seems pointles to go through all that trouble when its such a cheap and easy build.

But then again: read Charm Bracelets post.

I havent messed anything with mine but it seems im gonna have to

BassJunkie730 · #18 08-21-2007, 10:34 AM

My mistake on the clean preamp thing - I'm pretty sure it was designed to drive an amp - so maybe clean boost is a better term here - of course you can always add more diodes to get increased output before clipping - I really didn't like the sound of the silicon dioides clipping - so that's why I replaced them with two LEDs.

And Analogman apparently does a "true" mod of the Dod 250 using an LM741 chip.

Of course you could simply build one too - there are many kits and boards available, and after kicking about in the pedal for a considerable amount of time last night - it really is an easy pedal to build.

audienceofone · #19 08-21-2007, 10:44 AM

I couldn't download the song it said it expired

eyvindwa · #20 08-21-2007, 11:05 AM

"Sorry, this file has expired. Files uploaded by anonymous users expire after 100MB of transfer."