daddy-O mods, eq, more bass. Ge sound nice.

[spgjmf]

hi all,
I picked up a daddy-o pedal. I liked the sound well enough.
after a basic trace out of the curcuit I see it has 2 LEDs to ground for the clipping. I sawpped in to Ge diodes ( 2 1n270 one way and 1 1n270 the other was) and I like the sound better, I also added a 100 pf cap to ground with them to cut more harshness.

Anyone have other suggestions? I would like more bass and greater mid control. I am guessing the eq is sort a fender like network. maybe a cap or res change there? Anyone have a schematic ???

thanks for any suggestions.

Jeff

[Transmogrifox]

http://www.geocities.com/transmogrifox/daddyo.html

I think I got the schematic off some Russian site.  The link to the original is somewhere around in one of the old threads if you search--however All I did was print it, write on it, scan it back in, write on it some more with ms paint and post it.

The mods I did were quite similar to what you did except I used 1N4007 rectifier diodes instead of ge.

To get "more bass", you probably want to sneak a series resistor, shunt cap + resistor LPF after the clipping stage.  It will decrease the overall output level, but it will balance the high/low range--set the cut-off frequency at around 700 Hz if you like to retain the mids, 250 Hz if you want more of the deep notes and fundamentals.

If you want "more bass", like wider band width, make the .22 uF cap at the output of the mids pot larger, like .33 or .47 uF.

My mods of the pre-eq/amplifier stage helps to make it sound a little less thin, though it gets a bit muddy on a Les Paul neck pickup.

I personally kinda like the Daddyo eq stage.  It's operationally identical to the guv'nor, though some of the combinations of parts are different, and yes, it is the passive Fender type EQ.

[spgjmf]

thanks Transmogrifox!

I will download the schema....and give the 1n4007 a try....
with the schema I should be able to open up the sound and get a fuller more bass sound... btw ,my bass seem to like the daddy too...
I'll try adjusting the mid cap....

thanks again....something to do on a raining sunday.


best
Jeff

[Transmogrifox]

I'm glad to have been some help.  I hope you get some good sounds out of it--

It is funny that we who mod tend to get better sounds out of the pedals than the stock pedal.  You would think the cost difference between the mods I make and the stock pedal is almost none--sometimes even less--so it seems odd that the designers of the pedals don't actually toy around and experiment more to discover better sounds based on a good design.  What do the engineers for Danelectro do, anyway?  Most of their pedals are near copies of classic designs, requiring very little engineering to reproduce.  Maybe they peruse this forum and rip off our ideas after we have spent the hours with a guitar pick in one hand, soldering iron in the teeth and a handful of electronic components in the other hand--guitar dangling dangerously in between.

[spgjmf]

I agree, it does seem like just a few changes can make a pedal sound better and one cap can't cost more than another... maybe its about design time vs. cost ...oh well, more fun for us...

As far as the daddy-o mode, I put in the 33ohm + 1n4007 diode and left the back to back Ge and so far so good. I have not changed any caps for lack of the correct value which would fit the pcb.

I still notice a fizz distortion sound on top pf the od sound...me thinks its the op amp distoring...thinking of swapping in a DIP s%^&*et and tring the good old JRC4558 in place of the 72...thoughts? other opamps?
just looking for smooth full bodied OD

so far the pedal still seems to bright and just a little thin...but it sould be the new strings I have...GHS bommers.


-Jeff

[Transmogrifox]

Yeah, I did some swapping of op amps.  I never did completely get rid of the fizzley sound, but it's very likely a result of the op amps distorting.  Saturating opamps seriously reduce bandwidth--speaking of, at the higher gain setting, you may be experiencing some slew rate limiting problems.  I haven't done the calcs to determine if it's anywhere close to slew problems, but changing op amps did make a more than a subtle difference.

I think I posted a list of the IC's I tried with a few comments about it.  The best I liked was the TLC272.  The downside is it was a little more noisy and somewhat "wooly" sounding.  I preferred wooly in place of fizzly.  I have determined that head-toe diode clipping just can't be done in its conventional way and not produce that thin fizzly sound.  I have been exploring the use of JFETs and weird feedback loops with little improvement in distortion quality, significant increase in parts.

I'm still determined that a good, non-fizzly OD with solid sound is possible from semiconductor circuits.  My thinking is to determine a way to keep the output linear until it's near the rail, then let a soft limiting curve begin to take place up until a hard-limiting threshold for some "splat" and bite.

Circuits like the Daddyo and TS-9...various Boss pedals are all logarithmic amplifiers, so there is some nonlinear distortion in the small signal case.  i think this "linear" range's imperfect hi fi nature is largely responsible for the non-musical fizzle and wooley semiconductor characteristics.   In contrast, vacuum tubes are remarkably linear in single-ended mode until very near the limiting threshold.

The moral of the story is, I never did get rid of the fizzle in the Daddyo--it never did get 'perfect" but I was able to improve the sound quality considerably--likewise you have also improved your Daddy with some simple mods.