???symmetric vs asymmetric clipping???

[shtgoosephour20]

i know that Ibanez uses symmetric clipping in such pedals as the TS808 and TS9. I know that Boss has a patent on asymmetric clipping which they use in the SD-1 Super Overdrive. So what the differnece? which rocks more? IM goign to analogman.com mod my SD1 so it has all the TS808 org specs but i might want to keep the asymmetric clipping. just looking for any knowledge about the subject and preference among artists.

[Paul Marossy]

Check out the Distortion 101 write up at geofex.com
Here's also a cool page on distortion: http://www.mindspring.com/~j.blackstone/dist101.html

A lot of people seem to prefer asymmetrical distortion to symmetrical, myself included.

[brett]

My 2c worth.  I like assymetric too.  
Sym clipping has a very "plain" sound in comparison (there's extra undertones and overtones ).  Especially good in "overdrive" type pedals like the tubescreamers and the bluesbreakers.
cheers

[Peter Snowberg]

http://www.geofex.com/effxfaq/distn101.htm

I'll add my 2 cents behind asymmetrical arrangements. They just sound more "complex".

[jrc4558]

I like symmetrical! I always find that it sound more accurate/neat if you can call it that. Attack is much more finger controllable.

[WGTP]

Whatever floats your boat, but I too like the Asym.

But like most things in life, I  suppose you can overdue it.

I think the Fuzz Face is highly A.  

[toneman]

what BOSS patent???
got a number??

[shtgoosephour20]

i think im staying Asymettrical (cheers from the galery) i tested my ts7 (which is that shitty tone loc TS) agains the SD 1 and the Sd blew it away. i  too enjoy these so called overtones and undetones. im goign to have analog mike fix it up real nice like an org TS but leave it Asym....let u know how it sounds in a week or so


rock on

[bwanasonic]

im goign to have analog mike fix it up real nice like an org TS but leave it Asym....let u know how it sounds in a week or so

Good luck, and all the best to Mike. But don't forget this is a DIY forum :wink:  Next time you have to at least try it yourself!  :lol:

Kerry M

[stm]

My impression based on my own experience and comments from others in the forum is the following:

1) Symmetric clipping is good for high gain for lead playing.

2) Asymmetric clipping sounds more interesting on chord work, usually at moderate gain settings.

3) Typical mod for Tube Screamers is to replace one 1N4148 for a different kind of diode, like 1N4001, which means some but little asymmetry.

4) On Boss units the typical mod calls for replacing one of the two 1N4148's in series with a Ge diode like 1N34... again, moderate asymmetry only.

5) In summary, I tend to believe the 3 identical diodes used on Boss units do not give the best asymmetrical distortion.  It seems the general tendency is to have moderate asymmetry.  Experiment yourself to see which you like best!

Regards,

STM

[Mojah63]

I put a ge 1n34 in series with one of the stock diodes after I did a TS-5 mod and liked it. It is more "complex" sounding. It's amazing what tone you can get for $5.00 in componet changes.

[shtgoosephour20]

any ideas for a mod on this pedal? can i replace the op amp chip with the JRC4558D the TS808 uses? would changing the output resistors help too? this is a $20 pedal and if i can mess with it, spend another $20 and come out wiht a ts808 replica that would be SOOO HOT

let me know if im crazy...another good possibility

[Joe Hart]

Put in an IC socket. Then you can try dozens of different chips and see what you like better (oftentimes the differences are very subtle, and you cannot hear them if you stop to solder out an IC amd solder another back in -- too much time elapsed -- so use a socket).

I like a switch for different diode types. Different pairs, whatever.
-Joe Hart
P.S. I cast my vote for symetrical clipping.

[Paul Marossy]

Symmetric clipping is good for high gain for lead playing.

Agreed. And, what is happening at the corners where the clipping is occurring is significant as well. The sharper the corner, the harsher it sounds.

Asymmetric clipping sounds more interesting on chord work, usually at moderate gain settings.

Agreed. My Shaka Tube produces some asymmetrical clipping, and it sounds great with chords!



I have come to these same conclusions after looking at some circuits with my scope. I just never exactly put it into words, at least not as succinctly.

[WGTP]

I have found I like sym on the lows (to keep it from getting too woofy) and asym on the highs to make them fat.  Hadn't thought about the level of the distortion or type of part being played, but makes since.  

[mlabbee]

My 2 cents - I built a TS clone with two clipping circuits - one with identical diodes (symetrical) and one with a silicon and LED diode combination (asym?)

The asym channel has more gain and doesn't clip as much due to the higher forward voltage of the LED.  I think it sounds better for chording and bluesy riffs.  They sym channel is perfect with a treble boost and a good delay patch for "wailing" high-pitched solos, but it gumms up a little on chords.

I balanced the gain between the channels and put in a footswitch to pop between the channels - nice to have the choice readily available.

[Transmogrifox]

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

That's my TS cents.  I used the OP275.  The series resistor lets the "Clean" ride on top a little more on one polarity.  I like it.  It's still a buzzy little OD pedal, but I haven't built or heard anything yet that really feels just right, but the sound is good if I just sit back and listen to myself play instead of trying to feel the tone.  I think that's where us guitarists get so picky about our pedals and amps, that is, trying to feel it.  I'm still experimenting.

[stm]

Paul, good to see we agree.

Does anybody have any opinion on 1N4148 & 2x1N4148 v/s 1N4148  & 1N4148+1N34  for assymetrical clipping?

[Paul Marossy]

stm-

Yeah, sometimes I actually agree with people...  :wink:  :lol:

mlabbee-

I like the OP275 in my Freddy Fuzz clone. It's supposed to be the first opamp to incorporate a "Butler front end". Anyhow, the NE5532 outperforms the OP275, but the NE5532 also seems to have a little different sound to my ear...

[Mark Hammer]

I think the symmetrical/asymmetrical thing is frequently misunderstood when diodes and high gain are involved.

Consider...

The use of two discrepant back-to-back diode paths (e.g., 2+1, LED+Si, etc.) means that one side/half-wave will clip under conditions of less signal amplitude than the other.  IF the signal is of a sufficient amplitude that the likelihood of clipping is significantly greater for one half-cycle than the other, then there will be a noticeable difference in the distribution of harmonic content.  If we start applying more and more gain, however, what eventually happens is that BOTH half-cycles smash their "heads" against the limit set by the diode, and what you end up with is a kind of symmetrical clipping, except that one half-cycle is a lower amplitude than the other by the difference between the diode clipping thresholds.  So, if I have a 1N914 with a 537mv threshold on one side, and a 1N60 with a 219mv threshold on the other, then one half cycle will be 318mv greater in amplitude than the other.  Still equally square, but more amplitude.  What we have now is perhaps describable as the same distribution of harmonics as symmetrical clipping, but a slightly different weighting.

The key thing here is that "asymmetry" is a function of signal amplitude, and "real world" guitar signals vary so widely in amplitude as to present very different outcomes of signal-vs-diodes on a moment-to-moment basis.

Another aspect of discrepant diode paths is that it almost invariably results in greater *potential* for signal amplitude by raising the threshold for one half cycle.  So, tack on another 1N914 to a TS-9 to make it work like an SD-1, and you have not just  made it asymmetrical but have raised the clipping threshold for one half cycle so that increases in picking strength are still audible.  People talk about greater dynamic responsiveness of the SD-1 vs the TS-9, or complained about the "compressed sound" of the TS-9.  However, the greater dynamic responsiveness would still be evident if you used a 2+2 diode complement in a TS-9, rather than the 2+1 of an SD-1.  In other words, what they attribute to asymmetrical clipping is is actually a product of having a higher clipping threshold for one half-cycle.  You will note that it is very rare that people adapt devices for asymmetrical clipping by switching from, say, a pair of 1N4148's to a 1N34 and (even lower threshold) Schottky diode.  They always "go asymmetrical" by increasing the threshold on one side of the diode path.  What they like is the tendency to not generate as much harmonic content until they really "lean into" a note, but that is all about higher threshold, not the asymmetry of the threshold.

Again, I'm not dismissing distortion symmetry as a myth or foolishness.  Rather, the way in which it is usually implemented misleads many into thinking that what they like about the change is DUE to asymmetry and not to something changed by the addition of diodes, and consequent change in clipping threshold.