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.
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.
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
http://www.geofex.com/effxfaq/distn101.htm
I'll add my 2 cents behind asymmetrical arrangements. :D They just sound more "complex".
I like symmetrical! :( I always find that it sound more accurate/neat if you can call it that. Attack is much more finger controllable.
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. 8)
what BOSS patent???
got a number??
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
Quote from: shtgoosephour20im 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
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
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.
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
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.
QuoteSymmetric 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.
QuoteAsymmetric 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.
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. 8)
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.
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.
Paul, good to see we agree.
Does anybody have any opinion on 1N4148 & 2x1N4148 v/s 1N4148 & 1N4148+1N34 for assymetrical clipping?
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...
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.
I agree with Mark's comments regarding the higher headroom for one half-cycle has beneficial characteristics other than the assymetry itself.
In this respect, going back to something simpler, like comparing the "sound" of Ge, Si and Red LED clipping, you cannot make a fair comparison just substituting one type with because of the different voltage threshlods.
One way I want to try when I have time is symmetrical clipping with Ge, Si and Red LEDs in the following manner:
Let's assume nominal forward drop voltages are: 0.2V for Ge, 0.6V for Si, and 1.8V for Red LEDs. (Let's assume these are representative voltage drops. I know in practice Red LEDs can be around 1.6V, as Si can be around 0.55V and Ge around 0.15V; just let's stick to some representative values for the sake of making an initial calculation.)
Then, to have similar clipping levels, and as such leave out the "extra headroom" effect one could try the following three diode combinations:
1) One Red LED one way + One Red LED the other way (1.8V clipping threshold approx.)
2) Three Silicon diodes one way + three Silicon diodes the other way (3x0.6V = 1.8V clipping threshold approx.)
3) Nine Germanium diodes one way + nine Germanium diodes the other way (9*0.2V = 1.8V clipping threshold approx.)
Of course most of us don't even have 18 identical Ge diodes to try this out! But at least I think it would make an objective way of defining the "sound of diodes" debate for once and for all.
Regards,
STM
Excellent point. I have seen discussions of the "feel" being better with assymetrical clipping, which may be more noticible than the harmonic content difference.
I guess you could have an average clipping threshold. 2 5v diodes would average 5v. A 5v and 2x5v combo would average 7.5v. 2x5v on each side would be 10v. An LED would be more like 1.75v. I have generally found 2 SI diodes as you said, overly compressed and lifeless. An SI and LED, on the other hand, makes me want to Howl.
Also, I guess you end up with a situation where the SI will be clipping, but the LED doesn't. (I think you already said that).
That is why I think the Mosferatu is cool. It only uses a clipper on one side, so the other side doesn't clip until the op amp does.
Check out the Peavey patent if you want to think about what it takes to create assymetical clipping.
It AIN'T a clipping difference of 2:1 ----it's 40:1
It AIN'T one stage ------it's 4 stages in series with 2:1 attenuators in between.
My breadboard experience and design listening agree.
Mark makes a good point also - the diode/clipping threshold in the TS design or the Boss design is relative to the virtual clean signal in parallel with the clipped signal because of the follower configuration. BTW, that isn't the only circuit topology to parallel a clean signal and distorted one. Other topologies allow different tone shaping for each path which adds a lot of possibilities tone-wise. :idea:
Does the PV circuit clip the same side of the signal each time, or does it alternate? 8)
Quote from: stm
In this respect, going back to something simpler, like comparing the "sound" of Ge, Si and Red LED clipping, you cannot make a fair comparison just substituting one type with because of the different voltage threshlods.
One way I want to try when I have time is symmetrical clipping with Ge, Si and Red LEDs in the following manner:
Let's assume nominal forward drop voltages are: 0.2V for Ge, 0.6V for Si, and 1.8V for Red LEDs. (Let's assume these are representative voltage drops. I know in practice Red LEDs can be around 1.6V, as Si can be around 0.55V and Ge around 0.15V; just let's stick to some representative values for the sake of making an initial calculation.)
Then, to have similar clipping levels, and as such leave out the "extra headroom" effect one could try the following three diode combinations:
1) One Red LED one way + One Red LED the other way (1.8V clipping threshold approx.)
2) Three Silicon diodes one way + three Silicon diodes the other way (3x0.6V = 1.8V clipping threshold approx.)
3) Nine Germanium diodes one way + nine Germanium diodes the other way (9*0.2V = 1.8V clipping threshold approx.)
I think you'll find that the three different types will sound different even though they'd have the same 1.8v threshold.
I noticed a while ago that 1N270 Ge's and 1N34a GE's sound different. The 1n34a's have more bass/dulled treble compared to the 1N270's. This was with a two diode symmetrical clipping ckt. The threshold voltage is nearly indentical, the composition material (Ge) is the same. I have a large quantity of each and the results were consistant. I thought I was hearing things, but I sent some 1N270's to Phillip Bryant when he was testing the Liquid Drive, and he heard the same difference.
With TS type ckts, I hear a difference between 1N4148/1N4148 and 1N4148/1N400x combo's. Again, not much of a voltage difference, but a composition difference.
Whether it's really asymmetrical clipping or not, the composition also seems to make a difference. So I think that three different diode types that have the same threshold voltage, will still sound different.
BTW, here's some voltage averages of 25 each type diodes I measured awhile back:
1N4148 - .604
1N4001 - .565
1N4005 - .558
1N4007 - .566
1N270 - .260
1N34A - .272
1N60 black case - .264
1N270 black case - .252
I think the best way I can discribe the difference in a TS type circuit is as follows.
asymmetrical clipping:
increases the pedal's maximum volume (db's)
causes less distortion (less signal clipping)
causes less compression
at the same volume (db's) there is less background hiss
symmetrical clipping:
decreases the pedals maximum volume (db's)
causes more distortion (more signal clipping)
causes more compression (especially with the gain maxed out)
at the same volume (db's) there is more background hiss
So there are the main trade offs.
placing a pot in series with one diode of a symmetrical pair of diodes can alow you to dial in asymmetry.
Hope that helps
Dev
Quote from: stmPaul, good to see we agree.
Does anybody have any opinion on 1N4148 & 2x1N4148 v/s 1N4148 & 1N4148+1N34 for assymetrical clipping?
STM,
I LOVE the 2x1N4148 and 1x1N34a combo, have used it in my "SD-1 Blues" mod very sweet sound !!
1x 1N4001 and 1x 1N34a is also a nice sound
assymetrical floats my boat every time :D
Marty.
I tend to go for the 1N4148/1N400x combo in TS type pedals. It sounds a bit sweeter and smoother to my ears. However I lent a modded TS-5 to a friend and he doesn't like the combo. With his setup he gets problems with octaves ringing out when he plays doublestops.
WGTP,
The Peavey circuit inverts the signal in each stage so clipping "alternates" which side is clipped.
The significance of the four stages in series, IMHO, is that a least one stage is going to be clipping assymetrically at nearly all signal levels.
And very assymetrically, just like a real tube circuit. The patent was based on devising a solid state circuit that has a good overdriven "tube" guitar sound. Peavey 5150 amps use four 12AX7 stages in series (with attenuators between stages that cut the signal by about half) to get their overdrive sound, and the circuit does basically the same thing without wasting all that filament power. The patent shows a JFET version and one using darlingtons with diodes to clamp the signal voltage just like grid conduction.
Damn I like surfing the patent office... ALMOST as much as hanging out here. The conversation is a lot better here at Aron's though <grin>