Add diode clipping to existing build

[Howlin' Mad Mac]

Was just asked if I could add a diode clipping circuit to a build I'm currently working on. Any ideas, schematics, etc.? I've got a ton of 1N4148's just gathering dust, will these do even though they're not germanium diodes?

[defaced]

Mind throwing us some bones on what you're working on? Got a schematic? Could recommend alot of useless ideas shootin in the dark like this.

[Wilder Amplification]

Clipping diodes don't have to be germanium. Matter of fact, I've only ever seen them used in fuzz boxes.

The difference is the turn on voltage. Germaniums would clip at 0.3V while silicon will clip at about 0.7V. LEDs (yes you can even use LEDs...Marshall was noturious for it in the Jubilee and the JCM900 series) will clip anywhere from 1.2V to 2V. You can even do silicon in a 5 diode bridge to increase the clip voltage to around 2.1V if you want.

However, that's about all I can tell you without seeing a schematic of the circuit in question.

[Howlin' Mad Mac]

Thanks, I've dug up a schematic using an LED on one side & a combination of a germanium & a silicon 1N4148 on the other so it clips asymetrical. Personally I think the guy is nuts as he has this idea to incorporate it into a little 6 watt build I'm working on for him at the moment & I've never had a problem getting a little SE to clip all by itself so maybe I just don't get it. I could see where it'd be quite useful in a 20 or 40 watt (or more) amp with a master volume where you need to crank up the volume to deafining levels to get those tubes to clip though so I'm going to tuck it away for later but my thinking for now is to convince him it's not something that should be added to a little SE. I've got some JFET booster circuit boards from R. G. Keen & I'm thinking adding one of those behind the input would be a better idea. What do ya'll think? Anyway this is the schematic in question (can also be found in another of my recent posts) for your review. Suggestions are always well accepted & apprecieated so thanks in advance guys.

6V6 SE - Main Circuit v2.pdf6V6 SE - Power Supply v2.pdf

[redelephant]

Seems to me the guy wants all kinds of dist-tones at a manageable volume, sort of a swiss army knife of a studio amp. Good luck...it may end up too complex and the sweet tone of a simple toob circuit drowns in all the special features.
My understanding is different diodes give different clip characteristics. It's not really the voltage they start conducting, but rather how hard or soft they clip the signal. I haven't experimented much so can't use my own experience here. For non symmetrical clipping u could try one type diode for the positive going signal, and another for the negative. Or you can include a series resistor with one of the diodes for similar effect. Too many options and not enuff time...

[Wilder Amplification]

Or two diodes in series for the positive going clip while having just one diode for the negative going clip...

I have no idea where these guys get this idea to have this "high gain" amp in a 5 watt package. So they wanna pile overdrive on top of overdrive? The whole point of "high gain" is to have a high headroom power amp while you get the overdrive from the preamp! It's a totally different world than power amp overdrive.

I think most people have this false notion that "power amp overdrive" is what gives you that big tight high SPL punch and it is that big punch at lower volumes that they're really seeking...not "power amp overdrive. Truth be known though that that punchy overdrive comes from an overdriven preamp running into a high headroom clean power amp. If high gain is what you're seeking, a high headroom power amp would fare much better than a low wattage overdriven power section.

[GregS]

Another option for the high gain pre-amp sound would be to simply run a separate pedal into the amp. That way you don't have to compromise the tube amp and can have the best of all worlds.

[Regis]

I have no idea where these guys get this idea to have this "high gain" amp in a 5 watt package.

KOC has a section in TUT3 with a JCM800 preamp in front of a Champ power amp. I almost did it myself when I rebuilt an old VOM amp into a tweed Champ but didn't.

But you are correct, the thing overdrives like crazy just by itself and goes into warp drive with a TS pushing it.

In fact, here is a clip I did with it demonstrating an attenuator I built. My Les Paul copy through a Bad Monkey into a Weber reconed D130, with and without the attenuator.

[RudeBoy]

Was just asked if I could add a diode clipping circuit to a build I'm currently working on. Any ideas, schematics, etc.? I've got a ton of 1N4148's just gathering dust, will these do even though they're not germanium diodes?

I'm kind of digging the soft clipper in Fred Nachbaur's Dogzilla.