Diode clipping in a non-master plexi?

ledvedder

Well-known member
Is it possible to incorporate zener diode clipping in a non-master volume plexi? I believe the most common use is in JCM800 style circuits. But is love to know if, and how, it could be done in a classic plexi circuit with a post phase inverter master.
 

glpg80

Well-known member
They can be put anywhere. People put them before the tonestack after the DC blocking cap, in the negative feedback path after DC blockers, in with the voltage dividers combined with dc blockers, etc etc.

Where the master is at doesn’t matter. As long as you’re not changing the DC bias of where you place them by using proper DC blocking caps, you can experiment.

Make sure your cognitive of what DC voltages can exist in certain paths and how they’re impacted with volume. You’ll need to size your blocking caps voltage wise accordingly.

Jose style is across a master volume. That’s what people know and copy, but different topologies do different things.

I’ll be honest though, I don’t like diodes in my amps. What they provide is rarely worth what they remove from an amp tonally.
 

RedPlated

Well-known member
I absolutely love diodes. Especially with a Jose MV. They add a compression and feel that’s hard to attain otherwise. However, just simply following the standard zener clipping schematic posted all over the net isn’t going to give optimal results. In fact, I don’t like the way they sound that way. They get overly compressed and lose definition.

I’ve done tons of experimenting and have gotten diodes to sound really good without the drawbacks listed above. There’s tons of voltages and types as well. You can spend eons finding the best type.
 

glpg80

Well-known member
I prefer the big raw tightness that can only be had with tuned tube stages without diodes. I don’t like the smear attitude nor do I like the a-typical scooped character they add to whatever location you’re messing with. I just can’t stand them.

With that said, they do have their place. I’ve used them to add back in treble to a dark amp for example without losing the core tone of what the amp is doing. It’s possible for them to be useful but in the majority of topologies out there that are on the net, most of those are not the best sounding by far.

Also brands and types of diodes definitely matter.
 

ZEN Amps

Well-known member
Yes. It has nothing to do with what kind of master volume the amp has, or if it doesn't have one. The how is another question - many ways to do it, none very difficult in the right hands.
 

Racerxrated

Well-known member
Put a pedal or two in front of the NMV amp…best place to put those diodes. Any and every MV mod to a NMV circuit will tame the beast too much, imo. Play the amp as intended, without a MV. There’s a reason all the pros used these amps stock, without any MV mods….with a boost or two in front…they simply sound better.
 

CrazyNutz

Well-known member
Can you explain what you used, and where you put it in the circuit?
Right before the tone stack. While you're in there why not add the MV too, just one more part. and if you have it turn all the way up, it's out of the circuit.

Check the schem i posted
 

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harddriver

Well-known member
Right before the tone stack. While you're in there why not add the MV too, just one more part. and if you have it turn all the way up, it's out of the circuit.

Check the schem i posted
Yes you can do it just as Crazy Nutz describes. The Jose master isn't as effective in NMV as in a cascaged JCM800 preamp layout but it does work. You can install a 1 meg push pull pot and install the diodes across the terminals of the pot to ground, that way you can switch them in or out of the circuit.

I have a Jose master installed in my 68 plexi with 20V/20V diodes on the push pull. The diodes do add certain type of aggressive kerrang to the tone and feel IMHO but the effects a more subtle than using say 10-16V diodes in a JCM cascaded preamp.

You may like it you may not.... Rockstah had a Jose master layout diagram on Metro if you don't like schematic layout drawings.
 

ledvedder

Well-known member
Yes you can do it just as Crazy Nutz describes. The Jose master isn't as effective in NMV as in a cascaged JCM800 preamp layout but it does work. You can install a 1 meg push pull pot and install the diodes across the terminals of the pot to ground, that way you can switch them in or out of the circuit.

I have a Jose master installed in my 68 plexi with 20V/20V diodes on the push pull. The diodes do add certain type of aggressive kerrang to the tone and feel IMHO but the effects a more subtle than using say 10-16V diodes in a JCM cascaded preamp.

You may like it you may not.... Rockstah had a Jose master layout diagram on Metro if you don't like schematic layout drawings.
A layout would be awesome! But I find a lot of the old links on Metro don't work anymore. If you know where it is, that would be super helpful!
 

JackBootedThug

MODERATOR
Right before the tone stack. While you're in there why not add the MV too, just one more part. and if you have it turn all the way up, it's out of the circuit.

Check the schem i posted
you guys are crazy...that schem looks like chinese to me brother. I really need to study this shit so I can understand it more....
 

harddriver

Well-known member
In all honesty I think the Jose Master in a non cascaded NVM amp was only meant to shave a few DB of loudness while playing a stage volumes other than that the master is quite ineffective beyond that. I always have the Jose master on 10 and just switch the diodes in and out because I like how they affect the tone. The diodes on the other hand do affect the tone.



Here you go I couldn't get it any bigger.
 

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psychodave

Well-known member
In all honesty I think the Jose Master in a non cascaded NVM amp was only meant to shave a few DB of loudness while playing a stage volumes other than that the master is quite ineffective beyond that. I always have the Jose master on 10 and just switch the diodes in and out because I like how they affect the tone. The diodes on the other hand do affect the tone.



Here you go I couldn't get it any bigger.
There it is.
 
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