Hi
Yeah this one is at 50ex , 5000 dollars etc…
But what a sound
Here are the infos I have found :
« JCM800 with Jose mod. Gain controls for first two stages, bright cap on gain 2, goosed V1a plate load, pre-tone-stack master volume with clipping diodes. The rest is stock JCM800.«
« But yeah, it's pretty similar to an Atomica in many ways and also some Camerons I've seen. And also just a general DIYer take on the Jose mod. People discussing this kind of circuit on many forums over the years (Metro, SLO Clone, Amp Garage, etc.). The specific combo of cathode arrangements and voicing options are usually what most people suggest for a punchy modded Marshall sound. 2k7/.68 cathodes in the first two stages, 820R/.68 in the third. 330K v1a plate, bright cap and NFB to taste.«
«
What most people refer to as the "Jose Mod" in it's most basic form, is a pre-tone stack master volume control with some clipping diodes. This mod also utilizes a cap and a resistor between the cathode follower and volume control. So really... you have one resistor, one cap, one pot, and two zener diodes (or transistors) between V2b and the tone stack. About $8 in parts. The degree of clipping can be changed by using different zener diodes and you can wire them up symmetrically or asymmetrically for different clipping characteristics.
You can get creative and add multiple clipping options on a switch, alter the value of the cap to affect the sound/feel, add resistors in certain places to lessen the effect of the diodes and make them more "tube-like" in their response, and so on. All of this is outlined in books on the tube amps.
Now, that basic mod sounds much better when combined with other things in the circuit. Like utilizing independent gain controls for each of the first two stages, raising V1a plate resistor value slightly, adding a bright cap to one of the gains, biasing each stage to sound like how you want via cathode resistor and cathode bypass cap combinations, and playing with the value of the first two coupling caps. Anything goes. All depends on what kind of sound you want.
And the classic "Jose" amp itself had other things like dual/switchable masters.
Taking it further, you can then play with the bright cap value; NFB circuit; presence cap values; depth cap values; slope resistor values; grid resistor values; PI cap and resistor values; power stage grid resistor values; power section for voltage changes; and so on. All of this stuff is outlined in great detail on many DIY forums and in many books on tube amp design.«
Yeah this one is at 50ex , 5000 dollars etc…
But what a sound
Here are the infos I have found :
« JCM800 with Jose mod. Gain controls for first two stages, bright cap on gain 2, goosed V1a plate load, pre-tone-stack master volume with clipping diodes. The rest is stock JCM800.«
« But yeah, it's pretty similar to an Atomica in many ways and also some Camerons I've seen. And also just a general DIYer take on the Jose mod. People discussing this kind of circuit on many forums over the years (Metro, SLO Clone, Amp Garage, etc.). The specific combo of cathode arrangements and voicing options are usually what most people suggest for a punchy modded Marshall sound. 2k7/.68 cathodes in the first two stages, 820R/.68 in the third. 330K v1a plate, bright cap and NFB to taste.«
«
What most people refer to as the "Jose Mod" in it's most basic form, is a pre-tone stack master volume control with some clipping diodes. This mod also utilizes a cap and a resistor between the cathode follower and volume control. So really... you have one resistor, one cap, one pot, and two zener diodes (or transistors) between V2b and the tone stack. About $8 in parts. The degree of clipping can be changed by using different zener diodes and you can wire them up symmetrically or asymmetrically for different clipping characteristics.
You can get creative and add multiple clipping options on a switch, alter the value of the cap to affect the sound/feel, add resistors in certain places to lessen the effect of the diodes and make them more "tube-like" in their response, and so on. All of this is outlined in books on the tube amps.
Now, that basic mod sounds much better when combined with other things in the circuit. Like utilizing independent gain controls for each of the first two stages, raising V1a plate resistor value slightly, adding a bright cap to one of the gains, biasing each stage to sound like how you want via cathode resistor and cathode bypass cap combinations, and playing with the value of the first two coupling caps. Anything goes. All depends on what kind of sound you want.
And the classic "Jose" amp itself had other things like dual/switchable masters.
Taking it further, you can then play with the bright cap value; NFB circuit; presence cap values; depth cap values; slope resistor values; grid resistor values; PI cap and resistor values; power stage grid resistor values; power section for voltage changes; and so on. All of this stuff is outlined in great detail on many DIY forums and in many books on tube amp design.«
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