![marshall jcm800 schematic rob marshall jcm800 schematic rob](https://s3.manualzz.com/store/data/030916204_1-95f0f6f45bc70b022accb190aecccf16.png)
Red LEDs have a threshold around 1.6 V so they give a good "crunch" without much waveform "squaring".Ī combination of different diodes yields asymmetric clipping, which some find rather pleasing to the ear.
![marshall jcm800 schematic rob marshall jcm800 schematic rob](https://i.pinimg.com/736x/d2/c7/63/d2c7631760aba43a6fa3be9ba65af2f4--marshalls-electronics.jpg)
Silicon diodes' threshold voltage is around 0.5 - 0.6 V, so they clip less and thus the resulting waveform is more "gentle". Germanium diodes have a lower threshold voltage ( 0.2 - 0.3 V ) so they tend to clip hard and squash the signal to 0.4 - 0.6 VPP, the resulting waveform, especially if the input signal amplitude is high, is rather "squared" so the corresponding sound is rather "fuzzy".
Marshall jcm800 schematic rob series#
Putting diodes in series adds threshold voltages and this reduces clipping.
![marshall jcm800 schematic rob marshall jcm800 schematic rob](https://robrobinette.com/images/Guitar/AB763_Models/RR763_BLACKVIBE/RR763_BLACKVIBE_MICRO_Layout_small.png)
I can't read well the component to which D6 is connected, the letters are blurred, but that doesn't look look a clipping stage either.īack to the "clipping diodes" question and their effect, everything lies in the different threshold voltages different diodes have.Ĭlipping diodes are usually found "reverse-paralleled", this configuration allows the two halves of the signal to pass freely until the signal amplitude reaches the diodes' threshold voltage, at that point the diodes start to conduct and shunt the signal exceeding the diodes' threshold voltage to GND. Telling the truth, none of the highlighted diodes has a clipping function, two diodes (D2 and D3) are used as rectifiers, D1 is part of the V1B biasing network. I'm looking for a deep raw tone like this, if it helps: Also, does it make sense to solder those particular two in series?Īny other clipping combo's that would work well for this amp? Another guy also recommended me 1N4148's with a LED on one side and just one 1N4148 on the other side. My question was, does this make sense to you guys? Since I don't know the specifications and characteristics of different types of diodes. This would increase the warmth and depth of the tone and gain, and take out the sterile and cold buzz which seems like a great idea.
Marshall jcm800 schematic rob mod#
The mod was to replace the 1N914 diodes with 1N34A's and 1N4001's in series. It uses 1N914 clipping diodes, as seen in this image. I found a mod through someone, he strongly recommended it, to reduce the fizzy, cold, sterile gain this amp has. But I don't have much experience with modding amps. I'm interested in modding amps and guitar effects.