Well, I was busy and did just finish drawing out the Black Plate's schematic.
Those of you who also have the Black Plate: Are you also kind of not being satisfied to get a good Fender sound as I am? I tell you the reason why ...
Believe it or not: The Black Plate's schematic and signal flow is absolutely the same as the Plexi
The circuit-bord is the same, the designation of the components is the same, and so on.
The only difference are some lightly different values here and there - for example 1,5 kOhms instead of 2,7 kOhms.
The Black Plate is far away from being a Fender schematic. The EQ sits at the end of the signal chain as it is in a Marshall (or early Tweeds). In a Blackface Fender the EQ sits usually after the first gain stage, which is an important thing.
Once again, both preamps are basically the same, except a few value differences, which results in a different behavior.
Now knowing about this, it is funny to watch that Namm-show video again, where that guy talks about "everything from Tweed to Deluxe to Mesa" ...
Yes, I had success with moving the Black Plate's tone stack from the end of the schematic to after the first gain stage - like it is in the Blackface or Silverface schematics.Let us know if you have any success with moving the Black plate tone stack , it appears to be on a separate pcb so doable? One thing that bothered me [ and tipped me off ] was that the black plate has too much gain, or not enough clean range on the gain control. It's annoying because I have to switch outputs if I'm trying to get a clean sound out of it. moving the tone stack would cut some of the gain off the top, if the boost stage is not in front of it.
If someone has " official " Rocktron schematics should ok to post those ? [ or sent to me please ]
Excellent! You wonder why Rocktron [ or whoever ] didn't simply do that themselves in the first place since there's a ton of jumper wires and separate pcbs and it seems like a modular concept anyway. Look forward to seeing that mod!Yes, I had success with moving the Black Plate's tone stack from the end of the schematic to after the first gain stage - like it is in the Blackface or Silverface schematics.
It doesn't requier a separate pcb. Just changing the signal flow by moving some cables.
The sound goes much more in a Fender direction than before.
The gain is quite less compared to before, but still enough to crunch it up. I don't expect more gain from a Fender.
I will rework my raw drawings and then post them here.
BTW: The difference between line and instrument outputs are just 2 resistors. Life is easy ...As dirty Harry mentions the master is before the last gain stage, not a bad way to do as the output impedance remains constant but plenty of companies pedals & amps tack on output pots on the end of the circuit as more or less standard. One could use a duel concentric pot in the master position or relocate the power switch and use that hole for an over all output master. Maybe the extra drive will not be that dramatic or make a big useable difference but in my case It will allow me to stop having to switch outputs from line to Instrument [ especially on the black plate ] When I get a little more info I'll start a general valvesonic " Mods " thread. Thanks D.H.!
The resistor to ground at the inst output is R49 (2,7k). When replacing it with a pot, the pots value should be the same. Otherwise it will have an influence to the line output level also.right, I'm thinking for my black plate I replace that second resister to ground with a pot for the over all master?
[ which would be on the line out only ]