mzy12
Active member
Hey y'all!
I have a Yamaha DG-1000, a digital modelling rack pre-amp that is in my main rig, which I love playing very much. One problem is that the rack pre-amp is missing something from the combo and and head versions - a HIGH input that raises the gain by some amount (I can't tell by reading the schematic, to me it looks like it somehow makes for lower gain that the LOW, but I must be calculating stuff wrong). Consequently, with my setup, my input signal doesn't ever touch the red clipping light it's supposed to.
The solution is obvious - increase the gain of the non-inverting opamp at the input.
I just have to wonder first - why on earth was this limited to a gain of less than 9 in the first place? (This section also has the the same pot, same R to ground in series with the got and same 2 feedback resistors) I'm just going to increase R503 to something like 6.8K, maybe 8.2K, raising both the max and min gain to about 10-12. Unless I'm missing something, there should be no problems, right? I know it's good practice to not use, like, all the gain from one op-amp, but the common limit I see bandied about is 10x to 30. Plus this thing's supply is a total of 30 Vpp.
P.S. I know this technically isn't about pedals, but it's a guitar going into a non-inverting opamp. Sue me
I have a Yamaha DG-1000, a digital modelling rack pre-amp that is in my main rig, which I love playing very much. One problem is that the rack pre-amp is missing something from the combo and and head versions - a HIGH input that raises the gain by some amount (I can't tell by reading the schematic, to me it looks like it somehow makes for lower gain that the LOW, but I must be calculating stuff wrong). Consequently, with my setup, my input signal doesn't ever touch the red clipping light it's supposed to.
The solution is obvious - increase the gain of the non-inverting opamp at the input.
I just have to wonder first - why on earth was this limited to a gain of less than 9 in the first place? (This section also has the the same pot, same R to ground in series with the got and same 2 feedback resistors) I'm just going to increase R503 to something like 6.8K, maybe 8.2K, raising both the max and min gain to about 10-12. Unless I'm missing something, there should be no problems, right? I know it's good practice to not use, like, all the gain from one op-amp, but the common limit I see bandied about is 10x to 30. Plus this thing's supply is a total of 30 Vpp.
P.S. I know this technically isn't about pedals, but it's a guitar going into a non-inverting opamp. Sue me
