Hey all!
I have a Yamaha DG-1000 preamp which I am very happy with. There's really only one small problem with it, and that is that the input signal on my passive guitars doesn't get loud enough to bring it up the ideal level - just below where you are triggering the red clipping led. Now, I actually had a chance to play a Yamaha DG-100 combo amp (it contains basically the same preamp) recently, and the HIGH input channel on it seemed to be much better for my guitar, as it provided enough gain to clip the input. Of course, I obviously turn down the input trim pot afterwards as the manual instructs.
The Yamaha DG-1000 offers only one input, and, looking at the schematics, seems to basically be the LOW input section of a DG-80/DG-100 with some capacitors and resistors changed to be that of the HIGH channel. The differences between the HIGH and LOW inputs are rather stark if you look at the schematics. Although they are somewhat confusing to a relatively inexperienced hobbyist such as myself, I think the LOW input goes through an additional opamp, which simply isn't present on the DG-1000.
My question is as such - can I make the input of the preamp hotter by doing something as simple as changing the trim potentiometer from 50K to something else? Or even the resistor after it in series? I think it's a higher value I'm looking for, as long as the I'm interpreting the diagram correctly. (I very easily could be mistaken here) Another question follows - SHOULD I even do this? The input circuitry on this seems rather complex I don't just want to go fiddling around with it just because I think I have a good idea and then just ending up making it worse because of some unforeseen effect it will have on the circuit. If this is a terrible idea - no worries, there really is nothing fundamentally wrong with the tone/performance of the preamp as it is. I'd just hate to be missing out on some small benefit because of something as seemingly trivial as input gain.
Thanks in advance!
I have a Yamaha DG-1000 preamp which I am very happy with. There's really only one small problem with it, and that is that the input signal on my passive guitars doesn't get loud enough to bring it up the ideal level - just below where you are triggering the red clipping led. Now, I actually had a chance to play a Yamaha DG-100 combo amp (it contains basically the same preamp) recently, and the HIGH input channel on it seemed to be much better for my guitar, as it provided enough gain to clip the input. Of course, I obviously turn down the input trim pot afterwards as the manual instructs.
The Yamaha DG-1000 offers only one input, and, looking at the schematics, seems to basically be the LOW input section of a DG-80/DG-100 with some capacitors and resistors changed to be that of the HIGH channel. The differences between the HIGH and LOW inputs are rather stark if you look at the schematics. Although they are somewhat confusing to a relatively inexperienced hobbyist such as myself, I think the LOW input goes through an additional opamp, which simply isn't present on the DG-1000.
My question is as such - can I make the input of the preamp hotter by doing something as simple as changing the trim potentiometer from 50K to something else? Or even the resistor after it in series? I think it's a higher value I'm looking for, as long as the I'm interpreting the diagram correctly. (I very easily could be mistaken here) Another question follows - SHOULD I even do this? The input circuitry on this seems rather complex I don't just want to go fiddling around with it just because I think I have a good idea and then just ending up making it worse because of some unforeseen effect it will have on the circuit. If this is a terrible idea - no worries, there really is nothing fundamentally wrong with the tone/performance of the preamp as it is. I'd just hate to be missing out on some small benefit because of something as seemingly trivial as input gain.
Thanks in advance!