BA questions: VU meter, variable impedance
Posted: Mon Jan 31, 2011 9:30 am
Howdy,
I'm building a single BA with JLM14 transformer, LME49860 opamp, fet DI, and VU buffer+meter.
1) The table in the BA build thread says RL should be 2k2 + 50k pot for variable impedance, but my kit came with a 100k pot. Is it okay to use this instead of a 50k pot?
2) I want to power the VU buffer/meter off the BA board if possible. Is it okay to tap into the opamp + supply, since that will be less than 30v which is the max of the VU buffer?
3) Can I also tap into the opamp supply to power the led inside the 34mm VU meter (along with the right series resistor)?
Thanks! Looking forward to using the pre (and I can't wait to show off the custom case I'm doing, too)!
Chris
I'm building a single BA with JLM14 transformer, LME49860 opamp, fet DI, and VU buffer+meter.
1) The table in the BA build thread says RL should be 2k2 + 50k pot for variable impedance, but my kit came with a 100k pot. Is it okay to use this instead of a 50k pot?
2) I want to power the VU buffer/meter off the BA board if possible. Is it okay to tap into the opamp + supply, since that will be less than 30v which is the max of the VU buffer?
3) Can I also tap into the opamp supply to power the led inside the 34mm VU meter (along with the right series resistor)?
Thanks! Looking forward to using the pre (and I can't wait to show off the custom case I'm doing, too)!
Chris