I'm repurposing Yamaha m916 channel PCBs trying t build some API style line/EQ modules. The PCBs will be completely stripped of unused parts. Also will be using the m916 PSU (+/-25v) some Yamaha 2520 copies and some iron age audio M2 opamps. I have attached schematics/datasheet.
The Yamaha has a HPF that I'd like to keep in tact if possible, it also uses 50k center detent pots, could I use these in place of the 10k pots?
The low and mids are also selectable, I have plenty of quality inductor values and capacitors at my disposal so I'd like to keep them selectable but LRC based.
Also will be feeding this line level inputs so was wondering if I could possibly throw a 10k:10k transformer on the input since I have a few lying around.Not sure how to calculate the input impedance of the API 553. The schematic is a bit confusing and not sure of the gain trim pots value or it's affects on impedance.
Any advice or suggestions would be appreciated. I kind of understand how to calculate for center frequency using online calculators given the inductor values I have but don't really understand choosing resistance values or what I'm really trying to aim for with the results of the calculations like I can figure how to achieve a certain frequency, but don't know what q value to shoot for or any of the other parameters the calculations give me. Need to wrap my head around how the impedance of the circuit is determined and proper feedback resistance for the make up amp.
I've built PTP tube amps and have built/modded quite a few discrete circuits and have learned a lot over the past couple of years, but I still have a lot to learn so I apologize if these questions seems idiotic, I'm still a noob lol
M916 EQ part 2
M916 EQ part 1
API 553
M916 PSU
The Yamaha has a HPF that I'd like to keep in tact if possible, it also uses 50k center detent pots, could I use these in place of the 10k pots?
The low and mids are also selectable, I have plenty of quality inductor values and capacitors at my disposal so I'd like to keep them selectable but LRC based.
Also will be feeding this line level inputs so was wondering if I could possibly throw a 10k:10k transformer on the input since I have a few lying around.Not sure how to calculate the input impedance of the API 553. The schematic is a bit confusing and not sure of the gain trim pots value or it's affects on impedance.
Any advice or suggestions would be appreciated. I kind of understand how to calculate for center frequency using online calculators given the inductor values I have but don't really understand choosing resistance values or what I'm really trying to aim for with the results of the calculations like I can figure how to achieve a certain frequency, but don't know what q value to shoot for or any of the other parameters the calculations give me. Need to wrap my head around how the impedance of the circuit is determined and proper feedback resistance for the make up amp.
I've built PTP tube amps and have built/modded quite a few discrete circuits and have learned a lot over the past couple of years, but I still have a lot to learn so I apologize if these questions seems idiotic, I'm still a noob lol
M916 EQ part 2
M916 EQ part 1
API 553
M916 PSU
