Hi everyone,
I need a voltage buffer to match impedances in a summing buss that I am building. Can the LM3875 be configured to work as a voltage buffer with a gain of -1? My power supply is a bipolar 24V. I would be very grateful for a circuit. I'm unsure about what Rf/Ri ratio would be optimal for this.
I need to buffer a 50k or 100k pot. The pot atteunates the output of a John Hardy 990 discrete opamp configured a a summing amplifier. The output of the 990 feeds the pot which in turn feeds a cinemag output transformer. I can't really use a regular buffer chip because the 990 has a 28dBu headroom which means the 990 could easily output 19V signals. Therefore I need a buffer that can handle input voltages of about 19V (or 28dBu of headroom). The output transformer is a Cinemag CMOB 1 with a 680 ohm input impedance and a 1:1 turns ratio.
alternately do you folks out there have suggestions for another chip that would work better?
Thanks in advance!
Jason.
I need a voltage buffer to match impedances in a summing buss that I am building. Can the LM3875 be configured to work as a voltage buffer with a gain of -1? My power supply is a bipolar 24V. I would be very grateful for a circuit. I'm unsure about what Rf/Ri ratio would be optimal for this.
I need to buffer a 50k or 100k pot. The pot atteunates the output of a John Hardy 990 discrete opamp configured a a summing amplifier. The output of the 990 feeds the pot which in turn feeds a cinemag output transformer. I can't really use a regular buffer chip because the 990 has a 28dBu headroom which means the 990 could easily output 19V signals. Therefore I need a buffer that can handle input voltages of about 19V (or 28dBu of headroom). The output transformer is a Cinemag CMOB 1 with a 680 ohm input impedance and a 1:1 turns ratio.
alternately do you folks out there have suggestions for another chip that would work better?
Thanks in advance!
Jason.
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a discrete opamp follower by an IC buffer?
Use any of the discrete FET buffers that abound here. Select one that can run on >=+-30Vdc rails. Start with Pass.
Use any of the discrete FET buffers that abound here. Select one that can run on >=+-30Vdc rails. Start with Pass.
Why on earth would you want to use the LM3875?
Number 1 - it's not unity gain stable so it will make an excellent RF oscillator.
Number 2 - there are far better OP-AMPS with far lower distortion you could use.
Number 1 - it's not unity gain stable so it will make an excellent RF oscillator.
Number 2 - there are far better OP-AMPS with far lower distortion you could use.
Yes, I think a discrete buffer is the right way to go. Could you guys please post links to threads that discuss discrete buffers? I couldn't find any. I'm basically a tube guy ; ) this is really my first solid state project and its for a friend!
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