I'd like to try a simple BUF634 buffered passive preamp. Does anyone have a link to a good schematic?
I did search and found no shortage of schemes using a BUF634 with an opamp, but none using one without (i.e. as a zero feedback simple buffer). I may have missed some info but did search.....
I'm not sure what you are looking for. Look at Figure 2 on the datasheet; that's pretty much what you've gotta do. I'd add a PP cap in parallel with each of the electrolytic caps shown - 10-100nF. I'd make the input resistor (Rs) something like 1k; I'd probably add an output series resistor of 1-10 Ohms; As mentioned, the DC offset is pretty significant; that calls for some sort of servo or output coupling cap which seems to me a significant compromise compared to wrapping an op-amp around it.
Thermal issues and appropriate heat sinking should be considered.
Thermal issues and appropriate heat sinking should be considered.
I've tried BUF634 open loop right after a rail splitter and the dc offset wasn't all that bad, around 5mV I think and the output impedance was somewhat high, so might not really need an output resistor depending on what you are driving.
NO gain?! Well even ALL passive preamps MUST have GAIN. But it would have to be a gain of between zero and something less than one, for a passive preamp (i.e. a variable attenuator). <grin> Sorry, couldn't resist.
- Status
- Not open for further replies.