Hi diyers,
I would like to ask you for help on the diagram I attach.
I thought of the input buffer like this, because I have some selected lsk170 / lsj74 pairs on the shelf.
I would like to maintain DC coupling at both input and output.
If the signal comes from a preamp already equipped with a DC cancellation circuit, could I think about eliminating the input servo? or does the circuit itself require DC protection?
I haven't put values on the LP and HP networks but it will be a cut on 600hz.
I would like to try as shown in the diagram to use a small inductance instead of the usual resistance to decouple the output, could it work well?
In general, at the macro block level, do you think it could be correct?
I thank everyone in advance for any help.
I would like to ask you for help on the diagram I attach.
I thought of the input buffer like this, because I have some selected lsk170 / lsj74 pairs on the shelf.
I would like to maintain DC coupling at both input and output.
If the signal comes from a preamp already equipped with a DC cancellation circuit, could I think about eliminating the input servo? or does the circuit itself require DC protection?
I haven't put values on the LP and HP networks but it will be a cut on 600hz.
I would like to try as shown in the diagram to use a small inductance instead of the usual resistance to decouple the output, could it work well?
In general, at the macro block level, do you think it could be correct?
I thank everyone in advance for any help.
Frankly I don't see the need for a DC coupling in a filter. The high-pass filter does not have a DC coupling anyway. It is easy to design the low-pass filter such that the input capacitor has a reasonable value while maintaining a very low cutoff frequency.
I am not sure about the inductors in the output line. What is the purpose?
I am not sure about the inductors in the output line. What is the purpose?
NE5534A requires external compensation caps to be stable at unity gain. 22pF between pins 5 and 8 should do the job. Normally NE5532's are used for line-level circuitry like this as they are unity-gain stable and you get two opamps per package. NE5534A's come into their own for high gain low noise preamps.
FET input seems an unnecessary source of distortion, though they will be much less RFI sensitive compared to bipolar opamp if unprotected.
I presume the output inductors are to suppress RFI - but why not use the same for the input? Also its best to add 100R in series with the output so long capacitive cables can be driven stably.
FET input seems an unnecessary source of distortion, though they will be much less RFI sensitive compared to bipolar opamp if unprotected.
I presume the output inductors are to suppress RFI - but why not use the same for the input? Also its best to add 100R in series with the output so long capacitive cables can be driven stably.
Thank you for the suggestions.
The NE5534 is an example of an operational amplifier that I think could be good for this application, yes I had seen in the datasheet the need for a compensation capacitor for use in unity gain.
I would be very tempted to try the SS3601/02 discrete operational amplifiers from Sparkos, what do you think? could this be a good upgrade?
I will replace the input with a normal opamp buffer.
Clearly cannot be DC on the high pass, I had thought about DC coupling at the input to avoid any distortion mechanism due to the cap in series with the signal.
But I think it is useless to think about how to remove it, because in the end its presence is inevitable in the high pass filter.
Furthermore, if I have not misunderstood, if the maximum voltage value is adequate and the material is correct for use in the signal path (polyester or polypropyline) the distortion introduced should be negligible.
Regarding the output coil, the idea was to use it instead of the output resistor, could it work as a system to isolate the circuit from the capacitive load?
Could there be any better sound with coil instead of resistence?
The NE5534 is an example of an operational amplifier that I think could be good for this application, yes I had seen in the datasheet the need for a compensation capacitor for use in unity gain.
I would be very tempted to try the SS3601/02 discrete operational amplifiers from Sparkos, what do you think? could this be a good upgrade?
I will replace the input with a normal opamp buffer.
Clearly cannot be DC on the high pass, I had thought about DC coupling at the input to avoid any distortion mechanism due to the cap in series with the signal.
But I think it is useless to think about how to remove it, because in the end its presence is inevitable in the high pass filter.
Furthermore, if I have not misunderstood, if the maximum voltage value is adequate and the material is correct for use in the signal path (polyester or polypropyline) the distortion introduced should be negligible.
Regarding the output coil, the idea was to use it instead of the output resistor, could it work as a system to isolate the circuit from the capacitive load?
Could there be any better sound with coil instead of resistence?