Electronics Overview (4)
OPAMPSThere is a great deal of talk around the audio forums these days regarding opamps, from what they are to what they do and the all so important how to change them. Auzentech card have offered replaceable opamps for many members of their soundcard family and the Forte 7.1 is no exception.
LME4972
The LME4972 is the front Left and Right channel opamp for the Forte 7.1 and is considered to be a quality audio opamps by many.
This amplifier chip has a Gain Bandwidth of 55Mhz (typ), low distortion value of 0.00003% and a slew rate of +/- 20V/µs (typ)
Although considered a great audio opamp Auzentech say fit to put the chip into a socket so the end user could replace the opamp with a higher quality unit or a amplifier chip more to their liking for sonic signature.
Judging by the specifications and opinion of associates; many consider this opamp to be very close to the LM4562 which has gained a great following from the DIY audio crowds and PC audio designers alike.
NJM4580's
The 4580's are soldered on the card and cannot be replaced. The 4580s are a bipolar opamp and are considered to be a generic audio opamp mainly because of their widespread use in audio devices. The 4580's offer a Wide Gain Bandwidth of 15 MHz (typ), a Low distortion value of 0.0005% and a slew rate of 15V/µS (typ)
The JRC 4580's opamps are used for the output channels: Rear Left & Right Channels, Center channel, Subwoofer channel and the Rear Left and Right Channels. There are 4580 opamps used in other positions on the Forte for specific audio operations such as: Pre-Drive for the Headphone amplifier circuit, Pre-Amplifier for the Front Panel and rear Microphone inputs.
