Current feedback composite amplifiers

velvetsunrise · 23rd July 2011, 10:05 AM

Hi,

I have been searching for a good line amp with gain around X10, thats also suitable to drive long cables.

I stumbled upon this current feedback topology from an old Linear Tech application book,

Would this be suitable for a low gain audio line driver?

mickeymoose · 24th July 2011, 02:11 PM

If it is for audio this would be over-kill. How long is your wire? What are the impedances? Balanced or not? E

velvetsunrise · 24th July 2011, 03:22 PM

Hi thanks for your reply, cables are around 10 Meters, poweramp has a 10K input impedance and single ended.
It just seemed with the discreet buffer stage to be an easy to implement and cheep and slightly different approach that may make a nice line amp.

Cheers Steve

AndrewT · 24th July 2011, 07:28 PM

It's a 3transistor DC coupled amplifier with an output buffer.
The extra is a DC servo to minimise the drift in output offset.
If you AC couple this amplifier, you may be able to eliminate the DC servo, leaving a total of 12 transistors for the two channels.

24th July 2011, 07:28 PM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	It's a 3transistor DC coupled amplifier with an output buffer. The extra is a DC servo to minimise the drift in output offset. If you AC couple this amplifier, you may be able to eliminate the DC servo, leaving a total of 12 transistors for the two channels. __________________ regards Andrew T.

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24th July 2011, 02:11 PM	#2
mickeymoose diyAudio Member Join Date: Nov 2008	If it is for audio this would be over-kill. How long is your wire? What are the impedances? Balanced or not? E

24th July 2011, 03:22 PM	#3
velvetsunrise diyAudio Member Join Date: Jun 2005 Location: Leeds	Hi thanks for your reply, cables are around 10 Meters, poweramp has a 10K input impedance and single ended. It just seemed with the discreet buffer stage to be an easy to implement and cheep and slightly different approach that may make a nice line amp. Cheers Steve

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