LT1228 Anyone?

Dave S · 14th September 2007, 09:02 PM

Has anyone got experience of using this device or how it sounds?

It is transconductance amp with variable gain and a CFA output amp in one package. The gain appears to be varied by changing the LTP current, which means it should be possible to vary the gain without having the pot in the audio signal path.

Gordy · 15th September 2007, 03:12 PM

It's a nice idea, but the datasheet notes 0.2% distortion (presumeably as a best case figure, so it gets worse from there on in).

Advantage - audio signal not going through a pot / attenuator.
Disadvantage - audio signal going through an extra op-amp.

My guess is that this chip would be useful where several channels need controlling from a single pot... maybe on a mixing desk?

KSTR · 15th September 2007, 03:44 PM

You might consider the THAT2180. It's a professional VCA used in studio equipment. Requires careful design, though.

- Klaus

14th September 2007, 09:02 PM	#1
Dave S diyAudio Member Join Date: Mar 2003 Location: Searchin' for Sweet Singletrack	LT1228 Anyone? Has anyone got experience of using this device or how it sounds? It is transconductance amp with variable gain and a CFA output amp in one package. The gain appears to be varied by changing the LTP current, which means it should be possible to vary the gain without having the pot in the audio signal path.

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15th September 2007, 03:12 PM	#2
Gordy diyAudio Member Join Date: Nov 2006	It's a nice idea, but the datasheet notes 0.2% distortion (presumeably as a best case figure, so it gets worse from there on in). Advantage - audio signal not going through a pot / attenuator. Disadvantage - audio signal going through an extra op-amp. My guess is that this chip would be useful where several channels need controlling from a single pot... maybe on a mixing desk?

15th September 2007, 03:44 PM	#3
KSTR diyAudio Member Join Date: Jul 2007 Location: Central Berlin, Germany	You might consider the THAT2180. It's a professional VCA used in studio equipment. Requires careful design, though. - Klaus

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