Comments on: Parts: Programmable gain amplifier (MCP6S26)

By: Andrew

Andrew — Fri, 29 Oct 2010 19:34:43 +0000

Cool. I’m interested in this chip and was wandering if the gain is adjustable to 2.5? If not then one would have to lower the input voltage to a value that is acceptable for a gain of 2 for the desired output? I guess what I am asking is if the gain can be programmed to 2.5?

By: Derrick Borowik

Derrick Borowik — Sun, 17 Jan 2010 23:04:20 +0000

This web site is really quite good, but for some reason it does not display properly when trying to view on my Nintendo Wii. If it helps, the console uses the Opera web browser and am impelled to using the console for accessing the Net whilst my PC is away being restored.

By: dan

dan — Wed, 01 Apr 2009 08:16:23 +0000

tc: It would probably not be appropriate to connect this chip directly to headphones if that is what you are considering. You need something that can deliver more power. The LM386 chip is the most common choice in this situation, although there are more modern chips that can do stereo, such as the TPA302D. If you use the LM386 you will need two to do stereo.

By: eric

eric — Wed, 01 Apr 2009 06:52:57 +0000

@ the schematic pictured above: your grounds should always point *down* and one of your +3v3 tags is facing sideways too :P

glad to see you introducing this stuff to the hobby community :) i like the way things are going here

By: TC

TC — Tue, 31 Mar 2009 10:24:20 +0000

I was curious. I’m trying to get together a custom MP3 player setup for a motorcycle and need some sort of amp to kick it up about 12 or 15dB (I use helmet speakers with earplugs) so the fact that it has limited settings doesn’t bug me. I’d still have a pot of some sort afterwards.

Of course, it turns out that the MP3 player I was looking at (“MOD-MP3″) doesn’t support SDHC, so that one is out the window. :(

Another reason that I ask is to get feedback and suggestions. Sometimes I’m not even sure about what I’m looking for. :)

By: rasz

rasz — Tue, 31 Mar 2009 06:23:00 +0000

nice chip, could be usefull as a preamp for slow oscilloscope

tc why not use dedicated audio preamp chip for that? like TDA8425? its SPI controlled and has 2 stereo input channels

By: Mastro Gippo

Mastro Gippo — Tue, 31 Mar 2009 06:11:08 +0000

Very nice! I was thinking about using something similar for my EEG design, so it doubles as an ECG.

By: dan

dan — Tue, 31 Mar 2009 03:48:11 +0000

One more thing, tc: if you want input selection in stereo a good chip is 74hct4052

By: dan

dan — Tue, 31 Mar 2009 03:37:46 +0000

tc: the problem with using this as a volume control is that you only have a limited number of gain settings to choose from, as opposed to a traditional volume knob that has a continuum of settings. You might be better off using a digital potentiometer for volume. This chip could be combined with that though so that you can have the capability of selecting multiple inputs, as well as having the benefits of a preamp.

One interesting use for the multiple inputs is that a series of filters can be created and the inputs can be chosen to switch various filters in and out of the circuit. I’m current working on a sort of “universal amplifier” that uses this technique.

By: TC

TC — Tue, 31 Mar 2009 00:10:33 +0000

Can this be used as an audio volume control and selector?

By: Rolf Stenström

Rolf Stenström — Mon, 30 Mar 2009 22:33:11 +0000

As always, a great write-up. Keep ‘em coming!