Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Solid State => Topic started by: EL34 on July 01, 2011, 12:23:03 pm

Title: Stereo line mixer questions
Post by: EL34 on July 01, 2011, 12:23:03 pm

Ok, solid state guys, need to pick your brains.
Saw G Hoffmans post on his mixer needs and found a good link in that post.

I have several line level stereo signals that I want to feed into a single power amp.

Stereo outputs from a couple different computer sound cards.
Double mono outputs from my Palmer load box
Stereo line level signals from a couple other sources

I need a simple line level mixer with maybe 5 stereo inputs and one stereo output.
The mixer does not need separate eq on each input channel, but Eq on the overall output mix would be great.

Saw these diagrams on  this web site and it looks like the ticket.
I suppose dual gang pots would be the best way to go instead of trying to use individual pots for left and right channels on a stereo signal
Any tips or comments on this?

http://sound.westhost.com/project94a.htm (http://sound.westhost.com/project94a.htm)

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This would be all the inputs, except maybe I would have 5 sets on inputs
(http://sound.westhost.com/p94a-f1.gif)

This would be the output section with eq, except times 2 for the left and right stereo signal
(http://sound.westhost.com/p94a-f2.gif)

Title: Re: Stereo line mixer questions
Post by: Ritchie200 on July 02, 2011, 11:49:23 pm

Hey Doug,

PAIA had an old kit that may do what you want.  Here is a link to the assembly instructions and schematic.  Maybe you can get some ideas?  Click on the attachment.

http://www.paia.com/talk/viewtopic.php?f=6&t=117 (http://www.paia.com/talk/viewtopic.php?f=6&t=117)

Jim

Title: Re: Stereo line mixer questions
Post by: PRR on July 03, 2011, 04:12:59 pm

> it looks like the ticket.

Yes.

Title: Re: Stereo line mixer questions
Post by: EL34 on July 03, 2011, 04:25:05 pm

Thanks Jim but that PAIA, circuit is pretty old and does not have any EQ on the main mix
I am looking for a basic Treble and bass EQ on the main mix.

PRR, in my search for DIY audio mixer, I ran across another forum where you were posting several years ago.

Anywho, I was wondering if the TL072 op amp would be quiet enough.
Have seen many other post about the 5532 and 4580 op amps being much better for audio circuits such as this.

Title: Re: Stereo line mixer questions
Post by: PRR on July 04, 2011, 07:16:32 pm

> if the TL072 op amp would be quiet enough.

Yes.

Title: Re: Stereo line mixer questions
Post by: EL34 on July 11, 2011, 08:38:47 am

Was going to build a mixer until I found this 3 channel stereo mixer for $70

(http://images.guitarcenter.com/products/optionLarge/ART/240224.jpg)

It's not worth the time to build at this price

3 channels will do fine