==== MIDIBox AY 3 8912 Mixer ====

  * OP AMP Mixer (Tone ABC) for the MIDIBox AY 3 8912 (Ver. 1a)
  

{{mbay:mbayopmixerv1aboard.png}}

{{mbay:mbayopmixerv1bottom.jpeg}}

{{mbay:mbayopmixerv1.jpeg}}

{{mbay:mbayopmixerv1platinebestueckt.jpeg}}

{{mbay:mbayopampmixv1a.png}}

=== Notes: ===
  * Pot R4 (Volume Tone A), R5 (Volume Tone B) and R6 (Volume Tone C) are designed for volume finetuning (not for turning off tone A/B/C)

**Pot Options:**
  * R4, R5, R6 = 100k (less volume)
  * R4, R5, R6 = 220k (more volume)

**OP: LM324N (4xOP, +/-12V) - Datasheet:**
  * => [[http://www.cytron.com.my/datasheet/IC/linear/LM324N.pdf|LM324N.pdf]] /
  * => [[http://focus.ti.com/lit/ds/symlink/lm324.pdf|lm324.pdf]]



=== Download: Eagle 5.1 Files + Partlist - MIDIBox AY 3 8912 Mixer (Ver.1a) ===


{{mbay:mbay_eagle.zip}}

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==== MASTER VOLUME POT ====

{{http://www.subfrequenz.net/visuals/albums/userpics/masterpotay38912.jpeg}}


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==== No OP MIXER Option ====


**Notice:** 
"You can easily leave out the opamp buffer board for testing. Just connect all three outputs via 10k resistors and add a pulldown of 1k-5k from that signal to ground." (nILS Podewski, 2008-10-02)

{{http://www.subfrequenz.net/visuals/albums/userpics/mbayoutoptionnils2008a.jpg}}

 
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==== PCB ====

The OP-Mixer PCB are available at Mikes Onlineshop

http://www.mikes-elektronikseite.de/shop_englisch/index.htm

[26.09.2008]