How To: O2 with Triple Gain Switch (1x, 2.5x, and 6.5x)
Aug 13, 2012 at 8:00 PM Thread Starter Post #1 of 4


Aka: pizza, crichard, uloginhd. BAD TRADER.
Nov 19, 2009
As a general rule, amps perform better at lower gain settings -- the sound is cleaner, background darker, soundstage bigger, and sound less congested! Take O2 as an example. It is considered by many as TOTL comparable; it provides enough juice for power-hungry orthodynamic phones with its default 6x gain, and can also operate at a lower, 2.5x gain. Indeed, if you want, you can lower the gain further to 1x easily by simply disconnecting two resistors.
Well, we all like versatility, don't we? I have been debating whether to trouble Starfire again because I want to get the O2's gain lowered. Well, it turns out that Starfire was more than willing. Indeed, he came up with this idea:

As you can see, Starfire added a switch inside the enclosure. Now, when the switch is towards the front of the amp, the in position is 1x gain. When it's toward the back, the in position is 6x gain. And whenever it's an out position, it's 2.5x gain!
Don't know how he did it (I am sure Starfire will be pleased to answer questions here), but he told me that he used silver plated copper Teflon wire so SQ is not affected.
Sorry if I was too enthusiastic about this. Just thought I would share this idea. Thank you, Starfire!

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