# Is this a 6G3, 6G2, or "other"???



## StevieMac (Mar 4, 2006)

I was looking at the layout on this amp and it occurred to me that I can't actually identify it. It's _supposedly_ based on the 6G2 Princeton (as per the control layout) however the 3rd preamp tube is obviously out of place in that circuit. Which got me to wondering then...does that put it more in line with say a single channel 6G3? Wishing I was more knowledgeable about these things but I'm hopeful someone here can determine what's _really_ going on with this circuit...


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## nonreverb (Sep 19, 2006)

It has the 6G2 bias adjust pot however, it has a long tailed pair phase inverter like the 6G3....and then the 1500 ohm grid stopper resistors of the 6G2. It looks to me like a combination of both versions.....hope this helps.


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## StevieMac (Mar 4, 2006)

nonreverb said:


> It has the 6G2 bias adjust pot however, it has a long tailed pair phase inverter like the 6G3....and then the 1500 ohm grid stopper resistors of the 6G2. It looks to me like a combination of both versions.....hope this helps.


Thanks! I was confused by your comment about the 6G2 bias adjust pot and then realized I had the layout for an _updated_ _clone_ pictured. I've replaced that pic with an original 6G2 layout to reflect that brown-era amps lacked that pot, thereby eliminating that as a common element with the 6G2.

The amp in question appeared to me to have the 6G3's long-tailed PI as well so thanks for confirming that. I honestly don't know enough about "grid stopper resistors" to say what (if any) effect those have on the amp, and just assumed they were a fail-safe of some sort for the output tubes. Unless I hear differently then, I'll go with the "single channel 6G3" assumption.


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