PharmRock wrote:
One thing to consider, at least with the cabinet supplied by Trinity, is that with a 12" speaker you may have some clearance issues with the speaker magnet interfering with the tubes and switches. I have a 12" speaker in mine, but there are certain ones I simply could not install due to the magnet diameter. This is because the 10" speaker is normally mounted off center of the baffle, but the 12" ends up being centered more towards the middle of the cabinet where the speaker jack and output tube are located on the chassis.
I agree with you 100% on the speaker size vis-a-vis cabinet size. I'm building a custom cabinet, so I'm choosing its specs based on the actual speaker sizes of potential 12" models I might select. I've done a couple of sketches of the proposed cabinet, with speaker installed to see how the speaker does (or does not) clear the chassis and transformers.
The basic dimensions I am going with are 18.5"w x 16"h x 9.5-10.5"d (tapering from bottom to top for slight tilt). Using 0.75" fir for body, 0.5" plywood for the baffle (or possibly 3/8").
I attached the diagrams below for others going through same exercise. In this side view, you can see that 2 typical 12" models will fit (small Alnico, larger Ceramic). The power transformer is far enough to the side of the chassis that it is nowhere near the speaker magnet. And even the largest tube (EL34) will be farther back in the cabinet than the back of the speaker.
That said, some models of speaker will *not* work. For instance, Trinity recommends the 10" Blackbird 100 for this amp, which sounds like a fantastic speaker. If you try to go with the 12" version of the Blackbird 100, it has a gigantic bell on the back, and it won't fit in this cabinet. Could accommodate it by either making the cabinet 1 inch deeper (see last diagram).
Jensen P12R:
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WGS Reaper:
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Front View of Cabinet w/Reaper:
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Blackbird (larger cabinet):
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