Post
by ??????? » Mon Dec 13, 2010 7:41 am
There are no stupid questions, only stupid answers.
1) Deluxes and Princetons both use 6V6s. Deluxes do not use 6V6s. Therefore, changing to 6L6s and a 12" in your Princeton will not make it into a Deluxe.
However, You actually can use 6L6s in the Deluxe with no problems if you do it right--NOT so much in a Princeton. Both tubes share the same pinout, as do MANY output tubes. I've done it myself in a Deluxe. Didn't really give much more loudness, for the reasons I outlined in my first (long) post in this thread.
The Princeton has the same power transformer as the Champ. It likely wouldn't tolerate the extra filament current draw. If you really wanted to, it could be done with an auxiliary filament transformer (not worth it).
2) Princeton and Deluxe have the following design differences, among others, in addition to the fact that one has a 12" speaker and one has a 10" speaker. Princeton uses a Cathodyne phase inverter, which operates less than unity gain, and the Deluxe uses a Schmitt phase inverter, which offers gain. Princeton also has a smaller power and output transformer. There are others as well. Tube type isn't the biggest issue.
3) There's a bit of misinformation above. Many amps can run different tube types without modification, and without a "circuit switch" that "changes the wiring of the amp." They can/often do so with a flexible biasing scheme-- a cathode-bias design that allows several tubes to bias up in a safe range. All 6L6 types, 6V6, 6550, KT88, KT66, EL37, and several others ALL share the same pinout. Pin 1 in all is not connected. 7027 is the same (and in fact is typically identical to 6L6GC) except pin 1 has a redundant extra negative suppressor grid connection that doesn't do much. EL34 is the same except that pin 1 is connected to a third grid.
As long is pin 1 on the socket is not used for a "tie point" as it is in many older designs, an amp can be easily designed that can run several (if not all) of the above tube types without problem. Sometimes you will see a switch that will adjust taps on the output transformer for better impedance matching-- but this is NOT changing the circuit-- only the turns ratio of the OT.
4) More misinformation above: A 12" speaker would indeed make the amp noticeably louder in most cases. This is simply because 12" speakers are typically 5-10 dB more efficient than 10" speakers, partially a result of the increased (50% greater) surface area. This necessarily translates into an increase in loudness, and in fact is the biggest reason the Deluxe is louder than the Princeton. You may remember that doubling the power of an amp (from, say, 50 to 100w) gets you only 3dB of loudness, all else equal (power scale in watts is linear, SPL in dB is a logarithmic measure). Speaker sensitivity (a function of size, number of speakers, and also speaker construction) is easily a bigger deal than number of "watts." Easily. This gets confused, because higher powered amps typically have more speakers, and are therefore louder-- the extra amp power is only good for 3dB.
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If you love the sound of your Princeton but want to make it louder, I'd suggest getting an extension cab with a second 10" speaker (or if you like, a 12" speaker) in it. You can leave the stock 8 ohm speaker and run an 8 ohm speaker in parallel for 4 ohms, and the OT will likely handle the slight downward mismatch just fine (indeed, it was designed to do so). If you want to maximize loudness and be kinder to your output tubes, get a 16 ohm speaker for the onboard speaker and an additional 16 ohm speaker for the extension cab, for a total load of 8 ohms.
Your amp will be noticeably louder... probably louder than a Deluxe, even... and you'll notice greater extension in the lows, as well.
The "more efficient speaker" advice directly above is sound in theory, but remember that those measurements are made using 1W of white noise, not actual musical signal. So the differences don't always translate as meaningfully in practice. A speaker with more extension above 5k will measure louder, but not sound louder with a guitar through it (unless you use a fuzz)
Outside of that, you could just get a different amp. While you could squeeze a 12" speaker into the cab of the princeton, it's my experience that the cabinet is too small for a 12" speaker to sound good. The baffle is not wide enough, and you'd have a small, boxy sound. Know what it sounds like when the speaker is not inside a cabinet at all? Thin, boxy, tiny due to phase cancellations at low frequencies? It would start sounding more like that.
