I'm playing with a low power tube amp, want to pump it up with a 50L6 instead of the 50C5 power tube, but would want a bigger output xfmr to handle the increased power. Can I put the two OT primaries in series, then parallel the 8 ohm secondaries for one speaker? And would it bring the "reflected" primary impedance back down using a 4 ohm spkr instead of an 8 ohm? Would the xfmrs be out of phase? Or maybe keep the secondaries separate and use two 4 ohm speakers? Just want to utilize spare stuff I have laying around (and push the limits of my rudimentary knowledge of tube theory to the test...) Thanks!
Safest way to do it, as in absolutely sure it will work well, is to double the power stage to 2 of 50C5, with each transformer separately driven by 1 of 50C5, and the 8 ohm (I assume) secondaries paralleled and driving an 8 ohm speaker. I am guessing this is a recycled stereo amp, so you can avoid new parts, and keep your series heater string as original.
Short answer no.
or if you prefer it: not worth it.
To boot, primaries in series will halve power, not double, because you have same power supply (by the way, I didn't read you were upgrading it too) and double impedance.
And mismatching transformers to get the same you had before (hint: back to square one 🙁 ) won't help.
Build the amp with matching supply/tubes/OT and if you wish, experiment with sound, gain, EQ, whatever.
JM-thanks, I figured I was heading for a major mismatch....but I really like leadbelly's idea. I'm playing with a line powered tube intercom (on an isolation xfmr), and looking to go from 3 to 6 watts output power, and the 35W4 rectifer should handle the 2nd 50C5. But oops there goes my series heater string, hmmm, go to a bridge rectifier, change 12AT6 to a 12AX7, and get another gain stage!
Hi Guys
Doubling the output power only makes it "a little bit louder" - not worth it at all.
You can effect a significant loudness change by using separated speakers and sitting at their focal point. Even though you are still feeding a mono signal, the two acoustic sound sources will provide much more "apparent" sound to your ears and brain, which work as a phase differentiator. Just place one driver in each cabinet and separate them by a space.
There are good books to learn about how tubes work, how guitar amps work, how to build toneful speaker cabinets, how to wire things for lowest noise and best note articulation. The circuit you are playing with is rather limited but it can be rewarding to get some specifically "guitar" tones from it. This is mostly a matter of rewiring the preamp.
make sure the power tube has a proper value screen-stop resistor or the amp will eat power tubes.
Have fun
Doubling the output power only makes it "a little bit louder" - not worth it at all.
You can effect a significant loudness change by using separated speakers and sitting at their focal point. Even though you are still feeding a mono signal, the two acoustic sound sources will provide much more "apparent" sound to your ears and brain, which work as a phase differentiator. Just place one driver in each cabinet and separate them by a space.
There are good books to learn about how tubes work, how guitar amps work, how to build toneful speaker cabinets, how to wire things for lowest noise and best note articulation. The circuit you are playing with is rather limited but it can be rewarding to get some specifically "guitar" tones from it. This is mostly a matter of rewiring the preamp.
make sure the power tube has a proper value screen-stop resistor or the amp will eat power tubes.
Have fun
All else being equal, doubling power will only get you a 3db loudness increase. Not twice as loud, just 3db. Agree with not worth the trouble.
Try connecting the tiny amp to a 4x12 cab or other much larger speaker than what it now drives. Yu will be amazed how much more sound you get.
Try connecting the tiny amp to a 4x12 cab or other much larger speaker than what it now drives. Yu will be amazed how much more sound you get.
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