E-12 Amp

dsurplus · Post by **dsurplus** » Thu Nov 04, 2004 8:55 pm

I have an Electro amp that looks like an E-12 (single 6L6) and appears to be original: Jensen speaker, all the tubes are RCA. The amp has great tone with my ES-175 archtop, but the distortion starts way too soon. I'm sure that it would benefit greatly from retubing, and probably some other things as well. My questions are:

For retubing, what could I use for the pre-amp tube to get later breakup, but keep that nice warm vintage tone? Same question for the 6L6.

Should the rectifier tube be replaced as well?

Will it need to be rebiased?

The Jensen speaker appears to be in good condition, but how can I tell if all is well with it? Reccos for replacement?

I'm guessing this thing to output around 18-22 watts - is that correct?

Thanks for any and all replies.

jps · Post by **jps** » Fri Nov 05, 2004 3:09 am

Welcome Doug. This is just a guess, but I think most single ended tube designs (only one output tube) like yours will tend to distort quicker because of the SET deign. There is no push/pull output stage to cancel any distortion.

Phil Canard should jump in here as he may know better about these designs.

tracy · Post by **tracy** » Mon Dec 13, 2004 10:25 am

Hi Doug! The E-12 originally came with a 6V6GT output tube. I've seen many replaced with 6L6's in an attempt to get a little more out of the amp but ultimately the power supply dictates just how much any extra anything you'll get. Replacing the rectifier with a 5Z4 will give you some additional headroom. For less gain (distortion) replace the 12AX7 with a 12AY7 or for even less a 12AU7. That should clean it up, at least to it's RMS limits. Replacing the output tube is probably a good idea as well due to filament consumption, but try both and use your ears. And when you get your best combination, let us know what it is!

tracy · Post by **tracy** » Mon Dec 13, 2004 10:33 am

P.S. The amp would not need rebiasing as it is a single ended class 'A' design with a 'fixed' cathode bias. Although that value can be optimized, it's probably close where it is and not something to be overly concerned with. The amp is designed to deliver +/- 6 watts under normal conditions, similar to a Fender 'Champ'. You'll get closer to 8 watts with the 5Z4 rectifier due to it's lower 'voltage drop'.