6L6's in a Princeton Reverb?

[rduval]

I have a 1981 Blackface Princeton Reverb (Last year of the hand wired I believe). It's been modded back to the original circuit specs (John Fromel kit).

Can I put 6L6's in it? Will that get me some more clean headroom?

Thanks

Rick from Toronto

 

[jhundt]

The problem is in the transformers.

The power transformer doesn't really have the capacity to handle the increased heater current required by the 6L6 tubes.

and the output transformer isn't robust enough to produce the louder, cleaner sound that you want from 6L6s.

Allen Amps sells direct replacement transformers which can be dropped in to the existing mounting points with no modification, and which are designed to deliver the increased capacity that you need.

 

[fezz parka]

Ditto. That little Champ PT is already stressed to the max in a PR.

 

[slider313]

Use JJ 6V6's. They will give you the most clean headroom. You can also try a 12at7 in the phase inverter.

 

[jhundt]

Use JJ 6V6's. They will give you the most clean headroom. You can also try a 12at7 in the phase inverter.

this is true, you can acheive more headroom this way. But usually when someone asks for "more clean headroom" I think they are trying to say that they want the amp to be louder, and I think that the limitations of the transformers probably won't allow the JJs and 12AT7 to increase the volume too dramatically. Perhaps I am wrong about that, I never tried.

But I know that changing the transformers, doing the Stokes mod, replacing the filter caps, doubling the first stage capacitance and running 6L6s will make the amp considerably louder. Billm has written quite a bit about these mods on this forum, and I did the same sort of changes to mine.

 

[ThermionicScott]

this is true, you can acheive more headroom this way. But usually when someone asks for "more clean headroom" I think they are trying to say that they want the amp to be louder, and I think that the limitations of the transformers probably won't allow the JJs and 12AT7 to increase the volume too dramatically. Perhaps I am wrong about that, I never tried.

I think you're right. Due to their nature, JJ's are capable of delivering more clean headroom in an amp designed for them. But they won't magically convey that headroom onto an amp that already has a bunch of limitations.

- Scott

 

[celeste]

........ You can also try a 12at7 in the phase inverter.

Won't get you anywhere good in a PR, it has a split load PI, so it has no gain, and the other side is the tremolo oscillator.

 

[celeste]

More efficient speaker is your easiest and least expensive route if it has its stock speaker. As others have said, it needs to be changed a lot to get you where you want to be. Maybe a better choice would be getting a modern amp that can use 6L6's in a PR type circuit. I believe Allen amplification has something like that

 

[jhundt]

Won't get you anywhere good in a PR, it has a split load PI

good one celeste, I was off in Deluxe-Reverb dreamland and missed that. Thank heavens someone in class is paying attention!

 

[celeste]

good one celeste, I was off in Deluxe-Reverb dreamland and missed that. Thank heavens someone in class is paying attention!

LOL, everyone knows a PR and DR are different animals, but it is so easy to forget why

 

[twintwelve]

An efficient 12" speaker makes a huge difference in volume, clean headroom, etc. Plug that sucker into an extension cab w/ a 12" 100w ceramic magnet speaker-you'll be amazed!

 

[alnicopu]

My 65 blackface came with 6L6's in it and a 5y3 rectifier. Why, I have no idea. When I turned up the trem they pulsed on and off like a caution sign. They pulsed even with a gz34 in there. You'd have to beef up the transformers, then you'd have a deluxe with 6L6's in it. You would probably have lots of clean headroom, but I doubt it would grind like a 6v6 princeton reverb anymore.

 

[Wally]

+1 with celste...
Get an extension cab with a Eminence LEgend GB-128 in it or some other speaker with over 100db of efficiency.....you will be amazed at how loud that Princeton REverb will be. Put an EV in the cab and you would have an extension cab that would be usable with a lot of amps.
Or mic it....or build a line out an run the little amp's production to the PA or a larger clean amp.

 

[milocj]

Yep! More efficient speaker first, unless you've already done it. Doesn't even have to be a 12". The Eminence Patriot and Redcoat series, Weber 10F150 series, and the WGS will all bump you way above the stock speaker volume with their 10" models.