Why does the Pro Jr sound so much thinner than a Princeton Reverb ?

[Iplayloud]

The Princeton is bone stock, old original speaker with a small magnet. In the Pro Jr I put a Weber Blue Pup, new tubes biased on spot, all in order. And it's not just the smaller box because if I plug the Princeton in the Junior's cab it sounds good. Here's the things I'm thinking:

-Lack of a real EQ tone stack ?
-EL84 have less headroom than 6V6 ? (they have 319v on the plates versus 415v for the Princeton)
-Output transfo ? (don't think so cause I read somewhere a guy changed for a MM and did make a big difference)

[Chuck H]

Two different amps... I know... Thanks for nothin', right. But...

Some players really love the Pro Jr. for it's concise tone. Bredth of tone can be had with more output power, higher plate volts, etc... EL84's will chime in the upper mids all day. But if you want to get any bottom out of them you need to raise the voltage above the threshold that gives them their signature tone. IMHO 6V6's handle high voltage with a little more aplomb. Not that EL84's don't sound good at higher voltages. But they do lose more of their signature character than the 6V6's do. So it's really just a very different amp.

If tone for you means a wide frequency response then I should think that the big bottles (6L6, EL34) would suit you best of all.

Look at it this way, a Vox AC30 has "enough" bottom end. Not excessive and not too thin. But thats a four EL84 tube amp running class A into two 12" Bulldogs! The "18 watt" type amps do OK on bottom end. But these are usually heads running 330 to 400 plate volts plugged into 2x12 or 4x12 closed back cabinets. EL84's aren't very big tubes. 6V6"s are more rugged and linear overall. They're also more expensive.

Getting a big bottom tone from EL84's is a matter of either upping the plate volts (sacrificing that tubes best characteristics) or adding more tubes and using speaker systems that have more bottom end.

Any other complaints may have more to do with the preamp design.

Chuck