Tremoverb at 50 watts

[zillinois]

Hello All,
I recently acquired a used Tremoverb, as I'm making the switch back to playing guitar from playing bass. The previous owner has it setup as a "50 watt" meaning, that he pulled two of the power tubes and one of the rectifier tubes. I've found the manuals on the Mesa site, and only the "dual/triple rectifier solo" claims:

"NOTE: On the DUAL Solo Head it is possible to run two 6L6 or EL34 tubes by pulling the two center tubes leaving the far left and
far right tubes intact. This procedure reduces the power by approximately 50%. Remove one of the Rectifier tubes if you are using
the Tube Rectifier setting to assure a correct match."

There is nothing in the tremoverb manual about this. I realize these amps are similar, but should I re-add the missing tubes or is it basically safe to run this way?

 

[YellowJacket]

You can call Mesa to confirm but I'm pretty sure this is safe with the Tremoverb. Now, what you want to do is up to you. You'll get a thicker and beefier tone with 4 power tubes and 2 rectifier tubes and IMHO, it really doesn't affect the volume all that much.

Oh, if you keep running the amp at 50watts, be sure to plug the speaker lead into the 4ohm connection on the head and into the 8 ohm connection on the cab.

 

[elvis]

There's not going to be much, if any, real difference in volume between 2 and 4 output tubes unless you run it flat-out.

Running 2 tubes is a bit less expensive, as you are wearing out half as many tubes.

 

[zillinois]

You can call Mesa to confirm but I'm pretty sure this is safe with the Tremoverb. Now, what you want to do is up to you. You'll get a thicker and beefier tone with 4 power tubes and 2 rectifier tubes and IMHO, it really doesn't affect the volume all that much.

Oh, if you keep running the amp at 50watts, be sure to plug the speaker lead into the 4ohm connection on the head and into the 8 ohm connection on the cab.

According to the tremoverb manual - "If you have the tremoverb combo, your two 16 Ohm speakers are wired in parallel producing an 8 Ohm load." So are you saying that running at half power would produce a 4ohm load?

 

[YellowJacket]

Removing two power tubes changes how the amp handles impedance. While the math and science behind it is complicated, the rounded figures work out to approximately half of what the impedance is with all the power tubes in place.

So, 4ohm output from amplifier to an 8 ohm cab or,

8 ohm output to a 16 ohm cab.

Don't hook up a 4 ohm cab.

 

[zillinois]

OK, that makes sense in this case. Thanks!

 

[elvis]

Not that complicated, actually. Put simply, each pair of power tubes drives half the current into the speaker. Removing one pair of tubes forces the remaining pair to drive twice the current. Doubling the speaker impedance cuts the required current in half, reducing the current drive from the power tubes to the correct amount.

It's a bit more complicated in practice, as the output transformer converts the impedance, but it works for this situation.

 

[zillinois]

Thanks everyone. This change has made my tremoverb volume a lot more manageable.
One more question, as there is a 50 watt rectoverb available locally, do the rectos sound as good as the tremos?

 

[YellowJacket]

Keep.

Your.

Tremoverb.