45w Mode ... Not really 45w?

I remember reading something alone these lines a while back... that the amp was actually running closer to 20w? Can somebody explain? Also, is it Class AB or Class A when in 45w mode?

The Electradyne is running in Class AB in the 45 watt setting, with an output of...you guessed it...45 watts! Thanks!

Who cares how much power it puts out, it sounds awesome!!!

Haha, true. I was just curious based on what I thought I'd read!

Hmmm...If you check out some posts on this forum, you will read that the ED appears louder than the published wattage specs! 8)

Authorized Boogie said:

The Electradyne is running in Class AB in the 45 watt setting, with an output of...you guessed it...45 watts! Thanks!

Click to expand...

That's what one would think, but mine does not make 45 watts, not even close.

I have measured mine (and posted the results here previously) and it makes about 18 watts RMS before clipping starts and less than 30 pegged.

http://forum.grailtone.com/viewtopic.php?f=36&t=51980

The ED has since been remeasured with new tubes and there was no real difference.

Before taking the amp in for service work I spoke to the Mesa qualified service agent who confirmed with his own measurements on a different ED. The results were very close. I'm pretty sure I also conducted a pulse test to see if peak power was higher as with the Dynawatt amps like the Express 5:25 and found very little difference.

The fact that the amp performs as it does and is not faulty is fine by me, but I would love to know where the 45 watt rating comes from.

Authorised Boogie, could you please shed some light on this ?

I agree. If one pair of tubes is biased in class AB and the other is also class AB but closer to class A, then it is unlikely the two pairs will make equal power.

J.J said:

Authorized Boogie said:

The Electradyne is running in Class AB in the 45 watt setting, with an output of...you guessed it...45 watts! Thanks!

Click to expand...

That's what one would think, but mine does not make 45 watts, not even close.

I have measured mine (and posted the results here previously) and it makes about 18 watts RMS before clipping starts and less than 30 pegged.

http://forum.grailtone.com/viewtopic.php?f=36&t=51980

The ED has since been remeasured with new tubes and there was no real difference.

Before taking the amp in for service work I spoke to the Mesa qualified service agent who confirmed with his own measurements on a different ED. The results were very close. I'm pretty sure I also conducted a pulse test to see if peak power was higher as with the Dynawatt amps like the Express 5:25 and found very little difference.

The fact that the amp performs as it does and is not faulty is fine by me, but I would love to know where the 45 watt rating comes from.

Authorised Boogie, could you please shed some light on this ?

Click to expand...

In our tests with the Electra-Dyne, with 6L6GC, STR 440 YELLOW power tubes, it measures:

AC Line Voltage 120 VAC at inlet. Measurements taken at the 8 Ohm load.

Set in 90 Watt position.
27 VRMS into 8 Ohm load at onset of clip with a 1K Hz frequency. This equals 91 Watts.

Set in the 45 Watt position.
17.5 VRMS into 8 Ohm load at onset of clip with a 1K Hz frequency. This equals 38 Watts.

As we all know the transconductance of power tubes will vary, as will the line Voltage at the amplifiers inlet. We can get more out of this amp if we clip it hard as the poster above suggests, or we can get less Wattage if we go well below clip. If we set it up for hard clipping in the 45 Watt position we get 45 Watts, but at the onset of clip we get 38 Watts. That said If we set it up for a hard clip in the 90 Watt position we get 100 Watts into 8 Ohms.

Thanks!