- RE: Determining output power - thermionic addictions 10:58:06 02/23/09
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- In Reply to: RE: Determining output power posted by beeah on February 21, 2009 at 15:17:31
Here is an excellent artical by John Broskie that my help you
with what you want.
Cal
- RE: Determining output power - danlaudionut 01:51:33 02/23/09
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- In Reply to: RE: Determining output power posted by beeah on February 21, 2009 at 15:17:31
Beeah
I just drew the loadline and you'll get 2.75Wrms
from the 2A3 at that operating point and load.
I use loadlines to figure power ouput.
DanL
- Thanks, DanL (nt) - beeah 09:13:03 02/23/09
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- In Reply to: RE: Determining output power posted by danlaudionut on February 23, 2009 at 01:51:33
nada
- Thanks, DanL (nt) - beeah 09:13:03 02/23/09
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- RE: Determining output power - mqracing 17:16:05 02/22/09
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- In Reply to: RE: Determining output power posted by beeah on February 21, 2009 at 15:17:31
Here's a practical answer to your query...
independent of calculating the power output of a 2A3 at the operating points you describe---
the question of can the EXO-45 handle more than the nominal 2 watts we ascribe to the unit is the question of (perhaps) greatest import to you.
to make a long, long story a whole lot shorter--- our power rating is quite conservative--- and I generally like spec'ing conservative as this gives good magnetic headroom and allows the iron to operate in the region that we are aiming at...
however--- you already have the 045's in hand--- why not give them a try in the modified circuit--- worse case is that you would overload the outptuts and the tell tale sign of that would be a lot of distortion and just plain not very good sound. And it is likely only to occur (if at all) at the very, very lowest frequencies and at the maximum power levels--- so that if it begins breaking up simple solution is to turn down the volume.
But you might very well find that the 045's will just plain do fine with no change in your listening habits, volume levels, or etc.
You have the units--- why not just give them the workout and see (i.e., hear) if they work well in your app or not.
MSL
Builder of MagneQuest™ & Peerless™ transformers since 1989
- RE: Determining output power - Paul Joppa 19:41:07 02/24/09
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- In Reply to: RE: Determining output power posted by mqracing on February 22, 2009 at 17:16:05
Somebody above quoted 2.75 watts. That's the difference between response to 26Hz vs. 30Hz, or a hair over 1dB. You won't hear the difference.
In fact, there will be zero difference below the rated power, it's only the extra 0.75 watt that might be more distorted than it would be if the transformer handled more power - and only below the lower power-limit frequency, which must be in the 0-30Hz range. In other words, the 2A3 will have more power available, and be at least as clean up to the 45's power capability.
- Thank you, Mike - beeah 18:54:48 02/22/09
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- In Reply to: RE: Determining output power posted by mqracing on February 22, 2009 at 17:16:05
You're correct - my primary concern was the 2W rating. That said, it would be nice to be able to do the calculations if for no other reason than to expand my knowledge base that much more.
The answer to the "why not" question was my fear of damaging the coils. The circuit is operating happily with vintage 45s, but I thought I'd give the 2A3s (also in hand) a whirl if it was safe to do so.
If the worst case scenario is poor performance, I'll give them a go and proceed from there. Thanks again for the reply and the reassurance. Who knows - perhaps there's a pair of 050s in my future...
Cheers,
Joe
- RE: Determining output power - Paul Joppa 19:41:07 02/24/09
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