determinning wattage

Thread Starter

Mr.oaktree

Joined Dec 10, 2014
68
Surely wattage is fairly irrelevant? I thought that was just how much power it could handle before it went "pop!". What determines output volume isn't the wattage, it's the gain! A 20W per channel amp can sometimes be "louder" than a 50W per channel amp when fed with the same input signal, but the 50W per channel amp will handle more before you start hitting the limit of the components.

I would say your new channel doesn't have more power, it probably has more gain, in which case you may be able to just bias that with a resistor or two and match the channels.
you make a very good point
 

Thread Starter

Mr.oaktree

Joined Dec 10, 2014
68
ok so wattage be damned ;) I just put matching set of power transistors in other channel too . so it seems in order to insert new chips without blowing them up i had to replace r2-23 and r1-23 with a 5watt .68ohm resistor and replace r2-13 and r1-13 with a 20 ohm resistor , then all was stable and even and no pops lol . thanks for the help guys
 

Thread Starter

Mr.oaktree

Joined Dec 10, 2014
68
results were great :) amp is fully up and running more powerfull than before , all chips are stable i ran it at full volume for over an hour and no meltdown :) seems all is in order and best part is i learned alot about amps from this :) :p

ps: im definately getting a scope now lol :)
 

cmartinez

Joined Jan 17, 2007
8,220
ok so wattage be damned ;) I just put matching set of power transistors in other channel too . so it seems in order to insert new chips without blowing them up i had to replace r2-23 and r1-23 with a 5watt .68ohm resistor and replace r2-13 and r1-13 with a 20 ohm resistor , then all was stable and even and no pops lol . thanks for the help guys
Could't open the PDF file, it seems to be damaged.
 

Thread Starter

Mr.oaktree

Joined Dec 10, 2014
68
no problem . i actually think highly of this circuit after this project its wel built and easily allows for upgrade of wattage if desired with very little parts and effort :) but i got it hooked up to 2x 600watt speakers right now and it seems to be almost too much for them lol . it deffinately shakes the builing at 50% gain. my only issue is that the fan could be stronger . but that will soon be changed :)
 

Thread Starter

Mr.oaktree

Joined Dec 10, 2014
68
lol no i work for the anderson civic center . were like a event center for fairs, circus, expos, weddings , concerts ect... i do our equipment repair as well :) so when i say "shake the room at 50% gain" i mean a 80,000 square ft room lol
 

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#12

Joined Nov 30, 2010
18,224
Strange new world we live in. Nobody remembers what, "finger hum" is, but call for a, "smart phone" and half the audience stands up. o_O
 

#12

Joined Nov 30, 2010
18,224
Humans pick up 60 Hz radiation from the power wires around them, like an AM radio antenna. Touch your finger to the input of a high gain amplifier and the speakers should say, "HUM". Whadaya think we used for a signal injector before smart phones were invented?
 

cmartinez

Joined Jan 17, 2007
8,220
Humans pick up 60 Hz radiation from the power wires around them, like an AM radio antenna. Touch your finger to the input of a high gain amplifier and the speakers should say, "HUM". Whadaya think we used for a signal injector before smart phones were invented?
Yeah, I remember playing that way with my old guitar amp... I just didn't know it was called finger-hum... truth being told, I googled it right after your post, and not even google knows the answer that you just gave...
 

#12

Joined Nov 30, 2010
18,224
You learn something every day. :p

I wonder how many really ancient terms we can come up with that modern people don't know about. Shouldn't be too difficult with modern kids knowing nothing about Jackie Gleason, rotary dial phones, or how much horses pooped on the streets of New York a hundred years ago.
 
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wayneh

Joined Sep 9, 2010
17,496
Reminds me of the time I brushed my lips against a live mic. By "live", I mean 120V. Definitely got a 60 cycle signal "injected".
 

cmartinez

Joined Jan 17, 2007
8,220
You learn something every day. :p

I wonder how many really ancient terms we can come up with that modern people don't know about. Shouldn't be too difficult with modern kids knowing nothing about Jackie Gleason, rotary dial phones, or how much horses pooped on the streets of New York a hundred years ago.
Here's a very interesting book about that subject that I read a while ago. It's very, very interesting.
And if you like that sort of thing, I highly recommend this one, and this other one.
 
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