about amps

[nero1985]

im very interested on buying a marshall valvestate 8240 now its a 2x12 amp it has 40 watts per side, now my questiong is, if it has 40watts on each speaker does that mean its 80 watts wat u r going to get or just 40watts but stereo sounding? please somebody help me with this! thanks!

[Johan]

it is 40+40watts=80watts. and it is loud when everything is upp all the way...and a nice chorus, if I remember correctly..

johan

[Mark Hammer]

The 8240 uses a pair of TDA1514 power-amp chips, one per 4 ohm speaker.    My sense is that the two speakers receive sum/difference signals when the chorus kicks in.  

The TDA1514 is rated to be capable of delivering current to an 8ohm load, with a +/-23v supply, that provides 50w of "power".  The 8240 uses a lower supply voltage but a lower speaker load as well.  Presumably the combination provides for safe delivery of enough current to each speaker to yield something like 40w per side under certain circumstances.

Of course how loud that will be depends on things like the speaker efficiency, the degree of help the cabinet itself provides, the input signal, and the amount of gain that can be applied.  Note that, using the same input signal and speaker, the traditional rule of thumb is that a 10x increase in power = a 2x increase in perceived loudness.  So, same guitar and speakers, and this unit is roughly twice as loud as an 8w amp.

BTW, the schematic can be found here: http://www.drtube.com/schematics/marshall/8240-61.gif