Help with BTL power requirements

[dayveshome]

I have four small power amp modules I built some years ago for a project that I dropped and didn’t complete. I’ve never built a BTL amp before, so I thought these would be good candidates to experiment with. I know the power requirements for them (single module, mono), how do I figure the requirements if I BTL two together. I can’t find anything in any book on my shelf or on the net? HELP! Any suggestions or point me to an article. Thanks.

[AndrewT]

bridged gives double the power into double the impedance.

[sreten]

or double the power of the single channel into half the nominal
load, when connecting the nominal load to two bridged channels.

/sreten.

[dayveshome]

Thanks for the replies, but I think I might not have been clear in my question. I know how much output (theoretical) power should be. What I am trying to find is a formula to figure power supply needs. I know the voltage and current needed for one module (mono, single ended), how much is needed for two modules in BTL, that is the formula I haven’t been able to find. Thanks.

[sreten]

Hi,

BTL has the same power requirements as the two separate channels
into half the load connected, i.e. for an 8 ohm load it is the same as
for two channels into 4 ohms.

Generally speaking small amplifiers are not good into low impedances
and are therefore not suitable for a BTL amplifier unless the load
impedance is unusually high.

/sreten.

[AndrewT]

Hi,
if you know the power and smoothing requirement for a single amp then the power AND smoothing requirement will go up roughly 4times.