Ruby for bass?

[Gurner]

> for more headroom

If you need headroom, MORE POWER, don't use LM386.

By bridging two LM386s you do get more headroom though, because when you bridge - for the same power - you can reduce the signal voltage into the load by half, which means the signal into the load doesn't then need to be as 'hot vs  single ended.

Single Ended...
Signal   8.00V (peak to peak)
RMS   2.83V
Load   8.00Ohms
Current   0.35A
Power   1.00W
      
      
Bridged...      
Signal   4.00V (peak to peak, but on each load leg)
the above is effectively 8V 'differentially' therefore...
RMS   2.83V
Load   8.00Ohms
Current   0.35A
Power   1.00W

So for the same output power you've won back 4V of headroom, which is you're on a 9V supply is a massive win..

[PRR]

> Signal   8.00V (peak to peak)
> RMS   2.83V
> Load   8.00Ohms
> Current   0.35A

The 0.4A limit on LM386 is "peak".

The maximum swing into 8 ohms is 0.4A+8= 3.2V peak, 6.4V peak-peak.

Add ~~1V-2V for device drops, anything over 7V or 9V supply for 8 ohm load is excess heat, NOT potential output power.

Look at the datasheet curves:



Single-ended into 8 ohms, Output Power increases from 6V to 9V. But it hardly increases from 9V to 12V, and does not increase at all from 12V to 16V. Instead the heat in the chip is rising.

Max power into 8 ohms is 0.75W-0.85W.

Bridge into 8 ohms is equvalent to two single amps into 4 ohms each. At 4 ohms the Output Power is the same for 6V, 9V, or 12V, 0.35W. Two such amps bridged gives 0.7W, a trace less than a single amp at 9V.

An amp can be limited by voltage, current, heat, or other factors. The LM386 is typically VERY current-limited. Raising the voltage past whatever gives 0.4A peak does not increase load power, only chip-heat and battery-drain.

[Renegadrian]

[ayayay!]

Isn't a Maestro Brassmaster kinda octave up & down at the same time on the lower notes, then more more like a treble booster on the higher ones?  Just a thought.