Running Benchmark AHB2 in bridged mode and 4 Ohm Speaker

@georgehifi look at the following from Benchmark AHB2 manual page 22.

Signal to Noise Ratio
132 dB A-Weighted, Stereo Mode
135 dB A-Weighted, Bridged Mono

Distortion
THD+N
1 kHz, 80 kHz LPF, at full rated output into any rated load 
   < -118 dB (< 0.00013%) - Stereo Mode
   < -118 dB (< 0.00013%) - Mono Mode
THD
1 kHz, 20 kHz LPF, at full rated output into any rated load 
   < -119 dB (< 0.00011%) - Stereo Mode
   < -120 dB (< 0.00010%) - Mono Mode

This only leaves damping factor. 

Any thoughts?.

geek101 OP
Any thoughts?.

Yes! believe me? it’s in the wording, you need to read like a tech to find the tricks, as this is very misleading to the novices, as the last two distortion figures are NOT I repeat NOT in bridged mode, but measured one mono channel only.

Then find the output "current rms" output for a single channel and then what it does with two channels in bridged mode. And you couls also do peak current for both.

Then find the damping factor single channel and compare to bridged.
Also the output impedance for both, which is in relation to damping factor.

Cheers George

Quote from instruction manual:

The AHB2 power amplifier can be run in two modes: 

 STEREO mode - Two output channels 

 MONO mode - One output channel in bridged mono 

The bridged MONO mode will deliver almost 4 times as much power into an 8-Ohm speaker, and will do so without any increase in distortion. The MONO mode is an excellent choice for high-power applications. In MONO mode, two amplifiers will be required for stereo operation. 

kijanki3,

we still don’t get the full Bridged spec picture.
There are no specs accompanying these copy/pasted excerpts you put up, again misleading, if you are referring it back to the other figures on the other page that geek101 put up.

Lets see both distortion graphs THD+N  and THD for both bridged and non bridged into 4ohms or less. This will be the true test of what the OP wants to do.


Cheers George

Here you go: Page 26 "performance plots" fig. 1, 2, 3

https://cdn.shopify.com/s/files/1/0321/7609/files/AHB2_Manual_-_Rev_G.pdf?6581480924542235084

These plots show almost identical THD at 4 ohm, 8 ohm and bridged 8 ohm max power. As for damping factor - it does not make any difference, since it is already very high.