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Bridging an amplifier

I recently watched a YouTube video, a few years old, that featured Flemming Rasmussen, the highly regarded founder and engineer for Gryphon (now retired I believe). Flemming was speaking of his class A monoblock amplifiers in the Antileon Evo, Colloseum and Mephisto. Flemming was expressing his disdain for Monoblocks that are actually 2 internally bridged amplifiers, (such as DNA 500,Clayton M300s and also class A Luxman that can be used as Monoblocks in the BTL mode (bridged tied load), calling these types of Monoblocks inferior and not true Monoblocks. He claims dedicated Monoblocks where all push pull transistors are paralleled, are vastly superior to summing the two channels via bridging (antiphase summing). I’d love to know if most audiophiles and engineers agree with Flemming. I have owned and found both the DNA Monoblocks and Clayton M300 Monoblocks to sound excellent, and a friend uses two M-800A Luxman class A amplifiers in bridged tied load mode (BTL switch) with great clarity and power. Thank you for your thoughts!
audiobrian
audiobrian OP
186 posts
 
I only recently viewed the additional contributions to this thread I started 19 months ago. I appreciate the additional input. From what I gather, audio2design, dedicated bridged amplifiers can be every bit as good or better than non bridged parallel designs if implemented well. Perhaps this is why Constellation, Naim, PS Audio, McCormack, Clayton, and others build dedicated bridged amplifiers to great success.
As these manufacturers use robust power supplies, the extra current required with bridged designs is not terribly compromising even with lower impedance loudspeakers? Thank you!
georgehifi's avatar
georgehifi
10,312 posts
 
and others build dedicated bridged amplifiers
Yes a dedicated bridged mono block amps, but not stereo amps that have just been bridged, just to gain more wattage.
There is a big difference in how they will both perform. Re first post (Gryphon’s Flemming Rasmussen) and Almarg’s 5 post down.

The point here is, members are looking to bridging their stereo amps getting another one and doing the same, you end up with a pair powerful PA type amps where you once had quality stereo amps, and what Odyssey does with their monoblocks just their stereo amps bridged, or they used to be when the AU agent showed me the insides.

Cheers George
audiobrian OP
186 posts
 
Thank you, George!  I thought the Clayton S2000, a dedicated bridged balanced design, sounded too good to be characterized as an inferior topology. Just stay away from switching  stereo amplifiers into bridged mode. Got it.

audio2design
1,351 posts
 
George,

That is an assumption (stereo amps will be worse bridged) that is simply no guarantee of the truth. Since I know you love Class-D so much, here is one test (read to the bottom, test of a Monoprice amp).


https://melp242.blogspot.com/2019/05/measuring-bridged-and-balanced.html?m=1

However, lets go mainstream and look at the AHB2, figures 4-6. In this case, the distortion is a bit higher into 8 ohms, but we are already at exceptionally low distortion in both cases:
https://www.stereophile.com/content/benchmark-media-systems-ahb2-power-amplifier-measurements

Final result is going to be implementation specific.  Total distortion may not give the best indication of results depending on what the "offending" harmonics are w.r.t. listener perception.
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