F2 transconductance amp for Bass or Class D

[vizion]

Hi Guys,

I only need a few watts. Which amp would give the fullest bass, a transconductance amp or Push Pull Class A ? I am driving a vintage Cerwin Vega 15-incher. Listening at low volumes is the norm.

Thanks.

 

[gadut]

this post might help

http://www.diyaudio.com/forums/mult...fle-woofer-what-important-10.html#post5047584

 

[Nelson Pass]

You can take a look at my piece on current source amplifiers which shows
graphics of the differences in bass response.

http://www.firstwatt.com/pdf/art_cs_amps.pdf

 

[vizion]

Thanks, Nelson

 

[2 picoDumbs]

If you only need a few watts then Class A.

 

[OllBoll]

Normal dynamic speakers don't perform well driven close to fs by a current source. The distortion rises dramatically. They are, however, extremely awesome above say 4x fs.

Let us use a 6ND430 I tested a few years back. There is a thread somewhere (The NCore I think but I don't remember exactly) where Bruno Putzeys discusses the technical why when motivating why the bassmid amplifier in the Grimm LS1 behaved as a voltage source close to fs but changes to a current source above.

I use Class D voltage sources for my subs.

 

[Nelson Pass]

Normal dynamic speakers don't perform well driven close to fs by a current source. The distortion rises dramatically. They are, however, extremely awesome above say 4x fs.

Maybe. There is some data posted over in the Blowtorch thread that
current source drive lowers distortion, but it was taken at resonance in
a bass reflex, which I think makes it a flawed experiment.

My own tests show marginally more harmonic distortion in general with
current source drive.

And you have to keep in mind that the driver also has greater excursion
at resonance, which is why the response is bumped up.