Class D amp driving Thiel


I was honing in on a 2 channel system and had seriously narrowed down the contenders until last Saturday. After not being impressed with a pair of B&W CM7's I was encouraged to listen to a set of Thiel 1.6.

It was amazing. Driven by a Bryston amplifier they had detail and precision with beautiful tonality. Yes, they did lack bass under 50 hz. But completely different and world's better than the Thiel's I owned and powered with tubes years ago. So now I have to rethink things. I have only a small shelf for the SB3 and amplifier and can't fit (or afford) anything above 30 lbs or 5 inches tall.

Maybe a second hand Krell 400xi would work but Krell's rap is that they can be bright and fatiguing. And I can't do anything bigger or costlier. While the Naim forum has good reports of Thiel's being driven by even a Nait 5i I am a little cautious based on my previous experience. As I learned the hard way you have to muscle up on Thiel's or they sound bright and nasty.

So, the thought of a class D amp came to mind. Small, light, and powerful. Though I haven't even heard one before (hard to find them in Chicago, believe it or not) my interest is piqued. But would it be up to driving the load I am contemplating without getting bright or harsh? Any thoughts but more importantly experiences are appreciated.
wdrazek
Only Spectron Musician III Signature. With power of 1400 watts into 2 Ohms and stability up to 0.1 Ohms it can drive any speaker on Earth!!!! I know its synergy with Martin-Logan, Shahinian Acoustic, Apogy and few others. Plus immensely musical!!!
Steve, Unfortunately I can't seem to veryfy it but, I believe the unique TacT class D (perhaps the only true class D) amps (on the other hand perhaps they're not amps at all?) can pass a square wave.
Auh, I just got a new QSC PowerLight 380 for my Electric Bass rig and while it's not exactly intended for High Fidelity it definitely puts a grip on things. This is my third QSC and it never fails, people can be very hard on my gear with loading and unloading but I've never had a failure in the fifteen years I've been using their gear.

Another established and reputable amplifier manufacture who has embraced class D. Below is a description from their website


Products / Amplifiers

PowerLight 3 Series
Professional Power Amplifiers

The PowerLight® 3 Series is designed for the most demanding live audio users, whether in touring rigs or fixed installations. The most requested features of the PowerLight 2 series have been upgraded to deliver "the ultimate analog amplifier", while the QSC Dataport ensures full compatibility with advanced digital processing and QSControl. Three models range in power from 1250 watts to 4000 watts per channel at two ohms, all in two-rack space chassis that are only 15.6" (40 cm) deep and 22 lbs (10 kg).

In addition to higher power, the PowerLight 3 Series offers higher input voltage, selectable sensitivity, and easily adjusted rear panel switches with color coded LED indicators. For those users who simply want a high performance amplifier to go with their existing processor or console, the PowerLight 3 Series is an ideal choice, offering high power, excellent value, and zero signal latency. When complete integration of amplifier control, monitoring and DSP is desired, the PowerLight 3 Series is fully compatible with the QSControl BASIS networked audio platform, with its comprehensive drag and drop DSP functionality. Simpler DSP requirements can be met with the DSP-4 processing module.


PowerLight 3 Power Amplifiers
Watts at Clipping
Watts per channel
Model 8 ohms 4 ohms 2 ohms
PL325 500 850 1250
PL340 800 1250 2000
PL380 1500 2500 4000*
EIA 1 kHz 1% THD
* Burst mode testing required due to AC service current limitations
The flagship of the PowerLight 3 Series is the new 8000 watt PL380. This highly refined, all-switchmode amplifier incorporates nearly 40 years of QSC engineering experience, resetting expectations for Class D audio quality. The PL380 combines a pair of 4000 watt Class D amplifier channels with the well proven PowerLight supply, to deliver more than twice as much audio power as previous 2 rack unit PowerLight amplifiers. Reactive "back EMF" from the speaker is recycled to the power supply, and unmatched "plug-to-plug" efficiency of 85% keeps AC power needs to a minimum, while delivering more energy to the speaker.

Years of patient development have resulted in outstanding 20 - 20 kHz audio performance, plus complete protection from normal hazards of the trade. Even simple features such as dependably silent, surge-free on/off switching indicate the special care taken to keep things safely under control. The most pronounced "sonic signature" of the PL380 is one of immense headroom, sailing through even the most difficult loads with no signs of stress or change of tonality.

In keeping with normal QSC design standards, back-to-front airflow provides up to twice as much long-term average power as most competitors, without dumping hot air into the rack. All PowerLight 3 models are built in the same chassis size, with common back panel layouts to facilitate easy racking and hookup.