Hi Drummerman,
I'll try to answer your questions!
The amps are made by one of our main suppliers to our specification, we use various companies for cabinets, amps, drive units etc. Nothing we have made for us is "off the shelf" though, all is to our design and spec and we have very good long term relationships with these suppliers so they know our standards well. Some of the more expensive drive units are still hand-made in Cirencester, the Actives are all hand-finished and tested here too. They have a +/- 1dB tolerance from the reference.
The amps themselves were developed back in 2012 and we still have the original set running in a prototype pair of the Actives, they are basically unchanged from then and that original pair has something like 5000+ hours use on them with no problems. We ran them all day, every day for radio listening in our sales office for a couple of years as part of our long-term durability testing (they sounded better than our old radio too.
) We also showed that pair at the Munich show in 2014 and ran them at full volume from an iPad for the duration to much praise from listeners! (Input sensitivity from the RCA's has since been increased for the purpose of plugging in mobile devices with lower voltage outputs).
We chose class A/B primarily for sound quality; class D is very good now but in our testing at least the class A/B sounded a little sweeter in the treble and subjectively a touch more natural and "musical" to our ears. 50w per drive unit was chosen as an optimum which offers more than enough power, but for short bursts shouldn't be too much to blow drive units if something is plugged in at full volume (there is also an internal fuse for backup). Practically it was also the largest output amp that wouldn't require additional external heatsinks, the rear metal panel being sufficient, it can get quite warm but never too hot.
Some internal pics:
And specs (from the manual):
Input Sensitivity*1 104dB for 1VRMS @ 1kHz
Bandwidth*2 42Hz-28kHz
Horizontal coverage*3 130 degrees
Vertical Coverage 120 degrees
Peak SPL*4 115dB
Maximum SPL*5 105dB
Amplifier Class A/B with linear power supply.
Amplifier Power LF: 50W
HF: 50W
Crossover 3.5kHz 4th Order Linkwitz-Riley
Woofer 140mm chassis with Alu/Ceramic cone.
Tweeter 27mm Alu dome with WDT waveguide.
Cabinet 18mm MDF with bracing and damping panels.
Inputs RCA and Balanced XLR
Controls Volume adjust 0dB to -inf
HF shelf +/-2dB
LF shelf +/-2dB
Power connection IEC C13
Voltage selection Manual switching
*Notes:
1 Measured at 1m using pink-weighted MLS noise.
2 Measured at 1m using pink-weighted MLS noise, +/-6dB limits.
3 Measured at 1m using pink-weighted MLS noise, +/-6dB limits.
4 Measured using a toneburst signal.
5 Measured using a band limited sine sweep.
Let me know if there's anything else you want more info on!
Cheers,
Jim.