Icepower modules are complete amps, many of them with universal (90-240VAC) SMPS built in. As for usage by JRDG or Bel Canto - it depends on the price tag. The least expensive amps based on Icepower 200ASC (100/200W) just have addition of metal case and connectors - that's it (in case of Rowland's model 102 there is additional differential amp THAT1200 at the inputs). More expensive units like Rowland model 312 have even power isolation transformers built in.
B&O does not allow any mods to their Icepower units (voids warranty) but manufacturers like Rowland might do some mods anyway or order units with specific mods at their request. Until now Icepower was not selling modules to public, but recently Icepower was bought back by B&O (Karsten Nielsen left company) and now some vendors started selling them.
Damping factor at low frequencies is limited by the resistance of the inductor in series with the woofer to about 100. To avoid lowering it further an order better amp's DF is more than sufficient. At 20kHz similar limitation is placed by the speaker's cable inductance. |
Johnnyb53 - Onkyo is 85W and the smallest Icepower, as far as I know, is 100W/8ohm.
Damping factor is a little confusing. My Icepower has DF=4000 at low frequencies. Is it the reason for its tight bass? Atmasphere transformeless tube amps have DF=1.5 and very good sound.
Sometimes I get impression that sound is inversely proportional to specifications. Buying gear by good specifications is probably the biggest mistake.
As for small woofers - ask any bass player about bass rigs with good bass definition and he will tell you to look for stacks with a lot of 10" speakers. Larger 15" or 18" are also in use but have poor definition.
Few small speakers are far better than one large - just look at Dali Megaline design (perfect). |
Dcstep - My Rowland model 102 has two 200ASC modules inside (identical to picture in datasheet of 200ASC) and nothing else - just case. It is pretty much the same amp as Bel Canto S300 with different case. There might be some tweeking involved. |
312 is expensive while 102 is cheap (same price as Bel Canto but better finish). Rowland's cases/finishing is beyond believe. |
Magfan - IR published paper (google it) on class D with complete design (schematics, PCB etc). Your Maggies are power hungry and Icepower might be a good choice. |
Magfan - why not to buy Icepower modules with power supply built in like 200ASC? Switching power supply, when done right, can be better than linear one (also smaller and cheaper) |
Magfan - about half of Icepower modules have built in SMPS including mentioned 200ASC used in Rowland's 102, Bel Canto S300 and PS Audio Trio.
SMPS can put as much power thru 2" toroid at 100kHz as 10" dia, "big nice Toroid" at 60 Hz. In addition 100kHz is not audible and easy to filter out while 60 Hz is audible and difficult to clean. SMPS is regulated while linear power supply is not. |
Magfan - there is still some residue (about 1%) of 400 kHz but it is not harmful. Switching transients were already removed by output filter and 1% residue of 400kHz will radiate at 1/4 wave if speaker wires are longer than 615 feet. |
According to one of the editorial reviews (can find it) Bel Canto's S300 suffers thin lower midrange but after placing it on anti-resonance cones sound becomes fuller. Rowland's case is milled from billet of aluminium. |
Jeff Rowland hasn't released bad product in over 20 years. When he switched all amplifiers production to Icepower technology I seriously got interested and eventually bought one. If it's good enough for Jeff Rowland it's good enough for me. In addition Rowland gear used to be obscenely expensive and now offers good bang for the buck. |
Wonderful_electric - I put blankets over my speakers to make sound of my Icepower amp less detailed, gracefully warm and relaxed. |
Magfan - I know the IR amp - whole project with schematics and PCB was available on their web site. I like SMPS if designed right. They are regulated and work on non-audible frequency that is easy to filter out (not to mention efficiency). Layout for switching power supply is not a trivial thing and requires detail knowledge of chip's operation. SMPS are also much stronger for the size since 2" toroid at 100kHz can deliver as much power as 10" toroid at 60Hz. Unfortunately designers try to save money and often undersize SMPS.
Half bridge class D amps like your IR or Hypex sound like very good SS amp while full bridge (Icepower) sounds a little toward good tube amp (DIY forum). Full bridge also carries DC equal to half of supply voltage on speaker cables (relative to ground).
If you build your own standard power supply investigate "slit foil" electrolytic capacitors (used in Hypex kits) - very expensive but fast. Cuts in foil break induced currents and lower effective inductance.
Let me know how you like it when you fire it up. Icepower patent is just one of many variations on Sigma-Delta A/D.
Class D without sigma-delta modulator was only good enough for guitar amps since Mosfets were slow and just in recent years Mosfets got much faster (carrier moved to 0.5MHz or better). |
It is much better than few hours. Typical average power is only in order of few percent of maximum power and your 60 watt hours battery might give you 20 hrs playtime. Why don't you connect permanently slow/trickle charger. It will recharge over night and during usage won't be "visible" because of extremely low impedance of battery. Be carefull and wear glasses since you're dealing with batteries (no current limit).
2x juice mono is nice when you bridge half-bridges but people often forget that it quadruples power while power supply is only doubled - good for high peaks though.
As for speakers sensitivity - distance is even more important because sensitivity will get you only around 3dB (twice power) while half distance to speaker is 6dB (4x power). Maggies are not the point source and it might drop much slower with a distance but they are not beating sensitivity records.
I've heard a lot of good things about maggies but boy - are they huge!
20W is not bad because it is only half of the 200W loudness.
Avoid 180W (smallest) Hypex - even Channel Island D100 uses larger one (same as D200 at lower voltage). Look at D100 construction - very nice design. Monoblocks in small u-shaped chassis with torroidal transformer attached to front wall. They use a lot of small caps to drop ESR.
Somebody mentioned that they (Channel Island) modify Hypex but I don't know how. We are still on the subject of this thread but it gets more technical than perhaps Macdonj had in mind. |
