I've started to get interested in the switch-mode power supplies, but I'm confused by how the various amplifier makers use them. My current investigation is into the B&O ICE modules and Jeff Rowland amps.
From what I can see on the ICE web page, they only sell complete amplifier modules. If that's so, what does JRDG (or Bel Canto) do with them? I'd thought that ICE would supply the power supply and the output stage was then up to the end user...
Yes a FULL explanation probably would clear up a bunch of stuff.Like damping factor ,just exactly what difference is there going from 1000,2000 4000,my amp has 75 and if its on the disc to begin with there is big time bass,but it has to be on the disc,and pretty much every disc i listen to is different ,i suppose it depends on the recording,they are all quite different.As far as bass went anyway with the amps i listened to it wasnt any better anyway,if anything there was way to much.I'd say the most confusion is how can a module that cost hundreds translate into a product that sells for thousands?Oh its the implementation,sure it is.
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.
I don't think Onkyo uses an ICE module for its A-9555 class D integrated. Its damping factor spec is a mere 25, but you'd never know if from the sound in my rig. It's clean, tight, full, and extended. Anything but woofy or characterized by overhang. And I've been A-B'ing it with a VSP TransMOS 150, which has a damping factor around 1000.
In my rig, to the Onkyo's advantage (concerning damping factor) the woofers are a mere 5.5" in diameter, but to its challenge, one is augmented by a passive radiator and the other by a tuned port. Yet the bass is clean and totally tuneful.
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).
Amps with high damping factors can cause a reduction in perceived bass in speakers with limited low frequency capability. For example, when the midrange driver is also handling the lower frequencies.
The was an article at 6 Moons a while back discussing the optimum damping factor varying by speaker design.
Damping factor is not a ICEPower characteristic per se. There's been a lot of discussion of DF in other threads. DF is only one of a series of things to consider when matching a speaker and amp and maximizing the amp's ability to control the speaker's drivers. Some speakers need a lot of damping and others do not.
He's not going to tell you exactly what he does, but Rowland does a lot of things beside add Power Factor Correction to his latest amps (Continuum 500 and 312). He does enough that representatives from B&O have a hard time recognizing their ICEPower units. What matters is how well it works. Listen and hear for yourself.
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.
Yeah, the 102, 201, 501 and Capri are out of a single billet of aluminum, with all the attaching points machinced in to .003" tolerance. They're incredible. The face plates on the 312 and Continuum are single billets, the sides and backs are billet also, but "only" about 1/4" thick. Rowland was the first with this and now others are copying, even using the same supplier that he pioneered with.
Join the confused club. PSAudio makes use of the 3 different ICE modules in the GCC series of 'integrateds'. 100/200 250/500 and 500/1000.
What difference would it make if the ICE manufacturer didn't warranty a modfied module, if the Modifier DID?
Specs are *nearly* meaningless and I treat them as 'advisory' only...a pointer if you will. And yes, DF is also near-meaningless. speaker load as in 'easy' or 'hard' is only part of it. Phase angle, and impedence are also factored in. Add in efficiency/sensitivity and there 'ya go. Do my panels make much use of hi damping? I don't know and don't care....they sound fine with good, tight bass to the panels limit. While not overpowering, they wouldn't be so regardless of amp used...and I have the GCC250 which is 500 into the Maggies 4 ohms. There are bunches of applications of the ICE modules and other class 'd' stuff out there. cold power, International Recitifier, and others. I am currently trying to get my hands on the IR demo board to see what they came up with in the 60/side end of things.
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.
I agree. ICE power would and IS a good choice for my Maggies. I use the PSAudio GCC250 to good effect. I think, however, you've got it a little backwards. You can buy the ICE modules or the ColdPower or any of 'em and than be responsible for the Power Supply yourself. The IR unit, for example, needs up to about +-35v, so 5x6v GelCells would work fine. Oh! I work for IR and have spoken with the designers::
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)
My understanding is just the OPPOSITE. Manufacturer of the module makes the output/driver section and the USER supplies the power....be it SMPS or a nice big Toroid and a large selection of caps. I will investigate if the ICE modules have an integrated PS. I know Cold Power and IR stuff DOESN'T. It seems that if you bought a BUNCH of modules and were willing to warranty them, you could pretty much do as you please....change stuff for 'better' sound or even proprietary reasons...My GCC uses GainCell technology on the input side, for example and has some unique (selling point) claims. If all ICE module users were using modules from the same menu, they'd all sound VERY similar.
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.
For those interested in the ICE amps, applications and some detail, please try this:: http://www.icepower.bang-olufsen.com/en/downloads/ It is a complete list of available products and some downloads. Looks like the ASP series comes with on-board power which can also power an 'A' series module....Can you say Bi-Amp? I am unable at this time to get at the Product OR DataSheets for the ASP series. Hope you have better luck
Just coming to similar conclusions. Also, some of the 'd' amps run at 400khz which makes it even easier to filter out.. I'm sold! My GCC is a monster and Easily has my Maggies at full potential. Now, about those pesky fuses!
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.
The point you raised yesterday was the heart of my question. I'd seen the www.icepower... link and thought to myself: if everyone is using the same modules, won't the amps sound the same?
Kijanki and Dcstep have a partial answer: the lower cost Rowland gear is apparently similar or identical to the competition (say, Bel Canto); however, the higher cost Rowland gear has more modificaitons and may sound different.
I wouldn't expect Jeff Rowland to give precise descriptions of any modifications he makes to an ICE Power module when he uses it, but I would like a general sense of why his products are different than some other company's that uses the ICE Power units.
Macdonj, on the 312 and Continuum 500 one huge difference is the addition of Power Factor Correction. ICE and D can really spike the mains and cause harmonic currents that can be audible. The PFC presents a more sinewave-like load to the mains and eliminates the harmonic currents. Additionally, the PFC converts AC to 385 volt DC, giving ample, clean power to the unit. The DC operation also helps with quietness of the pre-amp stage, approaching battery power style low noise levels. (PFC can be added to most current JRDG products with his PC1 unit).
Add to that, dual-mono, fully balanced operation for the Continuum, short signal path lengths, heavy aluminum billet chassis, internal and external isolation from EMI and RFI and you end up with a total package that's beyond most of the competition. Jeff pays attention to each wire, trying different materials to arrive at what he considers the truest (most transparent) sound.
Jeff's chassis alone adds significantly to cost (even on the lower level 102, 201, 501 and Capri), but they aren't just things of beauty. They're functional parts of the RFI/EMI control scheme. With ICE and Class D this is very important because of all the energy given off by the unit itself. Combine that with a nearby CDP and it gets very important. My Continuum 500 and Playback Designs MPS-5 CDP are right next to each other in a tight armoire, with a gaggle of wires cramed in behind them. Despite all that potential, the system is almost dead quiet.
Jeff creates very elegant designs. Look inside his Capri preamp and you'll be amazed at how view circuits there are how clean things are. His phono modules are the size of the last joint of my little finger, yet they compete with Levinson, Sutherland, Manley, etc. for resolving capacity. The phono circuit is utterly quiet in my setup.
Clean and simple is a core philosphy to Jeff. He lives by that and it pays off in the results.
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.
In fact, on the Continuum the large flat surfaces of the chassis are ridged, to refract sound waves in those cases where it might be close to speakers. The tolerances on the Rowland chassis are .003". The nibs and screw threads for mounting boards, etc. are machined in, to the same tolerance. Like I said before, the Rowland chassis is no mere cosmetic design exercise, even though he highly values esthetic appeal.
Thanks for the report on JRDG equipment. I knew from past reviews that Jeff pays attention to things like case design (Stereophile made special note of it in their review of the Model 2). However, I've never been able to look into one of his components and the "official" web is mum on the modifications and particulars of the application of the ICE units. So, thanks again for spelling it out, that's exactly the information I was looking for.
A few yrs back, I bought a few Acoustic Reality ICEPower monoblocks to drive my then Revel Salon.
The ICEPower monoblocks made me sell my Mark Levinson No.33H that I used to drive the Salon.
ICEPower is simply fantastic.
I now use a DarTZeel but kept all my Icepower stuff...I plan to build an ICEPower based HT...
btw, anyone know how the new ICEPower modules compare to the older ones? The new ones supposedly has much higher current then the older generation... but what else?
I haven't heard the DarTZeel equipment yet, but I'm very confident that it's stunning; given the reviews I've seen from trusted sources.
However, it's interesting to compare DarTZ and Rowland to see that there's more than one way to skin an audio cat. Inside the DarTZ pre-amp there's a whole infantry of cards lined up, filling a relatively large case. In the amazing Rowland Capri preamp there's almost nothing, with phono cards about the size of the last joint of my little finger. Both work, apparently very well, but the design approaches are worlds apart.
BTW, the Rowland is designed by one guy and, I suspect, the same is true with DarTZeel. I know for fact that Rowland feel very strongly that his approach is "right" and I suspect that the DarTZ designer feels the same way.
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.
Audiobb, do you mean a raw modules on which to build your own amplifier? If so, I think that you need to be a builder, but B&O is the source, or the ICEPower division of B&O. Do a little Google or Yahoo search and you'll find them. I don't think that they license others to sell just the raw units, but I'm not certain.
Hi Dave, Yes,that is what i mean.Raw modules on which i can build my own amp.I am a DIY guy,i don't own audio bussiness. On ICEpower/B&O website it states there are no sales to individuals.I haven't contacted them,but i will.But i do believe there are some places where you can buy modules,just don't know where.
Ric Shultz was making some ICEPower amps and I believe that he stopped. Maybe he'll sell you an module or two if he has any left, or he can give you leads on where to find them.
Just took delivery of an International Recitifier AUDAMP7S stereo half-bridge class 'd' amp. I'll be trying to build a battery operated 2nd system with it. Unfortunately, it has NO built in PS, so it is either battery of +-55v or so....or the hardway of a conventional or SMPS. There are NO 'exotic' parts....caps and resistors all appear to be off-the-shelf. I wish I could post a picture! Kijanki, I don't know if I mentioned this before, but I WORK for IR, in the 'fab' making power and other semiconductor devices. I have spoken to the design guys and they will eventually make a house call to listen to there stuff in a Magnepan system. The voicing of these amps was not a major concern though many panel type listening tests were conducted.
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).
Yep, been in touch w/designer. He had to tell me about the 'bridge' switch.....basically 2x juice MONO! Can you spell 's u b a m p'?? My first (guess / intent / urge) is to go with 4x12 gel cells for each rail....This will give REAL clean low ripple power and allow me to hear it at its best and perhaps also allow the sound of various power supplies and associated components to be fairly evaluated. I suspect that with appropriate hi-sensitivity speakers, no need will ever apparent for more than 2x20 watts....which with appropriate speakers will drive you out of the room. 5amp hour batteries will provide 60 watt hours so should be enough for several hours of LOUD listening. Actually, 50v at 5amps is 250 watts, x2 rails.....well, you can do the math! I'm just confusing myself. Believe me, I've read the Hypex / ColdPower stuff avidly. This is what got me started on this kick in the 1st place. I was even thinking of springing for a HYPEX power supply and the 180 transformer. Should 'bout do it? If I could post a picture....can you post here? I'd setup the macro and get out the AlienBees (lots 'o light, trust me) and take a few pics. My buddy at IR is pretty helpful and one day I'll have him over for a listen and some Single Malt. My PSAudio GCC250 really likes the Maggies.....it should be a fun comparo:
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.
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