Hey guys, i want to upgrade my HT, its just an 5.1 channels. I want to sold the Receiver and want to use dedicated amps for each channel, i want to get at least 200Watts per channel. i really want to know if buiding and classD amp will get nice sound, (comparable with comercial ones like Rotel RMB-1095)?
I want to drive a pair of Polk LSI Series Speakers.
I want to drive a pair of Polk LSI Series Speakers.
Class D used to ultra low-end, and with the advances of technology they are becoming more mainstream.
Do your question to Jeff Rowland, Audio Research, Halco etc...
see : http://www.jeffrowland.com/ConcertoInt.htm
see : http://www.jeffrowland.com/ConcertoInt.htm
Asking if it's "high-end" is the same thing as asking if it's expensive. Class D's not. But it can sound pretty good, or expensive if you like.
mm i understand, but will be better to use an A/B or Class D amp?
or is not possible to get an answer like that?
i know that class D is great for high power amps like 1000w+ for subwoofers or stuff like that, but dont know for mid and hig frequencies.
or is not possible to get an answer like that?
i know that class D is great for high power amps like 1000w+ for subwoofers or stuff like that, but dont know for mid and hig frequencies.
There's no clear answer to that I don't think.
In terms of efficiency there's a clear answer. In terms of performance, probably in either case it depends on the amp itself and how well it's been implemented. Better amps cost more money, period, so how much you're willing to spend to get to your expectations is the deciding factor, unless it's the ultimate in power you're after.... what do you want?
Do you expect to cram 7 amps in a single case because it takes up less room... then you compromised performance in a big way, but also saved a good deal of money.
Is the ultimate in performance all you want, cost no objective? Full monoblock, or multi amped active speakers even better. That's about the ultimate you can get and I would sure as hell do it with D amps tweets and all.
Could you maybe buy a better commercial class a/b receiver for the same price as a commercial class d receiver? Very likely!
In terms of efficiency there's a clear answer. In terms of performance, probably in either case it depends on the amp itself and how well it's been implemented. Better amps cost more money, period, so how much you're willing to spend to get to your expectations is the deciding factor, unless it's the ultimate in power you're after.... what do you want?
Do you expect to cram 7 amps in a single case because it takes up less room... then you compromised performance in a big way, but also saved a good deal of money.
Is the ultimate in performance all you want, cost no objective? Full monoblock, or multi amped active speakers even better. That's about the ultimate you can get and I would sure as hell do it with D amps tweets and all.
Could you maybe buy a better commercial class a/b receiver for the same price as a commercial class d receiver? Very likely!
One thing to keep in mind is that it seems, as a generalization, that quantity of power is inversely proportional to quality....
There are certainly small class D amps that seem to be of comparable quality to the better of Class A SS & tube amps (not from personal experience yet -- i have a set of Brian West's 10W modules on the way)
dave
There are certainly small class D amps that seem to be of comparable quality to the better of Class A SS & tube amps (not from personal experience yet -- i have a set of Brian West's 10W modules on the way)
dave
True, yet the quality of that power in a good D amp is maintained at low levels, and the ability for much greater power/cost is unmatched. Having higher power ability does not mean that you have to give up quality at normal listening levels. You might find that sort of argument made by someone who makes a bad amp though.
For example I've heard Nuforce people say that it only sounds good at low power, therefore, the amps must be low power and speakers must be efficient.
They've failed in their meager attempts at addressing EMI though, so obviously quality goes to hell when the current starts to flow.
It not usually a good idea to over generalize things. The whole point to a good D amp is to attain higher levels of clean power than was possible before, or at least affordable.
For example I've heard Nuforce people say that it only sounds good at low power, therefore, the amps must be low power and speakers must be efficient.
They've failed in their meager attempts at addressing EMI though, so obviously quality goes to hell when the current starts to flow.
It not usually a good idea to over generalize things. The whole point to a good D amp is to attain higher levels of clean power than was possible before, or at least affordable.
One very important ingredient of a really good amp is the power supply. Because class d amps are much more efficient than other topologies you don't need a huge beefy power supply to get great performance. Conversely, a really good power supply makes them sound that much better!
What's amazing is that class d amps get more efficient as the power output increases. That is in stark contrast to class a and ab where power output peaks and then starts decreasing.
My little modules are good for about 7Wrms into 8ohms and about 13Wrms into 4 ohms and nothing on the board even gets warm when putting out maximum power into 8 ohms. Other higher power class d amps perform similarly in terms of heat dissipation.
What's amazing is that class d amps get more efficient as the power output increases. That is in stark contrast to class a and ab where power output peaks and then starts decreasing.
My little modules are good for about 7Wrms into 8ohms and about 13Wrms into 4 ohms and nothing on the board even gets warm when putting out maximum power into 8 ohms. Other higher power class d amps perform similarly in terms of heat dissipation.
BWRX said:
I think it is just the opposite: because most of class D amps have very bad PSRR, they need much beefier power supply to work. You can check out how TI proposed to control volume on its Class D chip set by changing power supply voltage.
One exception to that is the amps with feedback, aka the UCD.
BWRX said:
Hmmm - as I understand it, class-d reaches maximum efficiency very low in power curve. In other words, for a 100w class-d it is as efficient at 10W as it is at 100w - which would be like 90%
Class-ab doesn't reach it's maximum efficiency until its approaching full power. At 10w it'd be like 25% efficient, reaching 90% at full power.
As far as efficiency Vs output in a D amp it will be affected by type of modulation .... self oscillating amps would get more efficient at higher output though, because they usually aren't fixed frequency and it slows with increased power output.
An amp really should have feedback. As far as I know, there hasnt' been a good amp designed without it yet. TI speaks in terms of marketing their products as does Zetex and all the others. I find it best when looking for an example to follow to look up to those who've actually achieved their design objectives and had success in the market, rather than with marketing.
An amp really should have feedback. As far as I know, there hasnt' been a good amp designed without it yet. TI speaks in terms of marketing their products as does Zetex and all the others. I find it best when looking for an example to follow to look up to those who've actually achieved their design objectives and had success in the market, rather than with marketing.
well, so what do you guys recommend me? my budget are 2000u$s, i need at least 5 channels i was thinking abt rotel 1095 (200wx5). i will use an Rotel RSP-1068 as processor. Maybe building my own Amp will give me an nice looking system, (coz i can made custom boxes for each amp), but what abt quality? 😀
i really want to move away from receivers, i just want to build an good system and easy to improve/upgrade.
im tyred abt selling all my receivers year/year, i used sony, and yamaha, but this time i want to have all the pieces separated (amps, pre....)
i really want to move away from receivers, i just want to build an good system and easy to improve/upgrade.
im tyred abt selling all my receivers year/year, i used sony, and yamaha, but this time i want to have all the pieces separated (amps, pre....)
classd4sure said:
Maybe Class D amps... i know more than a few really good no feedback amps (well there is degenerative feedback across the cathode R in most cases)
dave
Yah, class D. It's possible to make it without it, but to do it well I think is counter productive in every aspect, just for the sake of making the "true digital" claim 😕
Hey I hope you have fun testing those modules that are on the way.
Hey I hope you have fun testing those modules that are on the way.
classd4sure said:
Me too... i need to start getting the power supply and a case togther (i'm using 4 x 13 V 110VA trafos with LM328 regs -- should put me into the overkill zone on the PS)
dave
fokker said:
I worded my other sentence poorly. It would have been better to say class d amps don't need as beefy of a supply as similar power class a and ab amps do because they're much more efficient.
Any amp, whether it be with a high or low PSRR will benefit from a more stable, quiet supply. Amps with low PSRRs will just benefit more. Feedback definitely improves that figure and reduces output impedance at the same time.
raintalk said:
Like Chris said, it depends on the type of class d, but most do not reach peak efficiency until they're near maximum output power. The efficiency curve usually looks like a logarithmic function, which means they reach high levels of efficiency fairly quickly and then it continues to increase slowly.
Class B has a theoretical maximum efficiency of 78.5%. Class D has a theoretical maximum efficiency of 100%. Class AB will obviously be lower than B.
planet10 said:
That's what I like to hear 🙂
You're splitting wires. 😀
Class-ab increase in efficiency as the power output rises. I couldn't find any documented humps.
Yeah sure, Class-d does jump up in the power curve quickly, and slightly rise - but it's mostly flat.
Seeing as music isn't always played at full output, and you need some headroom. Class-d is more efficiency for normal listening levels. No matter which class-d it is.
Class-ab increase in efficiency as the power output rises. I couldn't find any documented humps.
Yeah sure, Class-d does jump up in the power curve quickly, and slightly rise - but it's mostly flat.
Seeing as music isn't always played at full output, and you need some headroom. Class-d is more efficiency for normal listening levels. No matter which class-d it is.
- Status
- Not open for further replies.