Having a pair of the nxv-203 powered from a coldamp sps80 I'd be surprised if the rotel can keep up, especially once you use them in an active system. I am pretty happy with mine though decided to use different amps in my next speaker build (new amps are from The Wire series), mostly because I want to be able to build with an adjustable gain and remove need for attenuation in the active crossover. I am still very happy with the nxv203 and I'll still use them bridged into my subs and for centre speaker, if I wasn't wanting to experiment with active speakers I'd probably keep using them.
It might be worth considering gain of your chosen amps for your build too although it is more difficult to adjust the gain when buying pre-built modules. Just a thought.
It might be worth considering gain of your chosen amps for your build too although it is more difficult to adjust the gain when buying pre-built modules. Just a thought.
It all rather depends why you decided to go for Class D in the first place. I'm guessing because you want a lot of power and have space limitations? Or are you attracted to the 'high tech' aspects? Seeing as efficiency has always been the main reason for Class D, I'd suggest considering a normal 'linear' (meaning non-switching) amp for tweeter duty as it won't be much less efficient than a Class D (if at all) when just driving a tweeter.
I'm not aware of any commercial amp offering which has been specifically designed for tweeter duty. I guess the market is too small as active speakers aren't in the mainstream yet for audiophiles. DIY would be the best way to get a dedicated tweeter amp in my estimation. The power supply and heatsinking would be the main changes to be made over a conventional full-range amp.
If I was looking at A/B I would probably go with the same manufcturer of the DCN28 and buy these Ground Sound
That looks to be a generic design - the transformer is way bigger than required for driving a tweeter. Bigger trafos (especially toroids which are the worst offenders) result in more noise being let through from the mains, so for a tweeter amp I'd definitely choose an 'old tech' EI or perhaps R-core transformer.
abraxalito I am not opposed to running something like an class A/B on the tweeters if it is going to improve the sound quality of the RAAL tweeters. I must admit I have been a bit concerned that the digital amp might be a bit harsh on a tweeter.
Would require greater thought about how to integrate them into the speakers as they might need a heatsink where Class D typically don't.
Would require greater thought about how to integrate them into the speakers as they might need a heatsink where Class D typically don't.
I was thinking along the same lines - the criticisms I've heard of Class D have in the main been in the HF department, so running a Class A/B for the tweeter might allow you to get away with a cheaper Class D (UcD perhaps, rather than Ncore?).
An amp designed from the ground up for tweeter duty probably won't need much of an external heatsink at all - just PCB mounted ones probably will be fine, depending on how much power you're planning for...
Class D have on-board heatsinks too.
An amp designed from the ground up for tweeter duty probably won't need much of an external heatsink at all - just PCB mounted ones probably will be fine, depending on how much power you're planning for...
Class D have on-board heatsinks too.I have no objection to spending money on the best I can buy if it is worth it, as there is little point to spending $4.5k on a active cross over and saving a dollar on an amp.
What brands / models would you recommend for the A/B Tweeters (something with no pop is best considering the RAALs) and what D class would you go with.
So far ICEPower and NCore have been suggested
What brands / models would you recommend for the A/B Tweeters (something with no pop is best considering the RAALs) and what D class would you go with.
So far ICEPower and NCore have been suggested
hochopeper the DCN28 has individual channel attenaution built in.
http://www.groundsound.com/dcn28.php
- - - - - - - - - - - - - - - - - - - - - - - Volume regulation - - - - - - - - - - - - - - - - - - - - - - - The full scale audio signals from the 4 dual DA converters are attenuated in an analogue volume circuit in steps of 0,5dB. The attenuation range of the master volume is from -100dB to 0dB, where -100dB is the weakest and 0dB is the strongest. Each output can also be individually attenuated from -15dB to 0dB in steps 0,5dB. The volume circuit is high precision and controlled digitally. Note that although digitally controlled, the regulation is still done in the analogue domain.
http://www.groundsound.com/dcn28.php
- - - - - - - - - - - - - - - - - - - - - - - Volume regulation - - - - - - - - - - - - - - - - - - - - - - - The full scale audio signals from the 4 dual DA converters are attenuated in an analogue volume circuit in steps of 0,5dB. The attenuation range of the master volume is from -100dB to 0dB, where -100dB is the weakest and 0dB is the strongest. Each output can also be individually attenuated from -15dB to 0dB in steps 0,5dB. The volume circuit is high precision and controlled digitally. Note that although digitally controlled, the regulation is still done in the analogue domain.
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As I mentioned earlier, I know of no commercially available dedicated tweeter amps. Best to DIY one for yourself - that gives you a nice 'middle way' solution to your dilemma of whether to build or buy. Buy the LF amps - UcD or NCore and build the tweeter ones for yourself. I reckon there'd be a DIY market for your design of a tweeter amp I reckon a decent bridged chipamp design ought to do it, so long as it has a well engineered PSU.
I'd not build the amps inside the speakers though - a development and service nightmare, trust me
I reckon a decent bridged chipamp design ought to do it, so long as it has a well engineered PSU.I'd not build the amps inside the speakers though - a development and service nightmare, trust me
Not sure there would be any market for an amp I designed as I don't know the first thing about electronics
I can do a bit of soldering, but I need something that is semi complete ready to bolt together.
I could put all the various modules into a case and leave it close to the speaker. There is no reason why A/B can't share the same casing as D is there? (separate PSU obviously)
I can do a bit of soldering, but I need something that is semi complete ready to bolt together.
I could put all the various modules into a case and leave it close to the speaker. There is no reason why A/B can't share the same casing as D is there? (separate PSU obviously)
more than one case, please
you probably want the crossovers close to power amps
and power amps close to speakers
you probably want the crossovers close to power amps
and power amps close to speakers
.......service nightmare, trust me
Given this is DIYaudio, you don't need to know the first thing about electronics. You just need to know how to ask all the right questions
You could start out with a stereo chip amp kit (say 50W per channel, LM3886 or similar) and get advice for how to bridge it. This potentially would give you 200W short term output power into your tweeter (assuming its 8 ohms) The transformer normally supplied with such a kit would be overkill so you'd need to get a smaller one and not a toroid. Then beef up the power supply filtering to get a much cleaner sound - this means using RCRC filters not just a rectifier and single caps. You'll also want a balanced input for best sound, don't waste time with single ended at the performance level you're looking for.
I was thinking though that we'd really need to work out the relative power requirements for the amps, and potentially we could have a stab at that using Audacity. Choose the most tweeter-punishing music you like to listen to and load it up into Audacity. Then choose a filter and turnover freq - the ones you're going to use in the DCN28. Perhaps that'll be 4th order LR @ 3kHz. Duplicate the track and run the LP filter over one copy and the HP filter over the other and compare the peak values. One way to compare peaks is to use the amplify command and see how much gain it gives you as the max before clip.
Doing this exercise will give you a good estimation of the required peak power outputs of LF vs HF amps.
You could start out with a stereo chip amp kit (say 50W per channel, LM3886 or similar) and get advice for how to bridge it. This potentially would give you 200W short term output power into your tweeter (assuming its 8 ohms) The transformer normally supplied with such a kit would be overkill so you'd need to get a smaller one and not a toroid. Then beef up the power supply filtering to get a much cleaner sound - this means using RCRC filters not just a rectifier and single caps. You'll also want a balanced input for best sound, don't waste time with single ended at the performance level you're looking for.
I was thinking though that we'd really need to work out the relative power requirements for the amps, and potentially we could have a stab at that using Audacity. Choose the most tweeter-punishing music you like to listen to and load it up into Audacity. Then choose a filter and turnover freq - the ones you're going to use in the DCN28. Perhaps that'll be 4th order LR @ 3kHz. Duplicate the track and run the LP filter over one copy and the HP filter over the other and compare the peak values. One way to compare peaks is to use the amplify command and see how much gain it gives you as the max before clip.
Doing this exercise will give you a good estimation of the required peak power outputs of LF vs HF amps.
Of course it does (I can't think of any active crossover that doesn't have level adjustment) but for my active speaker build I am trying to avoid unnecessary attenuation before the power amp stage because it only increases susceptibility to noise and adds work for the power amplifier you chose for the tweeter, which for most isn't a problem but my tweeter amplifier of choice (The Wire - LPUHP) has roughly 8W into my 4ohm tweeter so I'd rather not have it doing any more work than necessary.
With balanced interconnects between crossover and amp and lots of headroom in whatever amp is chosen for the tweeter I agree this is less of an issue, still worth consideration.
hmm, given that its a 'new' thing to you, and cannot expect to build 'the absolute best', the first time, but have to start 'small', I would suggest two simple stereo amps for tweeter amd mids, one for each channel, and maybe classD module for basses
higher powr for basses
if you bridge 'smaller' classD amps, you could still run them on the same power supply a the mid/tweeter amps, and still get higher power
also be aware if you will need balanced or single ended signal
all in all, its probably not a beginners project
but no harm in trying, and maybe start small with a couple of stereo amps
higher powr for basses
if you bridge 'smaller' classD amps, you could still run them on the same power supply a the mid/tweeter amps, and still get higher power
also be aware if you will need balanced or single ended signal
all in all, its probably not a beginners project
but no harm in trying, and maybe start small with a couple of stereo amps
Ah I see you have a nice low distortion linear tweeter amp
What crossover freq and slopes and what's the power you have on LF?Rotel's older 2x 60watt classAB amps plays ok
now that you are 'aussie' member, why not consider Anthony Holton's amp modules
looks perfect for active speakerswow, you actually bought the new preamp/xo
I guess you will need balanced amps
you could wait for the LPUHP commercial variant to be ready, its about as close to the perfect tweeter amp you can get. balanced input 16WPC Class A/B with unmeasurable distortion and pretty much every other measurement was bouncing up against the levels of the rather high end measurement gear.
thats what i'm using them for (my tweeters), but for a completely software driven crossover with multiple sabre dac channels. it was a limited number GB only PCBs were sold (all 50 sold out in less than 24hrs), but the response has been so good that opc is in the middle of producing a commercial version, I do not think that there is a better suited amp available at any cost for this niche.
oh and it sounds brilliant! I was one of the lucky ones with the quick trigger finger
send opc a PM, he might be able to give you an idea of when they'll be available. afaik hes received the PCBs and they are in production
thats what i'm using them for (my tweeters), but for a completely software driven crossover with multiple sabre dac channels. it was a limited number GB only PCBs were sold (all 50 sold out in less than 24hrs), but the response has been so good that opc is in the middle of producing a commercial version, I do not think that there is a better suited amp available at any cost for this niche.
oh and it sounds brilliant! I was one of the lucky ones with the quick trigger finger
send opc a PM, he might be able to give you an idea of when they'll be available. afaik hes received the PCBs and they are in production
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