NaO Note II RS amplification recommendations

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sam j

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Joined 2013
#1
So I had a brainwave, temporary insanity or cabin(et) fever and ordered the plans for NaO Note II RS. I also ordered parts for some Overnight Sensations (MTM and center) so the Notes wouldn't be my *first* speaker build. See why I said it was insanity?

I think it would be interesting to discuss amp options. The Notes need 2 x 4 channels, and I believe John K mentioned 50-75 Wpc in some thread.

Here are some options I've come up with. I'm looking for value and quality, not faceplate. These will be hidden anyway and I don't need to impress anyone 🙂

Off-the-shelf:
1. Emotiva UPA-500 (2x), now on sale for $359 each. 80W x 5. Seems like a bargain.
2. ATI 180x (would need 2 amps for 8 channels). 180Wpc. Around $3000+ altogether. Linkwitz recommended for his designs.
3. Dayton Audio MA1240a 12-channel. 40-60 Wpc. $444 (!)

Kits/boards:
1. A 4x100W T-amp board from PE (4x100W @ 4 Ohm TK2050 Class-T Digital Audio Amplifier Board 320-302). I doubt I can recreate the lab conditions where that 100W was measured, and I don't know what a realistic wattage for these is. $45 each, power supplies about the same or more.
2. I've looked at 41hz, Hypex, etc, but I want to avoid messing with a kit with mains power.

Those Emotivas are awfully attractive, but I'm not sure if the power is enough. I have a smaller room (about 15' x 11' x 9') and I don't listen at ear bleeding levels. But I really like dynamics and transients to be *there*, so the amp needs headroom.

I wouldn't mind finding something like ATIs used, but finding two of the same might be a problem. Since this build is going to take a long time (need to build a desk and some shelves etc first), I'll probably start stalking Craigslist and Audiogon anyway.

(I currently have Maggie MMG, Emotiva XPA-2 and Onkyo TX-NR808 receiver).
 
#2
I use a typical dipole woofer setup. How loud do you play and what music?

I had no issues with 60 watts LM4780 for a loooong time, then I fell in love with the latest daftpunk album. Then 80watt suddenly is not enough for the woofers to play at 'discotheque level'. I also have the 4x100w and they are not 100w even with the maximum 30v rail. Perhaps around 70watt which is still a great value!

My next build is around a bridged and paralled 470 to get some 200watt. I'll report 🙂. Or if I'm lazy I'll just get ebay's 2x 300w Sure classd for the woofers. It should do 250w with 48v rails.

Mind you I'd never push my TK2050 anywhere close to clipping when SWMBO is around 😉
 
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#3
It might be more efficient, both cost-wise and in terms of power allocation, to think in terms of 2 amps, one for the bass and one for everything else.

There are a lot of 6-channel "whole house audio" amps around, and they often have useful features such as low-voltage input sensitivity and 12V triggers. For instance, a quick search on eBay turned up my test amp, a Xantech PA640, on offer new for a starting bid of $30. (No relation to seller.)

Then use something stouter (150-200W) for the bass drivers.

Another compact option is the Crown CT8150/Lexicon DD-8. Expensive (cheaper than the ATI pair) but 100W or so into 8 channels in a fanless, 1RU high case.
 
#4
Yes, I recommend a minimum of 50 to 75w into 8 ohms. I run a pair of AdCom 7605 amps. 125/8 ohms, 175/4 ohms. But remember, if you are using the miniDSP 2x4 the output of the crossover is limited to 0.9 V RMS so you need an amp which can be driven to max output with that level input. That is why I recommend the 2x8 miniDSP as it has higher output.
 
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#6
Hi John,
I am looking for a low cost amp solution for the NaO Note II RS.
I was thinking of powering the Lower Midrange,Upper Midrange, and 4 Vifa Tweeters with a 6 channel 3116D2 board, 6 x 50W @ 4 Ohm.
And for the Peerless SLS woofers TDA8950 that gives 2 X 120w @4 Ohm or bridge mode 300W @ 8 Ohm, and use two boards if you thought it's required?
Both can be driven to full output at 0.9V so could save money on the miniDSP and buy a UMIK-1 to use REW.

Any thoughts or recommendations?
Many thanks
Ian
 
#7
Hi Ian,

I've bought and tried a TPA3116 D2 red PCB module, I found the high section was lifeless.
Maybe with tweaks/mods it can be better.

I own few amps : Populse T150 based on TA2024 chip, two Hypex DS 2.0 plate amp based on UCD 180 ST module and a SA Roomplayer with a 50ASX2 module inside. The last is really the best sounding especialy for the high section.

ICEpower ? Class D audio amplifiers ? Consumer & Professional Audio
 
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#8
webby said:
Hi John,
I am looking for a low cost amp solution for the NaO Note II RS.
I was thinking of powering the Lower Midrange,Upper Midrange, and 4 Vifa Tweeters with a 6 channel 3116D2 board, 6 x 50W @ 4 Ohm.
And for the Peerless SLS woofers TDA8950 that gives 2 X 120w @4 Ohm or bridge mode 300W @ 8 Ohm, and use two boards if you thought it's required?
Both can be driven to full output at 0.9V so could save money on the miniDSP and buy a UMIK-1 to use REW.

Any thoughts or recommendations?
Many thanks
Ian
Click to expand...

The woofer amp (120x2 into 4) should be fine but I think the other amp at only 50 into 4 is a little low on power. Additionally, some digital amps don't like to see the tweeters in parallel with the result that the highs get rolled off significantly. It depends on the design of the output filters. If that happens the tweeters should be wired in series and the gain of the tweeter filter block increased in the miniDSP by 6 dB.
 
#9
john k... said:
The woofer amp (120x2 into 4) should be fine but I think the other amp at only 50 into 4 is a little low on power. Additionally, some digital amps don't like to see the tweeters in parallel with the result that the highs get rolled off significantly. It depends on the design of the output filters. If that happens the tweeters should be wired in series and the gain of the tweeter filter block increased in the miniDSP by 6 dB.
Click to expand...

Thanks john & pascal,
Do you know of a multichannel PCB with enough power?
How would I check if the tweeters in parallel would be an issue?
Should I ask in the class D forum?
Many thanks
Ian
 
#12
john k... said:
Yes, I recommend a minimum of 50 to 75w into 8 ohms. I run a pair of AdCom 7605 amps. 125/8 ohms, 175/4 ohms. But remember, if you are using the miniDSP 2x4 the output of the crossover is limited to 0.9 V RMS so you need an amp which can be driven to max output with that level input. That is why I recommend the 2x8 miniDSP as it has higher output.
Click to expand...

This 50 to 75W@8ohms figure is at what distortion level? 10%THD, 0.01%THD, etc?

Looking at amps currently, and the figures given vary wildly, or the THD value is not even given. The TPA3116 mentioned here is 50watts@4ohm but only at 10%THD.
 
#14
Hi there! When I say "or ..not even given", I mean some manufacturers give the THD numbers, while others do not. Bang & Olufsen are reputable and willing no doubt.

Actually the ICEPOWER modules interest me, though I heard the Najda DSP preamp I use has trouble driving their inputs🙁
 
#15
john k... said:
Yes, I recommend a minimum of 50 to 75w into 8 ohms. I run a pair of AdCom 7605 amps. 125/8 ohms, 175/4 ohms. But remember, if you are using the miniDSP 2x4 the output of the crossover is limited to 0.9 V RMS so you need an amp which can be driven to max output with that level input. That is why I recommend the 2x8 miniDSP as it has higher output.
Click to expand...

OK, the manual says 125/8ohms on the Adcoms is at 1.00%.
"125 Watts continuous average power per channel into 8 ohms at any frequency between 20Hz and 20kHz with all channels driven at less than 1.00% THD"
Adcom GFA-7605 User Manual - Page 2

I will then assume that this low circa 1% distortion figure is what John is recommending. The TPA3116 is therefore not 50W at 4ohms in this scenario, but more like - PO Continuous output power W THD+N = 10%, f = 1 kHz, PVCC = 21 V 50W - as described in table 6.6 of the TI datasheet. Therefore "50 into 4 is a little low on power" is a gross understatement?
Then again, diagram 8.2.3 on the datasheet seems to contradict my understanding by saying that 1%THD is achievable at 21V.
http://www.ti.com/product/TPA3116D2/technicaldocuments

Am I asking the wrong question, or should I indeed be careful to make sure the 50W figure is specifically at low distortion (say 1%)?
 
#16
Hi Sac,

Actually the ICEPOWER modules interest me, though I heard the Najda DSP preamp I use has trouble driving their inputs
AIsJFAhKTKc8PAYMFHhoCyBJboYEGJbEECEGCjAEi1MMzyYvlVREIRKG06tRj3YwEtjozw1caCaY0FQiEoEYimoMdLXI1IUlSBD04ECqCRSBWYCACCABAIACBZxSWgDLhhVIqNq82ZBpDRshDYzcclTnl6qBB3T18fHA1ocxQQwsFFglw6RclmRZ+IFC4UBWoc6k8qCjiBIWCaRQYYKoWCJPpSLwWdXrjhlfdHaRoKDFCQ07LdTUmsJLhANiMvR0eXIpB4xWR16UgVNBlIZTwnAg6LDnSzFBIcCMgOCHzIo0c7AQGIRpILAZcgIJ+CTgBC0us1zMFXjgSqwUheQuAgwIADs=
Click to expand...

Not a real problem, see IcePower 50AX2 thread post #56

http://www.diyaudio.com/forums/class-d/190311-icepower-50asx2-modules-6.html#post4425894


FYI Juhazi is using 50ASX2 SE modules on is Aino Gradient speakers for mid and high section.
 
#17
Thanks for that 50ASX link. It did lead to the following build which I would love to put together in two four channel boxes;
https://theslowdiyer.wordpress.com/2013/08/25/past-projects-6-channel-icepower50asx-amp/

The linked buffers may be beyond my very limited DIY skills. I really want a plug and play solution. I can solder well enough but I do not know why these things go together.

Mind you, the 50ASX is only 50W at 4ohms, down to 30W at 8ohms (1%THD). This is below the 50W@8ohms recommended🙁

I would get two of the Hypex UCD36MP modules today if I thought they were going to be powerful and high quality enough (2X6 channels@30W/4ohm with pre-drilled boxes and the works, only 358euros). Very little useful info on these on the web.
hypex module amplificateur avec alimentation ucd36mp 6x30w 4 ohm
Actually Pguerin, I see you are using the hifi2000 box for your 50asx build.
 
#18
SAC said:
Mind you, the 50ASX is only 50W at 4ohms, down to 30W at 8ohms (1%THD). This is below the 50W@8ohms recommended🙁
Click to expand...

Actually, I see the top two panel drivers have a power handling of;
3/4" Vifa "Power Handling (RMS)20 Watts"
SS 10F "Long term max power 30W"

So the 50ASX should be sufficient for the top two!? However, Anaview ALC and the newer AMS boards are compared favourably in some places to the Hypex Ncore boards which is impressive, have the SMPS on board, and to boot are the cheapest option for us in the UK.
ALC0100-2300 - Stereo Amplifier Module 2 x 50W | Power Amplifiers
8ohm 2X25W <0.5%THD (4ohm 2x50W <0.7%THD)
ALC0180-2300 - Stereo Amplifier Module 2x90W | Power Amplifiers
8ohm 2X50W <0.5%THD (4ohm 2x90W <0.7%THD)
Power Amplifiers


They also lack input buffers but it looks like the Najda preamp might suffice.

£53X2, £76X2, cables = £269.08+VAT. All to drive the Notes in a small living room! Would appreciate a yea or nay on this plan from anyone out there, before I place an order. Thanks in advance🙂
 
#19
Hi Sac

So the 50ASX should be sufficient for the top two!
Click to expand...
I use 50ASX2 with my Nomex164 by TG, those speaker have 90/91 db sensitivity.
I don't need more power in my 25 m2 living room.

I think the Anaview module compared as good as the Ncore is the new AMS range not the ALC.

AMS0100

I chose Icepower vs Anaview because it was cheaper for me.
One board was 115 € including shipping costs.
 
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#20
Hi pguerin,

The 50ASX board is around 100 euros, but the 125ASX2, which I would also need, is around 200euros🙁 Also, buying locally has its' advantages that appeal to me.

Yes, AMS are an upgrade in features and performance, though opinions are mixed and hard to come by. Some, including the manufacturer, say the difference between ALC and AMS "arent that far apart" and "subtle".
http://www.diyaudio.com/forums/class-d/268395-hypex-ucd.html
http://www.diyaudio.com/forums/class-d/190182-abletec-alc1000-any-experience-2.html
http://www.diyaudio.com/forums/clas...-anaview-ams1000-hypex-nc400.html#post4148169
http://www.diyaudio.com/forums/class-d/261596-anaview-ams1000-2600-project.html


Anaview says the AMS "improves THD significantly at high frequencies". In which case I could add an extra £70 to the total cost by changing just the tweeter amps. There is no equivalent to the more powerful ALC0180 in the AMS line however, so I would have to keep it as is, and hope the boards pair easily in terms of input impedance and the like.

AMS0100
8ohm 2X25W <1%THD (4ohm 2x50W <1%THD)
ALC0180
8ohm 2X50W <0.5%THD (4ohm 2x90W <0.7%THD)

£84X2, £76X2, cables = £331.52+VAT

Worringly, forum user Saturnus commented that the ALC180 module got terrible reviews "from reliable sources in the industry", but I cannot find his sources. Hifinews did not like the Audio Sprout implementation, Saturnus and others have commented - not least for frequency response and SNR issues, if that matters terribly.
http://www.diyaudio.com/forums/class-d/267977-sprout-kickstarter-thingy.html
 
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