• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Assembling new 2.1 system - questions about too powerful amps

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
Hey guys, my first post on here, love everything about this place! I'm not sure this is the best subforum to ask this, but it kinda made sense to approach the problem from amplification angle.

Here's what I'm up to. I now have a pair of Harbeth P3ESR speakers hooked up to a Yamaha A-S500. Sources are CA, phono and (smart) TV, in falling order of importance.
Now what's changing soon is, I'm getting a subwoofer. The P3s sound simply beautiful, but I think I want just a bit more bass.
My room - it's a relatively small living room / dining room / kitchen rectangular affair. Listening distance from speakers is 2.5 - 3m, so not exactly near-field, but pretty near. Speakers are almost to the frontwall, 20-30cm away. I also listen mostly at very low volumes. Quiet conversation level and regularly down to whisper-level. I almost never listen at high volumes.

So what I can't figure out myself, here's the new setup I'm thinking about:
- MiniDSP SHD - this should be able to take care of streaming instead of CA (Roon mainly, but I could still connect the CA to it digitally), hook up the phono via the analog input pair (will need a phono preamp), hook up the TV via digital. I'm betting a lot on Dirac to fix my unfortunate room problems.
- Some NCORE power amplification - along the lines of AUDIOPHONICS HPA-S250NC or MPA-S125NC.
- Money is not particularily important, but let's say I don't want to go the NAD M33 route becase that's too expensive.

Now what I'm worried about the most - is the SHD capable of attenuating the signal enough (without noticeable loss of quality), so the NCOREs can play at the volumes I'm comfortable with? If the above setup is not advisible for my situation, what else can I do? Basically my only requirement is Dirac for all mentioned inputs, with separate subwoofer output (volume controlled together with mains, but DSP controllable separately). Well and volume/source controls should be IR.

Seems to me like SHD is definitely the way to go (basically NAD C 658 is the only alternative, which I'm too scared to venture into, according to all the negative stories), so the power amp stage might be the real question - should I rather be looking at Class AB or even A, to use after the SHD preamp?

Hope I can spark some conversation, I've been thinking about this a lot and it would really help me to get some insights from others.
 

pjug

Major Contributor
Forum Donor
Joined
Feb 2, 2019
Messages
1,589
Likes
1,348
If you aren't unhappy with the A-S500, I wonder if a cheap solution is to use a miniDSP 2x4 connected to the tape in/out. That gives you good subwoofer integration and EQ for $85. Seems like it would work; hope I am not having a brain cramp.
 
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
If you aren't unhappy with the A-S500, I wonder if a cheap solution is to use a miniDSP 2x4 connected to the tape in/out. That gives you good subwoofer integration and EQ for $85. Seems like it would work; hope I am not having a brain cramp.
Hey man, thanks for your input. That won't work because even if my amp did have proper tape monitor loop (which it doesn't, unfortunately), it wouldn't help me get dirac separately for the sub - it wouldn't adhere to the main volume control.
 

pjug

Major Contributor
Forum Donor
Joined
Feb 2, 2019
Messages
1,589
Likes
1,348
Hey man, thanks for your input. That won't work because even if my amp did have proper tape monitor loop (which it doesn't, unfortunately), it wouldn't help me get dirac separately for the sub - it wouldn't adhere to the main volume control.
If there is no tape loop (I thought there was) then this is moot. But you can add a volume pot to the miniDSP2x4 and use this. Set and forget the volume knob on the Yamaha. So you have to do some DIY with the miniDSP, and it is a bit clunky unless you can make a nice case. But cheap.

This isn't the Yamaha you have? It looks like two tape loops.
1615664883106.png
 
Last edited:
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
It's not real tape loop as in you can't plug in anything in the chain to have source select work and then outboard processor and then preamp. You can only listen to the source you have selected and you can just listen to that thru the preamp. You can output the same fixed level source (or different one, if selected by a separate, non-remote-controlled rec selector) for recording.

But yeah, I could use the Yamaha as integrated and just use a single source that is the MiniDSP, which can be used for actual source selection and volume control. That is the simpler way, similar in function to having a separate analog attenuator between the separates I'm asking about. It's kinda kludgy though and I'm also interested in giving class-D a chance.
 

pjug

Major Contributor
Forum Donor
Joined
Feb 2, 2019
Messages
1,589
Likes
1,348
Is the NAD M10 over budget? nCore and I think does everything else you want.
 
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
Yeah that one would generally work, but I'd expect it include a quality phono pre for that price. Plus if I'm going all-in-one it's even sillier to have a separate phono box. Also quite more expensive than SHD+250NC. I'm also discouraged by NAD firmware shenanigans :/
 

pjug

Major Contributor
Forum Donor
Joined
Feb 2, 2019
Messages
1,589
Likes
1,348
Yeah that one would generally work, but I'd expect it include a quality phono pre for that price. Plus if I'm going all-in-one it's even sillier to have a separate phono box. Also quite more expensive than SHD+250NC. I'm also discouraged by NAD firmware shenanigans :/
Oh yeah forgot about phono. I have an old Pro-ject phono box I'd give to you if you were local, but shipping to Europe would cost more than it is worth. Maybe if I get the vaccine soon I can eek out a ski trip. How is the snow in Slovenia this year?
 
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
Heh thanks, it's not that I can't get a phono stage, it's just not the setup I'm thrilled about. I did think about the M10 for a while, but SHD appeals more to me.
The skiing season is pretty poor this year, some places are opening up now, but it's quite random. Neighboring Italy has much more to offer as far as snow conditions and places go, but I've no idea what's the covid situation there :)

So what I could do is put an active attenuator between SHD and ncore, essentially another simple stereo preamp... Hmm this would be an interesting spot to play with some coloration down the road, like some tubes. What is the simplest analog transparent stereo attenuator I could use, that would give better sound than SHD's digital attenuation, hitting the ncore?
 

pjug

Major Contributor
Forum Donor
Joined
Feb 2, 2019
Messages
1,589
Likes
1,348
I don't know the SHD but is losing touch at low volumes going to be a problem without the attenuator?

• To change the volume, rotate the encoder knob. Volume changes in 0.5 dB steps. Minimum volume is -127.5 dB and maximum volume is 0.0 dB.

Edit: I misunderstood your concern I think. But still I can't imagine you need the attenuator. The SHD is a preamp so I would be really surprised if it doesn't work well at low volumes, even with a powerful amp. I would go without the attenuator idea until you are sure you need it.
 
Last edited:
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
You mean volume control resolution? That's what I'm fearing yeah.
 
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
I think so too, but can I use it to control the volume in range that I need?
 

pjug

Major Contributor
Forum Donor
Joined
Feb 2, 2019
Messages
1,589
Likes
1,348
Here is an idea of signal level for a 50V (~300W into 8 ohms). Imperfect gain staging will mess this up but just to get an idea.

1615673029029.png
 
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
I can't really think in volts, but thanks for the effort. Seems like I really need to try it out and then possibly add attenuation.

The thing is, I feel like I would benefit from attenuator for at least four separate reasons:
  1. Retain more of DAC resolution by not having it attenuate digitally a lot - I might be wrong on this one, but that is my understanding.
  2. Improve (SHD's, so the main) volume control resolution by normalizing its range over my preferred zone of usable SPL - since I'm mostly listening at low levels, control resolution is really valuable.
  3. Not live in fear of somehow bumping (physically or in software) the volume control and blowing my speakers / breaking the windows - this is actually a serious concern for me. (this one is actually the same as the previous point, but still)
  4. I could go for a bit higher ncore class, maybe even stretch to purifi. This supposedly wouldn't just bring more power, but also better response at low levels - might be a really expensive way to inperceptible gains though.

I'm basing all of the above on the assumption that out-of-the-box, I'd be running the SHD at say -100dB-ish levels, if connected to something like 2x NC250MP. That assumption is not very scientific though - it's mostly from never ever having the A-S500 more than 12 o'clock, normally below 9.

The Yamaha A-S500 is rated like this:
  • Minimum RMS Output Power (8 ohms, 20 Hz - 20 kHz): 85 W + 85 W (0.019% THD)
  • Maximum Power(8 ohms, 1 kHz, 10% THD): 105 W + 105 W
  • High Dynamic Power/Channel (8/6/4/2 ohms): 130 / 150 / 185 / 220 W
I can't wrap my head around comparing the above (maybe it's not even the right numbers to be looking at, but I can't find anything resembling "gain") to Ncore modules specs, but I'm guessing since they're stating "250 Watts" it has to be some louder.
 

beefkabob

Major Contributor
Forum Donor
Joined
Apr 18, 2019
Messages
1,219
Likes
1,614
Good luck noticing a problem with digital attenuation in the SHD. You can set it to 32 bit if you wanna go crazy with resolution. Not a problem. The next step up is a Benchmark pre-amp or similar, but why bother when the SHD is translucent already?

And then get a powered sub and plug it all together. No reason to get anything else new. You're in Slovenia, so you get some kind of European sub and call it a day.
 
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
Good luck noticing a problem with digital attenuation in the SHD. You can set it to 32 bit if you wanna go crazy with resolution. Not a problem. The next step up is a Benchmark pre-amp or similar, but why bother when the SHD is translucent already?

And then get a powered sub and plug it all together. No reason to get anything else new. You're in Slovenia, so you get some kind of European sub and call it a day.
You mean keep the Yamaha and basically use it as a power amp? I might do that initially yeah, but something like a MPA-S125NC is so affordable that I'll probably just add it to the order, if I'll be getting SHD from Audiophonics.

So you're saying not using the full bitdepth on SHD's DAC as a consequence of digital attenuation shouldn't be noticeable? I'm not talking about its measured transparency at nearly unity gain ("dialed down to 4V"), but at significantly lowered outputs. I'm assuming only using the bottom quarter of the range should leave the 2 MSBs unused... Is there a good writeup on the topic of consequences of digital attenuation on here at ASR?
 

beefkabob

Major Contributor
Forum Donor
Joined
Apr 18, 2019
Messages
1,219
Likes
1,614
You mean keep the Yamaha and basically use it as a power amp? I might do that initially yeah, but something like a MPA-S125NC is so affordable that I'll probably just add it to the order, if I'll be getting SHD from Audiophonics.

So you're saying not using the full bitdepth on SHD's DAC as a consequence of digital attenuation shouldn't be noticeable? I'm not talking about its measured transparency at nearly unity gain ("dialed down to 4V"), but at significantly lowered outputs. I'm assuming only using the bottom quarter of the range should leave the 2 MSBs unused... Is there a good writeup on the topic of consequences of digital attenuation on here at ASR?

I'm saying that, with 32-bit digital volume control, it extraordinarily unlikely you'll be able to tell the difference versus the best analog volume controls. With a 16-bit control, you could probably tell if you had the right 16-bit file and knew exactly what to listen for, but you probably wouldn't notice it in normal listening.

The SHD can resample audio. I'm not sure if it has to resample a 16-bit file to a higher depth in order to use the full resolution of volume control. I never had a problem with all my 16-bit files.

As for getting a new amp, you should get the SHD and sub first and try them with your current setup. And then, if you feel the need, get a new amp. Since you listen so quietly, you're not stressing what you already have. So why spend the money?
 
OP
K

kokoon

Member
Forum Donor
Joined
Mar 13, 2021
Messages
86
Likes
45
Location
Slovenia
Thanks, I'll definitely try the SHD into Yamaha. The SHD-Power doesn't make me happy cause it has no analog inputs, plus it's not a Ncore.
 
Top Bottom