ZP80, ZP90 connected directly to Power Amplifier

  • 26 August 2008
  • 22 replies
  • 15447 views

I am thinking of connecting my ZP80 directly to a Power Amplifier (using RCA cables from the analogue out).

Does anyone have any experience of doing this?

I am not an expert in music engineering, so I have a few questions that I do not seem to be able to Google my way out of:

1. What is a suitable Input Impedance and Input Sensitivity for the Power Amplifier?

2. Will I find that the results are extremely loud (i.e. I will only be able to use the very bottom of the volume control and risk blow-out if I accidentally switch to fixed volume).

3. Is the volume control on the ZP80 an attenuator or is the volume controlled by altering the digital signal? (This question relates to the analogue out.)

Thanks for any help!

John

22 replies

Buzz will answer you 1) I am pretty sure.

As to number 2, you have a good chance of blowing up speakers if you set a ZP to fixed volume like that. Fixed volume means 100% volume, and as a power amp always is set at 100%, you'll be giving your speakers all the watts the amp will produce.

Number 3: Volume attenuation will be entirely done by the Sonos, who does this digitally by bit reduction. This means that at lower volumes the resolution of your sound signal gets smaller, degrading the signal. Depending how strong your amp is, you might never have it over 50%, so that is one thing to consider. If you are aiming for audiophile quality, I recommend using a Benchmark DAC1 as a pre-amp, it has analogue volume attenuation. (or use an integrated amp with volume control)

Of course you can avoid all the trouble with the ZP120, which has an amp already built in.

Number 3: Volume attenuation will be entirely done by the Sonos, who does this digitally by bit reduction. This means that at lower volumes the resolution of your sound signal gets smaller, degrading the signal.


This is true, but the Sonos DAC is 24-bit whilst the resolution of the sound files is 16-bit.

When Sonos lowers the volume, it does so by reducing the resolution, but this is done using the unused 8 bits first. These unused 8-bits give a potential volume reduction of around 48dB before the real signal bits are affected. -48dB is an impractical volume level for critical listening; it's practically "off".

I believe I saw somewhere that the Sonos volume control is calibrated so that this -48dB point corresponds with the first bar on the control (zero bars is "mute"). This means that Sonos will never degrade the digital signal by reducing the volume in this way.

This holds true for 16-bit audio with 24-bit output. If Sonos ever decides to support 24-bit then, obviously, it won't be true, but anyone expecting significant benefits from 24-bit audio should be using an external DAC from a fixed-output ZP80/90 anyway.

Also, if your DAC only recognises a 16 bit data stream from the ZP80/90 then it won't be true either .

Cheers,

Keith
Digby33,

Connecting a ZP80 to a power amplifier works well. Don't be too concerned about the amplifier's input impedance. Any power amplifier that I've come across will have an input impedance of 10K or higher.

I prefer power amplifiers that include input level controls.

The rated output for a ZP80 is 2.0V at full volume.

Input sensitivity is an interesting spec. Typically, an amplifier will be rated 1.0V for full power output. This means that at 1.0V the amplifier will deliver 20-50-100-200 Watts -- whatever the power rating is. Obviously, the 200 Watt unit will play louder than the 20 Watt unit for a given input voltage.

You may encounter an amplifier that is rated at 0.25V for full power output. This will be difficult to deal with if there is no input level control because the SONOS volume control will need to be at the lower end of its range -- full volume will be much too loud. If you are using a high powered amplifier, 2.0V for full power output would be more reasonable.

In a typical home listening situation an average power of 2.0 Watts is quite loud.
I am looking at the Quad 909 and Audiolab 800p, both of which have 775mV input sensitivity and reasonably heft wattage.

Sounds like they might be rather loud....

I am looking for some variable input amps now.

Cheers

John
Userlevel 2
If you don't find a variable-level input amplifier you like, you might search for a "passive pre-amplifier", which is basically a multi-input switch plus a volume control. Insert between ZP and amp, set level once, and voila! The simplest of these should be pretty cheap.
Userlevel 2
Good passive volume control type preamps are not cheap and you may not need all that flexibility, plus passives can be problematic (impedance matching wise) at the extremes of their range depending on the gear (source and load impedance) that they are used with. I've read some good things about these Rothwell In-line attenuators... you can get a fixed 10db or 20db attenuation. Fixed high quality attenuators like this should be less problematic and make for simple direct connection without additional cables/boxes which a passive preamp will require (these have been very well reviewed too, though I have not used/heard them). Here is their web page: www dot rothwellaudioproducts dot co dot uk/html/attenuators dot html (sorry, forum won't let me insert a link into the post... you can always google Rothwell Attenuators to which will get you there)

10db attenuation should work plenty for most power amps.
Userlevel 2
I have the same general question, but I am not an experienced audiophile, and I'm not sure I understand the answers above. I plan to use a ZP 90 in my living room, and I've ordered a Rotel RB 1080 amplifier, with B&W 804s speakers. The Rotel has no pre-amp (ie volume control) and I thought I would control volume using the ZP 90. I am now concerned that I should have purchased an integrated amplifier which would give me the ability also to regulate volume on the amplifier. I had assumed I would just use the analog outputs from the ZP 90. From reading the posts of this thread, some posts seem to indicate I won't have a problem, but others suggest that for excellent sound quality I'd want to purchase a separate DAC (which I understand only vaguely) or buy a pre-amp to regulate volume. I'd like to think everything will work fine as ordered, but if my inability to control volume at the amplifier is going to be a problem, the best solution might be to send back the amplifier when it arrives for an integrated amp with volume control (of course that might trigger shipping charges but I assume it would be better to deal with this issue before I take things out of the box). Thanks for your thoughts.
Pat Kennedy,

Plug the ZP90 directly into the RB-1080, you'll be fine. Even passive preamps will degrade the sound slightly. Unless you need an input selector or tone controls, a preamp will not add any functionality to the system.
Your setup will probably work fine. The ZP90 can vary the volume on its line-outs without affecting sound quality.

About the DAC: The ZP90 has a DAC built in, it is the part that makes "soundwaves" out of bits and bytes. Hence a Digital to Analog Converter. This is an important piece of electronics for audiophiles. Since the ZP90 only costs $349, its DAC is good,but nothing very special.

Some people like to spend 4 figures on an external DAC to upgrade the sound produced by the ZP90. As you are purchasing pretty high-end stuff, an audiophile would hear the difference on your equipment.

Anyways, it is a bit like comparing a violin from the shop around the corner with something like maybe a stradivarius. I myself wouldn't notice much difference, but some people are willing to spend serious money to get the better piece of kit.

The ZP90 will work just fine without an external DAC, but if you find the chance to try one, you might hear an improvement. On my side of the pond(=Europe), high-end shops will loan you one to test at home against a security deposit.
Userlevel 2
Does the ZP90 affect sound quality by sound control, when connected to an external DAC? I can't here that, but it would interest me from the technical point of view.

At the moment I use the musical fidelity v-dac.

By the way: The ZP90 does a amazing good job as DAC, too. Don't think you really need an external DAC. I listen on Denon PMA SA1 and B&W 804.
Does the ZP90 affect sound quality by sound control, when connected to an external DAC? I can't here that, but it would interest me from the technical point of view.


On this thread, malcolm kind of officially confirms that the bit reduction involved in volume control doesn't reduce the resolution of the 16-bit audio, since internal processing and digital output is 24 bit. So there is room to shift the entire information to less significant bits without losing any bits.
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I want to connect a ZP90 directly to a 2-channel power amp. I'm tired of switching on my amp, selecting the input and turning the volume up before I can use the CR200. I like the ease of my Play5 and ZP120.

The amp must have input adjustment and audio sensing.

There where a few that I found:
-I've read a lot about AudioSource on this forum, but I don't think I can buy one in Europe.
-I don't think any of the new models from Rotel have audio sensing.
-The only one I could find is the NAD C 275BEE Stereo Power Amplifier. But I don't like the looks of that thing.

Anyone tried one of the above? (Or another one?)
Userlevel 2
Badge
I use the Parasound A23 with a ZP90, works great and has the features you require. They also offer the A21 with more power, or the 2125 and the 2250, both are from the lower classic line. They all do what you want with audio sensing. The classic line allows for two stereo sets of speakers to be connected. The Halo line has loop out to allow additional amplifiers to be connected for additional stereo sets of speakers to be connected. Hope this helps.
Userlevel 2
I have the same general question, but I am not an experienced audiophile, and I'm not sure I understand the answers above. I plan to use a ZP 90 in my living room, and I've ordered a Rotel RB 1080 amplifier, with B&W 804s speakers. The Rotel has no pre-amp (ie volume control) and I thought I would control volume using the ZP 90. I am now concerned that I should have purchased an integrated amplifier which would give me the ability also to regulate volume on the amplifier. I had assumed I would just use the analog outputs from the ZP 90. From reading the posts of this thread, some posts seem to indicate I won't have a problem, but others suggest that for excellent sound quality I'd want to purchase a separate DAC (which I understand only vaguely) or buy a pre-amp to regulate volume. I'd like to think everything will work fine as ordered, but if my inability to control volume at the amplifier is going to be a problem, the best solution might be to send back the amplifier when it arrives for an integrated amp with volume control (of course that might trigger shipping charges but I assume it would be better to deal with this issue before I take things out of the box). Thanks for your thoughts.

I was thinking of doing a similar setup getting some decent speakers and an amp. How did your system do for you? I find most responses on these forums way too technical for me.
Hi , I have a Sonos Connect . I have ordered a Chord qutest DAC.

My plan is to connect it the following way...

Sonos to chord Dac

From Dac to power amp

So the only way I can control volume is from the Sonos app. Will this work?

Any suggestions much appreciated .

Thanks
AB
Yes, just don't forget to set the Connect to variable level first.
Ok thanks Kumar
Long ago it was confirmed that the digital output was 24-bit. (The ZP80 is an ancient forebear of the CONNECT.) This means that the Sonos volume can be adjusted right down to about -48dB before any of the original 16-bit information starts to be truncated.
I am subscribing to tidal hifi , how many bits is that?
I am subscribing to tidal hifi , how many bits is that?
Their standard FLAC is Red Book 16-bit at 44.1kHz. Some users have commented that Tidal's MQA, which is sent as 24-bit/48kHz (and possibly 24/44.1), is also playable. However the input is apparently truncated to 16-bit before Sonos processes it.
Oh. Ok thanks.
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I used my connect with a Rotel A14 Integrated Amp and it works fine had the software updated and the audio signal sensing feature works quite well for me and the sound is very good with Rotel , also has 2 sets of speaker plugs to drive A&B speakers to drive 4 Polk Audio outdoor speaker which sounds great and has run like a champ

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