• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Pre-amp for active digital / analogue speakers

andrew

Active Member
Joined
May 3, 2018
Messages
192
Likes
42
This thread is spawned from an initial discussion within the Dutch & Dutch 8c thread about digital pre-amps that can feed the speakers like the 8c which have digital inputs. To summarise, the 8c have a single input that can be configured for analogue or digital (AES), on-board volume control via a web-app and, soon, in-built Roon. All this works well for a single “enthusiast listener” but it’s a bit problematic when the speakers are used by others and/or integrated into a multi-source environment. One approach is to feed the speakers with an analogue input which opens up a wide range of main-stream remote-controlled options including stereo DAC with volume control or, if the situation demands HDMI connectivity, A/V Processor. The only downside with this would seem to be the A/D conversion in the speaker but it’s not clear to me that this would necessarily be audible (even at low volumes). Another approach is a “digital pre-amp” that, ideally, would provide multiple digital / analogue inputs with remote controlled source switching and a volume controlled digital (AES) output. The pro-audio interfaces (e.g., RME ADI-2 Pro, Tascam UH-7000) get close but don’t seem to include remote control whilst the emerging set of consumer solutions (e.g., Yamaha WXC-50) don’t have AES output. What, if any, digital pre-amp options exist? Or is modern A/D good enough in terms of both sound quality and latency to render this search irrelevant?
 

dc655321

Major Contributor
Joined
Mar 4, 2018
Messages
1,597
Likes
2,235
I think the RME ADI-2 has a remote. Or one is available separately.
 

Purité Audio

Master Contributor
Industry Insider
Barrowmaster
Forum Donor
Joined
Feb 29, 2016
Messages
9,051
Likes
12,150
Location
London
The ADI DAC 2 has a remote but doesn’t have A/D, probably most fruitful looking through the Pro Audio sector.
Keith
 

Dialectic

Major Contributor
Forum Donor
Joined
Sep 26, 2017
Messages
1,740
Likes
3,098
Location
a fortified compound
A Dutch & Dutch-designed knob for the 8Cs (analogous to the Kii Control) would be welcome.

(Also welcome is that an external, pricey knob is not needed to control all the functions of the 8Cs, as the Kii Control is with the functions of the Kii Threes!)
 
OP
A

andrew

Active Member
Joined
May 3, 2018
Messages
192
Likes
42
One option looks to be mini-dsp DDRC-22d or opendrc-di both of which have multiple digital inputs and an AES/EBU output that is volume controlled via remote (albeit a 32-bit volume control). Another option might be NAD M12 which is a lot more expensive but has an optional HDMI card (3 in / 1 video out) but it's not clear if the coax digital output is volume controlled.
 

oivavoi

Major Contributor
Forum Donor
Joined
Jan 12, 2017
Messages
1,721
Likes
1,934
Location
Oslo, Norway
One other option: An old Logitech Transporter. Can be found on ebay for 300 to 400 USD. Has aes/ebu out. The digital volume control is 24-bit only, so probably preferable to only fine-tune up and down with transporter, and do most of the attenuation another place in the chain (in the case of the 8Cs, internally in the DSP). The Transporter had/has stellar measurements, fully on a par with most of what is made today. Archimago uses one of those as his pre/streaming device of choice I think. No analog input though. Here are the measurements: http://archimago.blogspot.no/2013/02/measurements-logitech-transporter.html

I still think the Yamaha WXC-50 with a simple converter to AES/EBU is the most rational option from a consumer standpoint.

And then, the question if the extra DA/AD conversion is something to think about at all? I'm not sure. I doubt it, honestly. AD conversion is more of a worry than DA conversion. But still, if competently done I doubt it would be audible in any case. But if one can easily avoid it? I see no reason to have the two extra conversions there. Avoiding the extra conversions is just one more step to ultimate fidelity in the objective sense, should it be audible or not.
 

oivavoi

Major Contributor
Forum Donor
Joined
Jan 12, 2017
Messages
1,721
Likes
1,934
Location
Oslo, Norway
Another option would be this unit, which seemingly will hit the market in June: http://www.lake-people.de/index.php/produktdetails/product/DAT_RS_05.html

Starting price of 649 euro, with optional add-ons: Femtoclock, usb input and remote contol, for about 250 euro extra each.

As to the Minidsp units, my only concern would be that they by necessity do resampling, which could be an issue.
 
OP
A

andrew

Active Member
Joined
May 3, 2018
Messages
192
Likes
42
And then, the question if the extra DA/AD conversion is something to think about at all? I'm not sure. I doubt it, honestly. AD conversion is more of a worry than DA conversion. But still, if competently done I doubt it would be audible in any case. But if one can easily avoid it? I see no reason to have the two extra conversions there. Avoiding the extra conversions is just one more step to ultimate fidelity in the objective sense, should it be audible or not.
Yes, setting up a stereo DAC/pre or A/V process that feeds the 8c with a volume adjusted analogue signal is the simplest option (as it allows for all sorts of sources including those with HDMI) and it seems reasonable to me that the A/D that will occur in the 8c will likely be transparent. The fact that Keith et. al. are demonstrating based on this model gives me confidence but there is that niggling thought that ultimate fidelity will be lost.
 

fredoamigo

Addicted to Fun and Learning
Forum Donor
Joined
Mar 11, 2018
Messages
604
Likes
998
Location
South East France
Yes, setting up a stereo DAC/pre or A/V process that feeds the 8c with a volume adjusted analogue signal is the simplest option (as it allows for all sorts of sources including those with HDMI) and it seems reasonable to me that the A/D that will occur in the 8c will likely be transparent. The fact that Keith et. al. are demonstrating based on this model gives me confidence but there is that niggling thought that ultimate fidelity will be lost.
can you say more about your last
phrase ?


?
 
Last edited:

oivavoi

Major Contributor
Forum Donor
Joined
Jan 12, 2017
Messages
1,721
Likes
1,934
Location
Oslo, Norway
Yes, setting up a stereo DAC/pre or A/V process that feeds the 8c with a volume adjusted analogue signal is the simplest option (as it allows for all sorts of sources including those with HDMI) and it seems reasonable to me that the A/D that will occur in the 8c will likely be transparent. The fact that Keith et. al. are demonstrating based on this model gives me confidence but there is that niggling thought that ultimate fidelity will be lost.

As reported in the multichannel thread, I intend to try out multichannel upmixing with Logic 7 with the 8Cs, using an old Lexicon receiver (MC-4). That necessitates the extra DA/AD-conversion. Would have preferred it if it was pure digital, but what can you do... :) The rational part of me does think that these extra conversions won't be audible.
 
OP
A

andrew

Active Member
Joined
May 3, 2018
Messages
192
Likes
42
can you say more about your last
phrase ?


?
All I’m wondering is whether the A to D conversion might have a negative audible impact. My guess is that it won’t - unless volume is very low - but the nagging question remains.
 

fredoamigo

Addicted to Fun and Learning
Forum Donor
Joined
Mar 11, 2018
Messages
604
Likes
998
Location
South East France
there are always unanswered questions about signal integrity in case of double or triple conversions.
I don't know if anything's ever been done about it? I'd like amir to watch this sometime?
subjective listening feedback says that the differences are inaudible but in case of signal processing isn't it better to have a fully integrated signal??
how to know if different conversions don't add noise, distortion, jitter?
 

Purité Audio

Master Contributor
Industry Insider
Barrowmaster
Forum Donor
Joined
Feb 29, 2016
Messages
9,051
Likes
12,150
Location
London
Yes, setting up a stereo DAC/pre or A/V process that feeds the 8c with a volume adjusted analogue signal is the simplest option (as it allows for all sorts of sources including those with HDMI) and it seems reasonable to me that the A/D that will occur in the 8c will likely be transparent. The fact that Keith et. al. are demonstrating based on this model gives me confidence but there is that niggling thought that ultimate fidelity will be lost.
You can’t defeat the internal processing of the 8Cs what we can do is to demonstrate two pairs of 8Cs, one fed analogue signal and one digital, identical programme and volume and switch instantaneously.
Keith
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,524
Likes
37,057
I don't have the files up anymore, but have made available the original digital files and an 8th gen copy that has been through 8 AD and DA stages. I believe even Amir couldn't hear them as different except for a tale in one file that hadn't been edited correctly. I understand people having doubt, but having done this myself one AD/DA stage isn't scary to me anymore.

The two devices were good though nowhere near state of the art. Performance would have been characterized as maybe 18 bit. After the multiple generations it would be something like 15 or 16 bit performance. So yes noise was higher by about 9 db and distortion a bit more, but you couldn't hear it vs the original digital file.

As for a digital pre-amp, if you see any of the old Tact room correction pre's floating around they would be good for this purpose. They were meant to work with Tact's amps that only had digital input. These units take coax, toslink or AES/EBU on XLR. Output in those formats as well. Some were 96 kHz and some 192 kHz. The digital volume control was done at 48 bit levels. They have volume control and multiple digital inputs. So you could connect with a USB to SPDIF converter and have things digital all the way to the 8C's,
 
OP
A

andrew

Active Member
Joined
May 3, 2018
Messages
192
Likes
42
You can’t defeat the internal processing of the 8Cs what we can do is to demonstrate two pairs of 8Cs, one fed analogue signal and one digital, identical programme and volume and switch instantaneously.
Keith
I'd be interested in hearing the feedback from such a test
 
Top Bottom