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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
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Old 16th June 2018, 05:41 AM   #1051
Nonlinear is offline Nonlinear  United States
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Join Date: Jan 2006
Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
Quote:
Originally Posted by 69hotrod View Post
Any info on actual availability of first version or even new version.?
Ditto that. Great looking product but I've now been waiting 3+ years for it to materialize...
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Old 16th June 2018, 06:41 AM   #1052
bkdog is offline bkdog
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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
I've been listening to mine for well over 6 months (& VERY happy), but I'm a local and was an early beta tester. I'm sure that David will reply, but I think they are available even if manufacturing is problematic. Maybe contact him through the website?
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Old 16th June 2018, 10:59 PM   #1053
Stammheim is offline Stammheim  Germany
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Hi there,

Looks great, I'd like to see more of it.
From what I understood it's still not finally to order... What would be especially very interesting for me (and I'm sure for others) is this solution with a multichannel input so replace multichannel Interfaces for active loudspeakers.
So if your design is unfinished yet, such complementation could also find a lot of friends.

Anyway, looks great!

Best regards

Stammheim
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Old 6th July 2018, 10:11 PM   #1054
DSP_Geek is offline DSP_Geek  Canada
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Default Hello...hello...hello...

Is there anybody in there?

Just nod if you can hear me

Is there anyone at home?
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Old 7th July 2018, 12:28 AM   #1055
bkdog is offline bkdog
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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
You could try the website Analog-Precision - maybe Tranquility Bass is not getting notifications from this forum for some reason. That happened to me a few weeks ago, for no reason at all I was not getting any notifications and I had to uncheck and recheck all of the threads in my user CP to fix it.
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Old 7th July 2018, 01:23 AM   #1056
DSP_Geek is offline DSP_Geek  Canada
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Still "Coming Soon", I'm afraid, hence the ping in hopes of an answer from TB.
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Old 7th July 2018, 07:29 AM   #1057
Tranquility Bass is offline Tranquility Bass  Australia
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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
Yes I’m still here. Sorry for the lack of updates recently

Recently have been dealing with what I would classify as the customer from hell who owns a poorly designed power amplifier with an equally poorly implemented balanced input stage basically providing little or no immunity to ground induced noise and common mode noise produced by the DAC used in the Preamp. This dude has caused me no end of grief and has thrown road blocks in front of me so it has become impossible to resolve the problem by dealing directly with him !

It's a long story but basically my Preamp has been blamed for every noise problem in his system whilst his mates flawed amp design gets let off the hook. I have repeatedly requested that he sends me his amp or similar amp for evaluation so it could help me diagnose the problem and rectify any possible issues in future designs but so far, no amp has materialized. He has scoffed at the AES48 standard for balanced interconnect system saying in his own words that it is "unsafe" and a "dubious standard", so instead I have done the next best thing and through some detective work have found a similar schematic of this amp and entered it into a circuit simulator and have simulated all possible contingencies and have found that this amp has some serious design flaws. To summarize it has more holes in it than Swiss cheese when it comes to suppressing unwanted noise in the system !

Just a warning to young players. Please be careful of amplifiers that have balanced inputs. A lot of them appear to be poor implementations and provide little or no noise immunity. In particular ask the manufacturer whether their balanced inputs or outputs conform to the AES48 standard. One way of testing this is by measuring the resistance between pin 1 on the XLR connector and chassis ground. It should be a near short circuit and no more than half an ohm. If it is 1 ohms or more then this signals a potential problem with this equipment. Move onto the next vendors equipment if this is the case ! I don’t want to have to go through this crap again ☹

I have written up a white paper on the subject which you can download from here.

http://www.analog-precision.com/Down...ed_equally.pdf

I wasn’t going to get involved in amplifier design at this stage but because of this less than satisfactory experience along with requests from another customer for a custom designed power amp, the gloves have come off and I have decided to join the fray of amplifier builders ! I am now engaged in producing a custom multi-channel amp design for a stereo 4-way active speakers, which like the Preamp also doubles as a no-compromise high-quality, high-powered stereo power amplifier ! Will have more to say about this later.

regards
David

Last edited by Tranquility Bass; 7th July 2018 at 07:32 AM.
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Old 7th July 2018, 01:14 PM   #1058
DSP_Geek is offline DSP_Geek  Canada
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I see.

So the preamp is on hold until the aforementioned amplifier is done? It looked like a godsend because I had really hoped to avoid rolling my own DSP hardware, but if necessity compels then the task must be done, I suppose.

*sigh*

Last edited by DSP_Geek; 7th July 2018 at 01:21 PM.
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Old 7th July 2018, 01:44 PM   #1059
Tranquility Bass is offline Tranquility Bass  Australia
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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
Quote:
Originally Posted by DSP_Geek View Post
I see.

So the preamp is on hold until the aforementioned amplifier is done? It looked like a godsend because I had really hoped to avoid rolling my own DSP hardware, but if necessity compels then the task must be done, I suppose.

*sigh*
It was kind of on hold whilst I investigated this issue as I did not want to repeat the same mistake again on the next revision if I could avoid it. It could have been resolved a lot quicker if the said customer had of cooperated with me and communicated with me a lot better instead of funneling communications via another channel and instead preferring to take advice from people who had absolutely no design input into this project. Most of the time wasted could have been avoided

It turns out that the redesign to the post DAC processing in the next revision more or less eliminates or substantially reduces the DAC common mode noise on the balanced outputs. However this does not let bad amplifier designs off the hook with poor balanced input stages. These amps will most likely still have problems with the Ultimate Preamp or any other source unit if they are not AES48 compliant and wire their balanced interconnect shields directly to some magic ground plane on their amplifier pcb's which is just a magnet for noise problems.

Currently the amp I am looking at building is just a one off custom build for an existing Ultimate Preamp customer, however, if it proves to be an exceptionally good performer than I may add it to our portfolio

regards
david

Last edited by Tranquility Bass; 7th July 2018 at 01:56 PM.
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Old 7th July 2018, 01:59 PM   #1060
DSP_Geek is offline DSP_Geek  Canada
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Quote:
Originally Posted by Tranquility Bass View Post
It was kind of on hold whilst I investigated this issue as I did not want to repeat the same mistake again on the next revision if I could avoid it.
That is appreciated, thanks.


Quote:
Originally Posted by Tranquility Bass View Post
These amps will most likely still have problems with the Ultimate Preamp if they are not AES48 compliant and wire their balanced interconnect shields directly to some magic ground plane on their amplifier pcb's which is just a magnet for noise problems.
You have got to be *****ing me.

er, ah, that is rather against the intent of shielding as I understand it. From my days of working with & debugging multi-kilowatt sound systems surrounded by many, many lights on dimmers: isn't shielding supposed to be hooked up to the chassis and nothing else?


Quote:
Originally Posted by Tranquility Bass View Post
And the amp I am looking at building is just a one off custom build for an existing Ultimate Preamp customer, however, if it proves to be an exceptionally good performer than I may add it to our portfolio
Do please know you've others waiting for the Preamp, so with respect a release schedule would be appreciated so we could plan ahead.
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