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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
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Old 15th July 2018, 03:02 AM   #1101
Tranquility Bass is offline Tranquility Bass  Australia
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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
Mate according to the simulations on a similar amp to the one you are using any common mode noise and interference almost goes straight through this amp to the speaker output with at best 20dB attenuation. Over a 30K to 200K bandwidth it actually amplifies common mode noise. This isn't going to work out well for highly efficient speakers like the ones you are using. The balanced input on this amp is totally benign and pointless.

Why didn't you just send me this amplifier like you said you would ? What were you afraid I would find ? Instead you avoided contact with me and instead preferred to send emails and SMS messages whinging about it to another party from then on. I'm trying to resolve this issue whereas you appear to like playing games and then bitching about it when you think you have scored a trophy.

First it was the shield ground loop noise issue due to lack of compliance with the AES48 standard which you said in your own words was a 'wanky standard'. Then it was the DC offset protection issue. And now it's the DAC noise issue. All of these things should NOT be an issue if the amplifier was designed properly with a properly designed balanced input stage !

It appears to me that you are such a rusted on devotee to this amplifier and all its failings that you are blinded by loyalty to this amplifier vendor and any problems in your system are always directed at my equipment whilst your mate always gets let off the hook for his amplifier's short comings

cheers
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Old 15th July 2018, 03:40 AM   #1102
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 orangeart View Post
Anyone in the UK got one of these? I'm about to release a balanced multi channel amp onto the market and would like to test it with the Ultimate Preamp.

Stefan
I have one customer from the UK who has ordered one but won't be picking it up until he visits Australia at Christmas time. If you are going to build amps make sure you do the balanced inputs right so you can avoid all of these dramas

I recommend that you start with these articles

https://www.hypex.nl/img/upload/doc/...1_problems.pdf

https://www.hypex.nl/img/upload/doc/...The_G_word.pdf

cheers
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Old 15th July 2018, 05:42 AM   #1103
125dbmonster is offline 125dbmonster  Australia
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Quote:
Originally Posted by Tranquility Bass View Post
Mate according to the simulations on a similar amp to the one you are using any common mode noise and interference almost goes straight through this amp to the speaker output with at best 20dB attenuation. Over a 30K to 200K bandwidth it actually amplifies common mode noise. This isn't going to work out well for highly efficient speakers like the ones you are using. The balanced input on this amp is totally benign and pointless.

Why didn't you just send me this amplifier like you said you would ? What were you afraid I would find ? Instead you avoided contact with me and instead preferred to send emails and SMS messages whinging about it to another party from then on. I'm trying to resolve this issue whereas you appear to like playing games and then bitching about it when you think you have scored a trophy.

First it was the shield ground loop noise issue due to lack of compliance with the AES48 standard which you said in your own words was a 'wanky standard'. Then it was the DC offset protection issue. And now it's the DAC noise issue. All of these things should NOT be an issue if the amplifier was designed properly with a properly designed balanced input stage !

It appears to me that you are such a rusted on devotee to this amplifier and all its failings that you are blinded by loyalty to this amplifier vendor and any problems in your system are always directed at my equipment whilst your mate always gets let off the hook for his amplifier's short comings

cheers
Fairly simple
I have tens of thousands tied up in Amps and 5 K tied up in DSP units.
Is easier to get rid of a lesser expensive piece of equipment. The Amp Rack has proven very well in the past and is fine now thanks

No, no, won't be sending any of my equipment to you, your attitude is the issue

You seem to forget you are dealing with someone who sells more electronic equipment in a month over Australia that you would in a decade and I have never in my days seen a so called Business Manager carry on like you do with a paying Customer, it's a little disconcerting and repugnant.

You need to learn a lesson in humility and respect for others that put bread and butter on your table.

You started this and it finishes when you stop brow beating the rest of the World of other designers who, have backing of decades, thousands of Compliant Products in successful service.

The Customer from Hell, wouldn't have been a problem if treated with decency in Public. All and any response from me has been in receipt of your posts.

The fact remains, your Product is not suitable for wide bandwidth HiFi Amps.
You need to overcome this with your design or you will have more problems with other Customers. I would never have been involved to this extent if the product was ok and nothing was said.

Good luck in future you will need it.

Respond how you may, last time other than the return of the device you will hear from me, where you will be expected to treat the return as any other claim that falls under the ACCC
nothing more nothing less and without the monologue about "Other Manufacturers" or "winging" or reference to "hell Customers" or anything else other than the sticking exactly to the guides set out in the framework set out in Australian Legislation.

Consumer guarantees | ACCC

Might do some good to familiarize yourself with this as this is the playground now.

Thank you
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Old 15th July 2018, 07:08 AM   #1104
oohms is offline oohms  Australia
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So you invested even more in dodgy amps and it was easier to return the DAC?
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Old 15th July 2018, 07:35 AM   #1105
dch53 is offline dch53  Australia
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Again, this is sad, and yes, disappointing to see. I was hoping that some sort of peace had settled in.

Until #1079 "the customer from hell" was nameless. It would have been best if it had stayed that way.

This is supposed to be a technical forum but maybe things are different in the vendor forums.

Incompatibilities between equipment can even happen when tens of thousands of dollars of commercial equipment are involved. Recently a top-end CD transport/DAC (I'm talking $35K here) was found to produce low levels of noise when playing SACDs or DSD into an extremely expensive valve preamp (similar sort of price). I'm not familiar with the technical details but I'm guessing some digital artefacts beyond the audio band were exciting some sort of resonance in the preamp. Anyway, the manufacturer of the DAC had to add a brick wall filter to fix the problem.

These things happen and it's a shame they can't be resolved amicably. Get over it. Move on.
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Old 15th July 2018, 07:36 AM   #1106
yoke is offline yoke  Croatia
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Quote:
Originally Posted by oohms View Post
So you invested even more in dodgy amps and it was easier to return the DAC?
Don't "bite" the custimer, ha have right to choise what ever he wonts in his sistem.

He doesn't like DSP so he will look for another unit...
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Old 15th July 2018, 10:26 AM   #1107
Tranquility Bass is offline Tranquility Bass  Australia
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db125monster your options are very clear as I have on numerous occasions asked you to return the preamp for a refund along with your banking details after I have inspected the unit for damage or tampering.

If you keep spamming this thread with your propaganda I will have no alternative other than to ask the moderators to ban you and delete all of your posts from this thread. Also, anyone who has made reference to actual names or brands in reference to the alleged equipment should also request that the moderators delete those posts as well.

Seriously I need to move on from this, otherwise this is starting to affect my health and I really don’t need it. I didn’t go to University to get an Electronics Engineering degree with 25 years of experience to have to deal with this nonsense. I have spent a large amount of unpaid time on this project and the revenue from the initial run of Preamps certainly does not go anywhere near to even cover my food expenses. You could say I am selling these Preamps at a huge financial loss ! This is a total next level BS experience if I ever saw one !

Also can everyone stop responding to these posts from db125monster. Nothing good or productive is coming by responding to these posts !

Lets all move on

regards
David

Last edited by Tranquility Bass; 15th July 2018 at 10:48 AM.
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Old 15th July 2018, 01:39 PM   #1108
Max Headroom is offline Max Headroom  Australia
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Hi David, Anthony and Matt.

There are several sets of input factors, errors and misunderstandings in the overall equation here... First is AP DAC outputs excessive CM noise. Second is Holton amp has excessive input CM noise sensitivity. Third is the unusually high 115dB sensitivity of the final HF transducers. Fourth is the chain of communications events. Fifth we are all here to help to resolve all issues.

The first outcome is that for the domestic HiFi market 'any' DAC output CM noise is not acceptable BECAUSE not all well subjectively regarded domestic amplifiers can cope with input CM noise. The first solution is of course to ameliorate DAC output CM noise and this is done routinely, and if I understand it correctly David is implementing a pcb/schematic revision solution to correct this.

The second outcome is that Anthony needs to revise his balanced input stages and earthing arrangements such that his amplifiers are fully AES48 compliant, perhaps as a switchable option for when it matters. Anthony has been producing highly regarded amplifiers for a long time, David has come up with a world beating hardware and software solution.

Somehow the worst of compatibility issues have come to light with all parties involved being within relatively close physical proximity.

This is a learning experience for both parties, and with the improvements required implemented, both manufacturers should be in the position to stand proud on the world stage...at present this is not possible.

This a chance for all parties to put heads together and improve each others products going into the future and for mutual benefit.

Dan.

Last edited by Max Headroom; 15th July 2018 at 02:04 PM.
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Old 15th July 2018, 02:43 PM   #1109
orangeart is offline orangeart  United Kingdom
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Quote:
Originally Posted by Tranquility Bass View Post
I have one customer from the UK who has ordered one but won't be picking it up until he visits Australia at Christmas time. If you are going to build amps make sure you do the balanced inputs right so you can avoid all of these dramas

I recommend that you start with these articles

https://www.hypex.nl/img/upload/doc/...1_problems.pdf

https://www.hypex.nl/img/upload/doc/...The_G_word.pdf

cheers
All over those documents, and the product is based in the hypex modules, however there is a control board in between the connectors and the modules as the latest modules require some house keeping to be done. I have laid out the board according to AES48, however none of the balanced solutions I've got here have got any common mode noise on the outputs. Our customers are likely to be the same so it's prudent to test it with your DAC knowing that it's got a common mode 'problem'

Stefan
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Old 16th July 2018, 02:48 AM   #1110
Tranquility Bass is offline Tranquility Bass  Australia
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The next revision will not have any CM noise at all. But I suggest you feed a white noise source of about 1mV RMS from a signal generator directly into both hot and cold pins with both pins shorted together which more or less simulates the issue.

regards
david
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