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
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
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/an_wp/AN_Legacy_pin_1_problems.pdf
https://www.hypex.nl/img/upload/doc/an_wp/WP_The_G_word.pdf
cheers
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
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.
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.
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...
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
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
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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.
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.
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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/an_wp/AN_Legacy_pin_1_problems.pdf
https://www.hypex.nl/img/upload/doc/an_wp/WP_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
For perspective, here is how Benchmark handles this common noise phenomenon in the DAC3 (ES9028PRO) : Review and Measurements of Benchmark DAC3 | Page 16 | Audio Science Review (ASR) Forum
Yes well spotted article
I have already implemented the IV converter using diff opamps in the next revision some months ago in preparation for the change from the ES9028PRO to the ES9038PRO chip. Probably go for 0.1% metal film resistors in the IV converter if I can get them. However this won't fix the pin 1 problems I have been having with this other amp I have been dealing with but not much I can do about that. That is completely out of my control unfortunately Just some more measurements on it. It appears the CM DAC noise is about 30dB higher than the DM noise or background level of the sound card and rolls off at higher frequencies so is predominately audible and not RF like originally thought. Measured with an Agilent 6.5 digit DMM I get about 0.2mv RMS. Top trace is the CM noise spectrum. Bottom trace is the balanced noise or sound card background noise spectrum.
It appears that some balanced inputs on amps and other equipment just aren't up to the task of handling the CM noise from the DAC. I have had excellent results with some amps including a CARY valve amp which must have used a transformer in its balanced input because the noise was totally absent even right up to the throat of the horn. Same deal with a Valvet solid state power amp. No noise coming from an ion plasma horn tweeter ! However a Vitus power amp driving woofers was a different story. It's as though the balanced input was implemented by taking the signal from pin 2 and 1 instead of from pin's 2 and 3 of the XLR connector !! This one was an epic fail on its balanced inputs. It's a good test though
cheers
david
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The new board will be a drop in replacement to the existing board except for the higher power requirements. I will see what the current requirements are once I have the new board running otherwise everything else should work ok. I have already beefed up the power supply with a 50VA transformer to replace the pcb mounted 30VA one but it may be ok with the existing power supply.
cheers
david
I'm finishing new amplifiers that will go with DSP
you got me thinking about how to connect XLR to the PCB
As you see from the picture, I have connect only + and - from XLR to the PCB
should I connect pin 1 to the PCB (I have left the 0 wire just in case)
should I connect pin 1 on XLR to the case, or live it in the air ?
you got me thinking about how to connect XLR to the PCB
As you see from the picture, I have connect only + and - from XLR to the PCB
should I connect pin 1 to the PCB (I have left the 0 wire just in case
)should I connect pin 1 on XLR to the case, or live it in the air ?
Attachments
I'm finishing new amplifiers that will go with DSP
you got me thinking about how to connect XLR to the PCB
As you see from the picture, I have connect only + and - from XLR to the PCB
should I connect pin 1 to the PCB (I have left the 0 wire just in case
should I connect pin 1 on XLR to the case, or live it in the air ?
Follow this app note.
https://www.hypex.nl/img/upload/doc/an_wp/AN_Amplifier_signal_wiring.pdf
Pin 1 should be grounded at the chassis entry point and then connected to the GND pin on the module. The modules are floating above ground so no earth loop currents can flow through the module and cause buzzing.
cheers
david
It's probably possible to add additional hardware to do this but probably not worth me doing it from scratch as it's a major design in itself. Do you have any suggestions for any hardware ?
cheers
Maybe you could incorporate something like the Audinate Broadway chip for Dante network audio I/O. They are very helpful.
I know I would be keen on that feature because I use a lot of Dante as do a lot of studios.
One other thing I was thinking, it would be really nice if you had a ‘remote volume control’ input (three pins gnd, 5v and wiper) that could be fed to a remote pot as a volume control. For example a simple box for sitting in the listening position on a mixing console or on a desk where you wouldn’t have room for the entire unit.
Those three connections would then allow you to have volume, dim and mute. Very useful.
Just my thoughts form a different industry sector.
I know I would be keen on that feature because I use a lot of Dante as do a lot of studios.
One other thing I was thinking, it would be really nice if you had a ‘remote volume control’ input (three pins gnd, 5v and wiper) that could be fed to a remote pot as a volume control. For example a simple box for sitting in the listening position on a mixing console or on a desk where you wouldn’t have room for the entire unit.
Those three connections would then allow you to have volume, dim and mute. Very useful.
Just my thoughts form a different industry sector.