And on a somewhat less somber note I have been evaluating one of these new Hypex Ncore modules for a custom power amp design. As you can see below it has been connected up to the Ultimate-Preamp in a very slap dash manner and it is still as quiet as a mouse ! Even with my ear right up to the diaphragm of a tweeter there is only a very small amount of DAC noise which indicates a properly designed balanced input stage which I would not expect anything less from Hypex. 6 inches away and it is totally inaudible !
Have a nice day
Have a nice day
Hi David, very informative article
A question that's a bit off-topic but I was wondering if ...
Will an unbalanced hifi amplifier be suitable for direct connection to your preamplifier or will it need some 'Bal -> unBal' converter board, or a transformer, to avoid ground and other complications?
I normally 'float' the amplifier's central ground point 'above chassis earth' by a 10R CL-60 as commonly used in First Watt amp diy designs - this is for home hifi use with a First Watt F6, or F7 amp for the FR high pass speaker and a 150W/8R class AB amp for the bass.
A question that's a bit off-topic but I was wondering if ...
Will an unbalanced hifi amplifier be suitable for direct connection to your preamplifier or will it need some 'Bal -> unBal' converter board, or a transformer, to avoid ground and other complications?
I normally 'float' the amplifier's central ground point 'above chassis earth' by a 10R CL-60 as commonly used in First Watt amp diy designs - this is for home hifi use with a First Watt F6, or F7 amp for the FR high pass speaker and a 150W/8R class AB amp for the bass.
The shield of all of the unbalanced preamp outputs are hard wired to ground. Probably the best way of mitigating ground loop interference when dealing with the unbalanced outputs is the solution put forth in Brunos article but it sounds like you have already implemented something like this,
https://www.hypex.nl/img/upload/doc/an_wp/AN_Legacy_pin_1_problems.pdf
https://www.hypex.nl/img/upload/doc/an_wp/AN_Legacy_pin_1_problems.pdf
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How to treat a Customer
Will do now I have my system working again on a miniDSP Thanks
The Isolation Transformer "pesky" is rated at 100w and is used to form an electrical isolation from the PC front end and monitor, no, not used to plug in 4Kw Kw of amps.
1, An Amplifier Manufacturer that not only is a great bloke, but builds some of the best power amplifiers ever in the World, (and has done for decades), thousands of kits all with 100% success (in comparison to 1 product you have made and sold very few of). I feel like a guinea pig, playing with a tom cat right now and feel your animosity is money related.
2, A Customer that you can't obfuscate easily, because your product isn't doing what it should.
Maybe you should just help, rather than denigrate, your Customers
All I wanted was a product that does the job it was designed to do, not an elongated procrastinated electronics thesis about how poor everyone else's designs are.
Now half way down the rabbit hole, it's time to tell the punters what the problem is'
COMMON MODE NOISE, lots of it, speakers hiss like buggery, measured at +12dB over any other DSP DAC/PRE I own, which is 3, a miniDSP 2x8, a Burson DAC and, SoundCraft UI 24R. We also tested as comparison a Cambridge DAC.
Not only that but tested with at least 3 different Power Amplifier Brands, the Gryphon Antilleon, Sanders Magitech, All comply with the screen chassis Standard and all have the same hiss like buggery problem
You will be returning my coin after your little display here toward a paying Customer (me) who finds your product not suitable for purpose.
CAVEAT EMPTOR!
Yes and you conveniently forgot to add the photo with that pesky mains isolation transformer in it, otherwise your mates amplifiers make too much noise without it. Wonder why ?
And I am still waiting for you to send me your mates amplifier but don't worry I simulated it anyway and it's got more holes in it than Swiss cheese when it comes to noise immunity. I would have found this out if I had the amp in front of me. You can read about it here if you like
http://www.analog-precision.com/Downloads/Docs/Not_all_balanced_inputs_are_created_equally.pdf
Have a nice day comrade.
Will do now I have my system working again on a miniDSP Thanks
The Isolation Transformer "pesky" is rated at 100w and is used to form an electrical isolation from the PC front end and monitor, no, not used to plug in 4Kw Kw of amps.
1, An Amplifier Manufacturer that not only is a great bloke, but builds some of the best power amplifiers ever in the World, (and has done for decades), thousands of kits all with 100% success (in comparison to 1 product you have made and sold very few of). I feel like a guinea pig, playing with a tom cat right now and feel your animosity is money related.
2, A Customer that you can't obfuscate easily, because your product isn't doing what it should.
Maybe you should just help, rather than denigrate, your Customers
All I wanted was a product that does the job it was designed to do, not an elongated procrastinated electronics thesis about how poor everyone else's designs are.
Now half way down the rabbit hole, it's time to tell the punters what the problem is'
COMMON MODE NOISE, lots of it, speakers hiss like buggery, measured at +12dB over any other DSP DAC/PRE I own, which is 3, a miniDSP 2x8, a Burson DAC and, SoundCraft UI 24R. We also tested as comparison a Cambridge DAC.
Not only that but tested with at least 3 different Power Amplifier Brands, the Gryphon Antilleon, Sanders Magitech, All comply with the screen chassis Standard and all have the same hiss like buggery problem
You will be returning my coin after your little display here toward a paying Customer (me) who finds your product not suitable for purpose.
CAVEAT EMPTOR!
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I told you to return the Preamp back to me a month ago and to give me your bank details but instead you prefer to play these mind games and now you want to whine about returning it when the ball was clearly in your court. Now are you going to ask mindsp for a refund because it does not work with your mates amplifier without a mains isolating transformer ? No I didn't think so You just like to whine about my product whilst your mate gets let off the hook for an otherwise flawed amplifier design with a crappy almost useless balanced input stage.
To set the record straight the DAC section of the Ultimate Preamp is based on the Esstech reference design. ALL of the Esstech reference designs for the ES9018, 9028 and 9038 are all very similar in that they all produce this common mode noise at the balanced outputs. It is only a very small 1mV amount of noise but the Hypex Ncore module and several other amps I have tried including a cheap Chinese PA amp has no problem suppressing this noise whereas your mates amplifier has such poor common mode rejection it actually amplifies this noise over a 30KHz to 200KHz bandwidth ! It is only the amps with poor quality balanced inputs that have problems dealing with this noise as well as earth loop noise on the shield as in your case which explains the use of a mains isolating transformer. You will also find that this noise is not present on the unbalanced output from the preamp simply because the common mode noise is cancelled by an opamp filter stage implemented as a difference amplifier.
Because I shipped your Preamp with the coupling capacitors bypassed the 1.6V common mode DC offset on the output of the balanced connections should not have caused the DC protection on your amplifier to be triggered if the balanced input on your amplifier was correctly designed. A balanced input is supposed to amplify the difference between the two signal pins, and as such a DC voltage that is common to both the hot and cold pins should essentially be nulled out and certainly not drive a DC voltage onto the speaker terminals ! Why have a DC coupled amplifier if it can't even handle a small amount of common mode DC voltage from the output of a DAC ?
And regarding "help" you said you were going to send me an amplifier that was similar to the one that you were having problems with ? What happened to it ? I'm still waiting for it ! It was quicker for me to enter the schematic into a circuit simulator and diagnose the problems from the simulations.
And then to make matters worse you decided to funnel your communications through a third person which had nothing to do with this issue. It is impossible for me to diagnose this problem without the equipment in front of me and you have made no attempt to make it easy either. Instead you prefer to ask the advice of other people for a running commentary who have had absolutely no design input into this product whilst I am totally kept out of the loop.
I suggest that you return the Preamp ASAP so I can issue you a refund after I have inspected the unit. This has just gone on for to long it has become ridiculous.
And I repeat what I have said before about amplifiers with balanced inputs. Just because an amplifier has an XLR connector purporting to be a balanced input does not mean it is useful. Check for AES48 compliance and check its common mode rejection ratios across a broad range of frequencies ! Contrary to what the naysayers say, the AES48 balanced interconnect standard has been widely adopted by most reputable amplifier designers. It is the ones that haven't adopted it, you should be very cautious of ! CAVEAT EMPTOR applies here !
You just like to whine about my product whilst your mate gets let off the hook for an otherwise flawed amplifier design with a crappy almost useless balanced input stage.To set the record straight the DAC section of the Ultimate Preamp is based on the Esstech reference design. ALL of the Esstech reference designs for the ES9018, 9028 and 9038 are all very similar in that they all produce this common mode noise at the balanced outputs. It is only a very small 1mV amount of noise but the Hypex Ncore module and several other amps I have tried including a cheap Chinese PA amp has no problem suppressing this noise whereas your mates amplifier has such poor common mode rejection it actually amplifies this noise over a 30KHz to 200KHz bandwidth ! It is only the amps with poor quality balanced inputs that have problems dealing with this noise as well as earth loop noise on the shield as in your case which explains the use of a mains isolating transformer. You will also find that this noise is not present on the unbalanced output from the preamp simply because the common mode noise is cancelled by an opamp filter stage implemented as a difference amplifier.
Because I shipped your Preamp with the coupling capacitors bypassed the 1.6V common mode DC offset on the output of the balanced connections should not have caused the DC protection on your amplifier to be triggered if the balanced input on your amplifier was correctly designed. A balanced input is supposed to amplify the difference between the two signal pins, and as such a DC voltage that is common to both the hot and cold pins should essentially be nulled out and certainly not drive a DC voltage onto the speaker terminals ! Why have a DC coupled amplifier if it can't even handle a small amount of common mode DC voltage from the output of a DAC ?
And regarding "help" you said you were going to send me an amplifier that was similar to the one that you were having problems with ? What happened to it ? I'm still waiting for it ! It was quicker for me to enter the schematic into a circuit simulator and diagnose the problems from the simulations.
And then to make matters worse you decided to funnel your communications through a third person which had nothing to do with this issue. It is impossible for me to diagnose this problem without the equipment in front of me and you have made no attempt to make it easy either. Instead you prefer to ask the advice of other people for a running commentary who have had absolutely no design input into this product whilst I am totally kept out of the loop.
I suggest that you return the Preamp ASAP so I can issue you a refund after I have inspected the unit. This has just gone on for to long it has become ridiculous.
And I repeat what I have said before about amplifiers with balanced inputs. Just because an amplifier has an XLR connector purporting to be a balanced input does not mean it is useful. Check for AES48 compliance and check its common mode rejection ratios across a broad range of frequencies ! Contrary to what the naysayers say, the AES48 balanced interconnect standard has been widely adopted by most reputable amplifier designers. It is the ones that haven't adopted it, you should be very cautious of ! CAVEAT EMPTOR applies here !
It's sad to see this playing out in a public forum.
I've been enjoying one of Tranquility Bass' Ultimate Preamps for nearly 9 months now. I've never felt like a guinea pig and I couldn't be happier with it.
I'm not using the balanced outputs yet but I don't expect a problem when I do because I'm fitting high-quality 1:1 transformers to the inputs of my amps.
I've been enjoying one of Tranquility Bass' Ultimate Preamps for nearly 9 months now. I've never felt like a guinea pig and I couldn't be happier with it.
I'm not using the balanced outputs yet but I don't expect a problem when I do because I'm fitting high-quality 1:1 transformers to the inputs of my amps.
I am embarrassed to read this, hopefully less embarrassed than the writer.
I'm just disappointed I guess.
I had an issue too but I sent Dave my amplifier (cheap chinese class AB pro audio thing) and my UP for him to test both of them, which Dave paid for. Turns out that just because it says Balanced Input on an amp doesn't mean it is. This is where the whole question about AES48 come about. Cheap chinese balanced inputs are not high quality. When the UP is connected to a proper balanced input the UP noise is under the what the test equipment can measure. We had my problem solved in no time and it turned out to be the input to the amplifier. Its not a properly designed balanced input.
So now what the hell do I do, buy something that has an as yet, undiagnosed problem with the UP? I was prepared to spend the 12k or so on Holtons amplifiers. But how am I suppose to have any confidence that if there is a problem that it can be solved. What happens to me if I buy 4 amplifiers and there is something wrong, like Matty clearly has? This hasn't only inconvenienced you, it has stopped me buying Holton and left me with no other option than buy something from overseas. There is clearly a problem between the pieces of equipment that no one else has. I asked you many times on our phone calls to send the UP back to Dave but it never happened, Dave would have paid and all this would have been solved by now. I just dont understand why you didn't pack it up and send it back. If he had both bits of equipment in front of him I'm sure the problem would have been resolved, just like it was for me, even if it meant redesigning the UP outputs. Who knows both manufacturers may have actually been able to improve their respective products out of this but that's never going to happen now.
So rather than risk buying something that I have no idea if it will work, I will get an 8 channel amplifier with AES48 compatible inputs purpose built for an active system, no matter what it costs. What a loss this whole thing is for all concerned.
It didn't have to come to this.
Like I said more disappointing to me than it is sad.
I had an issue too but I sent Dave my amplifier (cheap chinese class AB pro audio thing) and my UP for him to test both of them, which Dave paid for. Turns out that just because it says Balanced Input on an amp doesn't mean it is. This is where the whole question about AES48 come about. Cheap chinese balanced inputs are not high quality. When the UP is connected to a proper balanced input the UP noise is under the what the test equipment can measure. We had my problem solved in no time and it turned out to be the input to the amplifier. Its not a properly designed balanced input.
So now what the hell do I do, buy something that has an as yet, undiagnosed problem with the UP? I was prepared to spend the 12k or so on Holtons amplifiers. But how am I suppose to have any confidence that if there is a problem that it can be solved. What happens to me if I buy 4 amplifiers and there is something wrong, like Matty clearly has? This hasn't only inconvenienced you, it has stopped me buying Holton and left me with no other option than buy something from overseas. There is clearly a problem between the pieces of equipment that no one else has. I asked you many times on our phone calls to send the UP back to Dave but it never happened, Dave would have paid and all this would have been solved by now. I just dont understand why you didn't pack it up and send it back. If he had both bits of equipment in front of him I'm sure the problem would have been resolved, just like it was for me, even if it meant redesigning the UP outputs. Who knows both manufacturers may have actually been able to improve their respective products out of this but that's never going to happen now.
So rather than risk buying something that I have no idea if it will work, I will get an 8 channel amplifier with AES48 compatible inputs purpose built for an active system, no matter what it costs. What a loss this whole thing is for all concerned.
It didn't have to come to this.
Like I said more disappointing to me than it is sad.
Agree
Gee it's been easy though to dismiss all my testing and evaluations with a fair range of gear, Aye, close your eyes and ears.
In between installing and commissioning remote area power systems, which is very busy, I've spent considerable time and money with professionals in my time off to try fix the problem. Modifying my amp rack inputs, employing people, testing.
Last resort is to send it back or give away and it's come to that.
As stated, happy with outcomes as solution was found, hold no grudge or malice.
Previous page post reply
Interestingly bench testing ring driver, 91dB efficient roughly, hiss disappears at 6 inches. IMHO toy driver
Cinema horn/JBL Compression Driver 115dB efficient, which is roughly 8 times louder for the same input, Do the Math.
My definition of quiet of a mouse is infinitesimally different. I call it liquid black silence and there is a couple of products capable of that on any amplifier input, not just a few.
Matthew Pullen
Operations Manager
SOLAR TASMANIA
Common-mode noise on a balanced signal is a sub-optimal condition, but a moot issue if the receiving end is doing its part. The primary function of a balanced transmission line is to reject common-mode noise. If it can't do this, it is not performing its intended function.
As I said before, the preamps balanced outs work fine into the balanced inputs of a Pass Aleph J power amps - zero noise or issues.
Also a similar recommendation from Esstech from a reply I received from them recently so they know about this issue and obviously assume that a balanced input is supposed to be a balanced input with all of it's claimed benefits
.Now it's possible that the preamp may actually be faulty which is why I have requested that it be packed up and sent back to me. And if possible send the amp as well so I can evaluate the two working together and see if there is a possible resolution. But to date neither has materialized even though the customer said he would.
Not sure what the hell is going on here but back-biting at the product on another thread is not going to help solve the issues. It's kind of like entering a one legged man into an a**e kicking competition and then later on whinging to everyone else about why he couldn't win
cheers
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