I prefer the soundstage of the standard buffer. It is as deep as the Sonic Imagery's but vocals are much further forward.
If Sonic imagery built that board it would come with a comprehensive spec sheet just like this. So don't give Richard credit for the finished Nord board.
http://www.sonicimagerylabs.com/pro...e_HD_OpAmp/994Enh_DiscreteOpAmp_Datasheet.pdf
Sebastian, nice speakers by the way. I haven't been fortunate enough to hear them but a friend of mine rated them very highly when he had a chance to hear them.
I have only just taken the buffers out, so I will do some listening this evening and over the weekend.
I don't think DSP is a magic wand for a bad sounding hi-fi. Treat it as something to fine tune the sound to what you prefer. E.G. add a BBC dip to bring out vocals, raise 100-200 hz to bring out more a mid bass hump - plenty of resources online to read through.
I always start from ground zero when comparing, I turn off HQplayer upsampling and remove correction filters. Then I slowly bring them back in to find what upsampling fiters I like, followed by room tuning tweaking. I have made the mistake in the past not changing my correction filters with a new peice of equipment.
The Phison is significantly better. The USB input is extremely tollerant of the four sources I have (Auralic Aries, Raspberry PI, HTPC with no USB addon's and a Cu-box - soon to add a Sonore Microrendu). The pre-amp has been an eye opener, I have mostly used Dac's for volume in the past but I did have an Ayre and Audio Reference pre 18 months ago. The Phison just sounds the same at any volume, my hifi is used a lot more now when just reading at almost barely audible volume but still super clear. The Dac has been documented in the other thread, but it is smooth, non-congested, natural and all the other hifi words you can think off 🙂 Too me anyway. I am waiting for a friend to pop over with his T+A Dac DSD which everyone seems to be hyping about at the moment to compare.
I have only just taken the buffers out, so I will do some listening this evening and over the weekend.
I don't think DSP is a magic wand for a bad sounding hi-fi. Treat it as something to fine tune the sound to what you prefer. E.G. add a BBC dip to bring out vocals, raise 100-200 hz to bring out more a mid bass hump - plenty of resources online to read through.
I always start from ground zero when comparing, I turn off HQplayer upsampling and remove correction filters. Then I slowly bring them back in to find what upsampling fiters I like, followed by room tuning tweaking. I have made the mistake in the past not changing my correction filters with a new peice of equipment.
The Phison is significantly better. The USB input is extremely tollerant of the four sources I have (Auralic Aries, Raspberry PI, HTPC with no USB addon's and a Cu-box - soon to add a Sonore Microrendu). The pre-amp has been an eye opener, I have mostly used Dac's for volume in the past but I did have an Ayre and Audio Reference pre 18 months ago. The Phison just sounds the same at any volume, my hifi is used a lot more now when just reading at almost barely audible volume but still super clear. The Dac has been documented in the other thread, but it is smooth, non-congested, natural and all the other hifi words you can think off 🙂 Too me anyway. I am waiting for a friend to pop over with his T+A Dac DSD which everyone seems to be hyping about at the moment to compare.
Hi Mike, both boards sound excellent. I wouldn't say either one sounds bad, just my honest preference.
I understand that, but you keep saying the sonic imagery board like the Nord board the opamp is plugged into has nothing to do with the end result. People will read this and get the impression that the attributes you describe are due to the 994. But having used the 994's and directly comparing them apples to apples with bone stock Hypex boards, as well as other boards with dip 8 LM4562's this isn't the case. The attributes you describe would likely be present even if you pulled the same LM4562's off the Hypex board, soldered them to dip 8 adapters, and plugged them into the Nord boards.
Maybe so Mike.
This is why I tend to avoid sharing my subjective opinions, someone will always have a differing one or as you say it may even potentially incur damage to someone. You have used my name twice on this forum recently and on another forum, as if I am some how an authority/pariah on the matter due to products I have purchased to defend your self-interests. Hence I felt indebted to share my experiences to hopefully the benefit of others.
Let's agree to disagree on this one, however I will admit you were spot on with the Phison.
I'm just saying that you shouldn't call the SIL 994's colored, recessed and all of that when you have no idea what is causing this.
If you put the exact same LM4562 opamps in both the Nord boards, and the Hypex boards and they sounded different, would this be due to the opamp or the boards?
Why do you think so? And how is the NC500 working without the buffer board then...
Because the power reserves in the regulator and bypass caps are being 100% dedicated to powering the section in the NC-500's, rather than sharing the task of powering the opamp. It's always better to have dedicated regulators for each section. Regulators always perform better with lower load as well.
The OEM board was originally designed as a basic means for OEM's to evaluate the NC-500's. Much like the evaluation boards you see for DAC chips. It wasn't designed to be the "ultimate solution"
A soundbite which doesn't always stack up. It would depend whether the 'lower load' is a less variable load. In general regs perform better the higher the output current, up to their current limit.
Well there's definitely more clean current reserves available for transients when they aren't operating at the upper limit. The opamp in this buffer is definitely a variable load, as music is dynamic.
No self-respecting audio engineer would design in regs that were operating so close to their upper limit that transients in the signal could take them beyond it.
Music is certainly dynamic, but it doesn't follow from that observation that all audio circuits require dynamically changing currents. An opamp with no appreciable load on its output wouldn't be a variable load for example, so its all down to implementation.
Music is certainly dynamic, but it doesn't follow from that observation that all audio circuits require dynamically changing currents. An opamp with no appreciable load on its output wouldn't be a variable load for example, so its all down to implementation.
Well this was the case with the Nord board with the HxR's. This is why coming switched to the Sparko's.
I'm lost now - what was the case?
Most implementations of opamps have them running in classAB so for opamps, there's normally variable current drawn. A way to improve opamp sound is to bias the output stage into classA with a current source - then the current demand is less variable, but its also higher and the regs will normally work better. Having said that the Hypex regs aren't the normal kinds of regs so what I've said might not apply to them.
Most implementations of opamps have them running in classAB so for opamps, there's normally variable current drawn. A way to improve opamp sound is to bias the output stage into classA with a current source - then the current demand is less variable, but its also higher and the regs will normally work better. Having said that the Hypex regs aren't the normal kinds of regs so what I've said might not apply to them.
It was because the SIL-994 opamps combined with the NC-500's were gobbling too much power from the HxR's. As a result they were overheating and shutting down. However before overheating, I can imagine they weren't performing at optimum levels. A great example of how using multiple regulators instead of 1 to achieve better performance is with the Phison PD2 DAC. On the Mirand DAC (designed by the same guy and based on the same AKM AK4490 DAC chip) a separate voltage regulator was used to power each channel of the DAC chip. On the Mirand DAC, a single regulator is used instead. According to Sonny, this resulted in higher performance. And it wasn't because the single chip was being overworked.
There are a few different issues there which don't successfully get boiled down into a single soundbite such as 'regs work better at lower currents'. Rather 'regs work better at stable currents' would be a better condensation of the patchwork of anecdotes. DACs such as the AKM series use opamps in their output stages so its best to load these as lightly as possible to minimize the power supply noise generated. Do you know what load Sonny's putting on the DAC chip's outputs? Following the DS recommendations will mean quite a lot of PS noise and hence the circuit becomes very sensitive to regulator quality. Far better to ignore the application schematic's focus on achieving lowest possible measured noise in my view.
Overheating is another issue entirely.
Overheating is another issue entirely.
He's not putting any extra load on the DAC chip's outputs on the PD2 vs the Mirand DAC when using the same output board the Mirand DAC uses. If you look at both, all the same bits are used after the DAC chip on the DAC board. He recently revised the output board for the PD2, but it was first released with the exact same Mirand discrete output board.
Actually I was wrong. He does use dual LDO's on both DAC's, 1 for each channel of the chip. That's the 3 square boxes around the DAC chip. He found using 1 for each channel offered better performance. Although a single unit could deliver far more power than required on its own:
http://www.mouser.com/ds/2/405/tps7a47-558308.pdf
However he has an extra 9 LDO's on the PD2 board to power the different sections vs the Mirand DAC. He finds dedicating LDO's to each subsection improves performance. Considering I have compared both DAC's, I definitely agree. The PD2 is much better. Even when the same DAC output board is used.
Last edited:
The reasoning in going from 'one reg per channel sounds better than pairing channels' to 'therefore regs always perform better at lower currents' still is eluding me.