Transients don't require a large reservoir. It is sustained peaks that drain the capabilities of power supplies.
You are right of course. If a signal requires a lot of power but for a brief time then it is doing only a small amount of work and requires little energy. In this case a linear supply may profit from bypassing the caps with small and fast ones but also a small reservoir would do. Thanks for correcting me, that’s what happens when I write without thinking too much!
I realize it's not you writing those words Maty.
Not having heard the purifi modules myself, but comparing various amplifier types and design ideals.
This seems to me a bit like my first confusion when listening for distortion and certain phase related issues.
A little bit of distortion can sort of add to the perception of the material, making it sound richer, or "more", than it really is.
I would not really worry about such a listening impression, it's just as likely to be confusion about what's supposed to be there and not.
I like to (slowly) go towards an active cross over for which three channels amplifier would be a good solution. I am considering a multichannel Purifi amplifier but could start with a stereo build to see how it matches my efficient speakers (~96 dB). The dilemma is the input buffer.
I read good things about the EVAL1 kit input buffer. The Neurochrome universal buffer is also good and easier to use for a three channel build. Do I understand it correctly that the EVAL1 kit needs 18V while the Neurochome buffers need 15V?
I do not like startup pops and clicks and was wondering if I need to add either a soft start module or a protection like the Neurochrome Guardian86 to prevent them from happening?
I read good things about the EVAL1 kit input buffer. The Neurochrome universal buffer is also good and easier to use for a three channel build. Do I understand it correctly that the EVAL1 kit needs 18V while the Neurochome buffers need 15V?
I do not like startup pops and clicks and was wondering if I need to add either a soft start module or a protection like the Neurochrome Guardian86 to prevent them from happening?
Soft Start
A convenient way to soft start is to use the feature that is built in to the 1200 power supply. It will control the 400a.
Pins J5.1 and J5.5 (ground) on the smps.
Applying a 3.5v - 5.5v at this point puts the smps in standby and soft starts/stops the module. More data on both the info sheets.
I simply recycled and old dc wall wart supply for this purpose. Mounted it inside the case at the power in location. Controlled by faceplate switch. Simple and works perfectly.
Dave in MN
A convenient way to soft start is to use the feature that is built in to the 1200 power supply. It will control the 400a.
Pins J5.1 and J5.5 (ground) on the smps.
Applying a 3.5v - 5.5v at this point puts the smps in standby and soft starts/stops the module. More data on both the info sheets.
I simply recycled and old dc wall wart supply for this purpose. Mounted it inside the case at the power in location. Controlled by faceplate switch. Simple and works perfectly.
Dave in MN
What is all this concern RE soft start? The Purifi eval board has the NAMPON switch, which defeats the output of the amp. For "soft start" all one has to do is turn the NAMPON "off" and then apply power to the amp. after everything is powered up, then enable the amp via the NAMPON switch. There is no need for additional circuitry or anything.
Even if one decides to use the Purifi modules with a different input gain stage, one still has to use some kind of adapter board (or the eval board in bypass mode) and any adapter board should include the access to the NAMPON for obvious reasons (previously posted pics of Mivera's input board shows it includes the NAMPON connection).
Even if one decides to use the Purifi modules with a different input gain stage, one still has to use some kind of adapter board (or the eval board in bypass mode) and any adapter board should include the access to the NAMPON for obvious reasons (previously posted pics of Mivera's input board shows it includes the NAMPON connection).
20th January 2020 - barrows
"I hope no one has been scared off from sharing their approaches here, the more information the better as far as I am concerned. We can be critical of each other's approach, in the interest of learning, but let us not be critical of each other for trying different approaches." - barrows January 20, 2020
"I hope no one has been scared off from sharing their approaches here, the more information the better as far as I am concerned. We can be critical of each other's approach, in the interest of learning, but let us not be critical of each other for trying different approaches." - barrows January 20, 2020
Huh?
Are you suggesting I am being critical? Please note my first sentence above has a question mark after it, and I fully expect to be corrected if I am actually missing something here. I am sorry if that is the way my above post was perceived... My point being only to help those building a Purifi based amp or considering doing so: there is no need for additional "soft start" circuitry to be added to the eval kit, as the NAMPON is built in and functions fine in this regard. All the concerns expressed about integrating a "soft start" looked to me like things which might discourage someone from taking on the project, all I am trying to do is to suggest that such concerns are really not, and need not be so.
Are you suggesting I am being critical? Please note my first sentence above has a question mark after it, and I fully expect to be corrected if I am actually missing something here. I am sorry if that is the way my above post was perceived... My point being only to help those building a Purifi based amp or considering doing so: there is no need for additional "soft start" circuitry to be added to the eval kit, as the NAMPON is built in and functions fine in this regard. All the concerns expressed about integrating a "soft start" looked to me like things which might discourage someone from taking on the project, all I am trying to do is to suggest that such concerns are really not, and need not be so.
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I use no preamp at the moment. Signal goes from the Soekris DAC1541 DAC to the Neurochrome UB (gain @ 7.3Db) and then to the Purifi modules, so you could theoretically say that the UB is the preamp, but I consider it part of the whole power amp.
For me it will be the UGS-Muses preamplifier. Not sure about the dac yet... which dac is a headache more or less 🙂
As long as the output stage of the DAC and the input stage of the amplifier are well matched, there is no reason to degrade the signal further by using a preamp in an all digital system. These amps are so transparent that one will easily hear the loss of resolution of adding an extra gain stage, and another set of interconnects and four additional connections.
Unless of course one is looking to add color to the sound, in that case, perhaps the Purifi is not the amplifier of choice anyway. As this is DIY, we can make our DACs such that they drive the input stage of the amplifier optimally.
Have my Purifi modules and eval board now, just a few things to arrive before I can wire it up and test it. My DACs will be Buffalo PRO 9038 with Mercury output stage (running synchronous clocking, with only a single 45.1584 XO for DSD 256 input only) and the DSC-2 with AMB a24 output stage. Eventually I will try raising the gain of the DSC-2 enough to bypass the gain of the eval board, but this may be pushing the a24 a bit close to its limits as I often play loud, and my speakers can use bit of power from the amp (I will have +/- 65 volt rails for the amp).
Unless of course one is looking to add color to the sound, in that case, perhaps the Purifi is not the amplifier of choice anyway. As this is DIY, we can make our DACs such that they drive the input stage of the amplifier optimally.
Have my Purifi modules and eval board now, just a few things to arrive before I can wire it up and test it. My DACs will be Buffalo PRO 9038 with Mercury output stage (running synchronous clocking, with only a single 45.1584 XO for DSD 256 input only) and the DSC-2 with AMB a24 output stage. Eventually I will try raising the gain of the DSC-2 enough to bypass the gain of the eval board, but this may be pushing the a24 a bit close to its limits as I often play loud, and my speakers can use bit of power from the amp (I will have +/- 65 volt rails for the amp).
What is the DSC-2 you are talking about ?
And I agree on the preamp. Running MAC-OS and using the on-board volume controller should be enough. No matter digital or analogue, you are adjusting the voltage output. So PC -> DAC -> Purifi is the shortest path.
And I agree on the preamp. Running MAC-OS and using the on-board volume controller should be enough. No matter digital or analogue, you are adjusting the voltage output. So PC -> DAC -> Purifi is the shortest path.
DSC-2
Signalyst DSC1
I have one of member ppy's boards, the 2.6.2 version, with an added aMB a24 gain stage (and sometimes I use a MUSES volume control added to it as well). This is a discrete DSD only DAC designed for input of DSD 256 or higher. I have the DAC working, but it is still not quite "finished" as I am still deciding as how to best control volume, and am not currently equipped to run HQPlayer. Right now I am using ROON to oversample all files to DSD 256, both for the Buffalo PRO and the DSC-2.
Signalyst DSC1
I have one of member ppy's boards, the 2.6.2 version, with an added aMB a24 gain stage (and sometimes I use a MUSES volume control added to it as well). This is a discrete DSD only DAC designed for input of DSD 256 or higher. I have the DAC working, but it is still not quite "finished" as I am still deciding as how to best control volume, and am not currently equipped to run HQPlayer. Right now I am using ROON to oversample all files to DSD 256, both for the Buffalo PRO and the DSC-2.
Okay, some stuff to read up on there. But why do you have both a Buffalo Pro and DSC-2, are they complimentary ?
DIY
DIY is fun, I like to try different things. The Buffalo PRO is complete and my main DAC (in a chassis, all finished). I am always looking for the "best" option for sound quality and I believe in the "less processing inside the DAC" approach. The DSC-2 has no processing inside the DAC, just DSD 256 in (or 512) and a straight discrete converter, all the processing is done in a computer in another room in the home (connected via optical Ethernet and a Sonore Signature Rendu SEoptical). The idea is to keep things as simple as possible in the actual audio system, and to isolate all the computer/processing noise from he audio system and analog circuitry.
Sorry for the off topic here, back to Purify now... Psyched to hear these things in the next couple of days.
DIY is fun, I like to try different things. The Buffalo PRO is complete and my main DAC (in a chassis, all finished). I am always looking for the "best" option for sound quality and I believe in the "less processing inside the DAC" approach. The DSC-2 has no processing inside the DAC, just DSD 256 in (or 512) and a straight discrete converter, all the processing is done in a computer in another room in the home (connected via optical Ethernet and a Sonore Signature Rendu SEoptical). The idea is to keep things as simple as possible in the actual audio system, and to isolate all the computer/processing noise from he audio system and analog circuitry.
Sorry for the off topic here, back to Purify now... Psyched to hear these things in the next couple of days.
My Purifi build, ordered the Purifi EVAL1 with cable kit, Hypex SMPS1200A400, and DIYaudio PESANTE chassis. I planned to drive the EVAL with a Benchmark DACHGC set to 0db on output and bypass the EVAL preamp buffer. Received all the parts and modified the chassis to contain the SMPS and EVAL module. I wanted to turn the amp on and off both with power on switch and the remote turn on/off from the DAC, so purchased a Meanwell – IRM-30-12ST 12VDC power supply for standby power supply. First implementation on turn on/off was using relay and IDC breakout boards, and switch with LED from off the shelf parts from Amazon and Digi-Key (block diagram and parts list available). Worked as intended which is to control the SMPS with SMPS standby J5.1 and use Amp enable from SMPS to turn on LED in switch. Wiring was a little messy so second implementation was just 4N35 opto isolators to control the signals (schematic available). Both methods work great with no turn or turn off pop. Very impressed with the amp I have built and owned many class A and class AB amps, but this is the first-class D with high power I have owned, very neutral of you don’t like the sound change the pre amp. Picture 1 relay implementation picture 2 opto implementation. Would like to do a shout out to the guys on Audio Science Review forum for all their help. Any questions please post.
