Hi all,
I need some help to build a system around Modulus-286, to play audio using a PC (Windows 7, 10) as a source. Speakers are going to be the Paul Carmody's Carrera, with minimum impedance 6 Ohm. Could you please check my options and correct me if I did some stupid mistakes? I'm trying to be back to the audio world after many years of not doing anything myself.
1. I like the option of SMPS, but I remember switching is audible and any switching power supply should squeak with a frequency dependent on the load. What about SMPS-86, does it produce any audible noise? Does SMPS-86 impact any parameters of the Modulus? Should I use the Power-86 board anyway if I go with the SMPS?
2. USB DAC. I need some kit with PCB or ready-to-use board. JLSounds' I2SoverUSB and AK4490 seems a good option. If I'm not mistaken, the I2SoverUSB transforms the signal from PC into something fed into the AK4490 and I get pure audio as an output of the AK4490. Am I correct? Probably, I'll need a separate power supply for the DAC and JLSounds' Power supply board, right? Are there any better options to be paired with the Modulus (budget for USB DAC is about USD300).
3. Pre-amp. Does the Modulus require a pre-amp if working with JLSounds? There should be a volume control, too, I cannot find any detailed info about that on the Modulus page. If yes, could you please recommend me some decent kit to accompany the Modulus (badget is USD300). Also, there is something new to me about differential mode. Do I need some special pre-amp with differential output to connect to Modulus?
Any help or comments are highly appreciated.
I need some help to build a system around Modulus-286, to play audio using a PC (Windows 7, 10) as a source. Speakers are going to be the Paul Carmody's Carrera, with minimum impedance 6 Ohm. Could you please check my options and correct me if I did some stupid mistakes? I'm trying to be back to the audio world after many years of not doing anything myself.
1. I like the option of SMPS, but I remember switching is audible and any switching power supply should squeak with a frequency dependent on the load. What about SMPS-86, does it produce any audible noise? Does SMPS-86 impact any parameters of the Modulus? Should I use the Power-86 board anyway if I go with the SMPS?
2. USB DAC. I need some kit with PCB or ready-to-use board. JLSounds' I2SoverUSB and AK4490 seems a good option. If I'm not mistaken, the I2SoverUSB transforms the signal from PC into something fed into the AK4490 and I get pure audio as an output of the AK4490. Am I correct? Probably, I'll need a separate power supply for the DAC and JLSounds' Power supply board, right? Are there any better options to be paired with the Modulus (budget for USB DAC is about USD300).
3. Pre-amp. Does the Modulus require a pre-amp if working with JLSounds? There should be a volume control, too, I cannot find any detailed info about that on the Modulus page. If yes, could you please recommend me some decent kit to accompany the Modulus (badget is USD300). Also, there is something new to me about differential mode. Do I need some special pre-amp with differential output to connect to Modulus?
Any help or comments are highly appreciated.
1. My preference is Power86 with toroidal transformer. I don't think the SMPS would be noisy (Tom designs well) but I don't think you'll get as much power out of the amps either.
2. I've read some favorable things about JLSounds. DIYINHK has a USB to I2S Converter that everyone seems to be talking about also. Twisted Pear Buffalo III looks like a very attractive DAC kit to me, with Amanero. Little above the budget you suggested, but you could get a cheap DAC on Amazon or something to get you by for a while, then upgrade??? Definitely do some reading at the Digital Line Level section of this forum.
3. Mod286 should run fine without a preamp. Mainly what you need is a potentiometer on the input to control the volume. You can also use pseudo-differential cable if your source is single ended. I have Neurochrome THAT Line Driver between my DAC and Mod 86 amp. DAC has volume control in my case. The extra 6dB of gain from THAT Line driver is nice, especially in those quiet passages in music, but not required. Most DACs these days will be putting out 1.8V or 2V, which I believe would be enough to drive your amp all the way to clipping.
For me the reality is that I don't listen nearly as loud as I thought I would. The finer details of music are audible even at lower volume levels. Is that because of the gain in the preamp? I'm not sure. I think that may in part be because the noise-floor is so much lower with the differential input.
2. I've read some favorable things about JLSounds. DIYINHK has a USB to I2S Converter that everyone seems to be talking about also. Twisted Pear Buffalo III looks like a very attractive DAC kit to me, with Amanero. Little above the budget you suggested, but you could get a cheap DAC on Amazon or something to get you by for a while, then upgrade??? Definitely do some reading at the Digital Line Level section of this forum.
3. Mod286 should run fine without a preamp. Mainly what you need is a potentiometer on the input to control the volume. You can also use pseudo-differential cable if your source is single ended. I have Neurochrome THAT Line Driver between my DAC and Mod 86 amp. DAC has volume control in my case. The extra 6dB of gain from THAT Line driver is nice, especially in those quiet passages in music, but not required. Most DACs these days will be putting out 1.8V or 2V, which I believe would be enough to drive your amp all the way to clipping.
For me the reality is that I don't listen nearly as loud as I thought I would. The finer details of music are audible even at lower volume levels. Is that because of the gain in the preamp? I'm not sure. I think that may in part be because the noise-floor is so much lower with the differential input.
I offer the SMPS-86 which provides ±24 V. The output current is limited to 2.5 A. That's enough for a small desktop MOD286 amp, but for those who really like to crank it, especially with a 4 Ω load, it's not enough for a stereo amp.
For a stereo build, I'd go with the Connex Electronic SMPS300RE. I've measured the MOD286 with that supply and see no significant difference in performance of that versus the performance of a linear supply. It sounds great too. For more than two amp channels the SMPS500R looks like an attractive option, though I haven't tested it in person.
Should you still not be sold on switching supplies, I do offer the Power-86. You can configure that with a power transformer to provide just about any voltage you need, including the ±28 to ±30 I recommend for the MOD286 (stereo) or ±35 V (mono, parallel).
If your DAC has built-in volume control, there's no need for a separate volume control. If it doesn't, a simple volume pot works, though better performance can be had with a differential volume control or with one of my THAT Driver boards and a volume pot.
Tom
For a stereo build, I'd go with the Connex Electronic SMPS300RE. I've measured the MOD286 with that supply and see no significant difference in performance of that versus the performance of a linear supply. It sounds great too. For more than two amp channels the SMPS500R looks like an attractive option, though I haven't tested it in person.
Should you still not be sold on switching supplies, I do offer the Power-86. You can configure that with a power transformer to provide just about any voltage you need, including the ±28 to ±30 I recommend for the MOD286 (stereo) or ±35 V (mono, parallel).
If your DAC has built-in volume control, there's no need for a separate volume control. If it doesn't, a simple volume pot works, though better performance can be had with a differential volume control or with one of my THAT Driver boards and a volume pot.
Tom
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Hi Alexwey,
I know your question was directed at Tom, and he would certainly have a more educated answer than I. I can say that although it may be possible to use the same powersupply for both, it certainly makes everything much more complicated. Not only do you have to consider that the power requirements for the DAC and the Amp are very different, you also will run the risk of creating ground loops if it is not implemented properly.
I know little about DACs, but from what I understand they can be very sensitive to certain power requirements. Some DACs even have multiple power supplies each powering only a specific part of the DAC.
It's one of the things I liked about the TP BIII is that much thought and care was put into the design of their recommended powersupplies, to work perfectly with their kit.
Again, just my uneducated opinion, but I do believe it will be much more simple and easy to use seperate supplies for DAC and Amp.
I know your question was directed at Tom, and he would certainly have a more educated answer than I. I can say that although it may be possible to use the same powersupply for both, it certainly makes everything much more complicated. Not only do you have to consider that the power requirements for the DAC and the Amp are very different, you also will run the risk of creating ground loops if it is not implemented properly.
I know little about DACs, but from what I understand they can be very sensitive to certain power requirements. Some DACs even have multiple power supplies each powering only a specific part of the DAC.
It's one of the things I liked about the TP BIII is that much thought and care was put into the design of their recommended powersupplies, to work perfectly with their kit.
Again, just my uneducated opinion, but I do believe it will be much more simple and easy to use seperate supplies for DAC and Amp.
I have four Mod86 connected to one powersupply. Works great. In a previous build (not Neurochrome) I thought that dual mono amps with seperate power supplies would be best. I think in that case I spent a lot for little benefit.
For Mod286, I would just go with Tom's recommendation. If he says a Stereo build will work fine with one supply, it will.
Check out Taming LM 3886 on Neurochrome website.
Really what I was trying to emphasize is not to use the same supply for DAC and Amp.
For Mod286, I would just go with Tom's recommendation. If he says a Stereo build will work fine with one supply, it will.
Check out Taming LM 3886 on Neurochrome website.
Really what I was trying to emphasize is not to use the same supply for DAC and Amp.
I think it's acceptable but you'll probably find that the supply voltage of a power amp is beyond what a typical DAC can handle, so you'll likely need a separate supply for the DAC.
Most DACs have on-board regulators. If they don't, I'd probably shy away from them as the supply performance in a DAC is part of the performance of the DAC.
People do a lot of things...
With the MOD286 or MOD86 there's no need for a separate supply for each channel. No harm (other than to the wallet) of building the amp with separate supplies for each MOD286 board, but there's no technical advantage of it.Due to the composite amp architecture of the MOD286, it is practically immune to supply perturbations, so the two channels will not interact in any meaningful way.
In other amplifier architectures (i.e. not composite amps) you can get slightly better channel separation by going with separate supplies. Whether the improvement is a meaningful one is a different story. Also note that there are many other ways to screw up the channel separation of an amp. For example sharing a ground return conductor between the two channels will do that.
As an aside: In my HP-1 headphone amp, the channel separation is about 115 dB when using the 4-pin XLR output connector (separate grounds) and about 95 dB when using the 3-pin 1/4" phone jack (shared grounds). The 20 dB difference is caused by the contact resistance (a few mΩ) of the 1/4" phone jack. While it is a measurable 20 dB difference, it's not likely to be a meaningful difference as a channel separation of 95 dB is still pretty darn separate. Just saying that in some corners of precision audio every mΩ matters.
That'd be this: https://www.neurochrome.com/taming-the-lm3886-chip-amplifier/
Tom
I have a link to your "Taming the LM3886 Chip Amplifier" article in my bookmarks for years, Tom
It's time to read it carefully, it seems the subject requires deep reading.
Good to hear. I actually need to go through that article series to update and add some information. Especially the stability page needs an update. I know the LM3886 pretty intimately now.
Tom
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