I'd be happy with an op-amp based buffer, although I don't disagree with your sentiments/viewpoint. What I really want is something which is effectively a high quality mono interface/breakout board giving ready access to the connections on the Purifi(/hypex) module. A mono version of the Purifi evaluation module really.
They obviously they exist for the various commercial amplifiers based on these modules, but I'm not aware of/haven't yet managed to find one available for DIY purchase - as a buffer module on its own. I don't know one of the existing manufacturers could be persuaded to supply them. I don't believe DIY users are actually competing with these commercial products. A DIY user wants the DIY process. If they can't get the components from one source they'll look around and work out another way of getting or making it.
You think you get away without any heatsinking?
This is from Eval1 User Guide:
6.2 Thermal Requirements
While 1ET400A has very low idle losses and high overall efficiency, adequate cooling is essential for sustained
power delivery. Careful considerations must be given to design of the thermal system in order to achieve
desired output power specifications.
It is recommended to mount the module on a heatsink, e.g., an adequately design aluminum chassis.
"True, but this is not the hypex module. Perhaps they have improved power supply noise rejection (I think they claim that). Are you suggesting to desolder the 7815 and replace it with a Belleson? Eek."
Yes, that is exactly what I am considering, but until I see the supply in person I will not know how possible it is. I have done plenty of mods like this before, and do not anticipate problems, but it would depend on how tight the fit is there on the board. IDK if the PSRR of the Purifi module that they talk about includes the VDR section or not, all I know is that there have been folks who have supplied a separate power supply feed (from an ultra low noise low impedance linear supply) to the Ncore modules and reported nice sound quality increases. if it is easy for me to replace the reg I will do so, I have a good relationship with Belleson, and have a lot of their regs at hand, so it is easy for me to try as long as the board allows it-they are direct pin compatible with 7815.
Ok, so I suppose you would refer to a SPM78 or SPX78.
The 7815s are easily reachable, see here:
The only problem then would be the width. I just measured with my caliper and the width of the space available is 11.5 mm.
Never unsoldered something in a nondestructive way. how do you do that? first melt and remove (with a pump) the solder below, then heat the legs so that the remaining solder is molten and lightly pull up the regulators? (after unscrewing, of course ;-) )
Well, that's for much later.
Roberto
In general, no. And I will provide a case. But my speakers have a sensitivity of 95Db/w/m. The amps rarely have to provide more than a few watts to listen at a reasonably low level (actually, a few hundred milliwatts normally and maybe 3-5 watts for peaks), and the metal plate underneath remains totally cool.
If I had some 85Db bricks I would need much much more power for the same sound pressure and of course the modules would heat and I would need a case. The plan is to use a modo slim line case with the internal 1.5mm iron baseplate and the amps would be there. So the heat would be immediately transferred to the plate and from there to the aluminum case.
The people who are interested in using Tom’s UB probably own one of his amps and know just what a talented designer he is. If you can find a more transparent buffer then I’d like to hear about it.
I think I have to partially revise myself. The result with the Connex supply is so good that it cannot be only due to the amplifier board. Yes, the components on it have no noble pedigree (Samxon capacitors) but Connex has a good reputation. I believe that the sound quality here is due to the fact that the supply is regulated.
Maybe when Cresnet will provide his own I will try and upgrade it
Roberto
Not sure how it's possible to draw this conclusion after only trying 1 configuration. With my testing the Connex sounded anemic compared to the Hypex SMPS1200. I suggest people should try multiple supplies before claiming any superior.
You are right. My phrasing was also a bit rhetoric. But it does sound so clearly superior to the NC500 that I cannot relate it to several claims that the two modules sound "very close".
Purifi told me to use the 800W RE version not the 600W RxE version, as it would not provide as much power. Depending on the speakers you are using, it is not a surprise that the 600RxE may sound a but "anemic".
And, yes, it is a shame that they show nice caps in the pics and then crappy caps when they sell. Sometimes I wonder how you can ever trust anything from China unless it is manufactures for a western company that can enforce quality standards - or threaten to move their contracts to another Chinese supplier.
Of course it was sighted. And I had to plug/unplug, but gain is matched, so are levels. I made sure I was listening to a few snippets of some recordings which experience teaches me are critical to reproduce.
Until the best option is Cresnet SMPS.
Audio SMPS units for sale
* Audio SMPS units for sale
-> YouTube
-> -> Switching power supplies
Audio SMPS units for sale
* Audio SMPS units for sale
-> YouTube
-> -> Switching power supplies
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I didn’t compare with the Purifi amps. I compared with class D amps with much worse PSRR. So the quality of the supply was even more critical. Either way the RxE is their best supply version.
I am absolutely aware of that! Also, quoting myself from ASR:
What I can say is that this little concoction sounds to me (yes, this is a subjective perception, and it may be the so called "cockroach effect" [1]) better than the NC500+Hypex power supply. More pleasing and smooth highs, for instance.
[1] The cockroach effect, in Neapolitan language "effetto scarrafone", from the proverb "Ogne scarrafone è bell' a mamma soja", i.e. "every cockroach is beautiful for his mom". This is the apex of confirmation bias for DIYers: if you have built it yourself, it sounds better than anything else.
Another type of confirmation bias is dear Maty taking my subjective and builder's impressions as another proof that anything is better than a hypex power supply. I should have phrased things differently.
Until the best option is Cresnet SMPS.
Audio SMPS units for sale
* Audio SMPS units for sale
-> YouTube
-> -> Switching power supplies
Where’s your evidence that this supply is superior? You know Hypex has 10000+ SMPS’s out in the field. And over the last 10 years it’s undergone 7 revisions. All weak links have been solved. There’s not a single SMPS in the audio industry more proven. Yet some people with absolutely no experience, or any data whatsoever are making claims that completely unproven designs are superior. How is this helpful to the DIY community?
By the way, in this Forum, in the Members Area, there is a subforum for introducing yourself