DIY Purifi Amp builds

[xyvyx]

Hey all,

I'm a little late to the party. I just recently started researching new amps to power my Atmos setup... I stumbled into lots of info about the Hypex modules & saw how they were being used by lots of other boutique manufacturers w/ various tweaks. I ended up purchasing a little NC252MP module & just got it into a Ghent case last week. I moved it and some of my speakers into another room to do some listening & I really liked what I heard.

Testing it out w/ my Magnepans:

https://imgur.com/a/5n6hKDh

Then I did some more reading & realized I'm about 8 years behind & that Bruno has churned out some new/better designs under a different name.
So a few days ago, I ordered the EVAL1 board & the SMPS1200 to go with it. But really, if I like this as much/more than the other ncore amp, I'm going to want to use these Purifi modules for my front 3 channels!

So in my research of buffer boards to handle this odd channel count, my options appear to be:
* Hypex NC500_OEMAdapter (LM4562's + adjust gain via resistor swaps)
* wasting half an EVAL1 board (assuming it functions correctly w/ only one module!?)
* something tomchr is/can build for us
* VTV custom buffer board (seems expensive at $145/module + cost of sparkos/SIL opamps)

But I hadn't seen anyone mention the VTV board (unless it got deleted earlier in all the drama from that Mike dude)
https://vacuumtubevalues.com/product/vtv-amplifier-custom-input-buffer-hypex-nc500-nc1200-nc2k/

Looks like by itself, it handles voltage regulation and not much else. And with 3 of those + 3 pairs of the SIL 990 opamps, I'm pretty much at the price of the 3 1ET400A modules... blarg.

Anyway, thanks in advance to the Jims & all the other pioneers on this thread!
Not yet sure what I'm going to do, but I guess I'll have the EVAL board here in a week... if it sounds good by itself, maybe I just need to worry about heat & standby/power switching and call it a day!

 

[March Audio]

They generate a lot of heat so a small box is counterproductive if we want them to provide a few continuous watts. In addition to being very expensive despite using very low price components.

No they don't.

@maty why do you insist on posting uninformed nonsense in every thread? You simply have no idea what you are talking about. You waste so much of everybodies time providing inaccurate and misleading information that needs to be continually corrected.

I think it is about time that you were prevented from doing so.

@Thomas savage

 

[SIY]

Hey all,

I'm a little late to the party. I just recently started researching new amps to power my Atmos setup... I stumbled into lots of info about the Hypex modules & saw how they were being used by lots of other boutique manufacturers w/ various tweaks. I ended up purchasing a little NC252MP module & just got it into a Ghent case last week. I moved it and some of my speakers into another room to do some listening & I really liked what I heard.

Testing it out w/ my Magnepans:

https://imgur.com/a/5n6hKDh

Then I did some more reading & realized I'm about 8 years behind & that Bruno has churned out some new/better designs under a different name.
So a few days ago, I ordered the EVAL1 board & the SMPS1200 to go with it. But really, if I like this as much/more than the other ncore amp, I'm going to want to use these Purifi modules for my front 3 channels!

So in my research of buffer boards to handle this odd channel count, my options appear to be:
* Hypex NC500_OEMAdapter (LM4562's + adjust gain via resistor swaps)
* wasting half an EVAL1 board (assuming it functions correctly w/ only one module!?)
* something tomchr is/can build for us
* VTV custom buffer board (seems expensive at $145/module + cost of sparkos/SIL opamps)

But I hadn't seen anyone mention the VTV board (unless it got deleted earlier in all the drama from that Mike dude)
https://vacuumtubevalues.com/product/vtv-amplifier-custom-input-buffer-hypex-nc500-nc1200-nc2k/

Looks like by itself, it handles voltage regulation and not much else. And with 3 of those + 3 pairs of the SIL 990 opamps, I'm pretty much at the price of the 3 1ET400A modules... blarg.

Anyway, thanks in advance to the Jims & all the other pioneers on this thread!
Not yet sure what I'm going to do, but I guess I'll have the EVAL board here in a week... if it sounds good by itself, maybe I just need to worry about heat & standby/power switching and call it a day!

Given that the EVAL1 board has superbly high performance and that the VTV site is mostly dedicated to selling snake oil, I'm not seeing any reason to not use the former or to even consider the latter.

 

[Matias]

@xyvyx or you can buy a 3 channel assembled power amp, or 3 mono amps, from March, Nord or Apollon.

 

[Tartaruga]

Guys I want to order the eval kit to usa, to a forwarding company and from there to israel (in order to avoid tax payment).
There is tax to pay in the USA? Shipping to orogon. BTW, what is the difference between the two shipment methods in purifi site?

 

[hyperknot]

Or this 4 channel monster from Audiophonics:
https://www.audiophonics.fr/en/powe...oies-class-d-purifi-4x400w-4-ohm-p-14452.html

 

[JimB]

@xyvyx, I too have interest in a nice 3-channel build, including a slightly sawed off FE02B for the third channel. I haven’t decided whether to just build two, nice stereo boxes, or something 3-channel, less refined DIY. In addition to the input buffer/regulator issues are decisions about power supplies, though I think I could be satisfied with a single Hypex SMPS1200A400 for three Purifi 1ET400As. I’ve considered a 300mm wide Ghent case as the basis.

Regarding that VTV board, it might be competent - not sure. But I do believe that the one from @tomchr will be.

 

[mocenigo]

@xyvyx, I too have interest in a nice 3-channel build, including a slightly sawed off FE02B for the third channel. I haven’t decided whether to just build two, nice stereo boxes, or something 3-channel, less refined DIY. In addition to the input buffer/regulator issues are decisions about power supplies, though I think I could be satisfied with a single Hypex SMPS1200A400 for three Purifi 1ET400As. I’ve considered a 300mm wide Ghent case as the basis.

Regarding that VTV board, it might be competent - not sure. But I do believe that the one from @tomchr will be.

Gosh, I would not saw a FE02B board. Yes, one can "reverse engineer" where to cut but the risk of shorting something on the cut side our causing whatever havoc may happen...

The VTV board is for folks that want to do opamp rolling. To get better performance one should use the larger socket, and the large opamps cost quite a bit. Sonic Imagery or (gasp!) Weiss. I also do not like too much the fact that the board is quite wide and deep. Also, they claim they choose the Sparkos regulators as the "best" and I beg to differ. They may as well be the best when they compared to other TO-220, better than the Hypex ones if you snip the two outer pins and install the onboard SMD cap. But, IIRC, the Hypex regulators used properly with the two outer pins and remote sensing measure better. And cost a half of the Sparkos. Comparable to LT3045 based regs, but once you start paralleling the latter in order to get more current, the cost skyrockets. They could have used the Hypex and get larger margins or a lower price. They could have left the user with a choice. I am not too impressed. I would wait for Tom Christiansen's breakout board-cum-buffer, even through this will require a bit of patience.

 

[maty]

...I would wait for Tom Christiansen's breakout board-cum-buffer, even through this will require a bit of patience.

I agree. If you already enjoy a good sound, it makes no sense to be in a hurry.

 

[mocenigo]

The problem is... the Hypex SMPS.

Care to elaborate? They put good components where they are needed. For instance, the rectification bridge uses mosfets, not power diodes - the mosfets are more expensive. But they can work like the rectification triodes in old-fashioned linear PSUs (they are after all solid state triodes in a sense), i.e. they can dump current. Therefore there is no supply pumping.

So do you prefer a SMPS with nice capacitors but prone to pumping with the risk of burning your amplifier or an SMPS with a solid design that will not exceed its nominal voltage? Do the Cresnet SMPSs use diodes? I have seen standard 4 pin bridges on the pictures.

 

[boXem]

... And cost a half of the Sparkos. Comparable to LT3045 based regs, but once you start paralleling the latter in order to get more current, the cost skyrockets...Tom Christiansen's breakout board-cum-buffer, even through this will require a bit of patience.

What would be the interest to parallel LT3045 to get more current? Isn't it delivering 500 mA, which is more than enough? (I'm too lazy to double check )

 

[boXem]

Care to elaborate? They put good components where they are needed. For instance, the rectification bridge uses mosfets, power diodes - the mosfets are more expensive. But they can work like the rectification triodes in old-fashioned linear PSUs (they are after all solid state triodes in a sense), i.e. they can dump current. Therefore there is no supply pumping.

So do you prefer a SMPS with nice capacitors but prone to pumping with the risk of burning your amplifier or an SMPS with a solid design that will not exceed its nominal voltage? Do the crescent SMPSs use diodes?

Another advantage of the Hypex SMPS is that it's compliant to the latest safety regulations.

 

[mocenigo]

What would be the interest to parallel LT3045 to get more current? Isn't it delivering 500 mA, which is more than enough? (I'm too lazy to double check )

Yes, for these applications it is probably fine, but it gets quite hot soon, esp with a large voltage drop (you feed a unregulated 24V to get a regulated 12V). If they get hot, their performance degrades significantly. So you may need a heatsink. Or parallel. Or work in two steps.

 

[Matias]

Or this 4 channel monster from Audiophonics:
https://www.audiophonics.fr/en/powe...oies-class-d-purifi-4x400w-4-ohm-p-14452.html

"On demand, we can assemble this amplifier into bridge configuration, which offer 2 channels with 800W output on 4 and 8ohm load."

 

[mocenigo]

Another advantage of the Hypex SMPS is that it's compliant to the latest safety regulations.

And getting certification is expensive. But the regulations are there for a purpose.

 

[mocenigo]

Another advantage of the Hypex SMPS is that it's compliant to the latest safety regulations.

I have also fixed a couple of typos in my post (a missing "not" for instance)

 

[maty]

In that discussion I was referring to the heat generated by the hard in a small box. PURIFI 1ET400A dissipates less heat than the Hypex NC500 being more efficient but the Hypex SMPS continues to generate enough heat.

 

[maty]

If you listen to recordings as bad as those of Billie Eilish in studio and not in a large room at high volume will not be problematic. But then what is the point of spending so much money on the amplifier.

With low sensitivity loudspeakers.

 

[Tartaruga]

Guys someone ordered the eval board to usa? Is any tax required to be payed? I want to use forwarding company based in the USA in order to ship it to myself.

 

[mocenigo]

In that discussion I was referring to the heat generated by the hard in a small box. PURIFI 1ET400A dissipates less heat than the Hypex NC500 being more efficient but the Hypex SMPS continues to generate enough heat.

Ok, but the Hypex SMPS has a large L shaped aluminium heatsink that can be used to attach to both bottom and a side of the case. I trust their engineering and I think this should be ok.