DIY Purifi Amp builds

[mocenigo]

Beside the reciprocal trolling/agenda aspects here, I would still be interested in seeing that nc500 evaluation board measured.
IIRC at least the first nc500 offering (from Nord and the like, but also from boutique vendors) were using that board, probably unmodified.

Does the purifi evaluation board also have the same so-called limitations?
After all it is marketed as an "evaluation platform" just like the nc500 one.

I would not be surprised if Nord used exactly the same board. However Apollon has modified the board to allow it to better drive the modules (so they told me). I guess this means a lower output impedance, which is a good thing, and perhaps also give lower distortion as a result.

 

[JimB]

And here's my build. Even more crude and sloppy than LondonLad 's because I only have a wood board for the moment.

Ahh, yes, but what a nice board it is - matched to your rack!

What was your attraction to that particular power supply over the Hypex SMPS1200, and for a future Sultzer regulated VAUX supply? The EVAL1 board already has discrete regulators for +VOP - are you going to bypass them?

 

[mocenigo]

Ahh, yes, but what a nice board it is - matched to your rack!

What was your attraction to that particular power supply over the Hypex SMPS1200, and for a future Sultzer regulated VAUX supply? The EVAL1 board already has discrete regulators for +VOP - are you going to bypass them?

No, I won't bypass the discrete regulators on the EVAL1 board, since they must regulate down to 12V. I will then have two steps of regulation and therefore an even cleaner power source. The +VOP of the 1ET400A boards are actually for the modulator, which is extremely critical for the SQ.

I preferred the Connex over the Hypex SMPS1200 because it is smaller, cheaper (!) and very well regulated. It is praised a lot in the DIY communities in France and Germany, for instance. It lacks some of the AUX outputs that the EVAL1 board requires (it has only two at 15V) but since I was planning to provided alternative supplies for other parts...

Yeah, and the rack is also DIY (more or less, I designed it and had a master carpenter cut the pieces with a CNC wood cutting machine, and lacquer it, but it is my design, I just took "a bit" of inspiration from the Naim Fraim).

 

[JimB]

No, I won't bypass the discrete regulators on the EVAL1 board, since they must regulate down to 12V. I will then have two steps of regulation and therefore an even cleaner power source. The +VOP of the 1ET400A boards are actually for the modulator, which is extremely critical for the SQ. ...

Thanks. Purifi does provide this note about +VOP:

with those qualifiers "normal" "best practice"!

 

[mocenigo]

Thanks. Purifi does provide this note about +VOP:
View attachment 46005
with those qualifiers "normal" "best practice"!

Well, you observe that they write "normal" and "best practice" together... which can mean anything right? Both the buffer and the linear regulators on the connection board are really minimalistic. I am sure that they are good but for my "feel good" feeling I will have my own "best practices" ;-)

 

[JimB]

Well, you observe that they write "normal" and "best practice" together... which can mean anything right? Both the buffer and the linear regulators on the connection board are really minimalistic. I am sure that they are good but for my "feel good" feeling I will have my own "best practices" ;-)

Right! And why not make our own builds whatever we want? That is a good part of the interest, and satisfaction with the result. I'll just note that the performance measured here was with just the EVAL1 set and SMPS1200, unmodified:
https://www.audiosciencereview.com/...of-purifi-1et400a-amplifier.7984/#post-194274

For your final configuration, are you modifying or bypassing the EVAL1 buffers? If so, what gain do you plan (if any)? I was going to lower the buffer gain to 7 dB, (https://www.audiosciencereview.com/...iy-purifi-amp-builds.10478/page-8#post-296652), but since my source will often be AVRs, and some of them seem to perform poorly at higher output voltages, I'll might just stick with the standard values.

What output connectors do you plan to use?

 

[Zoomer]

I've emailed both Ghent and Audiophonics about a case for EVAL1 + SMPS1200. Ghent didn't reply, but Audiophonics did, saying that next month they'll have a full amp on EVAL1 + possibly a DIY case.

Just heard from Audiophonics they're struggling to keep up with demand for the NCore amps, which has slowed down somewhat the development of the Purifi offerings.
On the bright side they aim to price them aggressively.

 

[mocenigo]

Right! And why not make our own builds whatever we want? That is a good part of the interest, and satisfaction with the result. I'll just note that the performance measured here was with just the EVAL1 set and SMPS1200, unmodified:
https://www.audiosciencereview.com/...of-purifi-1et400a-amplifier.7984/#post-194274

Yep, I saw these, and despite finding them admirable, I almost yawned - at this level these amps are all going to measure well. They are example of no-BS engineering of the finest. Dr. Putzeys had to deliver an improvement and he did. Amazing what the Benchmark AHB2 does though, that seems to be untouchable (where are the Halcro in that regard?)

For your final configuration, are you modifying or bypassing the EVAL1 buffers? If so, what gain do you plan (if any)? I was going to lower the buffer gain to 7 dB, (https://www.audiosciencereview.com/...iy-purifi-amp-builds.10478/page-8#post-296652), but since my source will often be AVRs, and some of them seem to perform poorly at higher output voltages, I'll might just stick with the standard values.

I will bypass the buffer and add a Neurochrome UB which I will probably configure for a 6-7Db gain.
I do not have the instruments nor the skills (nor the will, actually) to modify the eval1 board to replace a SMD resistor.

What output connectors do you plan to use?

Normal binding posts. Nothing boutique.

 

[tmortimer]

Anyone know where to find a breakout board that would give you screw down terminals (or something) to connect against the pin header on the amp module itself?

 

[LondonLad]

Man-O-Man that is nice Roberto. I want to try one of the power supplies you used. From which supplier did you get that?

 

[LondonLad]

I'm thinking that with the low sensitivity of the Revels perhaps they might benefit from 800W continuous and up to 1000W burst.

What is the equivalent burst spec for the Eval-1/Hypex?

 

[JimM]

Anyone know where to find a breakout board that would give you screw down terminals (or something) to connect against the pin header on the amp module itself?

I just ordered and received a breakout with screw terminals for the IDC 10 pin from amazon, but wasn't looking for the pin connector, but go to amazon and look for breakout boards, they may have one.

 

[JimB]

I'm thinking that with the low sensitivity of the Revels perhaps they might benefit from 800W continuous and up to 1000W burst.

What is the equivalent burst spec for the Eval-1/Hypex?

It is just what Amir already reviewed:
https://www.audiosciencereview.com/...of-purifi-1et400a-amplifier.7984/#post-194274

I think others have concluded that the 1ET400A is sufficient for reasonably loud listening, in a reasonable space, at a reasonable distance, with Salon 2s (check other posts on ASR). If you decide you want more, these are not the modules for you. If you want these types of class D amps, you can go to other Hypex and ICEpower modules.

 

[mocenigo]

Man-O-Man that is nice Roberto. I want to try one of the power supplies you used. From which supplier did you get that?

Audiophonics for the Connex, Mouser for the two little RECOMs

 

[LondonLad]

It is just what Amir already reviewed:
https://www.audiosciencereview.com/...of-purifi-1et400a-amplifier.7984/#post-194274

Where does Amir post the "burst" results?

 

[mocenigo]

It is just what Amir already reviewed:
https://www.audiosciencereview.com/...of-purifi-1et400a-amplifier.7984/#post-194274

I think others have concluded that the 1ET400A is sufficient for reasonably loud listening, in a reasonable space, at a reasonable distance, with Salon 2s (check other posts on ASR). If you decide you want more, these are not the modules for you. If you want these types of class D amps, you can go to other Hypex and ICEpower modules.

86.4 dB SPL with 2.83 V @ 1m!!! They are not speakers, they are bricks! (in my own language, and it is not an assessment of SQ, nor of lack thereof). Well, then they clearly need power, but the Purifi will probably deliver 300W onto 6ohms with a 65V supply. Maybe a tad more with a 70V well regulated one. Even with such a speaker one should be able to listen very loud in "a reasonable space, at a reasonable distance" (cit.) indeed.

 

[JimB]

Where does Amir post the "burst" results?

There is no special "burst" output case for these. They will output their maximum rated power (as permitted by the power supply) until the temperature rises, too much (>ten seconds). So, just consider the maximum rated power to be the burst power. You always listen at much less average power.

 

[JimM]

I'm thinking that with the low sensitivity of the Revels perhaps they might benefit from 800W continuous and up to 1000W burst.

What is the equivalent burst spec for the Eval-1/Hypex?

UNless you have a very large room, I would think you should not have a problem 86 to 87 spl is fairly common with today's speakers if you have been driving them with your Primaluna, I would be really surprised that you would have a problem.

 

[LondonLad]

UNless you have a very large room, I would think you should not have a problem 86 to 87 spl is fairly common with today's speakers if you have been driving them with your Primaluna, I would be really surprised that you would have a problem.

What continues to have me befuddled (in a good way) is trying to understand how "little" Class D amps are able to perform as well as the Class A/B ones that have hulking huge capacitors on board. I was poking around a Mark Levinson ML436 the other day and, whoa, it's got four of those big blue babies in each.

 

[JimM]

Finished the chassis did garage checkout with speakers running Benchmark Dac2HCG with 0 db attenuation and Purifi with no gain appears to have plenty of overall gain. Will hook it up to the Magnepan to night if it will drive the 1.7 it will drive anything I have. This is phase 1 next I am going to see what I can get connected, at minimum will try to do smps remote enable and amp ready to turn on led switch. On the little garage speakers it sounds like the Benchmark DAC seems to pretty neutral.