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Ultimate 1ET400A Purifi Amplifier sonic shootout - €820 to €8,344

cistercian

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For info, as I have seen recent forum commentary on this, the Hypex modules all display a degree of switch off click. It is variable and doing certain things can minimise it. It can be completely eliminated but does require additional circuitry to do so. Any implementation without this cicuitry is liable to have some degree of click. (yes we have this circuitry ;))

Do you use thermal paste or Indium for a thermal bond to the heat sink. I ask only because I have some Indium here I have been
fooling around with and saw it is used as a low thermal resistance bond. It is weirdly malleable.
 

SloPoke

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I very recently bought a VTV NC252MP. My experience is that assembly quality is fine. In my case there was no evidence of loose screws or sloppy drilling of mounting holes. The NC252MP is secured with eleven screws and all were properly used in my instance. Of course this is a non-custom case so there are additional holes accommodate other types of module

If you live in North America you might also want consider shipping times in this Covid age in which case VTV is likely to beat the other makers.
.View attachment 79366
sml-DSCF0984.jpg
Do you know what that little switch does on the bottom of the amp? Looks like a switch with "2--1--0" ?
 

CDMC

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The XLRs are wired correctly, and the soldering is fine, no cold solder joints. Pretty does not make it sound any better.

Well that would be a first.
 

rebbiputzmaker

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Well that would be a first.
Has been for a while. Was not incorrect was just not the AES grounding standard. Although a standard, tons of equipment over the years has been made without pin 1 grounded.
 
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CDMC

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Has been for a while. Was not incorrect was just not the AES grounding standard. Although a standard, tons of equipment over the years has been made without pin 1 grounded.

He is not following the hypex instructions, connecting the board to Pin 1 through the shield cable. He continues to do so, as he apparently cannot read the instructions, despite saying he is following them. This is still the case with amps sold in the last month as two different people posted photos here which showed they were not wired per hypex requirements.
 

rebbiputzmaker

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He is not following the hypex instructions, connecting the board to Pin 1 through the shield cable. He continues to do so, as he apparently cannot read the instructions, despite saying he is following them. This is still the case with amps sold in the last month as two different people posted photos here which showed they were not wired per hypex requirements.
You seem to be on a bit of a crusade, but you happen to be incorrect. Also, I do not think there are any "hypex requirements" o_O

What's next, he kidnapped the Lindbergh baby??? :eek:

From VTV site:

I have heard grounding is important using XLR cables. Is the VTV Amplifier grounded properly?

VTV Amplifier uses the AES-48-19 grounding scheme (industry standard) where pin #1 is grounded to chassis (including the XLR jack case). The amplifier has a three wire input which has the ground lead fastened to the chassis as safety ground. All VTV amplifiers are resistant to ground loops and are extremely low noise.
 

CDMC

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You seem to be on a bit of a crusade, but you happen to be incorrect. Also, I do not think there are any "hypex requirements" o_O

What's next, he kidnapped the Lindbergh baby??? :eek:

From VTV site:

I have heard grounding is important using XLR cables. Is the VTV Amplifier grounded properly?

VTV Amplifier uses the AES-48-19 grounding scheme (industry standard) where pin #1 is grounded to chassis (including the XLR jack case). The amplifier has a three wire input which has the ground lead fastened to the chassis as safety ground. All VTV amplifiers are resistant to ground loops and are extremely low noise.

Just correcting the information as the information you have posted is incorrect. He can write whatever he wants on his website, he is still not following AES-48 or the Hypex wiring requirements. It has been well documented in several threads. People should be aware of this and the poor quality assembly before they purchase. In my case it cost me $50 and hours of time to find the correct items to correct the deficiencies. In hindsight, it would have been a better value to purchase from another company and had it delivered properly constructed from the get go.
 

rebbiputzmaker

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Just correcting the information as the information you have posted is incorrect. He can write whatever he wants on his website, he is still not following AES-48 or the Hypex wiring requirements. It has been well documented in several threads. People should be aware of this and the poor quality assembly before they purchase. In my case it cost me $50 and hours of time to find the correct items to correct the deficiencies. In hindsight, it would have been a better value to purchase from another company and had it delivered properly constructed from the get go.
 

Feanor

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Has been for a while. Was not incorrect was just not the AES grounding standard. Although a standard, tons of equipment over the years has been made without pin 1 grounded.
To not directly ground Pin 1 to the chassis is, indeed, a common "mistake", one I have made myself during my DIY efforts. In my case there were apparently no adverse consequences.

As for my VTV copy, the XLR connectors are grounded -- I can't speak for other peoples' copies.

What I agree with, however, is that even a single shoddy copy can have negative consequences for a maker; makers need to take heed of this and apply adequate QA.
 

CDMC

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To not directly ground Pin 1 to the chassis is, indeed, a common "mistake", one I have made myself during my DIY efforts. In my case there were apparently no adverse consequences.

As for my VTV copy, the XLR connectors are grounded -- I can't speak for other peoples' copies.

What I agree with, however, is that even a single shoddy copy can have negative consequences for a maker; makers need to take heed of this and apply adequate QA.

That is only half the issue. The other is tying the shield wire from the amp to pin 1. It is supposed to be tied to the case. Tying it to Pin 1 brings any noise from xlr cable right into the amp and inside the case. This does not follow AES-48 or Hypex’s instructions and defeats the reason for using XLRs.
 

CDMC

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Nice. Should I call you shill for pushing a product that is poorly assembled and does not follow the manufactures own assembly instructions? Grow up.
 

rebbiputzmaker

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Nice. Should I call you shill for pushing a product that is poorly assembled and does not follow the manufactures own assembly instructions? Grow up.
There is not one absolute method of grounding. You are really not fully understanding the subject and its application.

Also we are talking about high level signals. Grounding becomes more critical when dealing with low level, digital etc.

 

CDMC

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There is not one absolute method of grounding. You are really not fully understanding the subject and its application.

Also we are talking about high level signals. Grounding becomes more critical when dealing with low level, digital etc.


So you continue on while claiming the other person is beating a dead horse, gaslighting at its finest. Meanwhile, you change your position. It was that he follows AES48. Once I pointed out how he wasn’t following it, and more importantly, the manufacture’s own instructions, your response is it isn’t critical, especially because you have deemed a preamp signal a “high level signal”. Perhaps you should let Hypex know that they should modify their instructions, as it doesn’t matter according to you. In the meantime, I will point out that VTV has poor assembly quality and does not follow the manufacture’s instructions and potential buyers can make an informed decision if that is an important issue for them.
 

Feanor

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That is only half the issue. The other is tying the shield wire from the amp to pin 1. It is supposed to be tied to the case. Tying it to Pin 1 brings any noise from xlr cable right into the amp and inside the case. This does not follow AES-48 or Hypex’s instructions and defeats the reason for using XLRs.
This technically correct: no dispute. We may refer to Hypex' application note ...
https://www.hypex.nl/img/upload/doc/an_wp/AN_Legacy_pin_1_problems.pdf

I have yet to open my NC252MP case to see whether the input GNDs are connected to Pin 1 only and not also to the chassis. The XLR connector bodies are directly connected to the case, as I mentioned; if the connector bodies have continuity with pin1, then my guess, (not being an electrical engineer), is that there is no problem. You may correct me if I'm wrong.
 
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March Audio

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There is not one absolute method of grounding. You are really not fully understanding the subject and its application.

Also we are talking about high level signals. Grounding becomes more critical when dealing with low level, digital etc.

Sorry reb it's you that has the lack of understanding here. CDMC is entirely correct on these technical points. You would know this if you actually understood the subject. So please desist from arguing about things you clearly don't understand.

For reference VTV is not following AES48. This must be a lack of understanding on their behalf as the most cursory of examinations betrays the errors.
 
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rebbiputzmaker

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So you continue on while claiming the other person is beating a dead horse, gaslighting at its finest. Meanwhile, you change your position. It was that he follows AES48. Once I pointed out how he wasn’t following it, and more importantly, the manufacture’s own instructions, your response is it isn’t critical, especially because you have deemed a preamp signal a “high level signal”. Perhaps you should let Hypex know that they should modify their instructions, as it doesn’t matter according to you. In the meantime, I will point out that VTV has poor assembly quality and does not follow the manufacture’s instructions and potential buyers can make an informed decision if that is an important issue for them.
Just trying to be fair and honest, something that seems to be lost by some here possibly due to misguided fealty.

A useful link from Benchmark:

https://benchmarkmedia.com/blogs/application_notes/grounding-xlr-connectors-neutrik-usa
 

echopraxia

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To not directly ground Pin 1 to the chassis is, indeed, a common "mistake", one I have made myself during my DIY efforts. In my case there were apparently no adverse consequences.

As for my VTV copy, the XLR connectors are grounded -- I can't speak for other peoples' copies.

What I agree with, however, is that even a single shoddy copy can have negative consequences for a maker; makers need to take heed of this and apply adequate QA.
Glad to hear you got a good one! I think the random sloppy drill holes on mine were because the DIY case supplier VTV uses (Ghent Audio) didn’t at the time make pre-drilled holes for the Hypex NC1200 (they do now, though). Of course it was very sloppy work as a matter of fact, and we should expect better at this price given how easy it is to do right (hopefully me stating this fact doesn’t revive a flame war again), but if the issues stopped at the drill holes cosmetic issue alone, I probably would have kept them. (But of course, the issues didn’t stop there.)

If I were you I would open it up and make sure the ground and AC mains power lines are all wired correctly, if only for peace of mind. The most worrying thing to me about my units was the grounding and loose connector issues (on top of physically missing screws just hinting at a very low degree of attention to detail during construction, thus casting doubts on its safety and reliability in other ways).

For example, the frayed pin 1 connector was worrying since the frayed wire strand comes uncomfortably close to the other signal pins. Note that these XLR sockets are very loose so that whenever you plug the XLR cable in and out, they wobble around quite a bit. Ordinarily this probably isn’t a big problem, except for when we consider the exposed frayed ground line there sticking out to the side towards the other pin lines (with no shrink tubing or other insulation to prevent this).

If you’re willing to open it up and do QA and manual repairs as necessary, then of course VTV can work. Personally I think they’d be far better off if they just shipped amp kits and leave the assembly up to the customer. When a product is delivered as a complete assembled product, the customer should not be required to open it up and do QA and repairs themselves. And if the customer has this technical expertise already to validate a sloppy construction job (which we know for sure happens for some percentage of their units), it would be better if VTV just shipped them as kits so that there is no mismatch of expectations about the quality of assembly. IMO.
 

echopraxia

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Back to the broader topic of this thread (various Purifi amp options), I just tested leaving my March Audio P451 (Purifi) amps on idling over night. Using a cheap laser thermometer, it reads 81 F. Just mildly warm to the touch.

As a point of contrast, I had used the same thermometer on my VTV NC1200 amps when I left them idling over night (same location, same indoor temperature), and they read 109 F. Felt fairly hot to the touch.

Granted, I don’t know how much of this is due to the March Audio amp running the lower power Purifi modules vs the higher power NC1200s in the VTV.

Anyway, just providing this as a raw data point; interpret it however you wish, as long as you don’t shoot the messenger :) Overall I am extremely happy with these Purifi based amps by March Audio, and are definitely on my “highly recommended” list!
 

Matias

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Higher power has higher losses, plus Purifi tech is also more efficient a little.
 
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