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

[echopraxia]

Another data point for Purifi amps in general, though not quite related to shootout between brands — in this post here, you’ll see some distortion measurements I made powering my Revel Salon2’s at 100-105db (e.g. 103db at 20hz). No signs of distortion/clipping, and those woofers were moving quite a lot at 20hz!

I haven’t really pushed it though, as I’m a little paranoid of clipping damaging my speakers if I push too hard. But I can probably test a bit further if anyone wants more data on the practical power capabilities of the Purifi amps into relatively power hungry speakers.

 

[rebbiputzmaker]

Some useful conversation on grounding:

https://www.gearslutz.com/board/geekslutz-forum/1222952-help-implementing-aes-48-wiring.html

 

[Kegemusha]

Great links, thanks for the efforts!

 

[Feanor]

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.

The sloppy drilling and loose screws are inexcusable for a commercial maker. So is the sloppy inside work.

I suppose the good news is that VTV has learned from it's mistakes. I opened my NC252MP case and confirmed that Pin 1's and XLR connector body are connected and both are connected to chassis ground. Also, the the +/1 and Gnd wires from the module look secure. So all seems good, and the unit is working fine.

 

[CDMC]

The sloppy drilling and loose screws are inexcusable for a commercial maker. So is the sloppy inside work.

I suppose the good news is that VTV has learned from it's mistakes. I opened my NC252MP case and confirmed that Pin 1's and XLR connector body are connected and both are connected to chassis ground. Also, the the +/1 and Gnd wires from the module look secure. So all seems good, and the unit is working fine.

What is the shield wire from the xlr to module connected to? That is the issue. See my post here which shows the proper way for it to be wired:

https://www.audiosciencereview.com/...its-all-amirs-fault.13195/page-14#post-467536

If your amp is wired like these two recent ones, then it is not correct:

https://www.audiosciencereview.com/forum/index.php?threads/slight-buzz-rca-to-xlr.15174/#post-478468

https://www.audiosciencereview.com/...build-and-customer-service.15220/#post-480194

Pin one on the XLR is not supposed to be connected to the amp board. Pin 1 is also not supposed to be star grounded, nor should the shields from the amp board. The wires from Pin 1 to the case are supposed to be as short as possible. All three of these things are done incorrectly by VTV, despite his claims he is following AES48. As I have said before, they are easily fixed, as is the terrible assembly quality, but it seems he doesn't understand or care enough to do so. If he did, I would happily recommend his amps, as they have the potential to be an absolute killer value.

 

[PNWer]

The sloppy drilling and loose screws are inexcusable for a commercial maker. So is the sloppy inside work.

I suppose the good news is that VTV has learned from it's mistakes. I opened my NC252MP case and confirmed that Pin 1's and XLR connector body are connected and both are connected to chassis ground. Also, the the +/1 and Gnd wires from the module look secure. So all seems good, and the unit is working fine.

Can you post some pictures of the inside wiring of the VTV amp ?
When did you receive yours ?

TIA

 

[Feanor]

What is the shield wire from the xlr to module connected to? That is the issue. See my post here which shows the proper way for it to be wired:

https://www.audiosciencereview.com/...its-all-amirs-fault.13195/page-14#post-467536

If your amp is wired like these two recent ones, then it is not correct:

https://www.audiosciencereview.com/forum/index.php?threads/slight-buzz-rca-to-xlr.15174/#post-478468

https://www.audiosciencereview.com/...build-and-customer-service.15220/#post-480194

Pin one on the XLR is not supposed to be connected to the amp board. Pin 1 is also not supposed to be star grounded, nor should the shields from the amp board. The wires from Pin 1 to the case are supposed to be as short as possible. All three of these things are done incorrectly by VTV, despite his claims he is following AES48. As I have said before, they are easily fixed, as is the terrible assembly quality, but it seems he doesn't understand or care enough to do so. If he did, I would happily recommend his amps, as they have the potential to be an absolute killer value.

So my amp is wired incorrectly as it would seem. I.e. the shield wire from the module is connected to Pin 1; pin 1 is connected to the XLR body's grounding stub which in turn is connected to the case adjacent to the IEC ground's connection to the case. The path isn't particularly short. I suppose this is a "star" ground to which you object.

I defer to your expertise. Some say the "prove of the pudding is in the eating": the amp operates and sounds fine, despite these flaws. I wonder how many small-maker Hypex-based amps are built to perfection?

 

[CDMC]

So my amp is wired incorrectly as it would seem. I.e. the shield wire from the module is connected to Pin 1; pin 1 is connected to the XLR body's grounding stub which in turn is connected to the case adjacent to the IEC ground's connection to the case. The path isn't particularly short. I suppose this is a "star" ground to which you object.

I defer to your expertise. Some say the "prove of the pudding is in the eating": the amp operates and sounds fine, despite these flaws. I wonder how many small-maker Hypex-based amps are built to perfection?

How much not wiring Pin 1 correctly will effect the sound is situation dependent. In my case, I didn't hear any audible difference when I corrected the wiring, but the turn off thump went from a sharp crack to a quiet thump. Whether this was due to an inaudible ground loop, DC offset somewhere or something else, I do not know.

Again, correcting the wiring and the poor assembly quality are both things that are not hard to do and add very little time (minutes) to the build time. Why VTV doesn't do this is beyond me.

 

[echopraxia]

So my amp is wired incorrectly as it would seem. I.e. the shield wire from the module is connected to Pin 1; pin 1 is connected to the XLR body's grounding stub which in turn is connected to the case adjacent to the IEC ground's connection to the case. The path isn't particularly short. I suppose this is a "star" ground to which you object.

I defer to your expertise. Some say the "prove of the pudding is in the eating": the amp operates and sounds fine, despite these flaws. I wonder how many small-maker Hypex-based amps are built to perfection?

Additionally to what CDMC said above, consider that CDMC and others have helpfully corrected VTV here several times now. Yet despite this feedback, VTV refuses to admit anything is wrong. This is very concerning in of itself, and it’s yet another data point among many others now, indicating that VTV fundamentally does not care about the quality of their products.

 

[echopraxia]

To make an analogy to software (a field where I am most famIliar), imagine you receive some software I wrote. Imagine that some people have reported it crashing randomly, though you personally do not yet encounter it. Imagine that upon inspecting the source code, you find a portion that would definitely cause crashing for some percentage of users and configurations.

In this scenario, which of the following do you think is the correct answer from the engineer:

(A) You're wrong, it works fine for me. The person who claims it crashed is probably lying — see, these other people don’t experience it crashing. Therefore the only problem here is the customer, and nothing on my part needs to change.

(B) Thanks for the feedback, let me look into this carefully and see if I can validate this fix and integrate it into the latest version. If dangerous issues are possible from the prior version, I will ensure all installations of the prior version have the opportunity to be fixed.

I guarantee you (A) is the wrong answer, and is a large part of why so much software today has bugs, crashes, etc.: insufficient attention to detail. This scenario is almost exactly the scenario VTV has gotten itself into, and (A) is the way they have chosen to respond to this.

When I say (A) is a deeply wrong answer, I claim that this is true for pretty much all fields of engineering (not just software) — most certainly including the assembly of power amplifiers, which take lethal AC mains power as input, converting that power into clean powered electrical signals feeding into potentially very expensive speakers that could be damaged if the amp malfunctions.

Yes, building a reliable and safe product requires extraordinarily strict attention to detail. And this requirement is not the exception, it is the rule. If you’re not an engineer, seeing safety and reliability issues pointed out may seem nit picky. But I promise you, this is not the case: Reliability and safety problems are almost always due to subtle errors, rarely blatant errors. In engineering, attention to detail is not just a bonus trait — it is an absolutely essential attribute of the design and construction of any technology product that you want to be safe and reliable.

 

[Feanor]

Additionally to what CDMC said above, consider that CDMC and others have helpfully corrected VTV here several times now. Yet despite this feedback, VTV refuses to admit anything is wrong. This is very concerning in of itself, and it’s yet another data point among many others now, indicating that VTV fundamentally does not care about the quality of their products.

Hopefully VTV will fix its mistakes going forward. Perhaps it's not so much that they don't care in general as that they don't want a flood of amps returned to them for repair. I suspect VTV is a very small concern and that correcting hundreds of amps, however much it might be "The right thing to do", could come close to putting them out of business, .

Once I'm very clear on the correct wiring, I will likely do a DIY repair, (not that I'm having a problem at the moment). I have posed a directly related question to experts in the DIY Forum.

 

[echopraxia]

Hopefully VTV will fix its mistakes going forward. Perhaps it's not so much that they don't care in general as that they don't want a flood of amps returned to them for repair. I suspect VTV is a very small concern and that correcting hundreds of amps, however much it might be "The right thing to do", could come close to putting them out of business, .

Once I'm very clear on the correct wiring, I will likely do a DIY repair, (not that I'm having a problem at the moment). I have posed a directly related question to experts in the DIY Forum.

While I am hopeful VTV will improve, I cannot anticipate that they will any time soon when they haven’t even admitted there is any room for improvement of their XLR wiring!

I’m not sure if you saw it, but VTV responded to my VTV amp thread and denied there was anything wrong with the many issues I had (and I got a much worse build than you, it seems —like missing screws and a very disturbingly floppy power connector).

IMO if VTV is a respectable company, if you ask them to fix your XLR wiring error, they should accept their error and repair it. If I were you, I would at least ask them — it can’t hurt to ask.

Otherwise, if they refuse to fix it and you find yourself DIY repairing their work (welcome to the club ), that’s a pretty bad sign. If this becomes the case yet again, I think VTV should seriously consider shutting down their assembly operation entirely and just ship out the parts as build kits. IMO it would be better that way, and that’s the only way I’d be comfortable buying from VTV. I won’t hold my breath though.

 

[CDMC]

Hopefully VTV will fix its mistakes going forward. Perhaps it's not so much that they don't care in general as that they don't want a flood of amps returned to them for repair. I suspect VTV is a very small concern and that correcting hundreds of amps, however much it might be "The right thing to do", could come close to putting them out of business, .

Once I'm very clear on the correct wiring, I will likely do a DIY repair, (not that I'm having a problem at the moment). I have posed a directly related question to experts in the DIY Forum.

If you follow my link: https://www.audiosciencereview.com/...its-all-amirs-fault.13195/page-14#post-467536 you will find instructions on how to properly fix it and replacement xlr plugs. If nothing else, it may give you a good starting point for the DIY forum, as they may be able to suggest a cleaner, faster, better, and/or easier way than my implementation.

 

[Feanor]

If you follow my link: https://www.audiosciencereview.com/...its-all-amirs-fault.13195/page-14#post-467536 you will find instructions on how to properly fix it and replacement xlr plugs. If nothing else, it may give you a good starting point for the DIY forum, as they may be able to suggest a cleaner, faster, better, and/or easier way than my implementation.

So it looks like the module input cable has its shielding connected to the chassis. The XLR pin 1 is separately connected to the chassis (and nowhere else).

What is unfortunate is the neophyte DIY assembler of module-based amps will intuitively assume that the input cable shielding should attach to the XLR pin 1 ... which it should not.

Module makers aren't always clear clear on the subject. E.g. in case of a pair of ICEpower 200ASC monoblocks I built recently, neither the data sheet nor the Design's Manual gave any clear instruction.

Vendors of the product, e.g. Parts Express for the ICEpower 200ASC provided a link to the following YouTube video which very explicitly says the input cable shielding ought to be soldered to XLR pin 1 ... not helpful, guys.

 

[Zoomer]

I think the random sloppy drill holes

etc.
etc
etc.

After your complaints thread about your VTV purchase was closed down, several people have reported receiving a VTV amp with which they have no problem. Even if there still seem to be issues with incorrect XLR-wiring.
Just to indicate that VTV seems capable of learning, or that you might have been very unlucky.

That thread btw was closed down because it was felt that the point of substandard VTV quality in your particular case had been made ad nauseam.
Yet here you are again with post after post repeating your complaints about VTV.

What's still sadly lacking in your account is any sense of taking responsibility for your own decisions.
- You took your business to a supplier who is known for two things: rock-bottom prices and quality issues (as per several threads on this very forum, dating from before your purchase).
- You declined a refund from VTV.

I would think those two decisions put an upper limit on how much complaining a reasonable person can do. By now those complaints feel about as cheap as a VTV amp.

 

[LTig]

Yes, building a reliable and safe product requires extraordinarily strict attention to detail. And this requirement is not the exception, it is the rule. If you’re not an engineer, seeing safety and reliability issues pointed out may seem nit picky. But I promise you, this is not the case: Reliability and safety problems are almost always due to subtle errors, rarely blatant errors. In engineering, attention to detail is not just a bonus trait — it is an absolutely essential attribute of the design and construction of any technology product that you want to be safe and reliable.

This is absolutely correct. Any law suite following a malfunction with serious harm to the customer will not only close his business for good but may also put him in jail - probably for a longer time when it's proven that the flaws had been shown to him, even multiple times.

 

[echopraxia]

That thread btw was closed down because it was felt that the point of substandard VTV quality in your particular case had been made ad nauseam.
Yet here you are again with post after post repeating your complaints about VTV.

What's still sadly lacking in your account is any sense of taking responsibility for your own decisions.
- You took your business to a supplier who is known for two things: rock-bottom prices and quality issues (as per several threads on this very forum, dating from before your purchase).
- You declined a refund from VTV.

I would think those two decisions put an upper limit on how much complaining a reasonable person can do. By now those complaints feel about as cheap as a VTV amp.

This is incorrect. @Thomas savage can clarify himself, but it was locked due to comments like yours and a few others endlessly harassing me for simply reporting to the ASR community the state of the product I received from VTV. Even @amirm stepped in to clarify that such reviews from members here are welcome and encouraged.

Regarding what I did after I received the VTV amps — that is none of your business, quite frankly. Yet still as a courtesy, I’ve already explained many times why I chose to salvage the Hypex modules in my amp. What I choose to do with product I buy is my decision and mine alone. If I had returned it (instead of taking on the responsibility of fixing it in my own way), would your view have changed? I doubt it.

Also in the post are referring to, perhaps you missed where I explicitly stated this:

(hopefully me stating this fact doesn’t revive a flame war again)

I do not think your ad hominem gripes / vendetta (with how I personally decided to salvage the Hypex modules I bought) belongs in this thread.

 

[Ric Schultz]

This Pin 1 thing is really silly. VTV has sold hundreds of amps with it wired the way they do and no one has told them they have ground hums or anything. Yes, it is theoretically best to just put pin one to the chassis and not anywhere else. Have you guys looked at Nord, Apollon, etc. They all have all wires going to the input board......So, is that shield wire connected to the signal ground on the board or does the connector on the board go directly to the chassis ground? I bet it is the signal. So, please get one of each of those guys amps in and see if they follow AES 48 and if not you can spend another 10 pages beating them up too....oh what fun! Please wave the AES 48 bible in the air very high. It is the only thing that matters......he he. You guys have nothing to say about anything.....since you think the only thing that matters is measurements and how something looks inside and wiring. So, you go on and on about really nothing.........All the latest VTV units have wires going from pin one to chassis ground.....if you do not want pin 1 going to the signal ground you can simply cut the shield wire right at pin one on the xlr connector. Will take you 10 minutes (taking the cover off, and cutting both wires and putting the cover back on)......then you can celebrate...you now have AES 48 and can be slightly more happy. No one can ever really be happy unless the AES 48 RULE (delivered by Moses from the mountain top) is followed on every piece of gear in the world. You probably won't hear any difference whether you do it or not. Of course, you guys never hear a difference.

Now you guys can beat me up about the above......he he. You really have nothing else to do. This forum is the last stand for the "pure objectivists". Fight with all your might.....no one will ever take your mountain.......eh mole hill.....he he. Meanwhile the rest of us that listen and compare will be enjoying better and better sound with each voodoo tweak we perform. BTW......here is a joke.....I am sure you won't laugh...
"Only the deaf need to do blind listening tests"......get it? deaf and blind?.....of course, you are not stupid.

Actually, you guys are not deaf.......in fact, every day there are more and more defectors from your mole hill top. You know the guy that says "How could a 6 foot power cord make a sonic difference when all the wire in the walls is crap?". Then his buddy loans him an "audiophile power cable" and his mind is blown.......so then he starts to buy other voodoo cables and realizes that voodoo is real. Your ears hear the difference, but your scopes won't tell you why.

 

[echopraxia]

This Pin 1 thing is really silly. VTV has sold hundreds of amps with it wired the way they do and no one has told them they have ground hums or anything.

Not true. For reference, here are some reports of buzzing and thumping/popping issues from VTV amps:

https://www.audiosciencereview.com/forum/index.php?threads/slight-buzz-rca-to-xlr.15174/#post-478163

https://www.audiosciencereview.com/...its-all-amirs-fault.13195/page-14#post-483685

 

[CDMC]

What is unfortunate is the neophyte DIY assembler of module-based amps will intuitively assume that the input cable shielding should attach to the XLR pin 1 ... which it should not.

Module makers aren't always clear clear on the subject. E.g. in case of a pair of ICEpower 200ASC monoblocks I built recently, neither the data sheet nor the Design's Manual gave any clear instruction.

Vendors of the product, e.g. Parts Express for the ICEpower 200ASC provided a link to the following YouTube video which very explicitly says the input cable shielding ought to be soldered to XLR pin 1 ... not helpful, guys.

It is frustrating. Imagine poor Bill Whitlock of Jenson transformers who has spent decades preaching how to do it correctly. Ultimately it resulted in the AES48 standard and has finally taken foot in the pro sound industry, but home audio is just finally seeing widespread use of balanced connections and still learning.

https://www.ranecommercial.com/kb_article.php?article=2107


And yes, the manufactures could do better at setting it out. Hypex does spell it out in their documentation if it is looked at closely.

Another issue is for those that want to use an RCA to XLR adapter, most are made incorrectly. The only two that I know for sure that are wired correctly are from March Audio and Benchmark.