Purifi/Hypex/Ghent Build Concerns (Newbie Questions)

[javajaws]

Does anybody know if the kit from Ghent has a 12v trigger (pictures don't show it)? Or is that only in the modified one VTV sells (modified/custom Ghent case)?

Also, it seems like VTV hasn't been accepting orders all week - keeps saying essentially "tomorrow", then changes the date every day. A firm date would have been nice instead of a rolling date that changes daily.

 

[Rottmannash]

Does anybody know if the kit from Ghent has a 12v trigger (pictures don't show it)? Or is that only in the modified one VTV sells (modified/custom Ghent case)?

Also, it seems like VTV hasn't been accepting orders all week - keeps saying essentially "tomorrow", then changes the date every day. A firm date would have been nice instead of a rolling date that changes daily.

I have a feeling he's having a hard time getting the modules, as popular as they've become.

 

[concorde1]

Those completed amps do look nice but they're missing SpeakOn, and have their own electronics which could impede or enhance performance, but they haven't been measured yet. Therefore I think I'll go DIY Ghent.

It seems in the Ghent the XLR's of the EVAL1 just poke through and then you can screw them to the rear plate somehow?

SpeakOn though I think you need to solder to the EVAL1 with wires and screw into rear plate? Where do you solder them to on the board?

 

[Rottmannash]

Those completed amps do look nice but they're missing SpeakOn, and have their own electronics which could impede or enhance performance, but they haven't been measured yet. Therefore I think I'll go DIY Ghent.

It seems in the Ghent the XLR's of the EVAL1 just poke through and then you can screw them to the rear plate somehow?

SpeakOn though I think you need to solder to the EVAL1 with wires and screw into rear plate? Where do you solder them to on the board?

My VTV Eval 1 does have SpeakOns.

 

[phoenixdogfan]

Those completed amps do look nice but they're missing SpeakOn, and have their own electronics which could impede or enhance performance, but they haven't been measured yet. Therefore I think I'll go DIY Ghent.

It seems in the Ghent the XLR's of the EVAL1 just poke through and then you can screw them to the rear plate somehow?

SpeakOn though I think you need to solder to the EVAL1 with wires and screw into rear plate? Where do you solder them to on the board?

The VTV replica Eigentact uses the original electronics (buffer) which Amir tested and found to have the 104 db SINAD (108 db bypassed).

 

[concorde1]

I'm now 90% sure I want to save for the Boxem Arthur 4215/E2

 

[concorde1]

Well I'm now going back to the DIY Ghent/Hypex/Purifi idea.

Or maybe a custom chassis, or Modushop Dissipante chassis, instead of Ghent.

What extra circuits (if any) must be added to make it usable? I'm sure a Speaker Protection circuit would fit in the Ghent case - I found a tiny one that costs only a few $ here in NZ.

 

[Rick Sykora]

Sure. But take boXem for example, all the little things like auxiliary power supply for soft turn on/off, variable gain, cables sleeved and tied, fancier binding posts, let alone the fancier looking chassis. Apollon Mini is similar.

There are customers willing to pay more and get these details. Nothing wrong with choosing a more premium build or saving some money, to each his/her own.

https://boxem-audio.eu/en/stereo-am...-4215e2.html#/2-faceplate_color-oxidized_grey

These are great points, but I also think there is also some tendency to overlook some of what is done by better designers that make for a more robust amplifier...

As I have been considering amplifier alternatives for the Directiva project, I came across this article. It is very well written and discusses some of the key circuits that should be considered when building an amplifier. Whether they protect the amplifier or speakers or improve noise rejection, often Hypex/Purifi leaves them to their OEM to do. These are often the difference between the bargain basement supplier and the more premium ones.

A Complete Guide to Design and Build a Hi-Fi LM3886 Amplifier - Circuit Basics

 

[Rick Sykora]

Well I'm now going back to the DIY Ghent/Hypex/Purifi idea.

Or maybe a custom chassis, or Modushop Dissipante chassis, instead of Ghent.

What extra circuits (if any) must be added to make it usable? I'm sure a Speaker Protection circuit would fit in the Ghent case - I found a tiny one that costs only a few $ here in NZ.

From my previous post, should have also mentioned that Neurochrome uses the same chip in his amplifiers and his site offers more powerful versions and some savvy technical information on some of the finer points too.

 

[Rick Sykora]

I can tell you that I bought the SMPS from Hypex, a case and wiring from Ghent and the Eval 1 from Purifi almost a year ago, and I still can't get it to work. I thinks I have a defective SMPS. I've sent that unit back to Hypex twice (actually three times, for some reason NY US customs refused to ship it to the Netherlands b/c they said it was a "dangerous" device), and they supposedly repaired the aux circuits (which are not protected with circuit breakers), and it still won't hold a constant voltage. Instead its voltage drops off the second current is applied to it. Ultimately. I think I will be buying a second SMPS.

Anyway, my advice is to buy a completed, assembled amp from VTV which sells for (believe it or not) less than the component parts if you buy them separately and assemble them yourself. I'd also advise buying the original Eigentact amp, rather than one with so called "improved ICs". It's cheaper. and every test Amir does indicates that the Nord Purifi which use the "superior" op amps don't perform as well as the original stock amp.

Bad power supplies seem to be a common complaint, but have (fortunately) avoided to date.

I am disheartened to hear you have not been able to resolve your issue. Would be willing to help if you like, just PM me.

 

[Rick Sykora]

I have a feeling he's having a hard time getting the modules, as popular as they've become.

More likely is on spring break! I just ordered Nc252MP from Hypex and arrives tomorrow. NC502s are more challenging.

Saw Madisound decided to pick up some Hypex kits. A couple of stereo UCDs and the NC400.

 

[concorde1]

It is very well written and discusses some of the key circuits that should be considered when building an amplifier. Whether they protect the amplifier or speakers or improve noise rejection, often Hypex/Purifi leaves them to their OEM to do.
A Complete Guide to Design and Build a Hi-Fi LM3886 Amplifier - Circuit Basics

That is a quasi-Class AB amp though. Do Class D amps (like EVAL1) even need additional circuits? Like speaker protection / amp protection / noise rejection? I will e-mail Purifi or Ghent.

 

[Rottmannash]

That is a quasi-Class AB amp though. Do Class D amps (like EVAL1) even need additional circuits? Like speaker protection / amp protection / noise rejection? I will e-mail Purifi or Ghent.

Nope

 

[concorde1]

The options I'm considering are:
Boxem Arthur 4215/E2
Apollon 1ET400A Stereo
Ghent DIY

If I do Ghent DIY, is there a different power supply I could use instead of the SMPS1200A400? One with better quality capacitors?

Boxem looks like decent value if it will actually perform as well as DIY with its in-house input buffer, and is built well.

Apollon is much more expensive and I don't know why I'd consider it.

I need help deciding!

Also, thank you all for all the assistance so far!

 

[NTK]

...
If I do Ghent DIY, is there a different power supply I could use instead of the SMPS1200A400? One with better quality capacitors?
...

You can see if @MicroAudio has one that is suitable (see thread).
https://www.audiosciencereview.com/forum/index.php?threads/smps-for-audio-applications.14307/

 

[Rottmannash]

Why aren't you considering the VTV Eval 1?

 

[concorde1]

Aesthetics not to my taste.

 

[Rottmannash]

Aesthetics not to my taste.

So the amp has to be pretty??

 

[concorde1]

I suppose

 

[Rick Sykora]

That is a quasi-Class AB amp though. Do Class D amps (like EVAL1) even need additional circuits? Like speaker protection / amp protection / noise rejection? I will e-mail Purifi or Ghent.

It depends. Not so much on the type of amplifier, but whether the manufacturer included the circuits. You can see the same filters in a Class D build like this one...
https://www.allaboutcircuits.com/projects/how-to-build-a-class-d-power-amplifier/

Whether Hypex includes depends on which module and which version. Purifi appears to be better, but am not as familiar with the offering. @boXem | audio likely knows.