DIY Purifi Amp builds

[tomchr]

And note the mains wiring. The IEC inlet is covered by a boot and a doubly insulated wire is used for the mains wiring. It further looks like the wire is secured to the PCB with a wire tie at the point where the outer jacket is stripped off. That's what good electrical safety looks like.

It would be trivial to implement these things in the DIY world where labour cost is zero. The parts are pretty cheap too.

Tom

 

[Rick Sykora]

Ever seen the inside of a Rega Brio case? That’s how it should be done.

I have now. Thanks for sharing!

 

[Rick Sykora]

Any suggestions on how to integrate the power button?
I found in the SMPS1200A400 user manual that there is also a SMPS-standby mode (jumper J5.1). What is the difference between using the EVAL1 standby mode vs. the SMPS-standby mode?
Additionally, I found that I could access GND from J5.5 of the SMPS1200A400. So I could place the power switch between J3.1 of the EVAL1 and J5.5 of the SMPS. Then J5.2 of the SMPS offers amp standby which likely would not do much as the VTV did not fully connect the SMPS to the EVAL1. I am really lost...

The correct way is at the end of the user's guide...

Does your amp have a trigger module?

 

[ironhorse128]

The correct way is at the end of the user's guide...

View attachment 145490

Does your amp have a trigger module?

No my amp does not have the trigger module.
I saw this user guide reference. This was my starting point. But JimB wrote in this post https://www.audiosciencereview.com/forum/index.php?threads/diy-purifi-amp-builds.10478/post-864505 that it is better to put the smps in standby mode. To do this an external voltage needs to be supplied. This smps standby mode is exactly what the vtv trigger modules uses.

I guess I have it all figured out. I am missing a few parts and somebody to drill the hole on my backplate to supply the external voltage. Nevertheless, I would be interested so understand the difference between the smps standby mode and the eval1 standby mode.

 

[Rick Sykora]

No my amp does not have the trigger module.
I saw this user guide reference. This was my starting point. But JimB wrote in this post https://www.audiosciencereview.com/forum/index.php?threads/diy-purifi-amp-builds.10478/post-864505 that it is better to put the smps in standby mode. To do this an external voltage needs to be supplied. This smps standby mode is exactly what the vtv trigger modules uses.

I guess I have it all figured out. I am missing a few parts and somebody to drill the hole on my backplate to supply the external voltage. Nevertheless, I would be interested so understand the difference between the smps standby mode and the eval1 standby mode.

You do not need external voltage for the amp standby. When I worked on phoenixdogfan’s amp, Purifi support was quite clear that you only need the wiring specified in the app note. If you want to check with them, they usually turn email in a day. Just remember they are 6 hours ahead of US east coast.

 

[ironhorse128]

You do not need external voltage for the amp standby. When I worked on phoenixdogfan’s amp, Purifi support was quite clear that you only need the wiring specified in the app note. If you want to check with them, they usually turn email in a day. Just remember they are 6 hours ahead of US east coast.

Awesome.
That would make things a lot easier. Thanks for the hint.

 

[JimB]

Awesome.
That would make things a lot easier. Thanks for the hint.

You first asked about SMPS standby versus EVAL1 standby. I guess the question is what you are really trying to achieve. You have three levels available:
1. If you just want to 'mute' the amp, then yes, it is relatively easy to use the nAMPON feature;
2. If it is to save power and heat, that is of limited value. Putting the SMPS into STBY is more effective, but comes at other power cost. Hence;
3. The suggestion to just really turn it OFF if that is the purpose.

 

[ironhorse128]

You first asked about SMPS standby versus EVAL1 standby. I guess the question is what you are really trying to achieve. You have three levels available:
1. If you just want to 'mute' the amp, then yes, it is relatively easy to use the nAMPON feature;
2. If it is to save power and heat, that is of limited value. Putting the SMPS into STBY is more effective, but comes at other power cost. Hence;
3. The suggestion to just really turn it OFF if that is the purpose.

Thanks for the clarification. I want to save as much power as possible without switching the mains. Therefore option 2 is appropriate.

 

[ironhorse128]

Is it known what the smps1200a400 draws in standby mode? Hope it is less than 1watt.

 

[boXem]

Is it known what the smps1200a400 draws in standby mode? Hope it is less than 1watt.

About 1 W.

 

[Rick Sykora]

Is it known what the smps1200a400 draws in standby mode? Hope it is less than 1watt.

This also requires external power to drive the SMPS standby input. So will use additional (though small) power there too.
Shy of connecting the switch to the AC line (may need a higher rated switch), the other option is the amp standby switch. This does power down the amp mains, so power consumption is lower, but not as low as SMPS standby/power down. How much power draw is a Purifi question as it does not appear in their specs AFAIK.

So, there are your tradeoffs. The simplest is the amp standby switch, but if the minimal power draw is a major issue, need to work on external power to drive. If you are not up for a major mod, then you might consult VTV as his trigger module is mainly a 5V power supply.

Hope this helps!

 

[mk1classic]

Alternative SMPS suppliers for Class D amp kits?

I've been lately looking at building a low powered multichannel Purifi amp for use with compression drivers.
The Hypex SMPS1200A100 would be nice, but it looks like Hypex has stopped selling it or limiting private sale.
This would have supplied a DC voltage 2x 36Vdc. vs the typical 2x63Vdc of the SMPS 1200A400.

What other SMPS suppliers are there suitable for use on Purifi 1ET400A amp module? 2x 25 to 35Vdc would be nice.
I see most alternative SMPS don't have the required Gate Driver supply (VDR). Or can this be provided in an alternative method?

 

[JimB]

Alternative SMPS suppliers for Class D amp kits?

I've been lately looking at building a low powered multichannel Purifi amp for use with compression drivers.
The Hypex SMPS1200A100 would be nice, but it looks like Hypex has stopped selling it or limiting private sale.
This would have supplied a DC voltage 2x 36Vdc. vs the typical 2x63Vdc of the SMPS 1200A400.

What other SMPS suppliers are there suitable for use on Purifi 1ET400A amp module? 2x 25 to 35Vdc would be nice.
I see most alternative SMPS don't have the required Gate Driver supply (VDR). Or can this be provided in an alternative method?

Why note use the commonly available power supplies, and use a lower input buffer gain? How many channels would you want in one box?

 

[boXem]

Alternative SMPS suppliers for Class D amp kits?

I've been lately looking at building a low powered multichannel Purifi amp for use with compression drivers.
The Hypex SMPS1200A100 would be nice, but it looks like Hypex has stopped selling it or limiting private sale.
This would have supplied a DC voltage 2x 36Vdc. vs the typical 2x63Vdc of the SMPS 1200A400.

What other SMPS suppliers are there suitable for use on Purifi 1ET400A amp module? 2x 25 to 35Vdc would be nice.
I see most alternative SMPS don't have the required Gate Driver supply (VDR). Or can this be provided in an alternative method?

SMPS1200A180

 

[ironhorse128]

I finished my little button project (adding a standby button to my VTV EVAL1 amp). It works fine and I am quite happy with the mod.
I drilled two holes in the back panel to offer two 5.5/2.1 power sockets. One is used to provide and an external power source, as the SMPS needs an external power supply to activate the standby mode. The second hole has no purpose yet. But maybe in the future I will add a trigger functionality.

Thanks to @JimB and @Rick Sykora for the support.

 

[NTSOS]

Alternative SMPS suppliers for Class D amp kits?

I've been lately looking at building a low powered multichannel Purifi amp for use with compression drivers.
The Hypex SMPS1200A100 would be nice, but it looks like Hypex has stopped selling it or limiting private sale.
This would have supplied a DC voltage 2x 36Vdc. vs the typical 2x63Vdc of the SMPS 1200A400.

What other SMPS suppliers are there suitable for use on Purifi 1ET400A amp module? 2x 25 to 35Vdc would be nice.
I see most alternative SMPS don't have the required Gate Driver supply (VDR). Or can this be provided in an alternative method?

https://www.audiosciencereview.com/forum/index.php?threads/smps-for-audio-applications.14307/page-6

 

[k525]

Hi all

My can someone explain me if it is normal my eval1 S1 switch is not working?
I cannot put in standby the amplifier

 

[idv_42]

Hello!
Recently bought a basic Nord 1et400a.
Looked inside, there are rev d buffers, but without voltage regulators. Instead, the jumper is simply soldered.
What do you think, if I buy Sparkos ss7815/ss7915 and just install them? Or maybe less expensive voltage regulators (lm/ldo)? There is a photo buffer on the nord website (without opamp).
In my amplifier, they look the same, only with opa 1612 and without voltage regulators. The name on the board is exactly the same.

It seems that it looks easy. Opa 1612 suits me perfectly, but regulators are probably better to install.

Thanks!

P.S. Sorry for my english, I am using google translator.

 

[tomchr]

FWIW: I've never been able to measure any difference in the output of the Hypex/Purifi amps with/without the fancy regulators or fancy opamps. I wouldn't change anything.

Tom

 

[Synergy4]

FWIW: I've never been able to measure any difference in the output of the Hypex/Purifi amps with/without the fancy regulators or fancy opamps. I wouldn't change anything.

Tom

Did you assemble a Purifi amp with your buffers?
Did you use a IEC inlet medical filter (no Y cap)?
Also, did you use a 8 mm tall mount spacer to align your buffer to the Purifi amplifier?