VTV Purifi Amplifier Teardown(SIL 994EnH-Ticha Pro Opamp)

[jimijoeb]

What about this thin secondary power supply AC wiring with just solder holding it? Looks dangerous...

View attachment 140328

Wires are so thin that it will cause minimal mechanical load on solder joint.

 

[sam_adams]

The other thing that gets me with assemblers is the use of ribbon cable. Sure the boards have ribbon connetors on them, but that doesn't mean that you have to use them. Better connectors that would allow you to use twisted pairs would much nicer and allow one to use better quality wire that would be less prone to failure.

Those cables are shockingly shoddy in their terminations.

 

[wineds]

Is there a fuse? And if so what is the rating?

 

[AndreaT]

Avoid. No excuse for poor topography of components in the case and thin speaker output wires.

 

[phoenixdogfan]

Does the design really require two SMPS 1200's? Does this really increase the output of the amps, or just the price? From what I saw on Amir review, the power output looked pretty much the same as the original Eigentact he first reviewed. And my unit has a single SMPS and seems plenty powerful. So why a second SMPS?

 

[phoenixdogfan]

And this is why you build your own folks:

~$750 Amplifier board (https://purifi-audio.com/vare/eval1/)
~$250 Chassis (https://www.ghentaudio.com/kit/purifi-eval1-se.html)
~$250 Hypex 1200W PSU

Except they do offer this one at $1039 which is an exact copy of what Amir originally reviewed--with speakon outs.

https://vtvamplifier.com/product/vtv-amplifier-purifi-eigentakt-stereo-amplifier-based-on-eval-1/

Clearly the one to buy, and for $211 cheaper than you could assemble yourself from your diy BOM.

 

[Gorgonzola]

It is VTV's more expensive model with dual power supplies.

The VTV standard model with single power supply seems to be a more sensible build.

https://www.audiosciencereview.com/forum/index.php?threads/vtv-purifi-1et400a-updates.17564/​

Yes, this is the standard layout for the VTV's with the Hypex or VTV buffers that permitted op amp rolling.

In my case I ordered the Hypex buffers since the EVAL-1 version wasn't available at the time -- sorry to mention sound, but I found the Hypex buffer unlistenable on account bright and grating high treble during louder passages. I purchased the VTV boards with Sparkos SS3602 op amps which, IMHO, were a great improvement.

Personally I would strongly suggest passing on the Hypex and getting the EVAL-1 version. If you want to roll op amps then get VTV's own buffer.

 

[AudioTodd]

so far im getting the apollon purify.

I’m very happy with my monoblocks!

 

[spigot]

What about this thin secondary power supply AC wiring with just solder holding it? Looks dangerous...

Most things in there use solder, it's very strong. And prevents fraying. Try ripping out wires or capacitors without desoldering.

 

[MakeMineVinyl]

I found this on the internet. Seems well sorted out to me.

 

[GWolfman]

I found this on the internet. Seems well sorted out to me.

View attachment 140376

What're we looking at?

 

[GWolfman]

Thanks for the teardown.

 

[Rottmannash]

Here's a few photos of my VTV Eval 1 amp internals.

 

[restorer-john]

What're we looking at?

How to do it properly.

 

[wwenze]

Safety advice (Or rather, a requirement)

The screw of the ground wire should be done in such a way that it cannot be unscrewed from the outside. From the photo it looks like a nut is inside the chassis while the screw head is outside the chassis.

Example using bent / stamped chassis

Spoiler

And I need to be anal about this because there are non-double-insulated AC wiring in there and clearly touching the chassis, so this chassis grounding is the second layer of protection.

 

[restorer-john]

Is there a fuse? And if so what is the rating?

The Hypex SMPS 1200 12A fuses (1 per PSU), are heatshrunk M205s, pigtailed and soldered to the PCB. Hypex regard the fuses as "non replaceable".

 

[restorer-john]

Safety advice (Or rather, a requirement)

The screw of the ground wire should be done in such a way that it cannot be unscrewed from the outside. From the photo it looks like a nut is inside the chassis while the screw head is outside the chassis.

Example using bent / stamped chassis

Spoiler

Ghent sell Purifi/Hypex cases where they provide one longer screw for one of the feet so their hapless assemblers can attach the safety earth to the foot screw.

It's unbelievable how safety standards and requirements are ignored by most of these module-in-a-box guys.

The ATI above looks to be great, the NADs are great. Everyone else, not so much.

 

[wwenze]

Off-topic, but I noticed that the Hypex SMP1200 is one of those designs that connect the secondary ground to half AC

I understand that they have to do this when the PSU is designed to be 2-pin, but... zzzzzzzzzzzzzzzzz..........

But yea, if anyone is wondering why you feel a faint high-impedance tingle when you touch secondary ground, this is one of those reasons.

Also from the layout it looks like the "black goo" is the fuse. So yea I don't think I would bother replacing that. I guess it is to deter the users from replacing it and troubleshooting a 1200W PSU (IMO: A lot of power) that blew up the fuse to begin with.

Oh a different angle makes things clearer with regards to the identity of the black stuff:

I took the pictures from the SMPS1200Axx0_07xx manual so maybe there are slight rearrangements.

 

[Stoutblock]

Great review @amirm !

Most of the concerns would be easy to solve so hopefully VTV is watching? The small wires going from the trigger to the mains is very concerning. The other small wires only carry 12v I believe?

I should point out this amp has Sonic Imagery Labs 994 Enh-Tricha https://vtvamplifier.com/product/so...ticha-dual-discrete-opamp-dip8-vtv-amplifier/

and not the 990 Enh-Tricha which you state which look like this https://vtvamplifier.com/product/pa...90enh-ticha-discrete-opamp-api-vtv-amplifier/

Probably not a big deal to the measurements but the 990 opamps are API pin out and a bit more expensive while the 994 are DIP8 pin out.

You should measure the amp with the Weiss OP2-BP opamps https://vtvamplifier.com/product/weiss-op2-ba-discrete-opamp-module/ to see if they are worth the extra money based on performance?

Would also be interesting to plug some much cheaper OPA1612 chip amps in the buffer just as a baseline?

Lastly, any logic to measure the amp with the buffer set to +7db gain rather than +14db?

 

[JohnYang1997]

Great review @amirm !

Most of the concerns would be easy to solve so hopefully VTV is watching? The small wires going from the trigger to the mains is very concerning. The other small wires only cary 12v I believe?

I should point out this amp has Sonic Imagery Labs 994 Enh-Tricha https://vtvamplifier.com/product/so...ticha-dual-discrete-opamp-dip8-vtv-amplifier/

and not the 990 Enh-Tricha which you state which look like this https://vtvamplifier.com/product/pa...90enh-ticha-discrete-opamp-api-vtv-amplifier/

Probably not a big deal to the measurements but the 990 opamps are API pin out and a bit more expensive while the 994 are DIP8 pin out.

You should measure the amp with the Weiss OP2-BP opamps https://vtvamplifier.com/product/weiss-op2-ba-discrete-opamp-module/ to see if they are worth the extra money based on performance?

Would also be interesting to plug some much cheaper OPA1612 chip amps in the buffer just as a baseline?

Lastly, any logic to measure the amp with the buffer set to +7db gain rather than +14db?

https://www.audiosciencereview.com/...-opamp-review-sonic-imagery-vs-sparkos.10325/