VTV Purifi 1ET400A updates

[nimar]

The numbers would be on the label on the side. You can barely see it in your photo above.

ahy, that’s just a screen grab from the VTV website. Couldn’t even make out the label until you mentioned it.

 

[mSpot]

Kind of painful to see this discussion keep going around and around. Just email VTV already

 

[Rottmannash]

Kind of painful to see this discussion keep going around and around. Just email VTV already

I have one of these amps. I can ask him. What specifically is the question?

 

[nimar]

Kind of painful to see this discussion keep going around and around. Just email VTV already

Asked. Though you could also have asked instead of posting this

 

[nimar]

Asked. Though you could also have asked instead of posting this

Seems like it does indeed include a filter. Someone link me to the article talking about this. I remember reading it but not where.

 

[Billy Budapest]

Seems like it does indeed include a filter. Someone link me to the article talking about this. I remember reading it but not where.

It includes an EMI/RFI filter but the question is whether the filter circuit is implemented with y-capacitors.

See here:

https://www.diyaudio.com/forums/class-d/38199-ucd180-questions-35.html#post466003

According to Bruno Putzeys:

Re: mains filtering
Quote:
Originally posted by anomalous
with regards to a power supply for the UcD modules,
what is the done thing in terms of mains filtering. a design posted earlier by paradigm used an X-Cap across the active/neutral mains lines. other designs ive seen use a varistor.
ive also seen IEC sockets with mains filters built in.
which one (or which combination) are the go?
thanks,
ben
Do not use mains filters with Y capacitors installed. An Y capacitor makes a capacitive connection (several nf) from the mains lines to your chassis and hence audio ground.
So there is the audiophile designer, using transformers with a shield to remove the slightest chance of the mains polluting his system ground, then installing a schaffner inlet that puts 2.2nF straight from the mains into the chassis, simply because he heard somewhere that mains disturbances are audible. They are, more precisely when such a filter is used.

All commercially available "combined mains filters" have Y capacitors. Don't use them. If all your audio devices are connected to one wall outlet (likely), you can use such a filter there, but by no means on individual boxes.

In principle you could make a filter with only chokes (cm/dm) and an X capacitor. Fine with me, but unless you have a problem with heavily polluted mains you don't need them. The UcD will not be a source of mains pollution. If your mains are polluted by an external cause (like you have a car factory next door), a centralised filter on the outlet is more effective.

 

[Rottmannash]

I have a simple question. It appears I have a faulty 12V trigger in my amp. I've plugged a mono 3.5 mm cable to the 12V out from the back of my AVR and the other end of the cable into the "in" socket on the back of the amp. Flip the switch to standby and nothing. The only way the amp works is to have nothing plugged into the 12V trigger inlet and the switch to "on". What am I doing wrong?

 

[Rottmannash]

Have you tried plugging your DAC straight into the amp? I saw somewhere else that you have a D70, I ordered a D70s and was wondering how its 5v output will work if the purifi gets to max with 1.5v input. Eg. Am I going to have to run it at -80db or something silly, and will that much digital attenuation start to degrade dynamics.

I finally got around to hooking the D70 directly via xlr to the Purifi and in pre mode and was able to tolerate to around-20bB and the volume was scary loud. I don't think you'll have any trouble getting the most out of the Purifi running out of the D70(s).

 

[nimar]

I finally got around to hooking the D70 directly via xlr to the Purifi and in pre mode and was able to tolerate to around-20bB and the volume was scary loud. I don't think you'll have any trouble getting the most out of the Purifi running out of the D70(s).

Interesting, I guess with the 70s having slightly higher voltage out. I’ll be hovering around -40 to -30.

As an aside, you can buy the Ghent IEC and replace the VTV one if you are worried about it adding noise

https://www.ebay.com/itm/Rocker-Swi...0?pageci=ba3c7161-6717-4865-b928-b9b053c06253

 

[Rottmannash]

Interesting, I guess with the 70s having slightly higher voltage out. I’ll be hovering around -40 to -30.

As an aside, you can buy the Ghent IEC and replace the VTV one if you are worried about it adding noise

https://www.ebay.com/itm/Rocker-Swi...0?pageci=ba3c7161-6717-4865-b928-b9b053c06253

It will depend on your room size as well but I don't forsee you having any issues getting to the amp's potential.
Should I be worried about noise?

 

[Rottmannash]

Interesting, I guess with the 70s having slightly higher voltage out. I’ll be hovering around -40 to -30.

As an aside, you can buy the Ghent IEC and replace the VTV one if you are worried about it adding noise

https://www.ebay.com/itm/Rocker-Swi...0?pageci=ba3c7161-6717-4865-b928-b9b053c06253

How do we know this IEC socket doesn't have Y caps?

 

[Rottmannash]

How do we know this IEC socket doesn't have Y caps?

Looking at the Ghent cases for the Eval 1 kit, it is identical to the VTV amp case on the rear plate. I assume that's where VTV are sourcing their cases and hopefully the IEC plug.

 

[Billy Budapest]

Looking at the Ghent cases for the Eval 1 kit, it is identical to the VTV amp case on the rear plate. I assume that's where VTV are sourcing their cases and hopefully the IEC plug.

VTV is sourcing their IEC inlet filters from Delta, according to VTV’s website. It’s got to be one of these series, although I don’t know which:

https://www.deltaww.com/en-US/products/IEC-Inlet-Filter/ALL/

 

[Billy Budapest]

Interesting, I guess with the 70s having slightly higher voltage out. I’ll be hovering around -40 to -30.

As an aside, you can buy the Ghent IEC and replace the VTV one if you are worried about it adding noise

https://www.ebay.com/itm/Rocker-Swi...0?pageci=ba3c7161-6717-4865-b928-b9b053c06253

Or splurge and spend $5.00 on a Swiss-made Schurter IEC inlet.

 

[nimar]

Or splunge and spend $5.00 on a Swiss-made Schurter IEC inlet.

likely, I just figured it would be easy to get it from Ghent as we know it’s the right size.
@Rottmannash this IEC is just bare terminals that you wire up yourself, nowhere to put any capacitors.

 

[Rottmannash]

I'm confused. These sockets don't have any capacitors inside for filtering? What is that silver box attached to the back of it?

 

[nimar]

I'm confused. These sockets don't have any capacitors inside for filtering? What is that silver box attached to the back of it?

The capacitors are inside the "silver box", on the label it may even show a schematic of the circuit.

edit. I got mine today, no marking at all on it that I can make out.

 

[Rottmannash]

Ah. That's what we need to know? Which model# on the silver box? I emailed Warren and asked what type of caps were in his. I'll let you guys know as soon as he responds.

 

[JimB]

In case you find it helpful, this is regarding a Ghent supplied mains filter unit I received:
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-96#post-613473
https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-98#post-617372

 

[GiFi]

Hi Rugger,

I am in a very similar position as you, looking to buy the VTV amp, a new DAC and a new pair of speakers (leaning towards the Klipsch RP-8000F at the moment). This is my first post!

First of all the amp looks well assembled, looks like the teething issues have been resolved. The price has also gone up a bit recently which could explain the difference in quality. At this quality/price level I think it is a no-brainer compared to other assemblers, even for someone from Australia like myself with all the additional costs. I would be keen to get the thoughts of a lot of the members here who have been bashing VTV (with a passion) recently.

I am contemplating the same amp however I have a few thoughts - with the stock input buffers the max capacity is reached at 2.35V, instead of say 4V which is the output Voltage of a typical balanced amp. Would a balanced amp work well with this amp? Is distortion higher at lower output Voltage of a balanced DAC? Is it better if I opt for an unbalanced DAC?

Furthermore, how are you finding the SQ and power levels of the amp so far? Have you hooked the amp up to your larger speakers already to give that a go?

The thing I noticed is that when the NAD M28 was tested (https://www.audiosciencereview.com/...8-seven-channel-power-amplifier-review.15939/) the power output was significantly higher - would it be worthwhile opting for mono-blocks to get more power out of the Purifi modules?

Cheers

Hi, wich is the volume level number on your smsl su-9 at max power of the VTV purifi ampli (xlr connected)?
Thanks G