Transformer Va.

All general audio posts go here.
Daniel Quinn
Posts: 8431
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 17 times
Been thanked: 288 times

Transformer Va.

Unread post by Daniel Quinn »

There are many disputes in hifi. Most are not worth caring about. Transformer va is however one I care about, because it baffles me.

NVA phono amps take a 25v or 30v dc output from the transformer , feed it to voltage regulator which in turn feeds the phono board with a consistent voltage. As such it should not matter the size of transformer you get to feed your 25/30 volts and theory would concur.

however , I, everyone whose tried the modification and everyone who as heard the difference between a phono 1 and 2 knows this not to be true. [ it should be noted these phono amps were at mcru bakeoff in Huddersfield and everyone heard the superiority of the phono 2 . The only differences is the size and location of the transformer.]

I can hear the difference between 50va , 160va and 500va and I would wager large sums anyone can. The larger transformer is staggeringly better.


So what's going on or is it beyond our current understanding.

Number Six
Posts: 21
Joined: Mon Oct 04, 2021 8:55 pm
Has thanked: 3 times
Been thanked: 10 times
Great Britain

Re: Transformer Va.

Unread post by Number Six »

500va transformer in a Phono stage is mad not to mention a waste of money. way way too much current on tap for such a thing.

User avatar
Latteman
Posts: 959
Joined: Tue Aug 14, 2018 7:20 pm
Location: S. Yorkshire
Has thanked: 260 times
Been thanked: 103 times
Contact:
Great Britain

Re: Transformer Va.

Unread post by Latteman »

As I understand it -the bigger capacitors with the larger va are a package that make the difference we hear- I’m ‘only’ 160va here but 63v 10000uf x2- have added small heat sinks to the rectifier board
Analogue Source -
Diy Turntable ,- Thorens Td321 donor
Diy tonearm- Well Tempered clone,
Benz Micro Silver
Hitachi HT-660, Ortofon vivo blue
Phono 1 (160va) & Ortofon MCA10
Digital Sources- MF M1 Clic, Diy IDE cdp, iPhone 6s.
Amplification 2x Nva A20; A30 mk2; AP10H; Khozmo passive pre
Speakers- Diy ‘Bipolar 5.25” in bamboo sphere ; Ls6/3
Dc blocker to Nva mini BMU

Daniel Quinn
Posts: 8431
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 17 times
Been thanked: 288 times

Re: Transformer Va.

Unread post by Daniel Quinn »

No 6 is unable to read. Pity.

I used the same capacitors in my mod to see what was going on. It was still better.

Small heathsinks is a very good idea.

Geoff.R.G
Posts: 1238
Joined: Thu Aug 11, 2016 2:46 pm
Location: Denham UK
Has thanked: 64 times
Been thanked: 248 times
Great Britain

Re: Transformer Va.

Unread post by Geoff.R.G »

If I told you that power is Volts x Amps x Cos power factor would that help? Probably not because you have never heard of power factor but it can be assumed to be around 0.8 for many domestic appliances.

We can’t rate transformers in Watts because we don’t know how they will be used, in some applications the power factor could be worse than 0.8 in others it could be better, 0.95 for example. What we can do is to state the current a transformer can handle and the voltage at which it is designed to work.

UK mains voltage is around 239V nominal so a 300VA transformer will handle 300/239Amps 1.25A in the primary. If the secondary voltage is 30V the output current can be up to 10A (it will be less than that for various reasons but we won’t go into that).

Thus a 300VA transformer can deliver more current to the load (amplifier) than a 150VA transformer. It is like driving a car with 300 BHP compared to driving the same car with 150 BHP, the difference is obvious.

Daniel Quinn
Posts: 8431
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 17 times
Been thanked: 288 times

Re: Transformer Va.

Unread post by Daniel Quinn »

Thanks Geoff, it makes sense.

Ultimately it deosnt matter of course, I just like to speculate on what's going on.
These users thanked the author Daniel Quinn for the post:
Geoff.R.G (Sat Oct 09, 2021 8:17 pm)

User avatar
Ithilstone
Posts: 548
Joined: Mon Jun 01, 2015 10:54 am
Has thanked: 56 times
Been thanked: 44 times
EUROPEAN_UNION

Re: Transformer Va.

Unread post by Ithilstone »

DQ look for Doc's door analogy - he written about it often enough
Geoff same car different engine analogy is also very good
These users thanked the author Ithilstone for the post (total 2):
Geoff.R.G (Sat Oct 09, 2021 9:47 pm) • Firebug1 (Sat Oct 09, 2021 10:31 pm)
Nothing to see here...
I am in the hi-fi trade
Status: Manufacturer
Company Name: NVA Hi-Fi
https://nvahifi.co.uk/

Number Six
Posts: 21
Joined: Mon Oct 04, 2021 8:55 pm
Has thanked: 3 times
Been thanked: 10 times
Great Britain

Re: Transformer Va.

Unread post by Number Six »

Daniel Quinn wrote: Sat Oct 09, 2021 7:12 pm No 6 is unable to read. Pity.

I used the same capacitors in my mod to see what was going on. It was still better.

Small heathsinks is a very good idea.
I can read, Im amateur just like everyone else on here that thinks they aint. :dance:

Daniel Quinn
Posts: 8431
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 17 times
Been thanked: 288 times

Re: Transformer Va.

Unread post by Daniel Quinn »

We're all amateurs.

I wrote I could hear the difference in a 500va transformer. You told me that was mad and a waste of money.

Ignoring how much I paid for the transformer, you questioned what I heard, which is a no no. By all means question why I heard it, even suggest it was psychological, but I would appreciate not being called a liar. 😉

Geoff.R.G
Posts: 1238
Joined: Thu Aug 11, 2016 2:46 pm
Location: Denham UK
Has thanked: 64 times
Been thanked: 248 times
Great Britain

Re: Transformer Va.

Unread post by Geoff.R.G »

Daniel Quinn wrote: Sat Oct 09, 2021 9:16 pm We're all amateurs.

I wrote I could hear the difference in a 500va transformer. You told me that was mad and a waste of money.

Ignoring how much I paid for the transformer, you questioned what I heard, which is a no no. By all means question why I heard it, even suggest it was psychological, but I would appreciate not being called a liar. 😉
If you say you can hear the difference, you can hear the difference. I would actually be more concerned if you said you couldn’t.

Sticking with the car analogy; drive the car with the more powerful engine and you will very soon realise how much more easily it does things, I would expect the same with a more powerful transformer.

Whether putting a 500VA transformer in a phono stage is a waste of money, only you can judge. Had you asked I might have suggested that it was excessive, it appears I would have been wrong. A bit like putting a 500HP engine in a Mini, you’ll probably never reach the limits of its performance.

Post Reply