Dual mono or separate transformers for input- and outputstage?

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Lurcher300b
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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by Lurcher300b »

Daniel Quinn wrote: Sun Jul 05, 2020 12:53 pm Lurch, you know its making amps not political economy don't you 😏
Honestly, no, I think everything that is not art should be evidence based, and I think we can apply the same perspective to both the small and the large.

Daniel Quinn
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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by Daniel Quinn »

Whilst I'm sure you are correct, my point was one matters one is just having fun.

29mile
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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by 29mile »

I think Nick is making a valid point illustrating how difficult it is to design a PSU given the complex interactions between all the connected components. I recall a post by Colin Wonfor making similar comments about the complexity of PSU’s. Richard’s design works for NVA but as designers I suspect Nick or Colin would maybe design a different PSU based on their individual design preferences experience and knowledge.
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Colin Wonfor (Fri Jul 31, 2020 11:35 am)

Daniel Quinn
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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by Daniel Quinn »

That's what everybody deos. It's still only making amps.

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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by valvesRus »

Daniel Quinn wrote: Sun Jul 05, 2020 4:12 pm That's what everybody deos. It's still only making amps.
I have spent a long time making amps, since my first one in 2006. I like to try and make my amps different in some way, put my personal stamp on them if you like, but because there is very little (if any) that has not been done before (more so with valves) accepted wisdom is usually worth following.

My "bible" is a book called Valve Amplifiers by Morgan Jones, a veritable tomb of accurate information, showing the theoretical and practical reasons for how, and why things are done. I've met Morgan twice now, at the Audio Talk Owston events, and he's a really nice guy, and he's probably forgotten more than I will ever know.

In today's world, I'm really fortunate because on Audio Talk there are seasoned DIY people who have done so much, and are prepared to guide novices in the right direction, none more so than Nick Gorham (Lurcher on here) whose knowledge and design skills are second to none.

So, I'm all for anyone trying different things in the hope of creating something really special, but it can be an absolute waste of time, and more importantly, money.

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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by Geoff.R.G »

I think we have to accept that the multiple PSUs for the Phono 3 produce an effect that Richard was intending. I hope we can all agree that splitting the power supply between input and output stages was something that was done for a reason. My role has never been to design power supplies nor for that matter amplifiers, I am a maintenance engineer but we tend to be able to see where things aren't what they might be. Sometimes things are designed so that an easily accessible part will fail to prevent a less accessible part from doing so. Other times things are made more powerful than appears necessary to improve response time or to remove complexity. Occasionally things are done from laziness, like using for large discrete diodes where a small bridge rectifier IC would be perfectly adequate simply because the diodes were to hand (yes I've done that).

So then, if having a bigger PSU for the input stage improves the sound, and there is no commercial reason not to, why not?
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karatestu (Sun Jul 05, 2020 6:07 pm)

Lurcher300b
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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by Lurcher300b »

So then, if having a bigger PSU for the input stage improves the sound, and there is no commercial reason not to, why not?
Because without knowing why it improves the sound we are just guessing. Now some may not worry or care, but some others do.

Lets imaging a situation, we start with a 75va transformer, we replace it with a 300va transformer. It sounds better, But what we don't know is will a 600va transformer sound better or would a 150va sound even better than a 300va. Would a 75va sound even better than all of them if we changes the cap or the rectifier, or would a 75va with a different voltage sound better. We can decide to try every possible variation, or we can try and create a model of what is happening and see what that suggests would be better, try that, if its better continue with the model, if not find a new model. Another name for that model is understanding.
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Geoff.R.G (Sun Jul 05, 2020 9:47 pm)

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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by Geoff.R.G »

Lurcher300b wrote: Sun Jul 05, 2020 6:38 pm
So then, if having a bigger PSU for the input stage improves the sound, and there is no commercial reason not to, why not?
Because without knowing why it improves the sound we are just guessing. Now some may not worry or care, but some others do.

Lets imaging a situation, we start with a 75va transformer, we replace it with a 300va transformer. It sounds better, But what we don't know is will a 600va transformer sound better or would a 150va sound even better than a 300va. Would a 75va sound even better than all of them if we changes the cap or the rectifier, or would a 75va with a different voltage sound better. We can decide to try every possible variation, or we can try and create a model of what is happening and see what that suggests would be better, try that, if its better continue with the model, if not find a new model. Another name for that model is understanding.
If we are to be subjectivist, we try it. If it works we may then try to understand why it works. If it doesn't work we, may be try something else or we seek to understand why. The difference is that we don't try to predict why, or indeed whether, something works we just try it. To quote Einstein, not everything that counts can be counted, not everything that can be counted counts.
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savvypaul (Sun Jul 05, 2020 11:00 pm)

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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by Lurcher300b »

Not a Albert quote.

If you are following that subjective approach why not start just connecting one wire. Or put a pot of yoghurt on the top. Or any other entirely random thing.

Daniel Quinn
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Re: Dual mono or separate transformers for input- and outputstage?

Unread post by Daniel Quinn »

Because we stand on the shoulders of giants.

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