Building a DIY amp with NVA amplifier boards

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Dr Bunsen Honeydew
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Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew »

So why do you presume massive power supplies don't do the same for solid state amps and only do it for valves. Massive power supplies on top of what you have in the A20x make the same musical differences. Why do people presume that bigger transistor amps are only about power.

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Dr Bunsen Honeydew
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Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew »

For example a set of A80's or even Statement Amps can be built as 20 - 30w per ch the same as they are for 80w per ch, it is just transformers of same va but less secondary voltage, but it doesn't protect your efficient loudspeakers or mean they are completely safe, a clipping amplifier is far more likely to take out speakers than a clean amp, especially HF drivers.

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Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu »

I picked the size and voltage of my biggest toroids after listening to what Les W has written over the years. He uses 500VA on his biggest amps i think with 50V being the limit for his boards. I considered 500VA but went for 340 with an oversized core, screen & gauss band. Looking back i should have gone bigger (for lower impedance) although statement sized transformers would probably be too physically large for what i am building.
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Re: Building a DIY amp with NVA amplifier boards

Unread post by valvesRus »

So, what secondary voltage would one want for an A80 type version ?

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Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu »

valvesRus wrote: Tue Mar 20, 2018 10:22 am So, what secondary voltage would one want for an A80 type version ?
Sorry, I am not at liberty to give that information. Ask the Doc and see what he says.

Stu
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Dr Bunsen Honeydew
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Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew »

From transformers 35 0 35

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Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu »

Dr Bunsen Honeydew wrote: Mon Mar 19, 2018 8:47 pm What all this proves, rather nicely, is never believe what you have is all you can get, as they say in just about all cases "you ain't seen nuffin yet".
Four psu's per channel ????????????????????????

Never say never :twisted:
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Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew »

You can't do it, it requires changes to the boards and board selection, stick to two per channel.

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Re: Building a DIY amp with NVA amplifier boards

Unread post by karatestu »

Dr Bunsen Honeydew wrote: Tue Mar 20, 2018 5:09 pm You can't do it, it requires changes to the boards and board selection, stick to two per channel.
:angry-screaming: Bugger it. Glad i asked you first :grin:

Looks like i have 3 things left to try on these then;

1) Hardwired (tinned solid wire) bridge rectifier and caps
2) Bigger (VA) transformers with my 340VA 35-0-35 on output stage
3) Front end regulation (Avondale regs) - higher voltage transformer to account for regulator drop .

I have all the parts to do these things. I think NVA does not reguate the front end but i wont be content until i try it and back track if need be. Not sure when the next installment will be - work will get crazy busy soon :roll:
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Re: Building a DIY amp with NVA amplifier boards

Unread post by Dr Bunsen Honeydew »

Don't use ANY regulation on those boards, they don't need it and they don't want it.

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