HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

valvesRus wrote: ↑Wed Jul 03, 2019 10:59 am If and / or when the NVA assets are sorted out I could be interested in a pair of amp boards like Stu and Steve have.

I've got three pairs

karatestu wrote: ↑Wed Jul 03, 2019 3:47 pm

valvesRus wrote: ↑Wed Jul 03, 2019 10:59 am If and / or when the NVA assets are sorted out I could be interested in a pair of amp boards like Stu and Steve have.

I've got three pairs

I had two pairs. Then I blew one of the pairs up

SteveTheShadow wrote: ↑Wed Jul 03, 2019 4:30 pm

karatestu wrote: ↑Wed Jul 03, 2019 3:47 pm

valvesRus wrote: ↑Wed Jul 03, 2019 10:59 am If and / or when the NVA assets are sorted out I could be interested in a pair of amp boards like Stu and Steve have.

I've got three pairs

I had two pairs. Then I blew one of the pairs up

Are the components on the boards ‘basically the same’ between amps and it’s the power supply that is the big difference.
How is an A20 different to the A30?

Boards are exactly the same.

Difference is bigger VA transformer and possibly higher voltage.

karatestu wrote: ↑Wed Jul 03, 2019 9:07 pm Boards are exactly the same.

Difference is bigger VA transformer and possibly higher voltage.

Interesting, thanks. As u know -my spares- I might be tempted to dabble

I like frame (EI) transformers and have tried them on nva boards. I liked it a lot but my EI transformers are small compared to my Canterbury windings toroids and have lower voltage. Richard liked toroids better, said they made his amps sound "better". As usual not giving too much away

Might try it again for kicks

Here is the piece of aluminum sheet i will be using as heat sink for all 6 (probably) of my nva amplifier boards



It's a real monster - that metal ruler is a metre and it nearly gets to the end. Should be enough heat sucking ability for 6 amplifier boards.



It's 6mm thick you know

Stu

T'other day i made some progress with the next four channels of nva based amplification.



It takes longer than you think just soldering in eight output transistors. Every transistor leg must be scratched with a knife blade to remove oxidisation, cleaned with alcohol, bent and inserted into the nva pcb. I use blutack to hold them in and press down to get them both level for when they are mounted on the aluminum sheet heat sink. When soldered i always remove the flux with alcohol and cotton wool bud.

Here they are lined up just to prove i have actually done it. Sorry it's been so long starting this Doc

Stu.......you never cease to amaze me bud.

Not a clue what your on about, but hats off to ya anyway.

Enjoy.