Another DIY SS Amplifier with NVA Boards

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r3xj0hn570n
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by r3xj0hn570n »

karatestu wrote: Sat Feb 12, 2022 10:49 pm I must be blnd, I can't see any circles :ugeek:
Sorry, should have used a thicker pencil tool. Right hand board. 4 rough red circles. 1 at the top, 1 middle, 2 near emitter resistors.

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Re: Another DIY SS Amplifier with NVA Boards

Unread post by Ithilstone »

let me help you Stu ;]
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r3xj0hn570n (Sat Feb 12, 2022 11:56 pm) • antonio66 (Sun Feb 13, 2022 12:55 am) • karatestu (Sun Feb 13, 2022 8:27 am)
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by karatestu »

Thanks Rex and Tomasz.

Modern boards don't have polystyrene caps - red Wima film. Time to get the soldering iron out :dance:
DIY FREE ZONE

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Re: Another DIY SS Amplifier with NVA Boards

Unread post by Adewitte »

I am also working on some NVA boards. I also want to try separate PSU for end and mid boards. I do not wan't to go with dual mono for my own reasons.

I have AP50 boards and a spare original NVA Rs 30v 160va transformer that i want to use with an extra bridge and caps. I know that NVA now uses 25v and that with older intergrated amps 30v for the output transistors and 25v for main board.

So, is there any objection against using two dual 30v power supplies for the NVA boards in this set-up?
With one 30v as in the original NVA AP50 the whole board gets the same 30v (before rectification) voltage anyways?

I have looked at the parts and one one or two 47uf caps needs to go to 50v.

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Re: Another DIY SS Amplifier with NVA Boards

Unread post by savvypaul »

Adewitte wrote: Fri Apr 01, 2022 9:09 am I am also working on some NVA boards. I also want to try separate PSU for end and mid boards. I do not wan't to go with dual mono for my own reasons.

I have AP50 boards and a spare original NVA Rs 30v 160va transformer that i want to use with an extra bridge and caps. I know that NVA now uses 25v and that with older intergrated amps 30v for the output transistors and 25v for main board.

So, is there any objection against using two dual 30v power supplies for the NVA boards in this set-up?
With one 30v as in the original NVA AP50 the whole board gets the same 30v (before rectification) voltage anyways?

I have looked at the parts and one one or two 47uf caps needs to go to 50v.
Our engineer, Tomasz, will be happy to have a conversation with you about what you are planning...but he is occupied full time for the next 10 days or so with building orders and replenishing stock. You could drop him a line here, by PM, in a week or so. His user name is Ithilstone.

Hope this helps. Warm regards,

Paul
I am in the hi-fi trade
Status: Manufacturer
Company Name: NVA Hi-Fi
https://nvahifi.co.uk/

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Re: Another DIY SS Amplifier with NVA Boards

Unread post by Adewitte »

Thanks Paul for the service,

Wil drop hem a line. Wil be interesting.
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savvypaul (Fri Apr 01, 2022 12:53 pm)

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Re: Another DIY SS Amplifier with NVA Boards

Unread post by r3xj0hn570n »

Adewitte wrote: Fri Apr 01, 2022 9:09 am So, is there any objection against using two dual 30v power supplies for the NVA boards in this set-up?
With one 30v as in the original NVA AP50 the whole board gets the same 30v (before rectification) voltage anyways?

I have looked at the parts and one one or two 47uf caps needs to go to 50v.
30V is well within the capability of the circuit and 50v or even 63v caps are better parts anyway, used at any voltage (< rating), IME.

I don't recall any of the electrolytics on the board being exposed to the rail voltage though... Tomasz?

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Re: Another DIY SS Amplifier with NVA Boards

Unread post by SteveTheShadow »

Over the last few days, the amp has had a bit of an internal and external facelift. I retrieved my old Khozmo 10K shunt stepper and an Elma 3 position rotary switch from our Ant’s place and did an internal refresh, incorporating the attenuator, and switch onto the front panel and moving the phono board to the internal side wall. Regulator for the phono board sits between the two amp boards:
FB7ECBC5-0561-4C41-B25A-4A5A841EF6E3.jpeg
FB7ECBC5-0561-4C41-B25A-4A5A841EF6E3.jpeg (482 KiB) Viewed 4676 times
Reworked the front panel to take two control knobs and moved the LED on indicator to the other end of the panel. Gave the front a re-wax and there you go.
0312A501-813A-413F-8E8F-2C94E88B0947.jpeg
0312A501-813A-413F-8E8F-2C94E88B0947.jpeg (429.15 KiB) Viewed 4676 times
From a distance with the Pat Metheny Group on the turntable:
A86F9822-B290-4279-A696-B2D657D7C20D.jpeg
A86F9822-B290-4279-A696-B2D657D7C20D.jpeg (394.11 KiB) Viewed 4676 times
Niiice. 8-) 8-)
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CycleCoach (Wed May 11, 2022 5:10 pm) • NSNO2021 (Sat May 14, 2022 9:47 am)
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by Latteman »

Love the front panel
Analogue Source -
Denon DP47f- Ortofon mc20 supreme
Ifi Zen Phono
Doug Self balanced Pre amp
Akai 4000DS mk2 R2R
Digital Sources- IfI stream, Ifi Neo idsd Dac; Tidal / Radio Paradise
Amplification Nva 30vdc mono blocks
Speakers Lii Audio F-15 in Open Baffle; Ls6
Weiduka AC8.8- for digital sources
Mini BMU for analog sources

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SteveTheShadow
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Re: Another DIY SS Amplifier with NVA Boards

Unread post by SteveTheShadow »

Latteman wrote: Wed May 11, 2022 9:44 am Love the front panel
Cheers,
It came up well.
Somebody’s telling me the latest scandals.
Somebody’s stepping on my plastic sandals. Joe Jackson (1979)

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