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SUN Audio SV-2A3 SET Valve Amp - new build

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I had a look inside mine and i think I could do one small upgrade to the copper foil caps.

Do you think Guru could send me the same 3 ones ?

Cheers

Maxime

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1 minute ago, maxsimonjp said:

I had a look inside mine and i think I could do one small upgrade to the copper foil caps.

Do you think Guru could send me the same 3 ones ?

Cheers

Maxime

Hifi Collective in UK can help you if you get stuck...best of luck....

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Thank you for the tip, i am thinking of a bigger list now

 

 

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44 minutes ago, maxsimonjp said:

Thank you for the tip, i am thinking of a bigger list now

 

 

If you went onto the Audio Note (Australia) site, you should be able to contact Bryan/Guru. 

SN

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It's strange that part upgrades are deemed acceptable, but improvement of the kit wiring layout appears to be naively overlooked. 

 

The B+ supply wiring for example doesn't route the CT and diode common cathode wires together and with the smallest loop over to the first main filter cap.  It can be easy for capacitor charging current pulses to couple over to nearby wiring when the loop is allowed to be that open. 

 

The ground of the main filter cap also doesn't go to a star point, but rather meanders over to the output stage 0V circuitry and then to preamp stages, where the ground currents again aren't separated.

 

And there doesn't appear to be any over-current protection added, or at least valve diode anode protection, to reduce the risk that a poor U52 will take out the power transformer as collateral damage at some time.

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2 minutes ago, stereonut said:

If you went onto the Audio Note (Australia) site, you should be able to contact Bryan/Guru. 

SN

Must be just about done Pete?

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5 minutes ago, trobbins said:

It's strange that part upgrades are deemed acceptable, but improvement of the kit wiring layout appears to be naively overlooked. 

 

The B+ supply wiring for example doesn't route the CT and diode common cathode wires together and with the smallest loop over to the first main filter cap.  It can be easy for capacitor charging current pulses to couple over to nearby wiring when the loop is allowed to be that open. 

 

The ground of the main filter cap also doesn't go to a star point, but rather meanders over to the output stage 0V circuitry and then to preamp stages, where the ground currents again aren't separated.

 

And there doesn't appear to be any over-current protection added, or at least valve diode anode protection, to reduce the risk that a poor U52 will take out the power transformer as collateral damage at some time.

Seriously, why would you poo poo someone’s build share?

 

Guru absolutely knows what he is doing.

 

This site can suck at times...

 

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2 minutes ago, Mendes said:

Must be just about done Pete?

Hi Steve, it’s run in and run through time at Bryan’s end. I know he won’t let go of it until he’s ready.

I’m still enjoying my ‘standard’ version - having fun rolling some 6SN7’s. Just dropped in some old Russian 6H8Cs in place of RCA VT-231 6SN7. Amazed at how smooth and open they are. 

 

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26 minutes ago, Mendes said:

Seriously, why would you poo poo someone’s build share?

Why would you consider it that way?  Lot's of reasons floating around to upgrade parts and wiring, and you obviously talked them through with Guru.  Without a technical background I'm sure many kit owners are naive on aspects of layout, so its easy to appreciate you may not have brought that up in any upgrade conversations with Guru.

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19 minutes ago, trobbins said:

Why would you consider it that way?  Lot's of reasons floating around to upgrade parts and wiring, and you obviously talked them through with Guru.  Without a technical background I'm sure many kit owners are naive on aspects of layout, so its easy to appreciate you may not have brought that up in any upgrade conversations with Guru.

It’s not my build...:thumb:

 

I was just enjoying the thread.....

 

 

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Interesting comments nevertheless, i have built only one and did not think much about cabling layout and grounding. I actually got few chocked and had ground problems in the past.

I am not in a position to comment on the design but i first heard about this amp 25 years ago and could not resist to build one for myself. I think if i could make it work, with my very poor skills, then to me it is proof that it is a good enough design.

And i have been enjoying it for 6 years now and it sings perfectly well with my system. I now use it only between 500 and 7000 Hz with 2 McChanson for the bass and twitter and they match pretty well.

So I am keen to upgrade some components like the caps and maybe to revise the internal wiring.

But i guess what matter the most and we all fell in love with are the Tamura irons :)

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Kits are great, and the level of care and attention to renovate the amp using updated parts and wiring is a joy to see.   Kits have been a mainstay of valve amps in decades past - the Williamson had kit sales of tens of thousands in the 1950's, and restoration threads keep popping up on a variety of forums.  It just looked strange to see the original kit wiring plan still being followed pedantically nowadays, and no added protection parts given the expense and quality of the iron. 

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This is a very (very) overdue update on my SUN 2A3 project.

 

There wasn't exactly a delay, but Bryan (Guru) wanted to get another pair of qualified eyes to run over his work before he wound up the power. As he explained it to me: “I can upgrade any Audio Note equipment with my eyes closed, but this one was new to me”.And knowing how careful he is with his work, I was fine with the that. 

 

Received the ‘box’ from Bryan on Wednesday 27 March. It was packed well enough for a moon landing, so by the time I’d got through the black plastic outer, the double boxing and the polystyrene I was drooling. 

 

Bryan had suggested using the stock tubes – Tung-sol 6SN7’s, Psvane 2A3B’s and Westinghouse 5U4G for the burn in (about 70 hours) before dropping in my favourites. Not an easy ask! Anyway, managing so far.  

 

I’ve had it running about 25 hours (45 to go) and each day it’s been opening up a little more. Definitely too early to say too much, but from day one I could feel the potential. And today (3rdday,) it’s really come alive and the 2A3 character is starting to blossom. It's now close to my original Japanese kit made version. So from here it’s going to be the Audio Note upgrades that will start to shine. 

 

I should have a better handle on things within a week and will endeavour to post an update with pics for next weekend.      

 

(the pics show RCA 6SN7's - proves I couldn't hold back on all the stock tubes!)IMG_6373.thumb.jpg.23884c25c3c9cc747839131401b610b3.jpgIMG_6380.thumb.jpg.2ca87da99cdfc7dbb67779a5a0d74a03.jpgIMG_6381.thumb.jpg.efc25110b907db39b3c049cc8c418256.jpg

Edited by stereonut

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Exciting times Pete.....:thumb:

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Guru has put in some meticulous workmanship! Really nice work.  Certainly a superb looking piece of equipment and I’m sure is a delight to listen to with the right speakers.

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1 hour ago, Mendes said:

Exciting times Pete.....:thumb:

And enjoying every moment Steve:)

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55 minutes ago, Buffle said:

Guru has put in some meticulous workmanship! Really nice work.  Certainly a superb looking piece of equipment and I’m sure is a delight to listen to with the right speakers.

Absolutely. Fortunate enough to be running with ANE Sp HE's

IMG_6388.jpg

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Really nice looking amplifier Pete.

Edited by Smp

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16 minutes ago, Smp said:

Really nice looking amplifier Pete.

Thanks Richard. 

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2 hours ago, stereonut said:

Absolutely. Fortunate enough to be running with ANE Sp HE's

IMG_6388.jpg

I was wondering what speakers. All suitably cornered up, good times.

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At last an update of my new SUN SV2A3 – Guru built with Audio Note innards.

 

Brief background: I’m comparing this to my original 10-year-old SUN SV2A3 – a 100v Japanese assembled version - running through a step-down transformer. Same tubes and supporting cast of ANE HE speakers, Garrard 401, Thomas Schick Arm, Shindo SPU and Shindo Partager pre, Antipodes DV plus other peripherals.  

 

Firstly, I have to say how amazing the basic SUN SV 2A3 is. In the first week of my new amp it was apparent that it had a way to go to better the Japanese kit level, but Bryan had predicated at least 70 hours of turmoil and frustration as the Audio Note caps, resistors and wiring bedded down – and he was dead right. It was almost hair ripping stuff, but hair-wise I was in a safe space!

 

More-or-less on the dot of 70 hours things started to happen. I could hear more texture and depth coming through. Overlaying (or maybe underlaying) the 2A3’s liner characteristic was a subtle mid-range which I hadn’t experienced in my older amp. Not quite up to a 300B mid range, but certainly more than I’d heard before – and I know there’s still a way to go as things settling in. Generally I’m hearing more air, separation and decay. Base is extended, but not exaggerated. And best of all for me, I’m getting more detail at lower volume.  

 

I have found this amp more sensitive to tube and cable changes and am still to settle on these. 

 

Overall, I am blown away by what the Audio Note upgrades have achieved and am already wondering what a few upgrades and tweaks to my old kit version could achieve.  

 

Pics show the completed amp and my old one as a comparison 

IMG_6405.jpg

IMG_5143.thumb.jpg.3ee881700ec5172b7a0b57be4c86df31.jpg

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Really great job @stereonut.......:thumb::thumb::thumb::thumb::thumb:

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Indeed, beautiful workmanship! Honorable. 

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Hi @stereonut - I built a Sun SV-2A3 around 10 years ago.

It's a nice amp, surprising good,  compared with many SET designs.

Seemingly conventional topology but I think the direct-coupled input-driver stage is key.

Also of course the Tamura output iron.

https://darklanternforowen.wordpress.com/2017/12/31/sun-audio-sv-2a3-amplifier/

Enjoy!

 

IMG_2717.JPG.61a42a6111e156194c9c5a8a87ff8189.JPG

 

PS Not sure what is the heat dissipation rating of the monoplate Psvane 2A3Bs, but the original cct was designed for Sovtek 2A3s, which are known to tolerate higher plate watts than the 'standard' 2A3.

 

Cheers, Owen

Dark Lantern blog - http://darklanternforowen.wordpress.com/

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Hi Owen, yep the TAMURA transformers are the key to these great little amps.

I’ve run quite a few valve amps over the past 50 or so years and have say these SV 2A3s just seem to draw you in. Very intimate and involving. 

Then, the AUDIO NOTE upgrades move it up a level and they become very sensitive to valve and cable changes, which I guess says not much else gets in the way. 

Pete

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