Sony vFET Amplifier Part 2

[Soundhappy]

It is possible to become datasheets (PDF) for 2SJ28 and 2SK82?

Regards,
Jean-Paul

Yes AES Papa great pdf you can download from this post :

http://www.diyaudio.com/forums/pass...2sk82-e-rank-2sj28-f-rank-13.html#post3859010

Early days transistors was sell in packaging boxes similar to vacuum tubes
Oh old good days nostalgy let's go see what bring us the future
Kind regards 🙂

 

[jps1964]

merci!

salutations vers Montpellier ou je pense vous avez un temps superbe?!

 

[R-K Rønningstad]

RCA logo

Yes AES Papa great pdf you can download from this post :

http://www.diyaudio.com/forums/pass...2sk82-e-rank-2sj28-f-rank-13.html#post3859010

Early days transistors was sell in packaging boxes similar to vacuum tubes
Oh old good days nostalgy let's go see what bring us the future
Kind regards 🙂

Don't you love that old RCA logo?

 

[Soundhappy]

Don't you love that old RCA logo?

Haha imagine we can buy at 2015 such transistors from Mouser
Excellent vintage

merci!
salutations vers Montpellier ou je pense vous avez un temps superbe?!

Oui Jean Paul le temps agréable Vielen Danke !
Autumn begins slowly now so is perfect for soldering works

 

[Lbud4]

i read some member reported that eternal hong store sell relabelled item

m.aliexpress.com/item/1443280472.html?tracelog=storedetail2mobilesitedetail

but any of member here who bought from taobao store?
m.intl.taobao.com/detail/detail.html?spm=a1z5f.7632060.0.0&id=40300679359

i'm still waiting 4pairs of them that was send thru sea shipping, dont know when it will arrive. hopefully they are real, just realise that i only paid ¥200/pair, a lot cheaper that acronman sold for $40/pair

hopefully the letter on taobao picture means "100% original, return if they are fake" 😀

otherwise, i think that i have to refresh diyaudiostore every hour to get papa vfets before it's too late

I don't know about the taobao parts but I can tell you that the Hong parts are most likely 2sk60s. I had a lot of twelve of them. I measured them on a curve tracer and they all exhibit gm (transconductance) ~250ms. From what I have read 2sk82s have gm of ~500ms. The parts I measured are fairly distributed with volts difference for Vgs to a give Id (i.e. 500ma, 1amp, etc.).

My guess is that all Hong parts are "fakes" or 2sk60s.

 

[WalterW]

Correct 🙂

 

[gadut]

just received my package from taobao, it was sent on 10Jul and amazingly it arrived on my desk, no customs fee eventhough invoice value is $130 (my coutry limit is $50 for free), maybe because of the ugly box 😀

anyway, i recon that there were previous post saying that JA-33 is the earlier batch, hopefully what i receive is original one, since i dont have any curve tracer to confirm.

i'll be waiting for papa vfet and pcb, i have already got irfp to3 from teabag. i'll keep this JA-33 as spare parts in the future

 

[WalterW]

Those look authentic, printing at the top.
What's the link to the shop?

 

[gadut]

????

Note that not every country can shop with TB, and many TB sellers cannot communicate with English (not sure about this one). I bought some Yamaha 2SK76/SJ26 from this shop before, and as far as I can tell they are authentic.

Hi Walter, i bought them from this store but the seller does not use english and the price already increase 50%

tonight when i get home, i'll get a close picture side by side with KD-33

 

[jps1964]

... is a PCB available?

 

[gadut]

when i flip those 2 vfet, tadaaa the G and S position is opposite to KD-33. is this possible?

 

[jps1964]

... the availability is virtualy given!

should I start with a PCB?

 

[Abraxas336]

Why? Tea-Bag will have a PCB soon and NP himself will provide a PCB to the DIYAudio shop.

 

[WalterW]

when i flip those 2 vfet, tadaaa the G and S position is opposite to KD-33. is this possible?

That's not a good sign.... my fakes (relabeled 2SK60's) had that same feature...
You have to measure them to tell if they are real or not...

 

[plasnu]

Yes it can.
Yesterday I tested two paralleled 2SK60s, they have exactly the same curves as one 2SK82.
But as Zen Mod already said, since they are used here as followers, and at only 10 Watt ( 19V x 0.5A) per device, it can be a direct substitute.

The final amp will sound different using 2x2sk60 instead of 1x2sk82?

 

[Zen Mod]

with some care , hardly

 

[jps1964]

... do you have a preference for the transistors Q13 and Q12?

work on progress... finishing before Tea-Bag?

 

[grimberg]

How do you envision attaching the VFETs and MOSFETs to a heat sink? Can you show us a sketch of it?

 

[jps1964]

PCB equipped with heatsink alu plate (or copper or...).

Mounting PCB verticaly to heatsink (faston for power input on bottom; faston for IN on top; faston for OUT in the middle) and screw it!

I need urgently the values for Q13 and Q14 so I can finish the PCB and start with the mechanic...

 

[jps1964]

I need also an idea for test point for the service measurements...

What should I use?