2SK79 with B1 buffer

[codyt]

Forgot to attach these

 

[maximax77]

As promised, here's my version of the standard SRPP design often seen with the 2SK79. Not sure who exactly to credit for the design, but rest assured it wasn't my creation 🙂

I have the original article plus follow up, but it’s in Japanese and probably also copyrighted since it was published in a magazine. I once started translating it using deepl.com, the translations made sense but the complicated layout made it quite an undertaking. One day…

Now, if there only was a fully differential circuit using vfets…

 

[codyt]

Yes, that sounds right. I remember thinking the power supply was the clever part of that circuit, though I can say for certain that the shunt measures/sounds better. Either way, it’s a nice all-in-one design

 

[marconi118]

Is there any reliable source of K79 still available?

 

[codyt]

I purchased mine from the Jim’s Audio website. I haven’t curve-traced them, but they look and behave like the real thing.

 

[maximax77]

I purchased mine from the Jim’s Audio website. I haven’t curve-traced them, but they look and behave like the real thing.

Same here.

 

[Vunce]

Great info Cody! Thanks for sharing your files.
I have the same preamp board from Jim’s based on the Japanese article and wanted to experiment with a different psu also. Your boards will make that easier and I can leave JA’s pcb unmolested. 😉

 

[codyt]

Sounds good Vunce! You should have mail any day 🙂

 

[marconi118]

I purchased mine from the Jim’s Audio website. I haven’t curve-traced them, but they look and behave like the real thing.

One matched pair for 95$.... No thanks!

 

[codyt]

And that price seems to go up every month…

 

[marconi118]

Unobtanium I know....

 

[Adams_Leo]

B1-K79

正如其他地方所提到的，我不久前拿起了一个匹配的 2SK79 四边形，并且一直在玩它们。最初，我构建了无处不在的 SRPP 电路，它在 DIY 圈子中经常被引用到 K79。对我来说，这似乎是一个相当简单的 SRPP 实现，听起来很棒（我将在接下来发布这些内容）。我尝试它们的另一个合乎逻辑的地方（阅读：容易/懒惰）是在 B1v1 赛道。

附件是我用 2SK79 而不是 2SK170 实现的 B1。它直接来自 Nelson 的文章，尽管我放弃了所有 PSU 部件，转而使用 Salas UltraBIB。总的来说，我真的很喜欢带有 K79 的 B1 的声音。只是一个很好的 H2 剂量——干净、放松、深度很好，等等……我尝试了许多不同的电源电压，但最终落在了 18-20v 的库存。

关于电路板，我试图容纳我手头的零件，而明显的怪物是“花哨”输出上限的大空间。您还会注意到输出端有一个较小的电解液。这是完全可选的。我用我的来驱动 AVC 的初级，因此需要一个可选的以便宜的方式包含额外的电容。正如您在我发布 SRPP 板时所看到的那样，我想要一些可以轻松更换的东西，因此保持两个板之间的尺寸。

最后，请注意 K79 的引脚排列与 K170 的不同，因此不要假设零件可以互换。你可以让它工作，但它需要一些摸索。我有一个版本的板子可以同时容纳这两个部分（K170/K79）——如果你想要那个，请问。

感谢尼尔森的精彩设计！

*编辑 - 由您决定您需要什么样的输出电容。不要依赖这个示意图。如有疑问，请坚持使用 Nelson 的示意图🙂

what is the power supply voltage? is it same as SRPP 36v?

 

[codyt]

18-20v seemed to be optimal for my parts and build

 

[Adams_Leo]

18-20v seemed to be optimal for my parts and build

thanks Codyt

 

[Adams_Leo]

18-20v seemed to be optimal for my parts and build

One more thing,do you measure the B1 K79 output impedance？is it low enough to driver the Pass SIT 50W power amp?

 

[Zen Mod]

most likely not, if speaking of original presented at BAF
but, you can make it as original original - Singing Bush, which is having high Rin
PtP, piece of cake

 

[codyt]

Unfortunately mine is without a case and PSU moment, so I can’t easily check. I never noticed issues driving any of my amps, though they all have fairly high input impedance.

It does sound terrific with Singing Bush.

 

[Adams_Leo]

thanks both

 

[Zen Mod]

that's rude, leaving it PSUless

 

[rhthatcher]

I just finished a B1 2SK79 build using a PCB from CodyT. I think the blue caps are from ZM. The power supply is 20V using an Artemis single rail regulated PCB.

Output caps are CDE films and parts bin Silmic II’s. Rather pedestrian compared to the fancy ones you see in some previous posts…

I put an Alps pot in, and I plan to swap in a stepped attenuator at some point. It tested out on the bench without smoke and with good sound. Now it’s on real speakers. Sound is quite open and 3D.

Thanks Cody!!!