50 minutes ago, Pars said:

I don't see any marking at all on the center 2 devices, and that is zooming in a bunch. I would find them suspicious. I do know of a user on diyaudio selling genuine at reasonable prices. I bought some 2SJ77/2SK214 from him and will try to post pics of those.

Thanks for your reply, Pars.

The photo angle isn’t ideal. In real, at a certain angle under light, I can barely make out the 2SK216 / 2SJ79 markings, but they are extremely faint. I’ve seen genuine Hitachi versions before and they look quite different. I’m not sure if Renesas production ever looked like this, but I personally haven’t seen any sands with markings this faint.

Below is a comparison. On one side is what I believe to be a normal 2SK216, and next to it is the suspicious 2SJ79. This T2 actually has a mix of both types of markings installed.

Edited April 7Apr 7 by Shawn
Photo updated

Here's a pic of what the guy on diyaudio has. This looks like the one on the bottom of your pic. The only way to know for sure would be to pull them and test them, but I'm not sure how to best do that.

 

Here is a link to the fs thread, and this guy is trustworthy. In Europe, but shipping hasn't been too bad not has delivery time.

Edited April 7Apr 7 by Pars

On 4/5/2026 at 6:10 PM, Shawn said:

I’m currently helping repair a DIY T2, and while inspecting the amplifier section, I came across something a bit suspicious.

The 2SJ79 / 2SK216 devices look like this (see attached photos). The marking on them appears very faint and somewhat unusual: not what I would normally expect from these parts.

This makes me suspect that they might be counterfeit or at least not from a reliable source.

Has anyone here seen this kind of marking before on genuine 2SJ79 / 2SK216?
Any insight would be greatly appreciated.

 

Those look like Renesas parts, which have very faint and hard to see printing. 

On 4/7/2026 at 5:10 AM, Pars said:

Here's a pic of what the guy on diyaudio has. This looks like the one on the bottom of your pic. The only way to know for sure would be to pull them and test them, but I'm not sure how to best do that.

 

Here is a link to the fs thread, and this guy is trustworthy. In Europe, but shipping hasn't been too bad not has delivery time.

Pars  Thanks for the link to RM. I’ve been registered there for a long time, but I didn’t know they were selling the 216. I bought the 216 and 79 on eBay in 2020. I was building a T2 in 2024. But the board didn’t work. Most likely, the 216 and 79 weren’t original. Replacing them with TA004 didn’t help. When RM sends me the old 216 and 79, I’ll try to get this model running again.  Right now, I’m happy with the modified version. The boards are from KGSSHV Carbon, but I replaced the C2M1001700 with EL34 tubes.

Edited June 10Jun 10 by micon21

After about a year of work, I've finally finished redesigning the PCB layout for the original T2. The new layout supports several different active battery implementations, as well as multiple CCS options, making it much more flexible for different builds and future experimentation.

I've also completely redesigned the chassis. Like the original concept, it will still use a two-chassis configuration, with the power supply and amplifier housed separately.

It's been a long project, but it's exciting to finally see it coming together. I'll share more photos and progress updates as the build moves forward.

That, good sir, is a thing of beauty!

Stunning piece of art!

We need to know more about... well everything.

It's looking quite small?

13 hours ago, G600 said:

Stunning piece of art!

We need to know more about... well everything.

It's looking quite small?

Both the power supply and amplifier chassis are approximately 290 mm × 400 mm × 90 mm, so it's actually fairly compact considering it's a full-size T2.

The power supply uses five GRHV regulators and features plug-in bias daughter boards, making it easy to switch between different bias voltages. Right now it supports both Normal Bias and Pro Bias outputs.

The PSU also includes about a 50sec high volt soft start. In addition, there's an AC inrush limiter on the mains input. After roughly one second, a relay bypasses the current-limiting resistor, reducing the inrush current seen by both the filter capacitors and the tube heaters during startup.

On the amplifier side, most of the passive components are SMD, which helped reduce the overall PCB and chassis size.

The amplifier topology stays very close to Kevin's original T2 schematic, but I added support for several different implementation options to make the design more flexible.

It supports three different CCS configurations:10M90, 10M90S + DN2540, and the original T2 complex CCS.

The active battery section is also configurable. It supports: LED string reference, LT1021 reference.

For the 2SK216 and 2SJ79 positions, I added an extra pin so they can be replaced directly with TTC and TTA devices without modifying the PCB.

The overall goal wasn't to redesign the T2, but rather to preserve the original circuit while making it easier to build, maintain, and adapt as some of the original parts become increasingly difficult to source.

The chassis is CNC machined by a local machine shop. One detail I paid particular attention to was the top cover of the amplifier chassis. I designed it so that the EL34 tube sockets sit perfectly flush with the top panel, which I think gives the amplifier a much cleaner appearance. Additional ventilation slots were added in the center section for airflow.

The side heatsinks are sandwiched between the top and bottom panels. This not only gives the chassis a cleaner look and prevents the sharp heatsink fins from being exposed, but also makes it much less likely that you'll scratch your hands when moving the amplifier. To make sure the heatsinks can still dissipate heat efficiently, I also added ventilation openings in the top and bottom panels wherever they cover the heatsinks.

I've also been thinking about turning this project into a group buy, although I'm not sure how much interest in the T2 still exists today. The main motivation would be to reduce the chassis cost, since having a single custom CNC chassis made is quite expensive. If enough people were interested, the machining cost could come down significantly.

Edited 2 hours ago2 hr by Shawn