Earlier I asked about the adequacy of Mouser. We discussed the STN9360. Today I took the MPSA06 out of the package. I measured the hFE and again was surprised by hfe= 438. According to the datasheet hfe= 100. I had three PZTA06's and they show hfe=207. I will have to use c2240, they show hfe=241. I am shocked at hfe=438.....

Edited July 21, 2025Jul 21 by micon21

I have well over 100 MPSA06 (don't ask). I've just measured a random sample of a dozen or so. Many are loose, and many are on bandoliers. Measured on a Peak DCA75, all the ones I measured were in the range 135-180 at 5mA Ic.

438 seems high.

But Mouser is a five-star excellent supplier - I've used them for years. Although the hFE seems high, it might be an outlier. How did you test it?

Well it really does depend on what you test. I've just run some of my stock of C2240's and they are all high. The one I've just put on the Peak is 453.

Sa am I surprised at 438? Well not in the least given the above C2240! 

53 minutes ago, Craig Sawyers said:

I have well over 100 MPSA06 (don't ask). I've just measured a random sample of a dozen or so. Many are loose, and many are on bandoliers. Measured on a Peak DCA75, all the ones I measured were in the range 135-180 at 5mA Ic.

438 seems high.

But Mouser is a five-star excellent supplier - I've used them for years. Although the hFE seems high, it might be an outlier. How did you test it?

 

16 часов назад Крейг Сойерс сказал:

Ну, это действительно зависит от того, что именно вы тестируете. Я только что прогнал несколько своих C2240, и все они показали высокий уровень. Тот, который я только что поставил на Peak, — 453.

Разве я не удивлён 438? Ничуть, учитывая вышеприведённый C2240! 

let's compare our devices when measuring 3675. I assume you have it.

Edited July 22, 2025Jul 22 by micon21
надо

That is about right for a C3675. You seem to be jumping around with what you measure. MPSA06, C2240, C3675. I've lost track of what points you are making.

I warn you in advance. I am not happy with the purchase from Mouser. I bought several parts from 
digikey - 9360, 004, 06, 56. They will arrive around August 11. I am  very interested in what I will see on the 9350 case, and what the device will show - in hFE mode.

Please be careful with words. I do believe Mouser is a reliable company.

Yup. Totally agree JoaMat. I've placed orders with Mouser for decades with zero problems.

If Mouser keep an eye on forums, or as a lurking member,  Micron21 could end up in hot water.

I used to be list admin for a Jaguar forum with 10,000 international members. And occasionally a list member would openly criticize a supplier. But all the major Jaguar parts and service outlets lurked as members on the list. So threats of legal action for defamation were regular, including to the list owner (me). I quit as admin because the stress of being potential sued was too much.

I showed you a photo of the transistors and the gain of the transistors that arrived. 
I am NOT happy with the big difference in measurements between the datasheet and what I see from the transistors from Mouser. I spent extra money for comparison. I made a test purchase from Digi. I will write the results.

Edited August 4, 2025Aug 4 by micon21

to achieve additional truth, I bought a device that was recommended to me on our forum - DUOYI DY294. I am waiting for the arrival of both DigiKey and Ali

A small factual statement.

I saw in the thread that forum members are also using inexpensive EL34 models, like the Tung-Sol. There are photos of German RFTs and Russian Mullards. I currently own all of the listed quartets. When listening, I noticed that the Mullards (2015) sound significantly better. 

 

 

 

 

 

Edited November 21, 2025Nov 21 by micon21

9 minutes ago, micon21 said:

I saw in the T2 thread that forum members are also using inexpensive EL34 models, like the Tung-Sol. There are photos of German RFTs and Russian Mullards. I currently own all of the listed quartets. When listening, I noticed that the Mullards sound significantly better.
 

It has been a while since I bought them, but the Russian Mullards worked very nicely in the T2, to the point where the benefits of pricier NOS tubes were marginal.

Is it possible to use E88CC instead of ECC88 in this T2? They have similar ratings but also some differences.

18 minutes ago, mdr30 said:

Is it possible to use E88CC instead of ECC88 in this T2? They have similar ratings but also some differences.

yes ecc88, e88cc and 6922 can all be used. I believe the e88cc is similar to a 6922 - which is what I have been using in the T2 for years.

Edited December 1, 2025Dec 1 by jamesmking

Some if not all 6dj8/ecc88 datasheet has spec'ed max plate voltage at 130V, which the top tubes operate right around that range, I'd think e88cc/6922 is actually safer bet.

Great. My build is proceeding slowly but well under the safe supervision of MLA. Four Mullard E88CC lie waiting in the box.

T2 build coming along, everything under control.

Problem: connectors ITT/Cannon KPT06F 12-8S missing locking nuts Anyone know where they can be obtained?

It’s 2026 and FJPF2145 (and 2SC3675 in some builds) have been discontinued for quite a while.

 

So far I’ve come up with a few candidates:

KSC5026

BUL216 (I remember this being mentioned before)

FJP5027

My main concern is output capacitance. I’ve seen comments that BUL216 has relatively high capacitance, and the other candidates seem in the same ballpark. Their Ic ratings are ~1.5A to 4A, and gain (hFE) looks acceptable. But I’m worried about any impact on stability.

Has anyone actually tried one of those (or any other modern parts) as substitutes for FJPF2145 / 2SC3675?

 

Datasheet attached:

https://www.onsemi.com/pdf/datasheet/ksc5026m-d.pdf

https://www.onsemi.com/pdf/datasheet/fjp5027-d.pdf

https://www.st.com/content/ccc/resource/technical/document/datasheet/group1/01/eb/74/95/d4/55/44/6c/CD00000009/files/CD00000009.pdf/jcr:content/translations/en.CD00000009.pdf

 

Haven't tried any of them in practice. I dodged the issue by buying 200 FJPF2145 instead when they were going out of production. Still have about 180 left  so ping me if there's a need...

Edited January 30Jan 30 by MLA

I managed to build few T2 in the past few years. Just sharing pics how T2 fits in Modushop Dissipante 400 enclosure. Many thanks to Mr. Gilmore and HC community

Edited February 3Feb 3 by Helium

Thanks to @MLA for sending me a few FJPF2145s.

To avoid turning them into smoke immediately, I’m currently still in the simulation phase. So far, the battery section appears to behave properly, at least in theory🙃

I’ll also try simulating a few alternative devices to see how they compare. From what I’m seeing so far, a Darlington configuration might actually make more sense in this position.

More updates once I move from theory to reality.

Edited February 22Feb 22 by Shawn

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.

 

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.