JFET-only Circlotrons without negative feedback

[jwjarch]

One toroid can be used. 250 W is enough. I used a non-working German amplifier in my prototype.
And I had to insert another small toroid to power the stabilizer, because I was too lazy to wind up the necessary windings on the large toroid.
It turned out ugly, but this is the first prototype. Now that the circuit is fully debugged, you can build everything from scratch as it should.
2sk209 Are they SOT-23? Or is there in TO-92?

I’ll have to give a little more thought on the toroids and what voltages to start with.

The 2sk209’s are SOT-23. EUVL, in this thread, developed a mini-PCL that carries 4 devices to mimic 2sk389 or 2sk170. UDNeSS, or You don't need Semisouth's

 

[jpatay]

Transistors still need to measure Idss (Vgs = 0, Vds = 12 V).
And select Idss, as written in the circuit. T3, T4 and T5, T6 must be matched. The more accurate the better.

 

[jwjarch]

Yes, jpatay, I'm planning on matching a whole bunch of 2sk209-GR and BL at the same time to have enough for a few different amp projects. Thanks for those diagrams. Very clear and handy to have.

 

[jpatay]

Transistors with a large current Idss (for example - J111) will heat up during measurement and the current will decrease. I measure very quickly, or then I need to attach a radiator to them.

 

[jpatay]

Jfet measurement information:
JFET matching information – diyAudio Store

 

[pras1170]

Functions in good condition 2SK1058 2SJ162 old used PCB
I can remove the circuit board and leave the transistor

 

[pras1170]

OLD USED 2SK1530 2SJ201 TOSHIBA pair
There is a surplus quantity of 2SK1530 which can be sold separately
Ordinary measurement method, can test the function is normal, will not affect the second use
1pair USD:22.2
Shipping is determined by your country and then the price is calculated

Functions in good condition 2SK1530 2SJ201 old used PCB
I can remove the circuit board and leave the transistor

Ordinary measurement method, can test the function is normal, will not affect the second use

my email is：378632242@qq.com
Email contact, will be convenient, fast, thank you

 

[pras1170]

There are 2SJ77 2SK214 old used 40pair in stock
Friends in need can be contacted
2SJ77 2SK214 and 6 new pairs
And there are 200 2SJ (2SJ alone) 76-79, you can contact friends in need

 

[mbrennwa]

OLD USED 2SK1530 2SJ201 TOSHIBA pair

PM sent!

 

[pras1170]

2SK1530 2SJ201 TOSHIBA

Yes it is true

We email, I can send photos

The function has been tested and will not affect the second use

 

[pras1170]

sell 2SK1530 2SJ201 2SK1058 2SJ162

 

[pras1170]

The pins of 2SJ201/2SK1530 are GDS, and 2SJ162/2SK1058 are GSD

 

[mbrennwa]

Yes it is true



We email, I can send photos



The function has been tested and will not affect the second use

I tried your email, no response. Please post your test results here (curve traces etc). I am interested in 8 pairs. You can also respond by personal message (PM) here at diyAudio.

 

[pras1170]

Yes it is true
We email, I can send photos
my email :378632242@qq.com

Toshiba 2sk1530 / 2sj201 is a simple measurement without curve test
I take down the PCB and do the normal measurement
Can be tested, use a universal meter to measure, the function is normal

 

[UltimateX86]

I conducted such an experiment. I used the N-channel jfet in the differential input, and the P-channel in the driver. The transistors were used in SOT-23 (MMBFJxxx) packages.

As a result, the MOSFET received an amplitude of ~ 14 V at the gates (5 Volts more than in the first circuit).
The transistor current is indicated in brackets:
Idss Zero-Gate Voltage Drain Current. For example: J202 - 2 mA.

hi,

do you know other Pchan equivalent idss of J113 J112 J111 ?

the J271 is very expensive and difficult to find

thanks

 

[jpatay]

Hi Sébastien!!! I have already ordered the J174 and 2SK2145GR. I will assemble the layout soon. J174 - Idss: 50-60 mA.

2SK2145GR has more Yfs than 2SJ103GR. And there is no need to compare T3,4 and T5,6.

 

[mbrennwa]

Yes it is true
We email, I can send photos
my email :378632242@qq.com

Why do you keep saying that, but then you don't reply to my requests of showing the test data? Is this just another scam with fake parts?

 

[pras1170]

Is this a scam?

I have sent a message to reply to you
I have told you that I am a general measurement method, not a curve test

Because in the forum, China Network does not support uploading pictures directly, they need to have a picture address before they can upload

But I didn’t make a picture URL. I can send photos directly in the mailbox
If you need me to upload the measured picture, you need to wait for me to upload it to the AliExpress website, and then you can copy it in the forum

 

[jpatay]

I found it in a non-working switching power supply unit 2SK1518 Hitachi. We'll have to see how they sound.
J174 we bought here:
https://aliexpress.ru/item/32608407872.html

 

[Yurik_V]

The dependence of the THD on the quiescent current. 1W/8R
Output transistors uj3n065080k3s.