micon21

you asked how I check transistors. I showed a photo of the measurement 06. I have no complaints about the 2240, with the datasheet declaring hFE 200, the ones I have show hFE 217 and showed what I see when I measure 3675, which you also have. I am sure the difference measuring the of the 3675 transistor, hFE for you and me will not be big.

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

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.....

sorry, I have one 100% original and 2 fakes, many do not know who the original is.

When I was looking for 2SA1968, I also got PNP. I couldn't make a claim to the seller, because according to the Toshiba datasheet, there is such a version too. Model 1968, one for the whole world, n-p-n and p-n-p

I'm not in the mass production business, so I'm not going to BUY expensive devices, meters, analyzers, for basic hFE determination. Over the last ten years, I've built many different versions of electrostat amplifiers. Yes, not all of them worked. Yes, I didn't like all of them. For example, the mini T2 really disappointed me. assembled version called carbon, I am happy for two years. But many music lovers always want something better. I hope that T2 will outplay Carbon.

In the batch that MOUSER sent me, the measurements were made at normal room temperature. One row of transistors had hFE 341, another - 315, the third - 295 and the fourth - 245. Which hFE would you use first?

when I bought in 2023 in Digi c2m1000170, they wrote that it was made in China. Now they don't have this model. I made a purchase on Aliexpress, alas, a fake arrived. I tried to make a purchase from another seller on Ali..., and to my surprise, transistors suitable for use arrived. I have already demonstrated photos of three purchases.

Please don't transfer your hobbies to me. I write only about radio components, that is, on topic. And you discuss about Gucci with women...

Yes, I'm interested to know why the increase is twice as painful, maybe it's better?

sorry. P.S. I wrote my conclusion on 9360 in Mouser. I wonder what the answer will be.

I have a question for those who bought 9360 from Mouser. Is Mouser 100% trustworthy? I bought STN9360, I see big difference between two other units I bought some time ago. 1 photo/ in the first photo with hFE -150 in photo 2, what mouser sent. here brand badge as a fake. hFE -341, and there are 15 of them.

Hello. My experience has shown that it is better to make several transformers to service amplifiers. For option T2, I would like to use four transformers. 2х for heating lamps. third for +250v and -260v. fourth for +500 and -500v. I have a question for experts. What currents should be at the transformer output 50 or 100 mA?, in order to hold the load +500v. The same question for voltage +250v. P.S. Sorry if everything is not clear, I use Google translator.

Sorry, but how does the signal get to pin8. I see that the cathode feeds transistor Q8, no signal comes to Base Q8 through R11.

Alas, I got a good result only after some changes in the board. I found that R32, R33 are detrimental to the signal, I do not understand why they are needed. I increased R43, R44 to 300k, R7, R8 to 470 oms got undistorted sine waves with a large range - 140v. I plugged the headphones, for normal listening it is enough for me on the output and 70v. It is also not clear what improves the section Servo, on one board I did not set the elements for Servo. I looked both on and off, but did not see the essence. Translated with www.DeepL.com/Translator (free version)

I understand and see that the first tube works only as a preamplifier, especially I see a small gain on the 3pin output.

? Maybe I'm wrong, but I understood it this way: the signal goes only to the first lamp 2pin. output from 3pin. through the second lamp 6922 signal does not pass, it has a different purpose, and you can use cheaper brands. EL34 also does not receive a signal, the signal goes through R43, 44

I checked everything yesterday, all resistors, transistors, no fault found, I put a different bulb, it didn't help, and was very upset. i planned to throw the board away and be done with it. but i accidentally discovered that increasing 100k leads to an increase in signal. The result is much more interesting than it was. the sinusoid is beautiful, not crooked. in the evening I will plug in my headphones and listen to how it plays....

Thank you for trying to help me. I got a good undistorted sinusoid, with a large sweep of more than 110v at the output, with an input signal of 1.2v. after adjusting the resistors R43, R44, R7, R8. In the end I replaced 100k with 270k and 100 ohms with 2k. now also on the third leg of the first lamp, I see a nice not crooked sine wave. This change did not change the voltages on all legs of both 6922 lamps.

I understand that it is very important that all resistors match the ratings. I strictly adhered to the specified values. I used one 197 and one 356, as JoaMat recommended

Tester measurements are as follows: lamp one, 1 pin - 74v. 3pin - 2v The second top lamp: 6pin-200v. 7pin- 61v el34, 8 pin - minus 365v

on the first leg of the first lamp, photo 1. on the third leg of photo 2

filed 220, 400, 460, but alas, the result is not happy. !!! fed the input BALANCED signal 0.35v, photo 1. the output received a swing of 82v and 84v, but in terrible condition, photo 2 P.S. I get an undistorted signal with a swing of 20v at the output if I input 0.170v It's not enough for headphones.

life is short, but music is eternal....