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Old 26th March 2010, 04:53 AM   #71
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2n2222A is a great transistor, it's counterpart the 2N2907A form the driver for my class D amp. nothing else I was able to find handled the switching loads as well. I did not know it was such low noise as well as > 600Ma Ic.
I am using a 2N5210 in the input stage of my preamp.
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Old 26th March 2010, 02:35 PM   #72
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Here's the old Ace circuit:
Click the image to open in full size.

I changed my output cap to 10uF/50V, the 6.8K to 12K and the 12K to 10K, probably for the zero distortion mod. Their addendum listed a couple of other changes as well.

CH
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Old 27th March 2010, 10:33 PM   #73
Ivey is offline Ivey  United States
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Default Times are hard, and we can not punish those responsible

To all my friends and fellow members:

Words are our defense, a weapon to hurt those, that we can not kill. We strike out because of fear, pain, and because we can not handle the truth.

We all suffer from some form of social ill, be it lost love, loneliness, being poor, or ignored. But we are all one race. Human. There is no other race. There are many creeds, but only one race. And we must live together or perish. And that in its self is a challenge.

We find a common togetherness in electronics, audio, and other likes and dislikes. And thou we grow old. We will always be children in our behavior. Because it is our avenue to escape.

Those who argue and fight or even disagree, are healthy in their minds. Give them what they need, the space to express themselves. Because some persons, can not express themselves without anger.

We must and will find common ground. Be it sand or Stone

Yes, the 2N2222A rules!!!!!!!!!!!!!!!!!!! You can pull it and place in thousands of circuits and it will work. If you are out in space and you need a npn, you know the 2N2222A will save you.

It is very low noise, excellent hfe and excellent current handling. You can place a heat sink on top and it will handle 800ma.

With the 2N2907A, the 2N2222A is kickass, for push-pull output drivers up to 450ma. I use it to design vertical amps for oscilloscopes, using 2N3906 and 2N3904 as input amps.

And at a pennie copy it is a great buy.

Take Care


Ivey
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Old 24th November 2010, 03:19 PM   #74
Ivey is offline Ivey  United States
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Default Do not forget Ivey.

I miss the challenge of speaking with all of you. I try to get well, but it is a slow and a long process.

I am tried of taking medicines, pills, shots, tubes up my butt and so forth. My parents would love to see me like this, it's pay back for when they were growing old. I should have been a better son, and spent more time listening, and less time talking. I miss them more today than yesterday.

I grew up with the 2N2222A. It was my passion, my go to friend when I needed to design a circuit quickly and cleanly. With the 2N2907, not the 2N2907A. I found it unstoppable. The clean wave forms, the thousands of circuits, chopper, switches, audio amplifiers, and rf amplifiers.

I became addicted to the 2N2222A and 2N2907. Any US military servicemen, who served between 1959 to 1977. Came across countless 2N2222A circuits and equipment designed by me and my fellow workers.

There have been many good transistors, like the 2N2222A's close cousin the 2N4401. But still the 2N2222A out performs it.

I told all of you members months earlier that I would post a PCB layout of the 2N2222A phono preamp. Well here it is.

I talked my nephew into building this circuit with PN2222A and 2N4401. He stated it was better and cheaper than the one he built using OP27 and LM833. OP27 cost $3.29 each and the LM833 was $1.69 each. The PN2222A cost 100 @ $00.04. And it used a single supply.

The 2N2222A, have a max. noise factor of 3.7db. The PN2222A has a max noise factor of 4db. It's hfe is 100 to 350 @ 1ma/10volts. Most BC transistors do not do that good. Most of them range from 2 to 10db. The 2N2222A does everything without going over 4db. That includes switching, chopping, and amplification.

Ok, here is the PCB layout. I am online this long because my wife and family is out shopping for tomorrows holiday. And my grandson is being nice to his grandfather. He better if he wants his name in my Will.

Take Care


Ivey
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File Type: zip PCB EXPRESS FILES.zip (11.8 KB, 134 views)
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Old 25th November 2010, 04:24 AM   #75
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I found the 2N2907A and 2N2222A / 4401
are both spectacular performers in my Class D amp @ 1.25 Mhz
both are used to drive IRFB4212s
3904/3906 have the speed they just lack the current and hfe.

I also found the 2N2222A performs very well as a x30 flat phono
input stage then fed into LF353 RIAA op amp.
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Old 28th November 2010, 07:56 PM   #76
Ivey is offline Ivey  United States
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Default 2N2222A Rules

I have used hundreds of different transistors. But I have always returned to the 2N2222A.

You can pair it with the 2N3819 and build a wonderful sounding gain block. Its low noise factor of 4db ensures you that you will have a silent circuit. Its switch speed is outstanding. Even it outperforms the BC107, which has bad current handling. Plus its noise factor is better than the BC107.

I design and built MC Phono gain blocks using it. That's 5 2N2222A and 5 2N2907 transistors. Which sounds a great deal better than Hitachi's 2SC458 and 2SA1029 combination. That people during the 1970's were crying about.

It is 2010, where is the 2SC458 today. Oh yes, it is no longer made. The 2N2222A is still being produced. Enough said.

Take Care

Ivey
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Old 29th November 2010, 06:19 PM   #77
Salas is online now Salas  Greece
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A forest.
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Old 29th November 2010, 10:42 PM   #78
Ivey is offline Ivey  United States
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OH MAN...., what a forest.

Do you have all of those. And if you do, what types of circuits do you use them in.

I have the Sprague's Transistor manufacture's data and process/production manuals, that details the making of all the transistor types that they produced.

Many people have no idea that Sprague made semiconductors. But they did, and they did a fine job, up until 1989.

Data points to the hfe gain of those transistors. Hold on and I will send my grandson to my shop to get volume for me.

Ok, got it. This volume is heavy, its about 3 kilos. Its states that the Sprague's part number is THC4401 for the 2N4401, using the DCA process of wafer design.

It hfe gain is 150min. @100ua @1v and 50 to 600 @ 1v @ 10ma. Noise factor is 3db max @ 1v/1.ma/1khz.

That is a damn good for a 4 cent transistor.

The 2N4403, uses the DDA process and has lower ratings. But not by much. Wafer size is .0019 X .0019 micros.

I over saw the making of special military transistors at SGS-ATES, in 1969 and 1970. I could not believe how far we came in the making of transistors in just 18 years. From a mere 20ma to 30 amp handling abilities.

SGS made the "Pro Electron Devices as well. The BC, BF, BX, line of transistors. They were really a sight to see.

When I left to return to California, they gave me 100,000 transistors, of 27 values. All the ones that I listed as my favorite transistors.

I will have grandson take some pictures of all the stuff I have in my shop. I only buy mosfets now. I have loads of fets. MPF102, 2N3819, 2N5457 and 58's, plus J112 and J175.

My favorite transistors are 2N2222A, 2N4401-3, 2N3904-6, MPSAS06-56, MPS8099/8599, and 2N5401/2N5551. But I have thousands that I do not use. Like MPS18's, 2N5210, PN2484, 2N4410, 2N6517-20 and the list goes on.

I also have thousands of Dale resistors, precisions, metal film, carbon film. Which I obtained from Dale when the closed they San Diego branch. The manager a friend of mine drop them off at my home in his pickup truck. The company did not want to ship them back to their company. So instead of the city dump, he gave them to me.

And not only that, in 1986, when WestCap close out their White Box radial capacitor line, I purchase their #2 pallet lot for a seal bid of $35.00 dollars. Now that was a problem. I had to rent a U-Haul truck to pick it up. The truck rental cost more than the caps.

What got me really upset, is that I missed the close out sale at WestCap. I could not believe I had let that one get away.

Ok, got to go wife is saying I have to rest and take my meds.

Take Care

Ivey
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Old 30th November 2010, 05:14 AM   #79
Salas is online now Salas  Greece
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Quote:
Originally Posted by Ivey View Post
OH MAN...., what a forest.

Do you have all of those. And if you do, what types of circuits do you use them in.
Got them for general purpose low noise enough use because its a competent classic BJT for almost no money. Got its 2N4403 PNP brother too. I have in mind to remake a classic British 70's BJT MC stage just for the sake of it, because I had made the MM version one when I was a teenager and gifted it away later on, so I remembered it and want to re evaluate, but with many crucial changes I thought of. I think that those transistors will show the trend in its head amp and I will not have to spare my few 2SC2545E on such fun tests, which would be overkill. Don't know if it will need changes in practice, but this is the theme I have in mind.
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Old 30th November 2010, 05:27 AM   #80
alexf is offline alexf  United States
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Ivey,

don't get me wrong - I love the good old 2N2222 and use them all the time mostly in the switching capacity as I mostly do digital design.
However there appear to be a range of transistors that are very good for audio work. For example the BC550. High VCE and low noise. (2.5 dB with 2K source). If you don't like high gain, don't use the "C" part
And the BC109 was used in a lot of low level audio circuits like the tape pre-amps where the noise really counts. Sure it has a low VCE (20V) but for the input stage it shouldn't be a problem. I didn't simulate your circuit but it looks like the collector of Q2 should be at about 10V DC.
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