2N2222A phono preamp

Below are two graphs, one with 150R for R1, the other one with 75R.
In red you see the FR and in blue the loop gain.
At LF loop gain is already very small. For a voltage feedback amp a figure above 40dB is to be preferred as it is @1Khz and above.
At 20dB loop gain, distortion will most likely increase, but one might be less sensitive to these harmonic frequencies.
When lowering R1 to 75R, gain increase by 6dB but loop gain decreases even another 6 dB !
So I would say, it is possible to lower R1 but the proof is in the eating of the pudding.
When you hear no difference in sound character, be happy with it, if not leave R1 at 150R.
One last remark, in the circuit diagram, I have used 1uF for the input cap C6.
This should definitely be 10uF.

Success,
Hans
 

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What about a bunch (19?) of D cells for a clean dc power supply?

I have a valve phonostage that I love (so much that I sold my Linn Linto on eBay) but this one is intriguing.
I came across an article a while back about the use of battery powered preamps, and studies were shown that it isn't as "pure' as touted.
It seems that batteries have their own little noises going on due to chemical changes.
 
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Trying to repair an old amp woodstock. Have a thread on it where Im talking to myself.
Long story short I replaced one of the 8 transistors on the preamp with a 2N2222 after reading this post.
But for some reason the BC149 that was originally there sounds better. i.e. one channel was working with BC149 and the other I put in the 2n2222 could be I need to use a different package size. Also the BC147B sounds better than the BC547 on the main amplifier board. But I cant find a BEL BC147B in my country.
 
Hello Voskresenie
This is a great coincidence

I already made and tested other board but I removed Zener diode and put one LM317 as voltage regulator.

I forked your project in github, but my desing is a totally different approach:
https://github.com/PedroPMartin/2N2222A_stereo_phono_amplifier

I ordered PCBWay and board is already mounted and testing.
phono-1.jpg
 
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I already made and tested other board but I removed Zener diode and put one LM317 as voltage regulator.
that's a great idea! LM317 can be found from every vendors and more effective then zener diode, so If I make it again later I will choose LM317.
btw I ordered my PCB from JLCPCB, and it is work well. (left one is isolated from tin box by bakelite board)
_MG_2731.JPG
 
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The max noise figure is a useless rating. Because in reality it is infinite; you can get more noise if you just keep pushing the transistor away from it's ideal low noise operating point.
Typical noise figure for the 2N2222 will be around 1.5 - 2db. Which any vaguely low noise transistor will beat.
Here's a more comprehensive datasheet with a noise chart: https://www.rfcafe.com/references/e...21-2n2222-2n5581-npn-transistor-datasheet.pdf
 
The design of a fast switching transistor and a low noise transistor are at odds - switching transistors benefit from gold doping to reduce charge storage time, but those same gold dopant atoms provide a mechanism for 1/f and popcorn noise by being charge traps. Fortunately despite being touted as a general purpose switching transistor the 2N2222 isn't gold doped.
 
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The Art Of Electronics (3rd edition) by Horowitz and Hill contains extensive tables of measured data -- actually measured by the authors themselves and not merely cribbed from manufacturer's datasheets -- of transistor noise. See Table 8.1a (p.501) for BJTs and Table 8.2 (p.516) for JFETs.

The 1970's vintage BJTs used by John Curl in his 1976 moving-coil pre-preamp -- described on their datasheets as General Purpose Amplifier; This device is designed for use as a medium power amplifier and switch requiring collector currents up to 500mA -- performed nicely in the H&H noise comparison. Not the best, but way waaaay better than the worst.
 
There's got to be good reason the 2222 became a classic, all round performer plus low price I guess, but the data sheet specifically mentions switching (presumably due to the good saturation characteristics)

Incidentally gold doping was an enabling factor for the TTL logic family I believe, allowing ~10ns propagation times - eventually Schottky TTL finessed the speed issue by prevent charge storage from happening.
 
The noise spec is right there in the datasheet I linked, there's no mystery about it.
If the less concise datasheets for the 2N2222 you most often find had "10db" instead of "4db" listed in the max noise figure, as it should've. This thread wouldn't exist.

Probably the only common transistor that would have worse noise in a phono preamp would be the 3906 which has quite a bit more current noise.
 
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To facilitate fast switching, you want low base resistance to be able to switch and then remove excess base charge. This also happens to be very good for low noise amplifier design because a major contributor to noise is rbb’ ie base resistance. A good example are the ZTX851/951 which were highly rated by H&H. No doubt the 2N2222 falls into a similar camp.