You will have builders soldering in LM317 and LM337 only to discover the pinout is right but the other parts are not implemented.
It will affect the signal to noise ratio. But hearing sensitivity is different so some people may be did not notice the noise.
You can order them at JLCpcb . To get a quote you must drop/upload the gerberfiles at their site.
When you can wait a week, there will be a update when i am back from vacation.
When you can wait a week, there will be a update when i am back from vacation.
Using Opamp @ input is not a good idea because jfet-input 627\134 has approx 5 nV/√Hz or more input noise voltage density and 5534 has bipolar input with too much noise current (for MM cartridge inductance up to 1 H). Much better for phono input is LSK389 or JFE2140 dual jfets (with less than 1 nV/√Hz).
What do you mean by too much noise? If I can't hear it it doesn't exist! Vinyl surface noise is exceeding ne5534 total input noise by 5 db... Actually there are far too many jfet preamps that sound worse than cheap bipolar preamps...and there's an explanation for it!
The noise spectrum of a mute vinyl groove and the noise spectrum of a phono stage are very different. The record makes noise in the lower part of the spectrum and clicks a little (both of them are decreased by IEC/ITU weghting noise filters), and the phono stage "hisses" in the high frequency.
It is fine if you do not hear the noise and satisfied. But if you will gain the power ...
I know there are much better phono stages. My goal was to build a stage were you can roll opamps and tubes. So you can finetune the sound you prefer. For me it is all about the sound and less important are the specs. Taking about specs, below my range in importancy.
- No humm
- No notacible distorsion
- No phase shift
- No hiss
- Straight frequency respons
- Good channel separation
Yes but the SNR of signal reproduced from vinyl also goes up with frequency too...you can't hear the phono preamp noise once the music kicks in.My everlasting argument is that SNR doesn't matter in typical phono circuits unless you live in Africa or the North Pole and you aren't able to find any low noise transistor...
Nice article! If we will keep in mind IEC-A or ITU-R weighting, LP will have even more advantage of dynamic range over CD. And my "aperiodic HF correction" scheme [ https://www.diyaudio.com/community/...ge-85-dba-sn-ratio.387375/page-5#post-7085462 ] is ideally suited for LP exteneded HF over 20 kHz.
Updated schematic, PCB and gerberfiles with,
- Tekst at pins.
- Extra parts for LM317/337.
- Muting startup delay.
- Ground reference resistor at output.
- Heaters in serie.
- Mounting holes.
Like the concept, thanks for sharing, I had thought of doing something like this ,and since I have most of the stuff I'm interested to build it. The final Gerber is already tested?
Yes, it is:
If you refering to the hybrid phono amp, the gerber is not tested yet.
But changes were minor. Just added start-up delay and different regulator options.