I slept well, thank you very much.
I put more thought into the BJT INA.
The current sourced caskode did not work so well with BJT´s so i simplified a bit.
They are now fed by a capacitance multiplier and the feedback goes directly from the collectors.
Circuits like that proved to work in designs by Douglas Self and Burkhard Vogel but they used them unbalanced.
Idle current in my design is adjutable for minimum DC offset and optimisation for an MC with higher impedance like the Denons and Clearaudios.
When i use 4 x 4 input transistors and reduce the feedback resistor to 1 Ohm i could get 0.3nV/qHz in a balanced design.
I put more thought into the BJT INA.
The current sourced caskode did not work so well with BJT´s so i simplified a bit.
They are now fed by a capacitance multiplier and the feedback goes directly from the collectors.
Circuits like that proved to work in designs by Douglas Self and Burkhard Vogel but they used them unbalanced.
Idle current in my design is adjutable for minimum DC offset and optimisation for an MC with higher impedance like the Denons and Clearaudios.
When i use 4 x 4 input transistors and reduce the feedback resistor to 1 Ohm i could get 0.3nV/qHz in a balanced design.
i promissed some photos.
I have build a lot of stuff where i only posted the schematic.
I changed now from building in the small metall boxes to groudplane construction.
I use a double sided board so in a double mono construction i have 4 groundplanes and i use a metal box under that for a 5th groundplane. I place connections of the groundplanes at strategic positions. I also earth the planes at one point with a 6.8uF cap to wall outlet earth.
I have a cable with two wires from the tonearm and one shield that is connected together at the tonearm side. That way i can try balanced and unbalanced.
I have build a lot of stuff where i only posted the schematic.
I changed now from building in the small metall boxes to groudplane construction.
I use a double sided board so in a double mono construction i have 4 groundplanes and i use a metal box under that for a 5th groundplane. I place connections of the groundplanes at strategic positions. I also earth the planes at one point with a 6.8uF cap to wall outlet earth.
I have a cable with two wires from the tonearm and one shield that is connected together at the tonearm side. That way i can try balanced and unbalanced.
Attachments
BHC Slit Foil 10000uF 50V I have used in many phono builds, they are excellent value. Good move. Very big box I see. You are going full force.
The best i tried is nonmagnetic Silver Mica. I can get them up to 10nF in 1%.
When you look carefull you can see them as compensation caps in the Discreet INA.
They are this little blue guys, dipped. I think they are made by Hitachi.
Never tried NPO/COG in RIAA but for decoupling OP´s they are just fine.
I use them when i make a PCB.
When you look carefull you can see them as compensation caps in the Discreet INA.
They are this little blue guys, dipped. I think they are made by Hitachi.
Never tried NPO/COG in RIAA but for decoupling OP´s they are just fine.
I use them when i make a PCB.
Had checked V1.2 regs double mono on phono recently. I think you will dig. Let me know when ready to implement, there are details.
Great Work Joachim
Man I thought that I was the only one that made prototypes like this.
We are very much alike.
Nice pic's and like Salas said I like P2P and you can make changes to it fast and listen within minutes.
Where are your 12 volt batteries?
Hey I see something I like very much, in the middle of the picture "Sonics"
Thanks for posting your pic's Joachim.
I'm going to bed now, it's way past bed time over here 3:50 in the morning, I'm almost finished, designing my new power amp
Tjuus,
Audiofanatic
Man I thought that I was the only one that made prototypes like this.
We are very much alike.
Nice pic's and like Salas said I like P2P and you can make changes to it fast and listen within minutes.
Where are your 12 volt batteries?
Hey I see something I like very much, in the middle of the picture "Sonics"
Thanks for posting your pic's Joachim.
I'm going to bed now, it's way past bed time over here 3:50 in the morning, I'm almost finished, designing my new power amp
Tjuus,
Audiofanatic
i tried MKP1837 in the signal path in front of my poweramp and i can not detect if they are in or out. I also use them as bypass in spaekers. Röderstein/Vishay make now also a KP (film-foil) in smaller values.
The LCR HX Styroflex behave very similiar.
As RIAA caps the nonmagnetic Silver Mica give slightly more speed and treble resolution.
I never tried Teflon but i owned a Lyra Phonostage that had them in the RIAA.
The LCR HX Styroflex behave very similiar.
As RIAA caps the nonmagnetic Silver Mica give slightly more speed and treble resolution.
I never tried Teflon but i owned a Lyra Phonostage that had them in the RIAA.
I want to try them bcs I will need 100n and 33n and found an Epcos 33n 30pcs batch +/- 10% so I see if I will get lucky for values. Cyrill Bateman found vanishing low distortion for them. My Silver Mica are excellent CCCP 15.72n ones but huge! The COGs will have layout benefit if they will sound decent. Else I will use Teflon. Biggies but sure quality.
Speaker Setup, little Monitors that i filter with 33nF into 47kOhm plus active mono Subwoofer (the black cube).
Goes surprisingly loud. I sit very close and have the speakers crossed before my ears.
The are difuse field equalised for this, so have slightly rising treble over 10kHz ( only 1dB).
Goes surprisingly loud. I sit very close and have the speakers crossed before my ears.
The are difuse field equalised for this, so have slightly rising treble over 10kHz ( only 1dB).
