Full m/lab SD2000 schematics

[salare12]

salare12, write mail address for pcb file

[email protected]

[ashkelon]

salare12, write mail address for pcb file

[salare12]

Can someone post PCB file??
Regards

[kt315]

GUYS DO NOT ASK ME ON SD2000 -!
I WILL NOT ANSWER ON YOUR REQUESTS IN MY ADDRESS -!
I AM NOT INTERESTED IN SD2000 JUST CAUSE I DO NOT SEE FULL DATA - FULL SCHEMATICS, FULL ORIGINAL LAYOUTS,
FULL PART LIST, FULL O-SCOPE DIAGRAMMS.

SD2000 WAS AND IS TERRA INCOGNITO. I DO NOT DO THAT IS KNOWN ON HALF. I DO ONLY FULL PROJECTS -!

[kadir6141]

As a little better lm394h (metall)

[kadir6141]

hi friends. trying too is noisy bc547

[Altra]

Mick,

Thanks for posting the diagram.

Here's another I found some where, maybe here?

[Mechanic]

As promised, how to use a 797 if you want to leave out the lm394.
I'm still not convinced that the 797 is quieter though, but I still have more experiments to do...

Cheers Mick

[WM6]

Aziz once did did a bunch of different transistor comparisons, I don't remember if it was here or elsewhere though.


cheers Mick

On AEGP forum.

[Mechanic]

Ad797can be used to replace the lm394 and the first ne5534. I will dig up a schematic for that later on. It will be much better than attempting to find a good pair of transistors.

Aziz once did did a bunch of different transistor comparisons, I don't remember if it was here or elsewhere though.


cheers Mick

[kadir6141]

thank you very much

[Davor]

Try some low Rbb types. BC337 has Rbb about 30 ohms, and yet it is still quite fast. Noise figure is directly related to Rbb, as it is added to the source resistance. Some other transistors have even lower Rbb, say BD135, but tend to be slower. Even those may be "convinced" to co-operate, but not in a configuration you need.
You'll seldom find Rbb in datasheets, so unless someone else measured it, you are in the dark. BC547 to BC549 have roughly an order of magnitude higher Rbb, and thus it is best to avoid them. These were measured by a fellow at DIY Audio (Ic=2mA, Vce=2V):

Type        Mfr    Prod. year    Ree      Rbb

BC549C      Phil    1980         0.85     430
BC550C      Phil    ~2000        0.72     234
BC550       Siem    ~1995        0.98     247
BC550B      MultiC   ~2000       0.57     >650
BC550C      Moto    1998         0.43     73
BC550       NS      1995         0.29     62
BC439       Hita    ~1980        0.71     >650

[Orbit]

Hi friends. The instead lm394. I want to use instead bc547 or 2N3906. Is it working?

Too much noise bc547 .

[kadir6141]

Hi friends. The instead lm394. I want to use instead bc547 or 2N3906. Is it working?

[mj123]

Sd2000 partlist, please