Power amp measurement system

G10 post-notch preamp. IMHO it has quite good performance.
 

Attachments

  • K4v3-G10-sch.png
    K4v3-G10-sch.png
    194.5 KB · Views: 363
  • K4v3-G10-LG.png
    K4v3-G10-LG.png
    103.3 KB · Views: 346
  • K4v3-G10-noise.png
    K4v3-G10-noise.png
    99.9 KB · Views: 336
I made a compact version of the post-notch preamp. Same box (enclosure) as for notch, powered by external batteries. Gain is selectable by jumper, 1x or 100x. The PCB has two versions, one for single op-amp (OPA627,827,828, etc) and another for dual op-amp (OPA1656,etc). On the picture you can see boxed OPA827 with bypassed input/output caps (4mV output dc @40dB) and unboxed OPA2141 version (waiting for OPA1656). Second picture captures OPA827 output noise (amplification 100x) , input impedance is 50R.
 

Attachments

  • Notch-pre827.jpg
    Notch-pre827.jpg
    700.2 KB · Views: 318
  • BUFFER NOISE OPA827_40dB  INP_50R BW_20K.png
    BUFFER NOISE OPA827_40dB INP_50R BW_20K.png
    48.9 KB · Views: 322
Last edited:
Almost finished voltage divider, AAA battery holders are on the way, till arrive I made a battery pack (white color on the picture).
The front board holds the divider/attenuator, mosfet SSR, mosfet driver while the rear one is a protection logic/driver.
 

Attachments

  • vdivider-pic1.jpg
    vdivider-pic1.jpg
    630.1 KB · Views: 187
  • vdivider-pic2.jpg
    vdivider-pic2.jpg
    827.4 KB · Views: 194
  • vdivider-pic3.jpg
    vdivider-pic3.jpg
    819.5 KB · Views: 176