Noname, I agree that the device specs were overstated - both the analog BW and sampling rate.
However, I disagree that the mod posted by bielec is misleading.
bielec stated:
“I now get about 10MHz sinewave bandwidth on all ranges and good pulse response with minimal overshoot and rounding. Trigger and good display of sub 100nS pulses is now possible. As delivered, the scope had less than 1MHz B.W. and poor risetime which varied depending on range.”
Notice that he mentions sine wave BW, which is what should really be used to justify these results. I already explained the reason why you would not see a nice square wave at 6 or 8MHz.
As a matter of fact I performed very similar mod using 0603 parts and got very similar results - my 3dB was shy of 11MHz. However, I would hardly expact this BW to provide a nice sharp looking 8MHz square wave. My TDS210 would do it with no issue, but the analog BW is 60MHz with 1GS/s sampling rate.
Yes, the QUAD has many flaws - you are correct, but as far as being rediculously expansive I don’t think so. A decent Fluke RMS DVM would cost as much or more and has far less capabilities than even immature QUAD.
In any case, this is just my 2c…