Hai guys
I have an offer for Keithley 2015/2015P THD Multimeter for 130$
The manual is here Keithley 2015 benchtop MM and THD meter
Its a 20 y old model .
Some features and spec I copied from manual
How much useful can this be for doing some in depth DIY work
Can any member can share the experience
I have an offer for Keithley 2015/2015P THD Multimeter for 130$
The manual is here Keithley 2015 benchtop MM and THD meter
Its a 20 y old model .
Some features and spec I copied from manual
- DCV measurements from 0.1μV to 1000V and ACV measure-ments from 0.1μV to 750V RMS, 1000V peak.
- The Model 2015 can make DCI measurements from 10nA to 3A and ACI measurements from1μAm to 3A RMS
- The Model 2015 can make 2-wire and 4-wire resistance measurements from 100μΩ to120MΩ.
- With a Model 2015, you can measure the forward voltage drop of general-purpose diodes andthe zener voltage of zener diodes.
- The Model 2015 can make distortion measurements from 0.002% to 100% (-94dB to 0dB).The 2015 uses a digital signal processor (DSP) to perform a fast Fourier transform on the signal applied to the front or rear voltage inputs. It then analyzes the levels of the harmonics present in the signal to calculate THD, THD+noise, and SINAD.
- The Model 2015 has a 10Hz-20kHz (60Hz default) two-channel function generator. It can be
used to evaluate amplifiers, filters or other devices, or can be connected to the 2015 inputs. The
function generator has selectable output impedances of 50Ω, 600Ω, and HIZ (50Ω default), and
is unbalanced (coaxial). Its amplitude is 0-2Vrms for 50Ω and 600Ω (0.5Vrms default), and
0-4Vrms for HIZ (1.0Vrms default). - and many more like frequency spectrum analysis etc
How much useful can this be for doing some in depth DIY work
Can any member can share the experience
Ok folks, work has calmed down and I am back to trying to debug the amp. I finally put my scope onto the amp and this explains some of what I am seeing. This is the gate of Q4. I am not seeing any oscillation anywhere else in the amp. Somehow just the gate is oscillating ??? I desoldered Q4 and R15. With those two removed I was able to confirm all the resistors in the bias circuit are correct. I also measured an hfe of 150 for Q4. I am at a loss. The only thing I can think of is to replace the pot with a fixed resistor, replace Q4, but that seems unlikely to work.
