Review on High-Precision Nobsound 8-Pin Dual Bias Current Probes Tester for EL34 KT88 6L6 🧪 6V6 6550 Vacuum Tube Amp Amplifier - 2 Meter + 2CT1-C - Cathode Current Measurement by Karen Gonzalez

Obviously this device is relatively inexpensive. It wouldn't help if I were an FT amp repair shop though, but it works fine for my personal tube amps. It seems a little fragile but with careful use, handling and storage it should be sufficient for all my needs. The actual meters are fairly accurate compared to my Fluke 87 (a deviation of 0.5mA at around 40mA). If you have a Marshall or other tube amp that allows you to adjust the offset for individual tubes (or sets of tubes), this should suit your needs. If you are a street warrior, it is best to keep the box and handle it with care.