Due mainly to a lack of availability of the Hammond choke used in the R8 upgrade in my part of the world, I threw caution to the wind and got a 250mA 4H choke from Aliexpress (https://www.aliexpress.com/item/1005004221303875.html). It cost me about half of what the Hammond choke would cost if it had been available to me. As my test equipment is limited to a digital multimeter, a capacitance meter and ESR meter, are there any measurements I can make to ensure its specs are what is claimed? Its physical specs are: Dimensions: (H) 50mm (W) 60mm (L) 60mm (mounting hole spacing) (70-75mm)
Weight: 644grams (1.4lb) (Note: The Hammond 194G is 570grams (1.25lb)
The label text translates to: EI573018 Copper Wire Inductor Zhongshan Lime Electronics Co., Ltd.
I realised I forgot to mention the general standard of components in my R8. They are essentially the same as those in the video series except that I could only find one resistor with a chipped coating (the green resistor on the right channel 6SL7 tube circled below). Here is my R8 post reliability mods:
I finished some of the reliability mods (replaced 3 caps for 550V versions and the choke. Also added resistors to bias board) as well as my version of your latest potential ground loop mod (replace ground cable with a shielded ground cable with shield only grounded at the volume control end. Then cut the L/R ground wire at the RCA end. Plugged it in and it works fine in spite of my blobby soldering, I always have problems soldering 3 or 4 wires to a single point. I also managed to drop a screw inside the R8 and I could hear it rattling around for 5 minutes until it finally dropped out. The old choke measured 3.72H on the cheap meter and 2.49H with the better LCR meter. Both measured its resistance around 39 ohms.
I purchased a GM328A component tester from Aliexpress (pictured). When I hooked it up to this choke, it measures 9.3 henry's. The instructions do state: "You should not expect very good accuracy of measurement results, especially the ESR measurement and the results of inductance measurement are not very exact" I wonder which is more accurate? Note, the resistance reading matches that of my multimeter.