I been wanting a receiver and after polling the zed collective here at various times in the past I purchased a 75A-4 from a very reputable source, pretty much sight unseen. It is a stock unit in every way except for some reason I was told, a tube socket was added to the back of the rig some time in the past. I was told this tube socket is no longer in use in the radio, any guesses to why this might have been added? It does have the 4:1 front VFO knob setup and I am very sure the rig will be in good shape once it arrives here this week. It will need some TLC I am sure to get back up and running in top shape. I will be putting in the new cap kit available from KE9PQ as it is 1 stop shopping for the most part. I have looked at 1 mod for the AVC circuit which includes changing out tubes and removing a resistor, which is suppose to improve the performance of the rig. Some folks say it works well and another school of thought is that all it does is just raise the noise level without gaining that much performance in weak signal work from the mod. I always like to ask the Zed collective here their opinions on these matters, as practical real World experience is very hard to beat. I don't want to reinvent the wheel in this project and that is why I am asking the Zed brain trust for their opinions on which mods to this receiver are worthwhile and which 1s aren't. I see new filters are available from the KE9PQ website, has anyone here on the Zed tried out these new filters as of yet in their 75A-4 radio? 75A-4s have been around close to 60 years now, so I am guessing here there aren't many new mods that could come along over the horizon and improve on what has already been established in upgrades for this rig. Thanks again to the Zed collective for their time & knowledge in this area.