Yes, I built a Standel-type amp with separate preamp and power amp chasses.
I used 2 umbilicals between the chasses: one standard 3-pin XLR for signal hot, signal ground and shield; and a 6-pin XLR for B+, ground, 2 filament leads and the 2 PT primary wires.
So what happens is the PT, rectifier and bulk of the power supply is in the power amp chassis at the bottom inside of the cabinet. The preamp chassis has a few extra filter nodes and the actual power switch. So the wires running to/from the power switch had to be carried in the 6-conductor power umbilical.
I bought the XLR jacks and plugs form Mouser. You have to plan ahead and be absolutely sure you're selecting the correct plugs and sockets. I made several mistakes in my choices and had to reorder twice. You also have to figure out from the data sheets if you have adequate space for the jacks. You will spend a bunch of time hand-shaping the hole for the jacks, as it's not a simple circle.
By the way, Amphenol is a company that makes a lot of different connectors, including XLR types. But when most people say "Amphenol connector" they mean their circular connectors.
Now I'm only familiar with one style of those, and maybe there are some that make a nice finished package simply. However, when I was in the Navy, I made some circular connector cables for aircraft wiring harnesses. I can guarantee that this particular type of circular connector (which from what I've seen perusing Mouser is the most common) is not something you can easily make into a nice finished-looking product at home or in any typical shop.
Why? The type I'm thinking of (and there very well could be others) doesn't have a nice external shell that covers the solder connection to the pins like an XLR type. The Navy shop actually had us use individual wires for each conductor, then we moved over to the shield machine. It literally wove the braided shield around the cable we made up of the individual conductors. Then we moved over to the jacket machine which wove the cloth outer jacket on the cable. There was even a color code to the weave in the otherwise OD green jacket that indicated which Navy facility made the cable.
I'd guess each of those machines to be in the $50k+ price range, and even that might be surplus prices; they were serious industrial machines that wove the jackets on with 8 or more spools of metal braid or nylon. There are also other steps I'm not describing, with special tools to insert the individual contact pins into the circular shell after solder to the individual wire in the harness, and some crazy type of silicone or rubber material to hand-make strain reliefs where the cable meets the circular connector.
Fine process and cost-effective if you're keeping multi-million dollar planes in the air, not so much if you're fixing/building an amp. My choice to use self-made XLR cables in my amp was informed by the tube mic preamps I own which use a 4-pin XLR cable to the separate power supply, and the tube mic I have which uses a 7-pin XLR between the mic and power supply. I bought the 6-conductor cable from Apex Jr, since I didn't need so much cable to get a good quantity price-break through Mouser.
Topic: Mesa 20/20 Power Amp Transformer (Read 5424 times)