No more 60 Hz hum in a PL2000 preamp.

[Gepetto]

I don't like the Switchcraft in this application. Look at the photo and you'll see that the traces will loosen from the board just from thermal cycling alone when using solid wire. Braided wire with slack would be the way to go. But disassembly for service or upgrades would be a nightmare with this setup.
As PL designed it, take out the 3 rear screws, desolder the secondaries and line at power switch, and the chassis comes right off. PL had this right, they just needed better jacks.
I'm removing those Switchcraft and looking for new plastic jacks.
I'll use lightweight skinny interconnects or make my own out of Belden 83284 to save stress on the jacks.
I've seen what appears to be NOS jacks on the Bay, VERY high priced, but that may be my only option. I have looked several times in the past for new production jacks, no luck. If anyone knows a source please let me know.

Hi George
Those NOS ones on eBay are the same junk plastic connectors that you just removed.

 

[George S.]

Joe, yes, made by the SMK Corporation. I see they're still in business. Going to look and see if they still make something similar.

 

[Gepetto]

I don't like the Switchcraft in this application. Look at the photo and you'll see that the traces will loosen from the board just from thermal cycling alone when using solid wire. Braided wire with slack would be the way to go. But disassembly for service or upgrades would be a nightmare with this setup.
As PL designed it, take out the 3 rear screws, desolder the secondaries and line at power switch, and the chassis comes right off. PL had this right, they just needed better jacks.
I'm removing those Switchcraft and looking for new plastic jacks.
I'll use lightweight skinny interconnects or make my own out of Belden 83284 to save stress on the jacks.
I've seen what appears to be NOS jacks on the Bay, VERY high priced, but that may be my only option. I have looked several times in the past for new production jacks, no luck. If anyone knows a source please let me know.

Hi George

The original plastic connectors translate the plugging force of the RCA plug directly into stress of the solder joint that connects the 3 connector tabs to the circuit board with zero forgiveness.

Mounting the RCA jacks on the chassis bulkhead makes the chassis bear the plugging force of the male RCA plug. Much better structurally than the original arrangement. Yes SMK is still around producing the same low grade connectors that they always have. In the world of connectors, they are a no-name manufacturer.

The Switchcraft are far superior connectors, even though they are not top of the line. You can purchase fully gold plated Switchcraft connectors as well.

 

[George S.]

Joe, O.K., I'm going to look at the setup again and see if I can incorporate stranded wire with a little extra length for strain relief.

 

[Gepetto]

Joe, O.K., I'm going to look at the setup again and see if I can incorporate stranded wire with a little extra length for strain relief.

You can do that with 22AWG solid bus wire...or use 26AWG Kynar wire.

 

[Gepetto]

It would have paid Phase Linear to seek out and use much better connectors in their products.

 

[George S.]

I was using that silver plated solid wire you send with the control board kits for those who aren't installing the backplanes. Very nice stuff, but I think the traces are just too fragile to handle a rigid connection to the chassis. They'll separate from the board over time, and if disassembly is required, the traces will separate for sure. Going to use some stranded with a little extra length for strain relief.

 

[Gepetto]

Hi George
You should consider rotating all the ground tabs to the topside of the Swithcraft RCA connectors (away from the PCB), putting a 90 degree torsional twist into each of those tab legs, running a length of bus wire straight through all of them and making one connection to the PCB ground trace at the end of that bus wire run (both ends of the run if desired and use that to join the once separated ground trace on the PCB). Much cleaner approach and eliminates that stress concern from the ground leg since it is now far away and gives you a length to work with.

 

[George S.]

Oh hell yes! Now THAT is a great idea. Will do!

 

[George S.]

Well, I'm short on parts because I wasn't expecting to replace these jacks because the test unit has good plastic jacks. Going to stop right here, order jacks, fiber washers, some of that silver plated bus wire. I'll start stuffing the board of #2 later today.

 

[George S.]

Sitting here listening to a Hendrix digital file on the preamp and sharing a bowl of dry Cheerios with the dog.
Really wanted to hear it, so soldered in 2 input and 2 output jacks that are good.
Think I found a source of the original jacks for 15 cents apiece, website says they have over 7000 pieces. Photo looks like a exact match, but they don't have a data sheet. Ordered 50 pieces and will update if they work. I like the convenience of the original jacks when working on the unit. Yes they are crap, but all on the test unit are good after all these years. Will do Switchcraft if I have to.
https://www.allelectronics.com/item/rcj-65/rca-jack-w/nc-switch/1.html

 

[Gepetto]

Sitting here listening to a Hendrix digital file on the preamp and sharing a bowl of dry Cheerios with the dog.
Really wanted to hear it, so soldered in 2 input and 2 output jacks that are good.
Think I found a source of the original jacks for 15 cents apiece, website says they have over 7000 pieces. Photo looks like a exact match, but they don't have a data sheet. Ordered 50 pieces and will update if they work. I like the convenience of the original jacks when working on the unit. Yes they are crap, but all on the test unit are good after all these years. Will do Switchcraft if I have to.
https://www.allelectronics.com/item/rcj-65/rca-jack-w/nc-switch/1.html

And now you know why PL used them

And AllElectronics is making a profit off of them at 15 cents

 

[George S.]

And now you know why PL used them

And AllElectronics is making a profit off of them at 15 cents

I agree!

 

[laatsch55]

Be careful when ordering George, they came in 2 styles, the ground tab and signal pluis tab can be reversed..I bought a BIG BAG of them off ebay and although they are THE same jack, they have the tabs reversed..

 

[George S.]

Lee, cool. I remember a a post from long ago about that issue. Will look at them closely and update. If they are correct then this will help many PL owners.

 

[George S.]

Abbreviated wiring.

Power switch using both contacts.

Sound seemed overly bright for the first 30 minutes, but it's starting to mellow out and gain more detail.

 

[George S.]

I really like Joe's WOAD Cylon meters. Freaking awesome.

 

[George S.]

Desoldering the jacks on #2. The Hakko doesn't have a big enough tip to go over the jack lug, so I use it around the lug and finish up with desoldering wick. Used to use Radio Shack desoldering braid, but it was junk compared to Superwick from M.G. Chemicals. Works wonderful. A must have.

 

[George S.]

I got lucky, #2 has good jacks, internals look good and no cracks in the plastic. Going to sit them aside until those 50 jacks I ordered show up.
Time to finish cleaning the board and then stuff it.

 

[George S.]

Some of the thru holes are too small for the new components and have to be carefully drilled out with a pin vise, from the trace side only. These old boards are fragile. Very carefully start the drill through the copper trace with light pressure. Do not allow the drill to catch and twist the trace loose from the board. This is one of those procedures where magnification like a Optivisor is a must have. It's very easy to twist a trace loose from the board. Take your time and be gentle.