Mr_rye89’s WOPL 400 Build Containment Thread

[Gepetto]

Well I dropped her in the main system tonight. It's something else.....I'm not sure where the 15" woofers in my Altecs end and the subwoofer begins. It seems to keep the same sweetness as the Dynaco but with much more control over everything.....

Welcome to damping factor...

 

[Vynuladikt]

Welcome to damping factor...

Yep, A WOPL can really reach down and grab you by the woofers!

 

[mr_rye89]

Got a ground loop hum, or what sounds like a ground loop hum. Happens with the Zoom interface and the Carver C-1. With nothing hooked to the amplifier's input jacks it is dead quiet. If I hook up any RCA cords a little hum starts. If I hook RCAs to preamp or interface hum gets louder. If unhook one RCA the hum gets quieter.

Now I checked to see if the input jacks are isolated from the chassis, they are. I tried lifting the single point chassis ground and it still hums, I took the copper piece that was between the jacks out and used the solder tabs that came with these jacks (Switchcraft). I also replaced the coax cable between the jacks and the driver board. Still hums......

 

[George S.]

Are they stacked? If I sit my preamp on top of my WOPL, it picks up the transformer hum. If I separate them, it goes dead silent with all cables connected. What's a Zoom interface? Like for Zoom meetings on the internet?

 

[mr_rye89]

No the amp sits by itself, and it hums on my bench. The Zoom interface is just a DAC/ADC with mic/line ins and outs and can drive a power amp. I attached an image of my inputs for reference….

 

[George S.]

Joe came out with a Continuous Improvement update saying the copper plate needs to be installed, and a ground wire run to the control board. Here's the link, post #430, by Joe.
https://forums.phxaudiotape.com/threads/pl-700-pro-build.9965/page-22

 

[Gepetto]

No the amp sits by itself, and it hums on my bench. The Zoom interface is just a DAC/ADC with mic/line ins and outs and can drive a power amp. I attached an image of my inputs for reference…. View attachment 65617 View attachment 65618

So Kyle
Where does that white wire I see soldered to pad 5 of the backplane board in your lower picture go to???

 

[George S.]

And a photo of the "improved" 400 S1 I'm working on now. Note the ground tabs soldered to the plate. Fiber insulators are installed on the RCAs, no grounding to the chassis allowed here.

 

[George S.]

And a photo of the new ground wire #5 R+L, removed the jumper from the backplane to #5 R+L, ran 2 new grey wires from a extra hole on the copper buss bar to #5 R+L on the control board. Used 16 AWG grey only because I had plenty of it and no 22 AWG grey.

 

[mr_rye89]

So Kyle
Where does that white wire I see soldered to pad 5 of the backplane board in your lower picture go to???

That goes to the driver board.

I looked at the thread George linked and it looks like pad 5L/R on the driver board are supposed to tie to the main ground buss bar........

 

[J!m]

THE RED WIRE! ITS ALWAYS THE RED WIRE!!!

 

[Gepetto]

That goes to the driver board.

I looked at the thread George linked and it looks like pad 5L/R on the driver board are supposed to tie to the main ground buss bar........

Yes, that is the update I posted about a month ago on PLPs thread

 

[mr_rye89]

Ok, I tied pad 5L/R to the main ground buss, put the copper thing back at the inputs/soldered the tabs down, and ran another ground to the DCP board from the ground buss for good measure. I still have a teensy hum but I can live with it for now......

 

[George S.]

Wonder if input impedance of the amp has something to do with the hum. PLP and Kyle both had hum issues, both amps have low input impedance due to not having attenuators on the inputs.

 

[mr_rye89]

Okay light board went in last night. All is good except the left meter which is stuck or dead. Eh whatever…I usually don’t listen loud enough to move the meters……

EDIT: The meters don't look that damn yellow in real life. Stupid Iphone.....

 

[mr_rye89]

Ok highlights are blown but this is closer to reality

 

[mr_rye89]

I installed the good meters George S. sent me and am trying out the cool white light/board. Thanks again George!