Jer's 700B Quasi to Full Comp/Backplane Build

[Phase Linear Phanatic]

Planning the AC wiring here.. Is there any reason to place the cutouts in line with one side of the 120 line, and the switch the other, or can/should I go ahead and leave it with both cutouts and switch on the same side?

View attachment 12745

On the buss bar, well looks like I actually have the length pretty much nailed on what I have left for the "big copper", so we'll just be drilling a few holes here and there.

Hey Dave.. to answer your question, note what is circled in red in the pic below - I've relegated the series I to "parts duty" for a few things here and there, for now. I just have this feeling that once this FC is put together, I might shy away from 700's that remain the old point to point style. And since the series I back wall patterns aren't going to match the WO backplanes...

Of course I MIGHT (with a lil help from Lee) put 'er all back together, and it could be the next "door prize" for when we reach our next higher membership level, heheheh....
seriously considering it... The Quasi 700 WOPL's are definitely not something to sneeze about...

My bad Jer. Near the end of my thread on David 's 700B; I remembered you had pictured both 700's on top of each other and lit up in blue. I was unaware you had the series I in parts status now.

I may not be doing any white oaking right now; but what I WILL tell you guys is that my fathers birthday is the 26th and boy is he gonna be PL happy! I bought him two amp racks just like mine. He will have four 8 fin PL 400's in one rack, and the other for preamp, cd, cassette dck etc. I also bought two walnut cases for his PL's that i was searching for. (He already has two) pricy. Like I told Lee, I never win anything or get a good deal. I always pay. Never even win a scratcher ticket. Plus i also got him an ad from 1975 of Bob Carver leaning over a 400. "Can you live without a 400 watt amplifier?"

He gets to put that framed ad on top of his PL rack. I will post pics later.

Looks good Jer. Are you considering leaving the Adcoms or replacing them when we get our bulk cap order in April?

 

[Gepetto]

Planning the AC wiring here.. Is there any reason to place the cutouts in line with one side of the 120 line, and the switch the other, or can/should I go ahead and leave it with both cutouts and switch on the same side?

View attachment 12745

On the buss bar, well looks like I actually have the length pretty much nailed on what I have left for the "big copper", so we'll just be drilling a few holes here and there.

Hey Dave.. to answer your question, note what is circled in red in the pic below - I've relegated the series I to "parts duty" for a few things here and there, for now. I just have this feeling that once this FC is put together, I might shy away from 700's that remain the old point to point style. And since the series I back wall patterns aren't going to match the WO backplanes...

Of course I MIGHT (with a lil help from Lee) put 'er all back together, and it could be the next "door prize" for when we reach our next higher membership level, heheheh....
seriously considering it... The Quasi 700 WOPL's are definitely not something to sneeze about...

View attachment 12746

No matter how you slice it Jer, you end up with hazardous AC inside the chassis and with a non polarized plug you could end up with either the hot or neutral on the chain with the fuse, thermal cutouts and switch. Your diagram is fine. Placement is what matters here and my strong recommendation is all AC on top and all DC down bottom. That is my standard treatment.

 

[jbeckva]

Outputs in and nailed

Got the outputs in and nailed down. I'm a "go for broke" kinda guy, but I do check for shorts after each one is mounted and again when they are all soldered in.

Joe thanks... yeah we're definitely going to go that direction with AC north and DC south, plus a lil "surprise" when it comes to the DCP...

Time to go watch Vikings on the DVR... man that show is cool. Whole lotta goin on.

 

[Northwinds]

Coming along beautifully Jer. That was interesting about routing the AC and DC apart from eachother, I sort of figured that would be a given anyway with that much power in a confined space

 

[jbeckva]

Coming along beautifully Jer. That was interesting about routing the AC and DC apart from eachother, I sort of figured that would be a given anyway with that much power in a confined space

Yes it has been a "given" for awhile now, Ron. We're just improving on it, as it makes a big diff in the noise level. Just wanted to confirm a few things since this'll be the first "B" I do the total rewire with.

 

[Northwinds]

Understood Jer. I remember trying to rewiring a tube guitar amp a few years ago and then having someone tearing it all a part because I was getting hums and other issues. This is why I do not mess with wiring at all anymore. He said stuff was not shielded well and my choice of wire was not that great LMAO

 

[jbeckva]

With the 700's it's more of an issue, since the AC comes in on the right and has to be wired over where the transformer and BR are at on the left. 400 isn't a big deal.. all of that stays on the left except the thermal cutout loop.

Going to knock it out this evening, I hope. Gotta get more screws and other hardware on my way home. I might have yours knocked out tomorrow or close to it this weekend.

 

[Gepetto]

Got the outputs in and nailed down. I'm a "go for broke" kinda guy, but I do check for shorts after each one is mounted and again when they are all soldered in.

Joe thanks... yeah we're definitely going to go that direction with AC north and DC south, plus a lil "surprise" when it comes to the DCP...

Time to go watch Vikings on the DVR... man that show is cool. Whole lotta goin on.

I love the Vikings too Jer, missed last night but will catch up, they have plenty of reruns during the week.

 

[jbeckva]

AC is DONE... but.. TWO wires only???

Here's the AC routing. Note... only 2 wires crossing.




So what about that DC Protect? Doesn't it also need a couple of AC runs from the BR on over? Well, sort of... couple of nights ago I thought about it, and what if we could rectify it to DC BEFORE it crosses over?? That's exactly what was done. The diodes were pulled from the DCP, heat shrinked, and mounted on the empty terminal ring, not 3 inches or so from the BR. On the DCP, I installed a jumper in place of one of the two, since at that point it's just rerouting the already-rectified DC voltage from one of the two "AC" terminals on the DCP, on into the DCP circuit. Electrically the same... but now it's DC for the majority of the travel from left to right!

(lil diode symbols scribbled on the heat shrink.. sometimes I get pretty anal like that, LOL... )



Diodes mounted and wired back to the BR. The red wire underneath will be ran across the bottom now, and connected to the "AC" terminal on the DCP where it goes across the installed jumper, and onto the DCP circuit, proper.

 

[laatsch55]

Brilliant!! And the DC will drop out imediately when the switch is thrown!!

 

[jbeckva]

Brilliant!! And the DC will drop out imediately when the switch is thrown!!

Exactly! Basically there's nothing different - the circuit is still the same electrically, but now with a couple of components relocated "off board". The only thing I am wondering about is if we now need a decoupling/filter cap on the left near the diodes?? Hey Joe!

 

[laatsch55]

Why would you? To prevent relay coil noise working it's way back?

 

[jbeckva]

Teeny voice in my head?? (really.. but not really.. hmmm)

My thinking is that ya generally would want to locate the ripple / filter cap close to the diodes.

(see "anal" comment above ... ).

Oh poop... --> instant karma for my smartass comments <---... toasted one of those caps around the BR with a slip of the iron!!! Now I gotta go huntin for one... maybe in the process I might find some rack handles too.. LOL

 

[laatsch55]

Bought a new set on ebay the other day...

 

[Northwinds]

What does BR stand for Jer? Bridge rectifier? Looks very neat so far, I admire your patience

 

[Gepetto]

Exactly! Basically there's nothing different - the circuit is still the same electrically, but now with a couple of components relocated "off board". The only thing I am wondering about is if we now need a decoupling/filter cap on the left near the diodes?? Hey Joe!

Hi Jer
That is the way to fix that shortcoming.

You should move the small electrolytic filter cap that is on the DCP over there too otherwise you will have noisy pulsating DC running across the chassis in place of the noisy AC

Also make sure you bring the AC switch wiring over to the switch hugging the front panel. Last bring the light board AC wiring over from the transformer side and not down the middle and also hug the front panel.

 

[Gepetto]

Hi Jer
That is the way to fix that shortcoming.

You should move the small electrolytic filter cap that is on the DCP over there too otherwise you will have noisy pulsating DC running across the chassis in place of the noisy AC

Also make sure you bring the AC switch wiring over to the switch hugging the front panel. Last bring the light board AC wiring over from the transformer side and not down the middle and also hug the front panel.

That would be C3 along with D1 and D2 on the DCP are the ones that are off the DCP board and over by the bridge. Put a small 0.1uF >150V ceramic or film cap on the DCP board in place of the original C3. It needs that for inductive flyback control. I would recommend taking the voltage rating of the relocated C3 up to 160V but leave the size the same (10uF). Resist the temptation to increase its value. It has to decay fast in a power loss situation to open the relays quickly.

 

[jbeckva]

Hi Jer
That is the way to fix that shortcoming.

You should move the small electrolytic filter cap that is on the DCP over there too otherwise you will have noisy pulsating DC running across the chassis in place of the noisy AC

Also make sure you bring the AC switch wiring over to the switch hugging the front panel. Last bring the light board AC wiring over from the transformer side and not down the middle and also hug the front panel.

Gotcha. I am just a lil hesitant on moving the cap tho - where to ground it? Maybe with a lug .. no, that'll introduce a ground loop (we want a SINGLE ground to chassis, no matter what). And since it's such a short hop in relative terms.. (like, E=mc2 .. "c" terms)... how long will it take them electrons to get from one place to another?

Maybe a cap on both ends? Still, where to ground.. hmmmm Star ground is my friend?? Going to need a 10uf 100v axial, ideally, then stretch it from the diode junction back through to cap/star ground. (these are thoughts.. any stick so far? )

Ron BR is bridge rectifier, yessir. Let the iron get too close to one of the .1 caps forming the ring around it.. ooops.. but hey, I found one so life goes on, lol. Working on getting the lugs and grounds wired up to the big hunka copper we call the BABB.. or "Bad Ass Buss Bar"..

 

[Gepetto]

Gotcha. I am just a lil hesitant on moving the cap tho - where to ground it? Maybe with a lug .. no, that'll introduce a ground loop (we want a SINGLE ground to chassis, no matter what). And since it's such a short hop in relative terms.. (like, E=mc2 .. "c" terms)... how long will it take them electrons to get from one place to another?

Maybe a cap on both ends? Still, where to ground.. hmmmm Star ground is my friend?? Going to need a 10uf 100v axial, ideally, then stretch it from the diode junction back through to cap/star ground. (these are thoughts.. any stick so far? )

Ron BR is bridge rectifier, yessir. Let the iron get too close to one of the .1 caps forming the ring around it.. ooops.. but hey, I found one so life goes on, lol. Working on getting the lugs and grounds wired up to the big hunka copper we call the BABB.. or "Bad Ass Buss Bar"..

View attachment 12791

Hi Jer
Go with the 10uF axial electrolytic but it needs to be higher than 100V, 160 is the next standard size up. Connect the plus to the barrier strip where your two diode cathodes come together and the negative side attach a wire and heatshrink the connection and route it to one of your ground connections on your bus bar.

 

[Gepetto]

Ponytail...

Lee and I ponytail all the control board wires together to keep them out of your way while working on it. Use a small ty wrap that you will cut off later when you attach the board. Makes working a lot neater and it strain relieves those wires in the process so you don't accidentally break one off.