700B and speaker out DC protection?

[laatsch55]

Google Hoosier movie. Great inspirational film..

 

[Northwinds]

and not sure what movie youre talking about.

Hoosiers is a 1986 sports film written by Angelo Pizzo

 

[BubbaH]

Actually I may have seen parts of that film. Reading about it, the gene hackman basketball coach refreshed my memory.

 

[laatsch55]

Good Stuff.

 

[Zach C.]

Good Stuff.

Who's a Hoosier? A Phoenix Geek other than myself?

There are many theories about the origin of the term Hoosier, but no agreement.

My favorite is that after a particularly gruesome bar fight, someone said...Who's Ear?

...and beins we caint read ner rite, it come out like "Hoosier"

Dumb, but it's one of the explanations that's out there.

WAY more than you wanted to know.

http://www.indiana.edu/~librcsd/internet/extra/hoosier.html

 

[Zach C.]

Who's a Hoosier?

Never mind.

Jason is a Hoosier. I knew that.

He's at the end of the state from me.

May as well be in Michigan...Like I may as well be in Kentucky.

 

[BMWR75]

I installed the DC protection board today. Put the amp on the dim bulb tester. It starts bright, starts to dim, then goes bright again and continues this cycle. Any ideas what might cause that?

The speaker output negatives were tied together on this amp (e.g., common ground). Is this typical? I thought common grounding on speaker outputs was a tube amp thing.

 

[laatsch55]

Need some pics Scott, of the DCP board and the bridge rectifier...

 

[laatsch55]

I installed the CD protection board today. Put the amp on the dim bulb tester. It starts bright, starts to dim, then goes bright again and continues this cycle. Any ideas what might cause that?

The speaker output negatives were tied together on this amp (e.g., common ground). Is this typical? I thought common grounding on speaker outputs was a tube amp thing.

All PL 400 and 700's grounds were tied together at the speaker binding posts.

 

[BMWR75]

The new green AC wires from the rectifier are attached to the same points on the rectifier as the white wires from the transformer. The new small white wire is attached to a new lug connected to the copper bus bar on the lower PS capacitor.

The speaker post connections are on J1-J4. White is positive left, then gray for left ground, red is positive right, then gray for right ground. Both of the gray wires were tied to the left negative speaker post initially and the both negative speaker posts tied together with a bare wire.

 

[laatsch55]

The Zoebel resistors need to be wired on each end like the top, but then one wire from one side goes through the board and then one from the other side goes through the board. Stood up, the common wire of the bottom goes in one hole, then the common wire from the top goes in the other hole.

 

[Gepetto]

The new green AC wires from the rectifier are attached to the same points on the rectifier as the white wires from the transformer. The new small white wire is attached to a new lug connected to the copper bus bar on the lower PS capacitor.

The speaker post connections are on J1-J4. White is positive left, then gray for left ground, red is positive right, then gray for right ground. Both of the gray wires were tied to the left negative speaker post initially and the both negative speaker posts tied together with a bare wire.

View attachment 11975

View attachment 11976

View attachment 11977

There should only be one white wire into terminal 6 of the DCP board. I see 3. This is not correct and will lead to ground loops.

 

[laatsch55]

Also Scott, if those are 10 ohm resistors on the DCP Zoebel, they are in series so the amp is seeing 20 ohms accross the outputs, not 5 like its supposed too. Also that blue cap looks tenuous, they should be flat on the board. Was this board assembled or did you populate this?

 

[BMWR75]

I bought the board assembled from Watts Abundant.

 

[BMWR75]

There should only be one white wire into terminal 6 of the DCP board. I see 3. This is not correct and will lead to ground loops.

Watts Abundant's instructions say twist the three white ground wires together. I am copy pasting the two steps that say this below. I wonder if since I have a White Oak board installed instead of the stock board, if these ground wires should be wired up differently?

30. You should now have 3 unattached white wires. There is a white wire that you connected
to the bare ground wire at the input terminals. There is a white wire that connects to the
driver board and the new white wire that came from the ground on the main capacitors.

31. The three white wires are now twisted together and inserted into terminal 6 on the relay
board. Make sure all strands are fully inserted or they will short to the AC wires on
terminal 5 and 7.

 

[laatsch55]

Oh......

 

[Gepetto]

Watts Abundant's instructions say twist the three white ground wires together. I am copy pasting the two steps that say this below. I wonder if since I have a White Oak board installed instead of the stock board, if these ground wires should be wired up differently?

30. You should now have 3 unattached white wires. There is a white wire that you connected
to the bare ground wire at the input terminals. There is a white wire that connects to the
driver board and the new white wire that came from the ground on the main capacitors.

31. The three white wires are now twisted together and inserted into terminal 6 on the relay
board. Make sure all strands are fully inserted or they will short to the AC wires on
terminal 5 and 7.

Sorry Scott
Those DCP instructions are incorrect and lead to ground loops.

There should be a single wire going from pin 6 of the DCP directly back to the ground bus bar.

There should be NO CONNECTION to the input jacks and ground plate other than the connection that originates from pin 2L and 2R of the White Oak PL14_20 board connected to the shield braids of the signal input wires, contiguous all the way through the connection at the 2 front panel pots and up to the shell of the input jacks which also ties in the small copper plate. If you ohm check the connection from the copper input plate to the chassis frame without the wire to pin 5L connected, you should measure OPEN.

There should be a single wire going from pin 5L of the White Oak PL14_20 board to the same ground bus.

Clear?

 

[Gepetto]

Watts Abundant's instructions say twist the three white ground wires together. I am copy pasting the two steps that say this below. I wonder if since I have a White Oak board installed instead of the stock board, if these ground wires should be wired up differently?

30. You should now have 3 unattached white wires. There is a white wire that you connected
to the bare ground wire at the input terminals. There is a white wire that connects to the
driver board and the new white wire that came from the ground on the main capacitors.

31. The three white wires are now twisted together and inserted into terminal 6 on the relay
board. Make sure all strands are fully inserted or they will short to the AC wires on
terminal 5 and 7.

This is how your input wiring should look Scott (heavily revised by White Oak Audio).

 

[frhodes]

Snow days!!! When we were kids it was fun! Sawe some pics from Jason and Ron, serious stuff.

Here in Salem,Oregon we are not used to this kind of snow. Have been snowed in for 3 days. (Snowplow, salt, chains what are they?)

Had to dust off the old dog:

 

[laatsch55]

That's nuts Jim!