12XXX Build 05/2010

[Omn]

(no deviation in the heater wire - well done)

(I had some small difference between V1 and V7 - so; my respect)

[vh junkie]

Kinda a like being there when a baby is being born

[Omn]

Sure, it is fun!
Hope she will live up to the expectancies

[vanhalen5150]

Not sure I understand the pot on the board at this point.

Insatlled power tubes. Im getting 101 on V1 pin1.

[Omn]

Switch pot is for low voltage
Use the board pot

[vh junkie]

If the pot on the switch wired correctly, the pot on the switch does nothing in HI. Only use the pot on the board to set the bias when in HI mode.

We need a pic of the switch

[vanhalen5150]

Ok, so I want pin 8 on V1 set to 0v instead of 2v?

[vh junkie]

Set your meter for mv and shoot for -35mvdc... and for gods sake don't turn up the volumes if it reading -101mv

[vanhalen5150]

If the pot on the switch wired correctly, the pot on the switch does nothing in HI. Only use the pot on the board to set the bias when in HI mode.

We need a pic of the switch

[vh junkie]

So your on HI volt with the switch pushed down towards the bench with the amp inverted? Check you meter scale and get the bias to -35mvdc on pins 1 & 8.

[vanhalen5150]

Ok, got it. Im reading about -27mv.

[vh junkie]

-27 mv I hope... can you adjust it to -35mv with board pot, and verify that the switch pot has no influence? If so, set the switch pot to the middle for now...

[vanhalen5150]

Pin 1/8 on V4 -46mv
V5-V7 all read-40mv

[vanhalen5150]

With V4 at -35mv V5-V7 all read about-28mv.

And yeah the switch pot isnt doing anything.

[vh junkie]

That's good for now... significant difference, but not a game stopper. Power down and move the highest tube to the other side of the quad... does the low voltage follow the tube?