Lead 100 Watt started

[angelodp]

Right right sorry, its the 100w SL board jumpers that carry B+ and the area around the Bias works. Metro mentions 22g with a thicker insulating tube. I was hoping to minimize the jumpers with 22g Teflon and still have them on top.

[xtian]

22ga is fine, but your insulation needs to be rated for ~600v.

[angelodp]

Copy, Teflon 22g from Apex is at that mark.

[angelodp]

Moving along. Should be firing up later this week.

[angelodp]

More

[Colossal]

Looking good...

[angelodp]

This is nearing completion. The board is populated but not soldered in yet. If you see any issues sure would like to get a heads up. The stacked caps worry me a bit but I can put some cushioning ...quick cure silicone or the like.

I noticed on Paul's stellar build ( and stellar sounding) that he has V1 with a common cathode and a .02uf instead of .0022uf on the bright cap. I suppose I can listen to this as is and then tweak.

See anything important to address?

PS PPIMV not wired yet.

best A

[xtian]

Great looking lead dress!

Gotta say, those 0.2uF caps on the rectifier are...silly. They're like an appendix or tonsils. Why? Someone learn me.

[angelodp]

I know they are loony looking, but I did see them on many great sounding amps. Paul V recently has a very fine sounding 100w that has the 'tonsils' - BTW Aaron thanks for all the guidance.

See any smoke inducing fuddery?

A

[angelodp]

Outer foil connections. In the SDM site the various layouts show a marking on the capacitors for the outer foil.
Its a small horizontal line, at least that's what it appears to be. It follows Aikens recipe. Now all I need to do is MM's trick.

"Here's another simple way to find the outer foil on film caps: Just insert the banana plugs with bent paper clips shown at the top of this thread into a DMM. The cap is placed across the terminals and held tightly between thumb and forefinger. The resulting noise voltage is read in mV. I find it takes about 10 seconds for the reading to stabilize, but there is a clear difference in the reading between orientations, as seen in the photos below. The cap shown is a 20n SBE6PS, and I also tried a 50n 6PS and a 100n CDE tubular. All showed a 2x or greater difference in voltage. Larger caps will have lower absolute levels due to their lower impedance at the dominant 60Hz test frequency. As mentioned above, these plugs are also very nice for quickly checking resistor values too."

Question is, am I correct that the SDM graphic is indicating outer foil on the caps in their layouts?

[adew]

Yes

[angelodp]

A question. In the schematic of the 100Watt SL the juncture between 100k plate (V3) and the choke shows 20k, while in the layout its setup as a 10k in series with an 8.2k. Why this arrangement and not simply use a 20k across the turrets?

[Roe]

A question. In the schematic of the 100Watt SL the juncture between 100k plate (V3) and the choke shows 20k, while in the layout its setup as a 10k in series with an 8.2k. Why this arrangement and not simply use a 20k across the turrets?

You ned two two watt resistors or one five watt one

[angelodp]

New caps from Mouser just in. PPIMV and then fire it up.

[angelodp]

PPIMV in, thorough check tomorrow then Variac w/ bulb limiter. Hoping it's all good.