Help identifying function of circuit please

[whopperplate]

Hello everyone, please can anyone tell me what is the function of the extra iskra resistor and fuse on the mini power supply tag board? Is this stock? I have never seen it in other archives. Thank you

http://www.amparchives.com/album/Marsha ... 003-1.html

[axeman]

It's a 1987 Super Lead

[whopperplate]

Sorry, I will edit the title to clarify:

What is the function of the portion of the circuit with the fuse and the resistor I n the extra Tag board?

[whopperplate]

Bump

[Tazin]

It's a Fuse and resistor for the heater circuit. It was required to conform with SEMCO electrical regulations. The resistor is in line with the heater center tap and the fuse is in line with one leg of the heater wires.

[whopperplate]

Thank you for the education!

I am also trying to ascertain the value of the grey capacitor can with the ground wire on top of the chassis. I assume the small Daly is a 32/32uf and the grey is a 50/50 ?

Any ideas are welcome, thank you!

Charlie

[RockinRocket]

There seemed to be a lot of variation on the filters until the Metal Panels 1987s came out then they became 50/50s consitantly but the Plexi panels were lower filtered than the 50/50s. Ceriatone suggests 32/32s and that might be as good as any for a guide line.

Heres some good information regarding filtering although it donst show all 3 cans values.

http://marstran.com/Historic%20Data%20Base.htm

[whopperplate]

Thanks for the link!

I am gonna guess and say that this specimen must be 32 (blue) and at least 50 (grey) on the top cans, based off of the dimensions and visible terminal posts from photos.

Charlie

[Tazin]

The gray filter capacitor mounted on top of the chassis is a Marcon 40uF + 40uF/450v. The smaller blue capacitor mounted next to it is a Hunts 50uF/450v. The blue filter cap mounted on the turret board is a Hunts 32uF + 32uF/350v.

[RockinRocket]

So that amps filtering is 40/40/50/32/32?.

The Hunts is only a 50?

The photo appears to have to halfs.. but only one side being used.

But a single 50 would be similar to a 32+ 32 can.

[whopperplate]

I think it would be 50/40/40/32/32, no? Isn't the furthest can the mains cap?

Also, is that two 8.2k resistors in the b+ line? Also, what would the bias slide resistor value be? Still 25k?

Thank you all
Charlie

[Tazin]

It's 50/40/40/32/32. Yea, the shorter Hunts cap is a single element 50uF/450v used for the mains filtering. The first two B+ dropping resistors are 8K2 and other two near the preamp filter cap are 10K. The bias slider resistor is either a 75K or a 100K.

[RockinRocket]

Yep thanks your right.

So ceratones 32/32 x 3 cans would be right on track with the filtering of this amp 192 vs 204 labeled capacitance.

[Tazin]

If your going by total capacitance then three 32uF + 32uF caps would be close to the amparchives amp.

[whopperplate]

Thank you for the info!

I notice that the power transformer seems to be oriented with the heaters near the switches, opposite of how most amplifiers I see are wired. Is that just more of the era specifics of the plexi? I have read that they eventually oriented the OT differently for noise reduction.

Thank you

Charlie