Any point in this?

[Oddvar R]

Hi. I was just wondering what the point of this heater "bridge"? Is it needed, or is it some greater idea behind it? Or can I just remove it and connect directly to the pilot light?

[erwin_ve]

You mean the terminal strip with the 330r and diode?
The 330r is to limit the current that will go to the pilot light(ohms law).
Without the resistor the pilot led will fail quickly.
The diode is for protecting the led for reverse voltage. The led don't like to see more than 5v reverse voltage.
When choosing a led don't use the super bright ones. They are annoyingly bright.

[Oddvar R]

Thanks for that. I have bypassed it for now, seemed to make some trouble. I have now started it up and I have sound out, which I never thought I would. Not from the jacks though. All the knobs are working, except the overdrive section. I can hear them react, but from a certain point, some terrible noise is introduced. I guess the jacks are not properly aligned yet.

I wonder about a couple of things. I haven't connected the half watt switch, since I don't need it, so I wonder if I need to connect pin 8 and 1 on the OT-tubes and ground them all four? Or?

Secondly I have on the primary side of the PT I have an orange lead named "SH", what could that be, ground or something else?

On one set of EL34's (layout #183) there are two 150R filament resistors, are they needed?

Hope I am not stretching the will of good people here, but so far it's been a steep learning process.

[norburybrook]

The filament resistors are there to create an artificial center tap. If your power transformer has a heater center tap you don't need them. If you are using EL34's then you do need to tie those pins together. That's also where you put the 1R resistors to measure you BIAS current in mV's



M

[Oddvar R]

So it worked. I am surprised.

[drew]

Secondly I have on the primary side of the PT I have an orange lead named "SH", what could that be, ground or something else

Faraday shield? What kind of PT is it?

[pompeiisneaks]

Yeah most likely that's connected to the copperish looking band on the outside. It is a faraday shield and has been orange on a few transformers I've gotten.

You should double check and confirm that's right, and then just ground it.

~Phil

[Oddvar R]

Faraday shield? What kind of PT is it?

IT's this Hammond.

[Charlie Wilson]

What are you using for a pilot light?
CW

[Oddvar R]

The old Fender type.

[M Fowler]

Pilot light.

Pilot light.pdf

[Charlie Wilson]

Dumble used an led. That is why the diode and resistor were a problem.
CW

[Markus55]

Hi,
The Orange lead is for the shield that runs between the Primary and Secondary winding for noise reduction from the Primary. Attach it to a good ground.

[Oddvar R]

Dumble used an led. That is why the diode and resistor were a problem.
CW

Ok, that was valuable news. What kind of led?

[norburybrook]

Erwin posted this in reply to you about a week ago.

You mean the terminal strip with the 330r and diode?
The 330r is to limit the current that will go to the pilot light(ohms law).
Without the resistor the pilot led will fail quickly.
The diode is for protecting the led for reverse voltage. The led don't like to see more than 5v reverse voltage.
When choosing a led don't use the super bright ones. They are annoyingly bright.

M