Phase invertor working voltage for resistors

[dragonbat13]

I'm rebuilding the phase invertor section of a dumble D'lite/102 build with a phase invertor trimmer.

I plan on using koa speer cf carbon film for now. 

According to the datasheet these have a working voltage of 350.  The plate voltage is going to be approx 390.  Not sure what the voltage drop will be, but it won't be above 350.

So, would these resistors work or do I need to find something else?

[stratomaster]

I was a bit perplexed by this as well, but I've come to think of them as two distinct but related ratings like the pressure and speed rating on tires. 

Best practice is to not exceed either, and depending on the resistor value and use case it's easier to exceed one or the other.

[pdf64]

I'm rebuilding the phase invertor section of a dumble D'lite/102 build with a phase invertor trimmer.

I plan on using koa speer cf carbon film for now. 

According to the datasheet these have a working voltage of 350.  The plate voltage is going to be approx 390.  Not sure what the voltage drop will be, but it won't be above 350.

So, would these resistors work or do I need to find something else?

Please include the info you're citing, eg amp schematic, Koa datasheet.
 
Do you mean that anode voltage of the phase inverter (LTP?) will be 390V?
I assume not but it's not possible to provide a valid response without key info.

Generally, the voltage limit applies to the maximum momentary / instantaneous voltage across the resistor.
The voltage between either resistor leg and other circuit nodes is somewhat irrelevant.

[HotBluePlates]

I'm rebuilding the phase invertor section of a dumble D'lite/102 ...

I plan on using koa speer cf carbon film for now. 

According to the datasheet these have a working voltage of 350.  The plate voltage is going to be approx 390.  ...

A sharp guy pointed this out in a book a number of years back, and prompted neurotic fits in conscientious builders.

Don't worry about it.  It used to be that most people ignored this rating, and got along just fine.  We might even say that any time you use 1/2w and up in a typical guitar amp (that doesn't have a multi-kilovolt power supply), you're probably safe to ignore this rating.


This will have a long-tail inverter, right?  That means from the power supply there will be a series-string compromised of:
  - Plate Load resistor
  - Tube
  - Self-bias resistor
  - Tail resistor
  - NFB shunt resistor


The rating means the resistor can have 350v across that one resistor 24/7/365 for decades.  Datasheets that bother to include this rating typically also have a rated "Overload Voltage" that's double the "Working Voltage."

As far as voltage ratings go, the 4 resistors from B+ to ground in long-tail inverter imply 350v x 4 = 1400v (plus whatever maximum voltage the triode can handle).  And then doubled for the safety margin of the "Overload Voltage."

[dragonbat13]

Lol. I believe I have that book and that's what started me to looking at all this.

The datasheet is attached:

[dragonbat13]

As far as the anode voltage being 390, I don't believe. 

I went back and looked at some schematics and layouts and I believe the B+3 node is where I saw that number. However I plan on getting to the bottom of this this afternoon.  I'll report with the schematics and layout just to make sure I'm on the right page

Not that it really matters, I'm using the resistors regardless.  But I want to document and have some data ready for when I fire the amp up.