Stocking some resistors for tube apm experiments? Standard convention with values?

[daemonsgr]

Hi all,

Are there any traditional conventions or classic values for tube amp/pre building?
Id like to stock some koa spr2/5 so I can experiment while reading the Valve Amp book and the hi-fid PreAmp book.

Thanks

 

[Osvaldo de Banfield]

Values above 100KΩ are common in tube devices, for plate, grid and screen electrodes. Also some about 1KΩ for cathodes. ½, 1 and 2 W are usual power needed.

 

[rayma]

Are there any traditional conventions or classic values for tube amp/pre building?

!/2 W: 1k, 10k, 47k, 100k, 220k, 470k, 1M

You'll still need other values on occasion.

 

[PRR]

Experimenting: Get a 1,000-pack of all 5% 1/2W values in carbon-film.
100Values 1000pcs 1-10M ohm 1/2W Carbon Film Resistor Assortment Kit: Amazon.co.uk
1460 Pieces Resistor Kit 73 Values 1%, 1/4 W Metal Film Resistors : Amazon.co.uk
When you need a 680 or a 150k, it will be in there.
(Yes, the 2nd pick is 1/4W. That's fine grid and cathode. Plate resistors can run hot (use Ohms Law) so you may need to series/parallel say 47k and 56k to get 100k 1/2W. Remember these are penny-parts, use as many as you need.)

*Then* when you have a basically happy amplifier, spend for your koa spr2/5 exotics.

 

[daemonsgr]

thank you all, you points make sense, especially the cheap full kit one. if I build a final schematic Ill then get the "better" parts.

 

[Mark Tillotson]

I would say 1W ones are a better investment, less likely to fry if you forget to check dissipation, and more likely to be available with a high voltage rating (yes, resistors have
voltage ratings).

 

[DF96]

Yes, be aware of voltage ratings especially if the supply rail is above 250V. You may need to use 1W resistors just to get enough voltage rating.

 

[daemonsgr]

Yes indeed! The majority seems over 250