Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: ncusack on March 08, 2012, 11:10:20 am
-
Hello everyone,
I'm wondering what people find themselves ordering when it comes to resistors. I'm looking to place my first decent sized order so I have a solid variety of parts on hand for tweaking and repairs. What I'm looking for is a so called favorites list for values and amounts that typically get ordered. For instance I'm thinking of things like the typical plate resistor value 100k so I should order extras of those etc...
Any suggestions here would be greatly appreciated.
Cheers
Neill
-
i started with a standard selection (the packages of common values you can buy) and if i ran out of a value i ordered that value but 100 or more at once. i do the same if i have to order a specific value for a project. that way you get a nice stock.
-
Checkout the schematic(s) of amps you expect to work on to develop a parts supply list: resistors; power resistors; signal caps; filter caps; diodes. I usually order 5-6 of ea value at a time depending on any quantity requirements or discounts. YMMV. Keep in mind your usual mods. Also, review Doug's parts categories above.
-
I second JJ's approach.
Go through the schematic of at least 3-4 amps you think you'd be likely to build/mod/repair. Make a running tally of resistors and caps, noting wattage rating as well as value (or for caps, voltage rating). You'll see quickly which values add up.
We could suggest the typical 100k, 1.5k, 1M, but if you build amps that aren't on the beaten path (something not Fender/Marshall, such as Magnatone, Valco or Gibson), you'll likely have some parts values that would otherwise be oddballs. Same is true if you get away from 12AX7's to pentodes or lower-gain dual-triodes.
-
After you fool around buying 3 100K and 10 220K, you will get one of the all-values boxes with 100 of every value from 22r to 10Meg. Resistor prices are all about VOLUME. Penny a resistor and a nickle every time someone touches it. Get resistors on-tape spewed into boxes, you may never use 80% of them, but it still works out cheaper, and you always have the right value for all the small-stuff. (You still need some 5K 10K 5Watt and some 1 ohm; in tube-work you want some 100K 1W/2W.)
-
When you order a big ol' box o' resistors, You'll find they come in standard sets.
http://www-k.ext.ti.com/SRVS/Data/ti/KnowledgeBases/analog/document/faqs/res_e.htm (http://www-k.ext.ti.com/SRVS/Data/ti/KnowledgeBases/analog/document/faqs/res_e.htm)
that links explains it pretty well.
I ordered an E12 set a few years ago, in carbon film, with 50 pieces in each value, which worked out to like 2500 pieces for $50 or about .02 cents each.
I decided after it went thin here and there, that I preferred metal film better and ordered an E24 set, again 50 pieces per value and spent 1.2 cents each and it only cost about $90
When most of the vintage amps were designed and built, the industry standard was E24.
Ray
The E24 covers more than 90% of the stuff I need, you can order 100 of a specific value for less than $5 not including shipping