[MaskdBagel]

OK, so I've posted a few times now about building another Cornet and really concentrating on amazing build quality this time and maybe doing some tweaking. Thanks for all the answers you guys have been giving so far. I can read instructions and a schematic, and I can solder just fine (i.e., I can build a good piece of equipment out of a good kit), but now I'm learning a ton about the principles that make this guy work and what parts do what, and for that, I'm extremely grateful.

Here's my latest question. I've just gotten all my resistors in the mail, metered them all, and sorted and labeled them by actual value. (Interestingly, other than the 220s, some of which measure at 221, any deviation from the marked value is lower in resistance in every case.) I know to match them all as closely as possible (201L and 201R the same value, for example), but I'm wondering which ones can stand to be just a little off in value and which ones will have a greater effect on the overall outcome if they're not as accurate. My instinct is to get the EQ section as accurate as possible, but A) I'm not positive which components that would be (help?), and B) that may not be exactly the best use of what I have. Obviously, having every piece exactly at value would be awesome, but that's never going to happen, at least at my budget. 

Any opinions or advice would be very much appreciated. Thanks again for helping out the most amateur guy on the board.


EDIT: Forgot to mention: the 1.8 5W resistor (223) measures at 2.0. Since there's only one of these, I assume it's important.  Is that an acceptable variance, or should I pick up a more accurate one here? Thanks!

[analog97]

What's the measurement precision of your DMM?      Seriously, don't obsess on this.  +/- a few % is just fine and dandy.  Enjoy!

[MaskdBagel]

Mmm, probably not amazing. It wasn't the cheapest meter at Home Depot (yep, Home Depot; that answers your question pretty well, probably  ), but it wasn't the nicest either. Ranges are 200, 2k, 20k, 200k, 2M, and 20M, I believe.
Good to know the design forgives as much as a few %. Still love to do the best thing if I can, at least in principle (so the question stands, I suppose...), but it's comforting all the same.

Thanks!

[WGH]

EDIT: Forgot to mention: the 1.8 5W resistor (223) measures at 2.0. Since there's only one of these, I assume it's important.  Is that an acceptable variance, or should I pick up a more accurate one here? Thanks!

R223 controls the heater voltage (H+). The 1.8W resistor may work fine for the original 5Y3GT tube, but change to another tube and you will have to adjust the value (usually lower) to hit the optimal 6.3V. Mills is a popular brand, I used a wire wound Lynk resistor I had laying around, just make sure it is rated for 5W or higher. Paralleling resistors works too.

http://www.audiocircle.com/index.php?topic=41430.0

and

http://www.audiocircle.com/index.php?topic=80031.msg783560#msg783560

Wayne

[poty]

...all my resistors ... metered ..., and sorted and labeled them by actual value. ... I know to match them all as closely as possible... I'm wondering which ones can stand to be just a little off in value and which ones will have a greater effect on the overall outcome if they're not as accurate. My instinct is to get the EQ section as accurate as possible, but A) I'm not positive which components that would be (help?), and B) that may not be exactly the best use of what I have. Obviously, having every piece exactly at value would be awesome, but that's never going to happen, at least at my budget. 

First of all - if you have "standard" resistors - they are 5% or even 10% tolerance. Even if you have recommended by others (PRP, Takman...) ones - they are almost all in 1% range. I've not mentioned temperature stability yet. Your "matching" could be just not true, because the resistor will work in different temperature range than you have while measuring and the resitor temperature dependence could be slightly  different for each resistor..
Then - all the circuits have some tolerance to changing values, and the resistors are not the greatest players in this field. The power supply is not regulated and changing voltages in your mains will led to changing sound (just for example).
Summary: check the resistors to be in the right value taking in account their tolerance - this is almost all you can do to be sure it works.