how much tolerance on Allen Bradley resistors are ok?

Share your home builds, knock offs and ground up customs.
Post Reply
Silmaril
New Member
Posts: 18
Joined: Mon Sep 03, 2018 3:07 pm
Just the numbers in order: 13492

how much tolerance on Allen Bradley resistors are ok?

Post by Silmaril » Wed Oct 31, 2018 6:46 pm

I bought Allen Bradley resistors with 5 percent tolerance. But when I measure it, many of them have 10 percent tolerance or a bit more. So now my question, I build a JTM45, is it ok to install resistors which are 10 percent over the value they should have?

Tazin
Senior Member
Posts: 793
Joined: Fri Jan 19, 2007 8:54 pm

Re: how much tolerance on Allen Bradley resistors are ok?

Post by Tazin » Wed Oct 31, 2018 7:07 pm

Personally I would stick with resistors that are slightly less than 10 percent. Just be careful not to over heat them during installation since that will cause the tolerance to go up.

User avatar
axeman
Senior Member
Posts: 2464
Joined: Wed Apr 02, 2008 1:21 pm
Just the numbers in order: 7
Location: Los Angeles
Contact:

Re: how much tolerance on Allen Bradley resistors are ok?

Post by axeman » Wed Oct 31, 2018 7:37 pm

They are ok to use in the signal sections like 820, 68k 2.7k V2 100k, 820, 47k feedback and 470k mixers. Do not use them in the power section or any area on the board with 300v and above.

RockinRocket
Senior Member
Posts: 262
Joined: Thu Aug 07, 2014 10:44 pm
Just the numbers in order: 13492

Re: how much tolerance on Allen Bradley resistors are ok?

Post by RockinRocket » Wed Oct 31, 2018 10:06 pm

axeman wrote:
Wed Oct 31, 2018 7:37 pm
They are ok to use in the signal sections like 820, 68k 2.7k V2 100k, 820, 47k feedback and 470k mixers. Do not use them in the power section or any area on the board with 300v and above.
Do you mean don't use drifted CC resistors in the B+ dropper rail or simply don't use CC in the B+ dropper rail at all and why please?? Thanks

User avatar
axeman
Senior Member
Posts: 2464
Joined: Wed Apr 02, 2008 1:21 pm
Just the numbers in order: 7
Location: Los Angeles
Contact:

Re: how much tolerance on Allen Bradley resistors are ok?

Post by axeman » Wed Oct 31, 2018 11:01 pm

Don't use CC resistors in the B+ dropping or power section. Because they will drift and give you problems. especially when you spend money on XF2 or any Mullards you'll end up buying new ones.

Silmaril
New Member
Posts: 18
Joined: Mon Sep 03, 2018 3:07 pm
Just the numbers in order: 13492

Re: how much tolerance on Allen Bradley resistors are ok?

Post by Silmaril » Thu Nov 01, 2018 6:53 pm

OK thank you.

But when I see it right The GPM45 and Germino Classic use CC in B+ or other areas than the signal path.
GPM45:
Image

Germino:
Image


So if they are not driftet it's ok to use them in sections like 10K1W, 1M, 470, 10K, 220K and 8.2K1W ? Or isn't it recommended?

User avatar
axeman
Senior Member
Posts: 2464
Joined: Wed Apr 02, 2008 1:21 pm
Just the numbers in order: 7
Location: Los Angeles
Contact:

Re: how much tolerance on Allen Bradley resistors are ok?

Post by axeman » Thu Nov 01, 2018 7:32 pm

First of all, WOW beautiful amps. Just because someone did it doesn't mean its correct or incorrect. What I'm saying is, for added protection use a better resister that's made for high voltage. I have some 10k, 8.2k 2 watt resistors if you need any, you could have some for free. For the anode section you could use 1 watt carbon film 100k. Remember you are investing in an amp that you might keep for ever or a long time, might as well build it dependable right? If you need a few resistors I'm welling to help.

RockinRocket
Senior Member
Posts: 262
Joined: Thu Aug 07, 2014 10:44 pm
Just the numbers in order: 13492

Re: how much tolerance on Allen Bradley resistors are ok?

Post by RockinRocket » Thu Nov 01, 2018 8:10 pm

My 72 JMP still has the 10k CC B+ droppers and the amp gives me no problems!

User avatar
axeman
Senior Member
Posts: 2464
Joined: Wed Apr 02, 2008 1:21 pm
Just the numbers in order: 7
Location: Los Angeles
Contact:

Re: how much tolerance on Allen Bradley resistors are ok?

Post by axeman » Thu Nov 01, 2018 8:11 pm

Then use them

Silmaril
New Member
Posts: 18
Joined: Mon Sep 03, 2018 3:07 pm
Just the numbers in order: 13492

Re: how much tolerance on Allen Bradley resistors are ok?

Post by Silmaril » Thu Nov 01, 2018 8:23 pm

OK, I just asked, because I have got these listed AB CC resistors (10K1W, 1M, 470, 10K, 220K, 82K and 8.2K1W). But when I get you and the circuit diagram right, I shouldn't use the 220K in all sections and the 8K21W because of high voltage (300V+). But the 10K1W, 1M,470, 10K and 82K AB CC's should be fine to use?

Post Reply