Resistor question - power rating

Get support and show off your MetroAmp JTM 45 kit builds.

Moderator: VelvetGeorge

Post Reply
shakti
Senior Member
Posts: 2053
Joined: Tue Apr 05, 2005 9:06 am
Just the numbers in order: 7
Location: Ramnes, Norway

Resistor question - power rating

Post by shakti » Sun Mar 05, 2006 10:37 am

In my JTM45 kit, there is no 10k metal oxide resistor. There is, however, a carbon film 10k resistor. Is this one fine to use in the slot right next to the on-board 16uF capacitor? I think the metal oxide ones are rated at 2W and the carbon films at 1 watt (although this 10k carbon film is physically larger than the other carbon films in the kit...).

In most photos I see here, and in George's kit photo, that slot has a metal oxide, that's why I'm asking.

On a related note, why does the kit ship with metal oxide resistors for the 820 ohm V2 cathode resistor and the 100k right next to it? Any reason for metal oxide there, and not standard carbon film?

shakti
Senior Member
Posts: 2053
Joined: Tue Apr 05, 2005 9:06 am
Just the numbers in order: 7
Location: Ramnes, Norway

Post by shakti » Sun Mar 05, 2006 11:11 am

And to follow this up...I asked for carbon comps for the typical positions (inputs, mixer, cathodes, tone stack and feedback), but see now that I got CCs for most positions. Are there any spots where I should avoid CCs to reduce noise?

shakti
Senior Member
Posts: 2053
Joined: Tue Apr 05, 2005 9:06 am
Just the numbers in order: 7
Location: Ramnes, Norway

Post by shakti » Sun Mar 05, 2006 12:44 pm

Even more specifically, I'm worried about the following resistors:

- 220k bias splitter resistors - are CCs OK there?

- What about the 220k in line with the diode on the board?

- And what about the 470 ohm which is between the two 1MOhm resistors (I'm not sure what this resistor is)?

- The 10k which connects to the common point of those three resistors mentioned above (2x1M+470)?

- 82k and 100k between the PI caps?

- 15k between the bias caps?

If anyone can tell me if CCs will be fine in all these positions or if I should avoid them somewhere, I'd be most thankful!

User avatar
Flames1950
Senior Member
Posts: 9294
Joined: Sun Feb 08, 2004 1:04 am
Location: Waukee, Iowa

Post by Flames1950 » Sun Mar 05, 2006 1:33 pm

Carbon comps are working fine in all those spots in my build........
Image

shakti
Senior Member
Posts: 2053
Joined: Tue Apr 05, 2005 9:06 am
Just the numbers in order: 7
Location: Ramnes, Norway

Post by shakti » Sun Mar 05, 2006 2:07 pm

Thanks!
I see that the Germino amps seem to have CCs pretty much in all positions. But that means I must get some 1M CCs to keep the look "complete"... :roll:

User avatar
VelvetGeorge
Site Owner
Posts: 7233
Joined: Tue Oct 14, 2003 5:12 pm
Just the numbers in order: 13492
Location: The Murder Mitten
Contact:

Post by VelvetGeorge » Sun Mar 05, 2006 3:22 pm

I had to sub in a 10K 2 watt carbon film because I was out of the MO's. I can send you one if you like, but the 2 watt CF is well within spec.

Just let me know.

george
Check out Plexi Replicas for my personal amp builds...
Image

Post Reply