Carbon comp mojo

[djroge1]

I'm looking at sourcing parts to build an amp in the D style and I'm wondering if there is any truth to the mystic and mojo that surrounds carbon comp resistors?

How about the caps? Is there any mystical mojo that stems from these?

Do you have any specifics you use? If so, where in the signal chain do you use what?

[groovtubin]

I'm looking at sourcing parts to build an amp in the D style and I'm wondering if there is any truth to the mystic and mojo that surrounds carbon comp resistors?

How about the caps? Is there any mystical mojo that stems from these?

Do you have any specifics you use? If so, where in the signal chain do you use what?

Dumble #40 has them!

[talbany]

A few things to know about CC Resistors

1 The new brown ones they sell now pretty much SUCK!!
The older Allen Bradley's much better tonally..
2 Very inconsistent amp to amp
3 Adds Hiss to high gain circuits (Plates)
4 Tone shifts with temperature flux
5 Can catch fire when used in power supply /Screen res..
6 Wide tolerance swings

Carbon Comp's do get a nice smoothing as well as a somewhat darkening effect on the top.. and in some cases down in the mid range floor..For this reason they work well attenuating some of the harsher frequencies associated with higher gain amps or harsh sounding caps.. Some people prefer them when using overdrive pedals in the front end to help with the harsh overtones associated with a clipping transistor especially germanium Fuzz Face....

I wouldn't build a D-style amp loaded with them since a big part of the tone in these amps resides in a pronounced mid range articulation and clarity on the top end..CC's have a tendency to throw a veil over the sparkle of a clean channel..
You can try using them sparingly here and there.. Places I would recommend trying would be grid resistors on V2 and power tubes or maybe the OD entrance network (Just 1 there goes a long way)..
Other places would be 100k before the drive pot or the 150/180k before the level pot... keep an eye on your low end too..CC have a tendency to smear the low end a bit
as far as any mojo associated with CC... NAH!!!!


Tony VVT

[Noel Grassy]

I can't comment on this application in a Dumble but some of my amps have improved primary tone when I changed the grid resistor between the input jack and V1's grid from a metal film to an AB carbon comp.

[odourboy]

Interesting article here:

http://www.geofex.com/Article_Folders/c ... oncomp.htm

[butwhatif]

Carbon comps are great for a lot of things, like if you want build variability, and performance variability. Who knows, maybe that's what made one tweed amp sound better than another, and also the ability to change with conditions and time. One thing for sure, as plate resistors and other hi gain area components, they add a fair bit of the 'mojo' noise to the circuit, which in the context of some types of music, actually helped ! And just by ordering a particular value, you can get a bunch of values at no extra charge, although A-B considerably changed that and the noise factor. Much has been written on the 'mojo' of these devices, and although I've never been able to measure it, some things are best left alone.

[bluesfendermanblues]

I'm looking at sourcing parts to build an amp in the D style and I'm wondering if there is any truth to the mystic and mojo that surrounds carbon comp resistors?

How about the caps? Is there any mystical mojo that stems from these?

Do you have any specifics you use? If so, where in the signal chain do you use what?

My Ceriatone, Overtone Special kit, came with
- A carbon comp 22k grid resistor, between inut jack and V1a grid.
- And 22k carbon comp on output tube grids, pin5.

Don't know about mystic and mojo or if the carbon combs has any major impact on the tones.

To me the 'magic' in a NON-Hrm lies in adjusting the trimmer (which I have converted to a pot on the back) in order to accomodate guitar being used, and the level of input volume and OD gain.

And my amp sounds great. IMHO

[djroge1]

Interesting article here:

http://www.geofex.com/Article_Folders/c ... oncomp.htm

That's a good article and helps a lot. Thanks.

[collinsamps]

Talbany speaks the truth. Very well written.

[talbany]

Talbany speaks the truth. Very well written.

Thanks!!

Tony VVT

[BobW]

I haven't read the articles yet but except for the leads, CCs have no inductance properties, and have a resistive value / positive temperature drift.