Carbon comps do make a difference to my ears

[Psalm150]

I have an amp that had all metal film resistors in it. I decided to check out if there's anything to this carbon composition deal. Well let me tell you, I heard a huge difference. Same amp, just changed the resistors. Much smoother, sustains better, less brittle, more complex sounding. A bit warmer sounding somehow.
People may have different opinions, but this is what I heard.
Anybody have any experience and/or comments? What do youse guys use?

[Plexi]

You'll open up a can of worms with that post. I have to agree,i also know the sound of caps can be different in the types or brands...Seems the old orange drops aren't to bad..but i don't like useing the newer orange drops.
And then again,it depends on where they may be used. It just seems they can make an amp sterile sounding.I don't know if they make them different now,or material used,who knows? As for the CC or CF Some like using them in all parts but the power section. Another thing that happens when people do the test you just did, the values change in the CC over time..or even NOS ones. So when you change them,the circut changes,gain etc.\
After working on amps for many years.. one thing i'd like to point out.
When the CC are used in boards, more so with eyelets than turrets, but either one,what happens is..one end is soldered in,then the other end. Try NOT to pull or put strain on the resistor,have the ends bent so there is no strain or stress.. almost like stretching it or pulling it to get it soldered in.
Over time the added heat/cold off on..the strain will make them crack or break in the middle. I guess its really up to what one likes,or what they like to use. Some people have built identical amps,but used different type resistors,and couldn't hear a difference..So its very weird. I have seen on Ampage people do this test and report that it did change the amp sound. And as some have seen on here..they don't like the soldering iron put to them too long. One good thing about them is most have extra long leads..
Richie

[MarkB]

Ever heard of double blind testing?

MarkB

[markh]

Double-blind testing is very difficult to do when you only have one amp to work with.

But to MarkB's point, it's hard to be objective about your own "baby." I don't think you would have went to all that resoldering trouble if you weren't *expectng* to hear a diference.

Richie also makes a good point in that most MFs are 2% tolerance, and most CCs are 10% or worse. If they're old, probably worse! Just overheating them a bit with the soldering iron can change their value.

An interesting experiment would be to measure the precise value of each CC in there and replace it with the same MF value.

It is a fact that CCs will slightly distort a *high amplitude* signal, and so will make a difference when used, say, for PI plate resistors. I don't think I would use them anywhere else.

I have several paper shopping sacks full of CC resistors I got for free when a shop closed some years ago. I've never been tempted to use them, other then as experiments. Hmmm, perhaps a job for zBay....

--mark

[zaphod_phil]

Hey Bro, are you sure they were carbon comp and not carbon film? The carbon comps have a completely cylindrical, dark-brown body. They aren't too popular even with vintage amp fans because (a) they are very hissy and (b) they change in value as they get older. To quote Randall Aiken, "...higher wattage metal films should be used everywhere in an amplifier. I don't want the tone of my amplifiers to be determined by something as variable as a noisy carbon comp resistor, which will drift and change with time, temperature, and humidity. I'd rather tailor the tonal response with known, repeatable circuit design rather than depend on the variable lot quality of carbon comps. "

However, there are two things they could do to warm up your sound. The first is because they have some wide variances on value, they can introduce more imbalance into the PI and power stage, hence more nice even-order harmonics. The second is that carbon comp resistors will vary in value to some extent depending on the applied voltage. I have seen an article that suggest that this effect will also help create even-order harmonics, if carbon comps are used as plate resistors, as you get large voltage swings at that position. Also using higher wattage resistors will help reduce the hiss somewhat. IIRC the same article recommended strongly against using them anywhere else, due to their noise problems.

I have an amp that had all metal film resistors in it. I decided to check out if there's anything to this carbon composition deal. Well let me tell you, I heard a huge difference. Same amp, just changed the resistors. Much smoother, sustains better, less brittle, more complex sounding. A bit warmer sounding somehow.
People may have different opinions, but this is what I heard.
Anybody have any experience and/or comments? What do youse guys use?

[drgork]

Here is a link that was put up several months ago on carbon comps. I too like to use them when I can find them. Seems like they really make a bigger difference in the higher voltage positions. It's getting harder to find NOS stuff that's within tolerance.

Danny


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

[Psalm150]

They sure don't have em at Radio shack, but Hoffman sells carbon comps.
I know there is a lot of disagreement on this. Just thought I'd share what I heard. And see what others thought.

[MarkB]

If CC resistors make your amp sound good to you, then that's all that counts. Amps and guitars are just tools to do the job of making music. That being said, I'd bet dollars to donuts that in blind tests the only difference you'd notice would be the noise of carbon resistors. And the noise would take away from sustain, not add to it.

Just my opinion
MarkB

[Plexi]

"""the only difference you'd notice would be the noise of carbon resistors. And the noise would take away from sustain, not add to it."""

If they made that much noise i'd be changeing them..lol

Some are noisey..some aren't, and work fine. I've worked on many amps that sound like thunderstorms and pops..etc I've also seen some that when changed,were dead quiet no added or extra noise.. Preamp tubes can be somewhat like this in noise.. so say you have a loud hissing old Mullard or telfunken..you'd change it. Caps also have a life span or rated hrs of life.. Just trying to get across that they don't have to be noisy. I think alot of it comes from when people have the noisy racket making resistors, they think all of the CC sound like that. but you can replace them and not hear any noise or added hiss..its usually just the bad ones that do that. Or one that has gone way up in value,then the circut gain will change,which could add more hiss...hey but there are many types of resistors out there,and use what you like,or think is best. The others seem to hold up better. Just trying to shed some light on some of the reasons they get a bad rap ..

Richie

[Psalm150]

The only way to decide on this one way or the other is to try em out and see. I know I've tried things based on a lot of people's positive opinion that sounded terrible to me and some things that were reputed to be rotten sounded great to me. And maybe they sound good to me but I may have a tin ear compared to someone else.

As far as the noise thing goes, I haven't noticed excessive noise, but I do admit to not being too concerned with noise either. My house has freakin ungrounded outlets so I'm definitely not the one to ask about that aspect!
Humbuckers do ok here, but single coils...way too much hum. But that's the way I like it anyway.

[Plexi]

I hope you didn't misunderstand my post..
i was agreeing with you..lol

So i just did a small search of some of the big name amp builders. Or some that have the guru status of amp building..lol

Alot of them also swear by useing carbon comp or carbon film. so heres some of those links and a small paste of a couple things. This was just the few i found in a short time..but i'm sure there are many who claim just they don't use them.. more things to ponder or look over Oh well have fun reading... Hopefully waiting to hear of Graydons show details for later..
Richie

Komet amp..The carbon film resistors are 1-watt types throughout the amp.

Holland Amp

http://www.carramps.com/carrframeset.html

And this on Victoria amps

These amps are built with the highest grade of components, and intense labor expertise. One example of this is the common and simple resistor. Today's amps use carbon film resistors. They are great, but do not have the same qualities as a carbon composition resistor of the past. As carbon comp resistors get hot, their values change more than a modern resistor. This adds even more subtle character to these vintage amps.

Today, many boutique and high end builders mention that they use "carbon comp" resistors for their musical properties. This is terrific, but just like most other things, these can be made offshore (for the guitar amp market that can make this a great bootleg item), or even if original stock, they may have been sitting in some warehouse for decades, unprotected. In the case of Victoria, Mark Baier bought enough of these a decade or so ago (all sealed and from the same batch, which had AEC storage), to last a few lifetimes. This is one of the "smaller" aspects of Victoria focus on their product. There are many "larger" aspects.

[MarkB]

As carbon comp resistors get hot, their values change more than a modern resistor. This adds even more subtle character to these vintage amps.



?????



MarkB

[Dai]

You can read about sound all you want, but really the surest way to figure out what they mean for you is to actually things out. IME, sometimes I do hear a difference with them and sometimes I don't. There have been cases where I preferred carbon film over comp. There was a situation where I liked carbon comp better than film for a B+ dropping resistor. Sounds crazy but that's how it sounded. At one time, I assumed that higher tech parts would automatically improve the sound and that things like that wouldn't matter, but in practice, I found that this was not the case. As for noise, when it comes to hiss, it doesn't bother me that much unless it's really overbearing, plus some hiss sounds better than other hiss (seemed to have some sort of calming effect--weird, huh?). Maybe it makes more sense if you are building a high gain amp (or modding something into), but is the difference in hiss really that bad with something like an 18-watter (or any other relatively low gain amp)? I remember something in ye olde Angela catalog. "If you're that worried about noise go build a metal detector!", or something along those lines. Also, ask yourself this. "Is there a major hiss problem showing up on old recordings coming from carbon comp-equipped amps that have been used on countless classic recordings?" I'm open to trying out non-vintage type parts, but I'll do things like try metal films for the mix Rs in a Marshall once in a while and I still have not liked them (which does not mean I'll not like them everywhere else or that they won't sound good anywhere else).

Then there's also the subjective aspect of hearing. Recognition, taste, ear fatigue, ageing, maybe some general differences according to sex. Something I heard recently was that women have a better ability to differentiate between shades/spectrums of colour like different shades of red. I've heard of differences in hearing according to sex. Sometimes people will have sound clips, and something someone else thinks is great, I might think "That's horrible!". Or someone describes a clip in a way where it seems like they're experiencing the sound in a similar way. Or ask yourself if sound/recording engineers come straight out of the womb, or is it the case that you have to learn sound manipulating skills? And so on. When you're talking about double blind testing, double blind testing on who? Andy Johns, Eddie Kramer, etc. or some young kid who just started playing and likes too much distortion (I'm not pointing any fingers but this is something I've observed in myself as well as others)? I would think that there would be a difference in perception in such a case. So the hearing experience I really doubt is the same for each individual (though I'm sure there are valid generalizations you can make).

Personally, I like to try to obtain a bunch of different types of parts and go with what sounds best to me, but I feel whatever approach you take is valid as long you get results. Getting results that make you want to keep playing or are inspiring to manipulate is the important thing, IMO.

Dai

[zaphod_phil]

As an EE, this sounds more like total marketing BS to me! And so incredibly subtle that no one can tell at all....

As carbon comp resistors get hot, their values change more than a modern resistor. This adds even more subtle character to these vintage amps.



?????



MarkB

[Plexi]

""""As an EE, this sounds more like total marketing BS to me! And so incredibly subtle that no one can tell at all.... """"

Welllllll not exacly, they do change, but when you see a major change would be for example,you had a resistor that is in a spot to drop voltage/current and its to the point its very HOT..this is when the value will change.. May have to look and see if i can find some things to back it up.
But i think thats what they are getting at..the values change,slight so the circut may have a bit more or less gain due to this..but should be subtle change if any. So your probably right on a little hype on that part.
I'd say any resistor may do this, but i've seen some CC that have been in amps and while hot the resistor measures way off,and will change as it cools. But this was some that were barley smoking lol.. They almost look like they boil at one point before they start to smoke..

There was also a post years ago on Ampage, of cooking your resistors in an oven at low temp to heal them..removing moisture and supposed to help them. I've never gone that far..lol i just usually replace them.

Richie

[zaphod_phil]

Well, I have no problem with the idea of using a couple of carbon comps for the plate resistors of an 18W's PI. It's quite likely for the reasons already discussed that you *will* get a somewhat warmer/sweeter sound. In fact I think I might try that myself, witha couple of carefully-selected carbon comps. As for the rest of the amp, no way! I have another old Marshall combo that I've been restoring. It's got a a nice warm sound and very little hum, after some work on the power supply filtering, and it's been re-tubed. However, with all those old resistors, it hisses like snake pit stirred with stick....

[markh]

I used all carbon films in my smallbox recreation (because the original I was re-creating did , and it's not noticably noisier than my plexi6v6 which used all metal films. I wonder if carbon films have any special mojo, however! Most of the huzzah seems to be over the noisiest and least reliable resisitors, carbon composition.

--mark

[zaphod_phil]

Yes, I agree it's specifically only carbon comp resistors that give all the noise and stability problems. Carbon film are fine. In fact the Lite II I'm building at the moment mainly uses carbon film (see pic). I'm hoping they may impart some of that Mojo...