resistor types

[Bruce / Mission Amps]

What about the carbon film resistors. Wouldnt this be the best of both worlds. Just askin.

Here is what was just said in the post above yours...

"AC20 build sounded quite flat and lacking sparkle until I replaced the 1w CFs with CCs."

I don't know what an AC20 is but I can tell that from my perspective I have never heard a CC resistor set make an amp sound better... especially more sparkle.
However I have had a number of amps (mostly helping home builders) with wrong value or misread CF resistors in them, sound very good with the correct value CF resistor.

[jrfrond]

.....but I can tell that from my perspective I have never heard a CC resistor set make an amp sound better... especially more sparkle.....

With my experimentation, it was not sparkle that was gained. In fact, very little about the actual tonality changed. It was all feel, a certain "bounce" that was not as prominent before, somewhat akin to opening a negative feedback loop, except that the test amps use no NF, and already had that feel. FWIW, the amps were built with CF.

[HTH]

Here is what was just said in the post above yours...

"AC20 build sounded quite flat and lacking sparkle until I replaced the 1w CFs with CCs."

I don't know what an AC20 is but I can tell that from my perspective I have never heard a CC resistor set make an amp sound better... especially more sparkle.
However I have had a number of amps (mostly helping home builders) with wrong value or misread CF resistors in them, sound very good with the correct value CF resistor.

I call it an AC20 because it's just a top-boost Vox preamp into a pair of cathode biased 6V6s, hence AC20. It's a cool sounding little amp, really fat and grindy.

I don't know why the tone changed, but I know what my own ears tell me.

I've got other amps that have sounded great with CF and MF resistors, so CC are not the magic ingredient or anything, just happened to make a difference on this specific amp of mine.

[cminor9]

I read this: http://www.geofex.com/article_folder...carboncomp.htm This article does mention that there is benefit to using CCs, namely, resistor distortion. I am a big fan of "it means nothing if you can't measure it" when it comes to electronics. According to the article, CCs do provide a measurable effect. Now whether it makes a sonic difference or not, well, I guess that's wide open. I have always read that CCs will aid in giving a nice swirl, and when you read this page I think it makes sense as to why.

The main conclusion that I drew from this article was that using CCs on cathodes is bad, and using them on input stoppers and for the bright inputs is also bad and provides little sonic value.

I recently built a 5E3 using all carbon comps. This afternoon, I spent some time replacing the 68k input stoppers, 1meg bright inputs, 820 ohm cathode resistor on v1, and the 1500 ohm cathode resistor on v2a. I left the 100K plate resistors alone only because I didn't feel like removing the board in case my B+ lead came out. The hiss that was there before is almost completely gone. I have read posts on here stating that the 5E3 should not hiss, but mine did (no hum, just hiss). Replacing the CCs as described really cleaned the amp up a lot.

Still get nice swirl, a good warm tone, etc, just much quieter. I think I'll keep using metal films on mostly everything before the PI on new builds. It really made a difference in all the right ways. Oh, and for cost, the metal films cost much less. I get them from Antique Electronic Supply for $1.5 for five, compared with $2 - $2.5 for five CCs.

[Tubis]

Yea, the CC is not quite linear so some distortion is the result. Note that some caps do the same thing. Ever noticed the crisp that cheramic caps tend to give to the treble?

[BackwardsBoB]

Cminor9 wrote:

I left the 100K plate resistors alone only because I didn't feel like removing the board in case my B+ lead came out.

Based on the non-linearity argument, these are the ones that should stay carbon comp. They have a large voltage swing on them, they're high value, and a bit of noise won't get amplified (more likely, it will get attenuated). Thanks for reporting your results. Hiss is much easier to accurately note changes in compared to "sparkle".

Me? I like to play clean, and I value dynamic range highly. Hiss bad.

[baddog]

resistor type

I changed all of the 1/2 watt & 2watt CF resistors with CC resitors and noticed a big diferance. alot brighter and fuller and it was plain fun to do. I wonder what would happen if i changed out all of the metal poly capcitors with orange drops or mylar caps.

[Tubis]

I changed all of the 1/2 watt & 2watt CF resistors with CC resitors and noticed a big diferance. alot brighter and fuller and it was plain fun to do. I wonder what would happen if i changed out all of the metal poly capcitors with orange drops or mylar caps.

Hmm, aint those caps also polyester.I dont think you would hear much difference. If you switch to another material like polypropylen maybe. Or did you mean that by the short poly?

[baddog]

resistor type

Im not sure it would make a diferance in the sound either. I do have some vintage ceramic disk capacitors that i installed in a varitone switch and installed it on one of my guitars and there is a big diferance in tone from brand to brand . some have creamier tone and some just sound muffled. Im not sudjesting using them as a replacement for all of them just in the tone control area. Or if anyone has any ideas where to install them in my crate VC50 it would be apreciated. see attached schematic of the preamp

thanks
baddog

I have changed all transistors.diodes,zener diodes, 5watt resitors ,1/2watt & 2watt resitors with CC and installed new filter capacitors with standard size ones not the mini pieces of crap they came with.

[Tubis]

Ceramic disks come in different classes. Class 1 is more linear than class 2 so that makes a difference. The most effekt is in the treble filters. A class 2 ceramic will make the treble more crispy.

Man, English is hard. I´m from Sweden

[mbratch]

Ceramic disks come in different classes. Class 1 is more linear than class 2 so that makes a difference. The most effekt is in the treble filters. A class 2 ceramic will make the treble more crispy.

Man, English is hard. I´m from Sweden

Your English is excellent. Grammar and spelling as good as any native.

[reet]

do different types of resistors effect the sound of a guitar amp. I have a Crate VC50 3x10 amp and it has metal oxide resistors in the power amp section. How would it change the sound if i installed carbon composite resistors like Allen Bradleys?

thanks
keith

Different types of resistors effect the sound of the amp. Metal oxide resistors can withstand higher temperatures than carbon or metal film resistors. The noise properties are similar to carbon resistors. Therefore the effect is small in your case.

[bob p]

ANd I would think the application makes a difference. The high gain input stages where the signal level starts out tiny will be a lot more sensitive to noise from a resistor than something like the cathode resistor in the output stage. I don't worry much about noise in the power amp coming from resistors.

I was recently working on a Super Twin Reverb that crackled and sputtered like there was no tomorrow. With a sextet of 6L6 the amp is a furnace and a real parts baker. These amps have a reputation for being noisy and this one was no exception. conventional wisdom says that you have to change the power supply, get rid of the pseudo-UL arrangement for the output tubes, add a choke filter for the screens, etc. Much to my surprise, I just replaced the 1k5 grid resistors and the 470R screen resistors on the sextet of 6L6 with 1/2 W metal film 1k5 grid stoppers and 2W metal oxide 470R screen resistors. Now the amp is dead silent and I didn't have to do any of the PSU mods. Go figure.

[pdf64]

If that amp's a furnace, those resistors are closest to the element!

How come it's described as a pseudo-UL arrangement? I seem to remember that the UL taps are more like 20% than the more conventional 40% but it still conforms to the UL concept.
Pete

[TompaTheMan]

Hi! I got this Bogner Alchemist that sounds dead in the tone... it's like a blanket over it! Can I get a more OPEN sound changing resistors? Or what can I do?

PLEASe help me! I got service manual if anyone wanna help!
Thanks!
:-)