Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Please login or register.

Login with username, password and session length
Advanced search  

News:

SSGuitar has moved to PHP 7.1, enjoy the speed!

collapse
Pages: [1]   Go Down

Author Topic: Using vintage carbon comp. resistors in effect circuits.  (Read 3280 times)

LJN

  • Legendary
  • ******
  • Chip Points: 6
  • Posts: 302
    • View Profile
Using vintage carbon comp. resistors in effect circuits.
« on: March 17, 2016, 02:55:41 AM »

Hi, everyone. I was thinking about all of those old resistors I recently scored from that old Kimball organ. They're all 1/2 watt carbon composition types and I'm planning on using them in my more important fuzz pedal builds. They seem to work really good in my Tone Bender MkI clone. In fact, it sounded better to me after changing over to these old resistors, which have drifted with age. Anyway, I'm wondering what you guy's opinions are on the subject and if a few hundred ohms difference is really enough to significantly affect the outcome. Thanks.
Logged
If it sounds good, USE IT!

 Epiphone Les Paul, Kasino U100- P, Sears 125-XL

phatt

  • Legendary
  • ******
  • Chip Points: 221
  • Posts: 1928
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #1 on: March 17, 2016, 04:25:31 AM »

How to become an entrepreneur overnight?
Sell them on Ebay to all the ignorant fools who believe in that hype.  :lmao:

I was going to patent my genuine 1960 Valve dust,, comes in a convenient spray pack, gives any Valve that classic sound of yesteryear. ;) ;) ;)

Nah,,, I would not be able to sleep at night. :-[

Seriously ,,,,Easier to just use a pot to vary the resistance same result. 8|
Phil.
Logged

J M Fahey

  • SSGuitar Global Mod
  • Legendary
  • ****
  • Chip Points: 427
  • Posts: 4143
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #2 on: March 17, 2016, 05:19:07 AM »

Define : "sound better"  8|

99.99999999999% psychological desire for them to "sound better" , whatever that means.

*IF* using different-than-original values (because that's what drift means) , please do ... if schematic asks for 10k and actual resistance is 9687 ohms and it happens, just by chance, to "sound better" , then ***any*** actual 9687 ohms resistor there will do exactly the same.

Electrons are going from "here" to "there" and have no clue about what colour the "pipe" carrying them is painted on the outside.
Logged

phatt

  • Legendary
  • ******
  • Chip Points: 221
  • Posts: 1928
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #3 on: March 17, 2016, 08:29:02 AM »

Yeah but if you spray that pipe with my Magical 1960 Valve dust,,,,,, :P
Phil. ;)



Logged

R.G.

  • Master SSGuitarist
  • ****
  • Chip Points: 241
  • Posts: 87
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #4 on: March 17, 2016, 09:51:56 AM »

[...]1/2 watt carbon composition types
Organ makers used 1/2W carbon comps because they were the *cheapest* resistors back when the organs were made. The organs had signal levels of several to many volts so the internal uglinesses of the carbon comp resistors were not very noticeable.
Quote
I'm planning on using them in my more important fuzz pedal builds.

?? More important fuzz pedal builds??
Really?

Quote
They seem to work really good in my Tone Bender MkI clone.

How exactly are you measuring "good"?

Quote
In fact, it sounded better to me after changing over to these old resistors, which have drifted with age.
In formal psychological research, designing experiments to find out what people really like or not requires that the experiment hide what is being tested because people simply cannot be objective about outcomes on tests they make themselves. They will like **whatever** they do, thinking it makes a positive change.

So what this proves is not that carbon comp resistors sound bettter, but that you have the response to your own tinkering that a human would.

Quote
Anyway, I'm wondering what you guy's opinions are on the subject
First, some facts, rather than opinions.
Carbon comp resistors have excess noise above what pure carbon would as a result of their construction. Carbon film resistors have lower noise. Lower yet is metal film, and lowest is wirewound. Carbon comp resistors drift worse than any of these, and have a higher failure rate. Carbon comp got the reputation for "good tone" because they also have a high voltage coefficient of resistance, and so in vacuum tube circuits where the voltage across the resistor varies by something over 100V, they can introduce a little soft asymmetrical distortion, which guitarists have a sweet tooth for.

My opinion is that it's silly to introduce noisier, driftier, more-likely-to-fail parts into a pedal build *unless* what you're really after is advertising bragging rights to sell the pedal to less-well-informed people.
Quote
and if a few hundred ohms difference is really enough to significantly affect the outcome.
No. A few hundred ohms is not enough to significantly affect the outcome.

Being human is, though.   :)
Logged

LJN

  • Legendary
  • ******
  • Chip Points: 6
  • Posts: 302
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #5 on: March 17, 2016, 04:07:04 PM »

Thanks for the reply. I'm only building pedals for my own personal use and what I meant by the more important builds is there are certain ones that I've been wanting for a long time. I measured each one with my multimeter prior to installing them in my Tone Bender. MkI clone. I had used some modern types in there at first, but I wanted to switch it over to more vintage type parts. I don't really plan on selling pedals at all. And by saying they worked out in the Tone Bender, what I meant was it is pretty much noiseless. It does make a bit of noise with my Kasino amp, but not with other amps. To make sure,  I plugged it into another amp and listened as I turned the level knob on the pedal to it's maximum setting. There was no noise.
« Last Edit: March 17, 2016, 04:16:05 PM by LJN »
Logged
If it sounds good, USE IT!

 Epiphone Les Paul, Kasino U100- P, Sears 125-XL

R.G.

  • Master SSGuitarist
  • ****
  • Chip Points: 241
  • Posts: 87
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #6 on: March 17, 2016, 06:40:34 PM »

OK then. If it went into your own personal pedals and sounded fine to you, that's all that matters.

As you can tell from the range of answers you got, the pedal world has been filled with a combination of charlatans and the deluded who think some magic somehow attaches itself to sound as it wanders through your resistors. This is of course false, but the advertisers are quick to say *anything* that will make another sale.

Long-timers in this forum and others have seen so very many people spend about one week learning which end of the soldering iron to hold while soldering, build a first pedal, then open up a boutique pedal shop, referring to themselves in the first person plural and describing vintage components lavishly. The first few posts of these people are often worded like yours.

Forgive us our mistake.
Logged

LJN

  • Legendary
  • ******
  • Chip Points: 6
  • Posts: 302
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #7 on: March 17, 2016, 07:24:23 PM »

It's all good. I can certainly understand that and it hadn't occrued to me that it would be taken in that context. I tend to be skeptical of advertisements, too. Especially after my disappointment with a couple of commercially built fuzz pedals, one of which that was advertised as a "vintage reissue " that actually IS built with modern parts, but has WAY more noise than any of my home built clones that were largely just built with whatever parts I salvaged from old circuit boards. That Tone Bender MkI clone is the first one I've built using those carbon comp resistors all the way through and I am quite pleased with that one. Though, as you said, those probably didn't make too much difference.  But it made me feel better about the build.
« Last Edit: March 17, 2016, 07:26:04 PM by LJN »
Logged
If it sounds good, USE IT!

 Epiphone Les Paul, Kasino U100- P, Sears 125-XL

murrayatuptown

  • Chipper
  • *
  • Chip Points: 2
  • Posts: 4
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #8 on: February 19, 2017, 02:16:12 PM »

They drift in storage too...absorb humidity.

A once-retired engineer (working again to combat boredom) I crossed paths with, said it was standard to 'bake out' stored CC resistors to dry them before installing in (new) circuit boards.

Something similar is done with surface mount parts sometimes too...

I sold all my CC's on eBay, as advised...
Logged

Retrovert

  • Chipper
  • *
  • Chip Points: 0
  • Posts: 2
    • View Profile
Re: Using vintage carbon comp. resistors in effect circuits.
« Reply #9 on: March 28, 2017, 06:48:42 PM »

They drift in storage too...absorb humidity.

A once-retired engineer (working again to combat boredom) I crossed paths with, said it was standard to 'bake out' stored CC resistors to dry them before installing in (new) circuit boards.

CC resistors are a mixture of carbon black (conductor) and clay (insulator), with some phenolic binder to hold it all together.  The ratio determines the resistance.  The early phenolic coatings were often poorly applied or leaky, and moisture migrated in, swelling the grains and altering the characteristics.

The problem is that even when moisture is removed via baking the characteristics may not be fully restored to their original values.

CC is a horrible technology that was only used because it was inexpensive and nothing better existed.  We have access to wonderful technology, like 1% metal film resistors, which are rock stable with voltage and age.

As long as one is not building circuits in the hundreds of MHz or GHz, metal film is the way to go.

I sold all my CC's on eBay, as advised...

Wise decision.

You thereby simultaneously reduced their wallet thickness while enhancing your own wallet thickness in a totally honest fashion.

The problem with CC mojo is that the varistor effects only show up with large voltage swings.  So no magic could possibly occur for coupling stages, bias stages, etc.  The only place it could possibly matter is at the plate, with the large voltage swings.

Otherwise the resistor is just out of spec at the rated voltage.  (If a resistor's value declines with voltage, but the voltage is constant, than no mojo can occur.  The resistor is just out of spec at that voltage.)

Most claims about CC mojo are a combination of wishful thinking by those who either want to believe they've made some magickal change to their amplifier, thereby establishing a special relationship with it and conferring bragging rights, or by vendors who make outright fabrications to increase sales.
Logged
Pages: [1]   Go Up
 

* User Controls
 
 
Welcome, Guest. Please login or register.
Did you miss your activation email?
* Recent Posts
Peavey Filter Caps by phatt
[December 13, 2018, 04:50:35 AM]


HH IC100L schematic anyone? by maxkriz
[December 12, 2018, 05:22:35 AM]


Fried Ampeg SVT-200T by Used.Benz.Parts
[December 07, 2018, 02:57:06 PM]


Simple SS Power Amp Build - +/- 40V Push/Pull by Jazz P Bass
[December 05, 2018, 01:19:15 AM]


British Maine solid state amps by FanofJapan
[December 04, 2018, 03:11:47 PM]

* Sponsors