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Best brand and types of resistors and caps

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Frank Prince, Oct 28, 2005.

  1. Frank Prince

    Frank Prince Member

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    What are some standard recommendations for replacement of caps and resistors in vintage amps?

    Particularly with caps, there seems to be several ways to go for different functions like coupling, decoupling, tone, and filter.

    I've seen Sprague Atom Aluminum Axial as a standard suggestion for filter caps. What about the others. What brand/material would be considered "best"?

    Also, any technical reasons for these choices would be interesting to read.
     
  2. hasserl

    hasserl Member

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    Man, that's a loaded question. You're likely to get a lot of opinions on this topic, as everyone seems to have one.

    With resistors many think carbon comps are required for true mojo, especially as plate loads. Others discount the mojo factor completely and go with metal film as the most stable and quiet in operation. While others split the difference and use carbon film for some of the mojo with better stability and quieter operation.

    For coupling caps lots of people like polypropolene Sprague Orange Drops. Some people think those give a sterile feeling to the amp and prefer the tubular polyester Mallory 150's. It seems those who like the OD's like them in Fender style amps, they don't seem to have the same appeal for those with Marshall style amps. The Mallory's seem more favored there. Sozo makes a cap they claim is based on the old mustard cap, and lot's of folks seem to really like them in Marshall circuits.

    Then there are the expensive paper in oil caps favored by the hi fi crowd.

    There are a lot more than I've mentioned, you've got ceramic discs and silver mica. Many people think the ceramic discs give a very harsh unpleasant tone, and so favor the silver mica over them. These are common in the pf value range, though not exclusive to that small range.

    I have never been religiously enamored with any particular caps. The different caps do sound different, but which is better or worse is pretty subjective. I especially don't get into the brand name thing. IMO the type of cap is far more important then the brand name. I typically use no brand polypropolene and polyester tubular caps from Weber VST, for coupling & tone caps. And silver mica for bright caps and other caps in the of ranges. They are very reasonably priced and I've had very good results with them. I'll use ceramic discs for snubber caps, and for cathode bypass caps I use electrolytics from a local electrnics shop, whichever brand they have in stock, usually Xicon or Sprague.

    For resistors I typically use metal film NTE's, as I like the stability, quiet operation and they are flame proof. But I have some carbon comps and carbon films in some sizes that I've bought in quantities. I don't buy the mojo thing though and would prefer to use metal film.
     
  3. Reeek

    Reeek Member

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    And trust me, hasserl knows his stuff, both technically and philosophically. I know first hand.
     
  4. Wakarusa

    Wakarusa Member

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    I refuse to suck into the cap discussion again :cool:

    For resistors, regardless of composition, consider replacing with higher wattage than what was originally in the circuit for some of them. Two reasons: the voltage rating of a resistor is usually related to wattage rating with 1/2 watt often coming in at 350V and 1W often as high as 750V. Higher wattage also translates to lower noise.

    FWIW, I use 1W carbon films in most applications here, reserving the metal films for > 1 Meg values. The stash of carbon comps is primarily for repairs on vintage gear to keep the look consistent.
     
  5. Frank Prince

    Frank Prince Member

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    Thanks, Hasserl and Wakarusa, this is exactly the kind of info I'm looking for.

    I imagine that some people can get evangelical about these things. I'm not interested in starting one of those wars, I'm just trying to understand the differences and get some opinions before I start spending a bunch of money on stuff.

    Keep 'em coming! :)
     
  6. hasserl

    hasserl Member

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    One other thing I didn't mention before is that I like to mix up the caps, I do not use strictly one type of cap. Because of their differences I like to use the different types in different places. It takes some experimentation to decide which you like in which place, but it really is the only way to find out. Listening to people's various opinions will never really give you a clear picture, you really need to experiment with them yourself to find out. Kind of like speakers, you can read all the descriptions you like, but until you actually buy and try them you'll really never know.

    When I look at pics of a chassis and I see all the caps are all the same brand & type all across the board it just tells me the builder doesn't have a lot of imagination. Or he's just going for the mojo thing.

    Use whatever you like, but my advice would be to try a lot of different ones, and mix em up. And rely less on name brand and more on type.
     
  7. Big Dan

    Big Dan Member

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    Hasserl gave a great rundown for you. He knows his stuff.

    I'll add my opinions. For filter caps or any board electrolytics, the Sprague Atoms are the standard. Great cap.

    For tone caps and coupling caps, I like Mallory 150's. As Hasserl said, the Sprague Orange Drops are also very popular. Stick to high quality caps though. Don't go buying the junk from Radio Shack. Companies like AES have a nice big selection without overwhelming you with choices. Once you know what you like, companies like Mouser have a TON of stuff in every value possible. I ordered some Atoms from them that were odd values and no other company stocked them.

    Also, I personally like to use a similar type of cap that came stock in the amp. Unless you are looking to change the sound of the amp, I reccommend you start there.

    Dan
     
  8. Normster

    Normster Member

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    I've been wondering about that. I'm new to amp building and I always see the same cap type used throughout on every build I've seen. As I newb, I didn't want to take chances so I did the same thing, but I was curious about why you couldn't mix them up. Question answered before it was asked...now THAT's a great forum!!!
     
  9. Wakarusa

    Wakarusa Member

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    You can (and I'd argue should) mix up resistor types as well.

    Metal Oxides or wire-wounds in the power supply and on power tube screens, 1% metal films for high resistance (>1 Meg). As previously discussed, I like to use 1W carbon films in most places, but a carbon comp for a plate load does make an audible difference --

    Interesting tidbit about the carbon comps -- the 1/2 watters are inexpensive and plentiful but I've only found one vendor for current production 1W carbon comps and they go for $2 each. ouch.
     
  10. TheAmpNerd

    TheAmpNerd Member

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    If you have the cash you can try out the following:

    There are
    $4.00 CarbonComps that are wonderful
    sounding.

    Then there are special NOS
    $7.00Tantalum resistors
    that are the ****.

    When all else fails and you really need to fork over
    the cash, then you have to splurge for the really
    high dollar stuff, you have to buy the
    $15.00 Teflon
    Caddock resistors--nothing else like them.

    For your standard Fender amp, I'd budget for
    15 of the latter in various values and use them
    in select locations throughout the amp.

    Thats only
    $225
    for the resistors.

    Don't even get me started on caps.

    That takes the budget to a whole nuther country.

    Let's just say for the right cap
    $1,389.90 each.
    So your standard Fender takes 5 of these which
    puts your cap job parts at $6949.50....PS - don't forget
    to add labor.

    And you thought
    $750 for the silver face Fender
    was high!

    DON'T BE CONFUSED BY MY
    Lo-budget FRIENDS HERE
    you can get good tone from regular stuff.

    But when only the
    BEST
    will do...be prepared to pay.

    There is nothing quite like the

    color of money!

    AND

    The tone of ultra-high-end components.
     
  11. Damon

    Damon Member

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    I bought a few "audiophile" coupling caps to try a couple years ago, and tested them for their ability to block DC. Two out of the three (the two most expensive) didn't do a very good job. Price in this case did not equal performance.
     
  12. glasman

    glasman Guest


    That is why I have decided to go into the component biz. Only problem is coming up with the million bucks for the initial inventory...... :D

    Gary
     
  13. hasserl

    hasserl Member

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    And don't forget the audiophile grade solder and directional wire and cryogenically treated components!
     
  14. TheAmpNerd

    TheAmpNerd Member

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    don't forget Randall's business plan to be a millionare
    in the amp biz...

    ..."start with two million!"
     
  15. Frank Prince

    Frank Prince Member

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    Yikes! :eek:
     

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