1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  
    TalkBass.com has been uniting the low end since 1998.  Join us! :)

rectifier tubes

Discussion in 'Amps and Cabs [BG]' started by MCR, Apr 24, 2004.

  1. what do rectifier tubes do?????
  2. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    I believe they convert AC power from the outlet, and convert it to DC power. Somebody correct me if I'm wrong.
  3. Garey

    Garey Supporting Member Commercial User

    Apr 23, 2003
    Northern California
    Artist Relations/Product Specialist: Mesa Boogie
    No, That is correct....they convert AC to DC.

    Aloha, Garey
  4. ah thanks

    so rectifier tubes chagne AC to DC..
    is there a difference in sound ?
  5. Most amps, ESPECIALLY bass amps, don't use rectifier tubes. The major exception is the B15N which uses a 5AR4, but it gets away with it because it's an extremely low powered design.

    SS rectifiers have several advantages. They don't cosume near the amount of power to convert AC to DC that a tube does. They're cheap, usually costing less than 25 cents apiece. They don't generate heat because they don't have a heater, and they put less of a strain on a tube amp's power transformer because they don't have to draw current for said heater.

    Typically tube rectifiers power supplies have lower current capacity and slew rate, which makes the output of an amp much more "mushy." It's not typically a desired effect in a bass amp. I did just pick up a Sunn 2000S amp today which can use either s/s or tube rectifiers. I'm going with s/s diodes for it. I'm fixing to tear into it right now.
  6. BTW, why do you ask?
  7. braun-jovi


    Mar 25, 2004
    Evansville, IN
    Speaking of, "by the way", you didn't happen to get that from a guy from the great northwest off of ebay did you? I miss that one and I never even had it! Congradulations if it was you...or curse you! I'm not sure which... ;)

    Sorry for the hijack.
  8. Nope; found it local today. I was hanging out at the vintage shop drooling over a '78 P-Bass and the owner told me he'd let me have it for $75. He said it doesn't work, but it didn't even have the right tubes in it. I've already taken it apart; didn't even bother trying to play through it, and there's no burnt places or bulging caps. I'll put it up on the variac and see what kind of readings I get. Even if it's trashed, it had three fat bottle Sylvania 6CA7's in it (supposed to have 6550's) , and they're worth 60-90 bucks themselves. It's even already got diodes across the rectifier sockets.

    BTW, if you're referring to the one in that thread on the Dudepit, it has junk Chinese 6550 outputs. I'm going to put the remains of a sextet of KT88's in mine. I've got four left, one shorted when the amp they were in fell over and the other is on its way to Rickenbackerman.
  9. braun-jovi


    Mar 25, 2004
    Evansville, IN
    Nope, not the dudepit one as far as i know. It was on e-bay. Anyway, I would buy one with the crap tubes at this point. I've been wanting a Sunn 2000s ever since I tried one...and that's been about three years ago! Agh, the other one is the Musicman HD-130. I sold mine because my Ampeg V-4bh sounded so much better with my L-2000 that I didn't think I needed it anymore. Nothing made my Jazz sound better than that HD-130. I miss that amp like crazy. I never thought about it, but I must have a thing for low powered tube amps...hmmm. Congradulations on the amp by the way. Thats a great price for a guy that knows how to fix them up.

  10. This is the amp I was referring to. It was/is the subject of a thread on the Dudepit.
  11. braun-jovi


    Mar 25, 2004
    Evansville, IN
    That was the one. Something about unanswered prayers there I suppose. Anyway, I'm surprized at how much it when for. I figured that I had found a sleeper in that amp. You don't hear to much about them. Not that I think it's not worth it sound wise, it just surprized me that they were that sought after. What is this Dudepit? Do you have a link? Is it an amp tech site or a bass site? Thanks in advance.
  12. braun-jovi


    Mar 25, 2004
    Evansville, IN
    Found the site, thanks for your help!
  13. Sorry, braun-jovi. Didn't mean to leave you hanging. I was posting from work and had to get off the computer to do the 11 o'clock news.
  14. Trevorus


    Oct 18, 2002
    Urbana, IL
    Hey, Psycho, I'm sure you probably thought about this, but there are also rectifiers that fit in the tube socket. But if it's modded already, this probably woulnd't do too much for you.
  15. Yeah, Weber's Copper caps are awesome if you want tube rectifier performance, complete with sag, but for bass, I like a better damped power supply.
  16. Hi Psycho,
    I may have diodes put in. I prolly should have before. Now I have 2 Mullard rec tubes. Maybe I can ebay them.
    BTW, do you have any spare chassis bolts for the Sunn.? I am missing 2.
  17. It's funny because I have a pair of Amperex 5AR4's I was all set to at least try in it, but I'm not undoing the diodes since they're already there.

    Mullards? Ebay? You'll probably get twice or more what you paid for out of them.

    So am I! Are you missing the front or rear bolts? Mine is missing both bolts and one of the threaded inserts in the front. The chassis is signed 2-28-69.
  18. country_boy


    Apr 13, 2004
    Houghton, MI
    You probably already know this if you're modifing tube amps, but tube rectifiers have a larger voltage drop the silicon diodes. Replacing them with diodes makes all your supply voltages higher and this can cause some problems; changing operating point, burning out caps, etc. It's just something to be aware of.
  19. Thanks. I will try to find out what date mine is. It must be an earlier one with tube recs. I'll let you know if I find a good solution for the bolts.. Bob.......P.S., check out my music page www.bobmelnik.com
  20. Mine has the rectifier sockets, too. The diodes have already been solder across the plate connections of the sockets. AFAIK, there is only one versiuon of the 2000S.