Tubes Asylum

Thanks everyone, ordered a SS rectifier !

64.2.112.30

[ Follow Ups ] [ Post Followup ] [ Thread: Display All Email ] [ Tubes Asylum ]

HiFiBuff

(A)

In Reply to: What Russ and bean said... posted by rodney on January 22, 2004 at 10:51:56:

Thanks, Russ! Anything special that I need to do when bringing up the tuner on the variac?
-Dave

Follow Ups:

Re: Thanks everyone, ordered a SS rectifier ! - Jimmy 13:28:47 01/22/04 (6)
Remember, the solid-state rectifier does apply more voltage than the cathode based GZ34. Using a variac, I would limit the input to about 100 volts AC.
As for the solid-state replacement, perhaps a series dropping resistor is installed to help that over-voltage condition.
- Re: Thanks everyone, ordered a SS rectifier ! - HiFiBuff 14:01:11 01/22/04 (5)
  Iam only going to use it to power up the amp with a variac. Sounds good to me as to keep it under 100 volts, then switch back to the Tube rectifier for use.
  -Dave
  - WAIT a minute here... - rodney 14:41:12 01/22/04 (4)
    Dave,
    Please be sure to read the postings here and elsewhere (Angela Instruments, ect...) regarding the reforming of old electrolytic caps. I tend to apply a very small amount of B+ at first, say 1-2 volts (You will need a volt ohm meter). This translates to VERY little AC voltage. I then step up to about 10 volts B+ and hold for a while. I then begin a slow, step wise process to about 1/2 the normal B+. Also remember that the downstrem electrolytics will see less B+ than the first section or two, so you need to take that into account. Again you should measure voltage and make sure these caps see 10 volts or so for some time before increasing voltage. As I understand things, the caps reform best at these relatively low voltages. My own measurements of current support this conclusion.
    Also, you will need to take the unit up to full operating voltage slowly on the variac. You need to pay attention here because things may fail as you do this (resistors, tubes). Look for smoking parts, check voltages at all electrolytic caps against the published values, ect... Vigilance is bliss, negligence can kill you. Remember if the tubes start to glow red, bring the voltage back down and turn the unit off. Often bias resistors or settings are off when this happens. Most recomend this process be done with a load connected to the output transformers. Speakers or dummy loads will do.
    Now, I hope I scared the sh*t out of you. Relax, be vigalent, and you will be fine.
    Good luck,
    Rodney
    - Re: WAIT a minute here... - Jimmy 07:12:36 01/23/04 (3)
      After starting up well over 200 pieces of tube gear, I have never experienced a high voltage capacitor failure to date. For the most part, I eventually replace the B+, bias and all coupling caps if I keep the equipment.
      Anyone else experienced a failure?
      - You must go to church daily. nt. - rodney 10:51:22 01/23/04 (2)
        
        In Reply to: Re: WAIT a minute here... posted by Jimmy on January 23, 2004 at 07:12:36:
        
        .
        
        Re: You must go to church daily. nt. - Jimmy 13:21:04 01/23/04 (1)
        
        In Reply to: You must go to church daily. nt. posted by rodney on January 23, 2004 at 10:51:22:
        
        I figured I have been lucky.
        
        Yeah, I average about... - rodney 15:13:49 01/23/04 (0)
        
        In Reply to: Re: You must go to church daily. nt. posted by Jimmy on January 23, 2004 at 13:21:04:
        
        ...10% failure of electro's at first start up.
        and 10% more that make it for a while before giving up the ghost.
        I would guess these numbers includes 20-25 int. amps, 30 or so monoblocs and stereo blocs, a 15-18 tuners, preamps, and 4 recievers.
        Like you, if I keep it, it gets fresh caps (with some exceptions where cap is very overrated as in some pro gear).
        Take care,
        Rodney

This post is made possible by the generous support of people like you and our sponsors:

Sonic Craft

You can not post to an archived thread.