Follow Us On Follow us on Facebook Follow us on Twitter Watch us on YouTube
Page 2 of 2 FirstFirst 12
Results 16 to 17 of 17
  1. #16
    sanjivdas's Avatar
    sanjivdas is offline Tabber
    Join Date
    Mar 2005

    testing tube

    Talkien>> there is no real way to test whether the tubes actually work fine, but you can do a basic test to check if the tube is a dud or not. You would see the filament in the tube right? the tube would have a number of points depending on whether its a triode , quatrode, double diode, pentode etc. trace the two points connecting the filament. Usually shops selling tubes should have a 6V supply with them. connect the supply and make sure the filament glows. Or connect a multimeter and check continuity. This will ensure you don't take home a dud, but I guess the sound etc will differ from make to make. Thankfully in Bangalore we do get plenty of matched tubes.

    Now, to help a fellow guitarist out, would you like to tell me a bit about the output transformer? Like maybe the ratings and turns ratio and type of wire & core used etc, so I can get one made here? I would be really grateful. I'm talking of the big transformer at the end, right after the main amp output tubes. Thanks in advance, expecting a response or PM.


    PS: I can help you with buying tubes here in return if you want.
    Fender Stratocaster
    Ibanez GSR390 Bass guitar (might sell if i get a price)
    Laney RB30 Bass amp (might sell if i get a price)
    Bunch of Boss pedals

  2. #17
    tallkien's Avatar
    tallkien is offline DIY GURU
    Join Date
    Apr 2006
    Hi sanjiv,

    Testing a tube for filament glow is the least of my worries. Yeah there are many that don't even light up, I suppose I could just carry a 9v battery to test for those the next time I'm shopping. My main problem is avoiding microphonic ones. These tubes, being very old its hard to tell how they've been handled. You knock these tubes around a few times or handle them roughly they can go microphonic, which means they'll work but in the middle of your set they'll start screaming when they feel like. They're also prone to oscillation from rough handling and age. Those unfortunately cannot be tested across a counter without large expensive equipment ( that I know close to nothing about).

    As for the output Transformer, If you're referring to the amp I built, The one at the end is the power transformer. As far as making one goes, Its actually pretty cool if you know a transfomer winder who knows what they're doing. What turn ratios you'll need depends on a few things. like I mentioned elsewhere, you need to answer a few questions

    1. What amp are you building
    2 what output tubes you want to use
    3 how many watts output
    4 what Power tranny are you using (voltage and current ratings)
    5 Is your amp a single-ended, parallel single-ended or push-pull design
    6 Is your amp going to run Class A, class AB or B
    7 what kind of secondary impedences are we trying to match to? 4, 8, 16 ohms?

    and you'll find the relevent numbers in the tube's data sheet, not on the schematic

    If your amp is somewhat simple like mine I could help you with the design of an output tranny if you answer the above questions. For something more complex you might want to look to someone more knowledgable. In any case these questions will give you a very good Idea of what you need. If I know what you want to build hey, I could get it made and ship it to you. If you hurry I could get it with me.

    And don't worry about the tubes, I'm a bangalore boy myself (working in mumbai), In fact I'll be in Bangalore in about a week or two, so if you want an OT, let me know at the earliest so I can carry it. Like I said, answer the questions, you should be ok. The guy who winds my trannies has been doing this for 40 years and CLEARLY knows what he's doing, you can tell by the questions he asks, and the way they sound . I've made two single-ended (harder to get right) sets from him and they've both sounded great. I have no way of comparing these to hammonds or Heyboers but I promise you if you were blindfolded you'd think my little wonder was a Marshall.

    In any case, ask your tube guy, I'm sure he'll know somebody who makes trannies for tube amps

    cheers and good luck



Page 2 of 2 FirstFirst 12

Similar Threads

  1. REQ: Help Needed
    By Cool Guitarist in forum Pakistani Guitar Tabs - Submit or Request
    Replies: 2
    Last Post: 01-31-2008, 10:39 AM
  2. Tubes
    By Genesis in forum Guitar Gear Talk Forum
    Replies: 3
    Last Post: 12-19-2006, 09:53 AM
  3. help needed
    By vickycrazy in forum Hindi Guitar Tabs - Submit or Request
    Replies: 0
    Last Post: 03-03-2006, 10:57 PM
  4. Help Needed!!!
    By #iR@ in forum The ChitChat Lounge
    Replies: 20
    Last Post: 01-26-2006, 08:56 PM
  5. Help Needed
    By tantalize in forum Pakistani Guitar Tabs - Submit or Request
    Replies: 0
    Last Post: 11-07-2004, 04:00 AM


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Single Sign On provided by vBSSO