Vaccum tubes needed

Discussion in 'Guitar Gear Talk Forum' started by tallkien, Apr 4, 2007.

  1. tallkien

    tallkien DIY GURU

    Does anybody know of anyone selling current production versions (new stock) tubes 12AX7, 6V6, EL84, EL34. I realize these aren't commonly discussed here but I'm hoping someone can forward me the number of someone I could call for more info. I'll gladly import them but if there's anyone selling tubes in the country I'd like to talk to them first

    Thanks in advance

  2. laneymaney

    laneymaney Banned

    I think importing would be good but i remember someone gave me an address of a place in bangalore that had it, forgot who it was. Sorry...he will post here soon enough though.
  3. thehundredthone

    thehundredthone New Member

    Bombay would also be a good place to look, I don't have contacts though, sorry.
  4. ronnieanand

    ronnieanand n00bier th@n th0u

    You name the tube and it's available in Bangalore....
  5. tallkien

    tallkien DIY GURU

    Thanks guys, There are plenty of tubes in Bombay too, although I'll be sure to visit SJP rd next time I'm in Bangalore. I have a growing collection of tubes already but the problem is these are all old ones. Often you'll find cheap chinese ones that somebody has painted trademarks over selling them as expensive NOS(New Old Stock) tubes. I've been burned like that a few times over. Every once in a while you do find a few genuine gems though that sound like heaven but I want to keep them for special occasions. Most of them are lets just say *inconsistent*. For regular use I'm looking to buy a set of new ones, hopefully...

    Another problem is finding matched pairs of output tubes, next to impossible unless you're really lucky, I'm clearly not very lucky.

    I've been hearing rumors of tube amps available in India now so I suppose if the amps are here the tubes must be too. If you've seen any please let me know where so I can follow up

  6. nebuchadnezzar

    nebuchadnezzar G34r G33k

    Ronnie, has anyone put tubes from that shop into an actual tube amp?That is where the real quality will come through.
  7. tallkien

    tallkien DIY GURU

    That's exactly my problem. I've already spent a pretty penny on those. Many of them don't work at all. guess I'll just have to order
  8. laneymaney

    laneymaney Banned

  9. sanjivdas

    sanjivdas New Member

    Laney maybe you were thinking of me?

    Cheap chinese as well as western tubes like original philips, telefunken, and our very own super reliable BEL tubes are available in Bangalore. And I am really surprised Talkien got dud tubes. You should have checked them while buying. Once the corresponding points work, no reason why they would not work. They would work in a radio or an amp the same. I have some Philips tubes myself, not able to find time to put them to any decent use. Both EL34 and AX7 (or equivalent, I don't exactly remember). Secondly, if you are making an amp, you need to import the output stage transformer from Hammond. Thats about all. I got the rest ready myself, only the transformer is a problem, no bloody circuit gives the correct parameters or windings, so can't get one made too.
  10. tallkien

    tallkien DIY GURU

    I got my trannies made locally and they rock, The amp's built. The problem is as I keep swapping tubes there's a huge difference in output and/or gain, headroom etc. It's not that I can't find tubes, they're just not consistent. I'm having to buy 5 for every two I can use without fear of failure. Around here the ax7's are in short supply. I'll definitely check out the Bangalore scene next time I'm home.

    I'm doing a push-pull now and I need a matched pair of EL84s and /or 6V6s but fearing the worst I've modified my schematic for independent bias pots so I should be ok. Gotta take what you get around here :) I do have two very closely matched Matsushita tubes although they're not a pair

    BTW how on earth do you check them while buying? have you got some kind of tube tester. I have to actually plug them in when I get home which usually means making another trip to replace the duds or less than acceptable performers

    If you need trannies, just let me know what kind of amp you're building, I can get them for you. They're not quite Hammonds or Heyboers but they sound sweet enough for me not to care. Not to mention I built a whole amp for less than the cost of a single Hammond PT :). I need to know what amp you're building, what tubes you want to use and how many watts, Single ended or Push-Pull and what PT you've chosen, that should be enough, Oh also whether you're using solid state or tube rectification, I think that's all

    Bollywood apparently uses a lot of tubes for their amps, so much so the tube trade in Mumbai is something of a racket, apart from that you've got a couple of smart westerners coming down every few months and buying off all the goodies to sell abroad at NOS prices :(
  11. tallkien

    tallkien DIY GURU

    Hmmm, turns out Roy of Guruamps is selling tubes, at a price though. Not sure if it would be cheaper to import but I'm ordering a few from him anyway
  12. nebuchadnezzar

    nebuchadnezzar G34r G33k

    This radio tube shop in Bangalore(SP Road)actually has a tube-tester. He will test it for you himself before selling it.
  13. tallkien

    tallkien DIY GURU

    Interesting... Could you tell me the name of this shop and maybe some landmark as to where on SP road?

    thanks a lot I'll look into it
  14. nebuchadnezzar

    nebuchadnezzar G34r G33k

    Contact Ronnie, he knows the shop. I just tagged along once with him, so got to know about it.
  15. tallkien

    tallkien DIY GURU

    I really should do that. Ronnie seems like a very resourceful guy :)
  16. sanjivdas

    sanjivdas New Member

    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.
  17. tallkien

    tallkien DIY GURU

    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


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