Tubes Asylum

• Svetlana EL34 do have _deep_ bass - if used correctly. mb-de 04:31:47 04/09/01 (2)
  In Reply to: Svetlana EL34 posted by steve on April 07, 2001 at 09:35:27:

  Hello Steve!

  How are you using the Svets? What kind of amp/circuit/voltages/bias currents, etc.?

  What makes you feel there is no deep bass - and with which EL34s did you feel you had deep bass?

  Questions over questions, but if you want a sensible answer, you have to describe the circumstances.

  Regards,

  ---mb---
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  PS: I am using Svetlana EL34s with good success in several Ultralinear and classical pentode amplfifiers - with good iron and proper surrounding circuitry they are second to none in bass - but I am talking about controlled bass, not _boom_ box effects for lack of control. I have as well Mullards (xf2/xf3) and EH, and I tried some others in the past (including Telefunkens (Ulm production) which were unfortunately worn out).
  
  

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  • Re: Svetlana EL34 do have _deep_ bass - if used correctly. Beam Tube 07:45:05 04/09/01 (1)
    In Reply to: Svetlana EL34 do have _deep_ bass - if used correctly. posted by mb-de on April 09, 2001 at 04:31:47:

    Dear mb-de: I have tried the Svetlana EL34's in my 80 watt monoblocs under the following conditions: 525 plate VDC; screen VDC set at 325Vdc; and 40 ma idle current per tube. The tubes ran sort of hot (no red plates/screens), but I got lots and lots of bass out of the amp. Take care ..Joe..aka the "Beam Tube"
    
    

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    • Agreed! mb-de 13:17:08 04/12/01 (0)
      In Reply to: Re: Svetlana EL34 do have _deep_ bass - if used correctly. posted by Beam Tube on April 09, 2001 at 07:45:05:

      Hi Joe!

      You confirm what I am saying - the Svetlanas _do_ plenty of good bass.

      Regards,

      ---mb---
      ======
      PS: Your bias point (Ua=525V/Ug2=325V/Ia=40mA) means a static dissipation of 21W - comfortably far away from the allowed 25 W which they survive without difficulty as well...
      
      

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• How old were the tubes you tried?. . John PA 17:24:48 04/07/01 (0)
  In Reply to: Svetlana EL34 posted by steve on April 07, 2001 at 09:35:27:

  Were they new or used? I swapped out my 34's about 1/2 an hour ago for some new ones and noticed an improvement in bass that I was already happy with (the used ones have many hours on them, I know a realative term but they are past their prime).

  ja in, sure is sunny here in Tucson, AZ
  
  

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• I use the Svetlana 34's . . John PA 12:16:44 04/07/01 (10)
  In Reply to: Svetlana EL34 posted by steve on April 07, 2001 at 09:35:27:

  all the time and enjoy the music produced. I have plenty of quality low bass. I run them in class A at 390volts with about 55ma of bias. I also have a number of other tube types, and in my opinion, Sovtek KT88's, which I like, Bugle Boy 34's, KT90's, GE6550's, Sylvania 6CA7 fat tubes, do not out perform them. Yes, they are different but I think the smoothness of the Svet 34's and overall presentation is very, very good. My system does go down into the twenties with bass and with the 34's the quality of the bass can be growling and very true.

  Hope this helps.

  ja in sunny, recovering from rain, Tucson, AZ
  
  

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  • Re: I use the Svetlana 34's . . Peter. 15:35:16 04/07/01 (6)
    In Reply to: I use the Svetlana 34's . . posted by John PA on April 07, 2001 at 12:16:44:

    Hi ;

    I have also a EL34 SE amp with Philips or Telefunken tubes , I can get my powersupply higher than about 350 volt , do you know a good biass point for me , the load is 3,5 or 5 K (can both).
    My low freq are verry good , the middle and high part is a bit "dusty",i'v try'd a lot of change things but cant get it better,
    not realy dynamic.
    the driver is a 76 with a 6688 as load , a Mu- stage.
    Thanks a lot;
    Peter.

    
    
    

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    • What do you have the bias set at now? John PA 17:22:14 04/07/01 (5)
      In Reply to: Re: I use the Svetlana 34's . . posted by Peter. on April 07, 2001 at 15:35:16:

      How old are the tubes? And has the unit always sounded this way?
      Also, have you tried any other output tubes? What class does your amplifier run it?

      Story, or Steve Oda would have more information than I do but I am sure one of them will answer your question.

      ja in sunny, and hey where did the cool weather go? Tucson, AZ
      
      

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      • Jhon , bias is 53 ma / 350 v. Peter. 15:33:45 04/08/01 (3)
        In Reply to: What do you have the bias set at now? posted by John PA on April 07, 2001 at 17:22:14:

        Hi ,

        The fixed bias is now 53 ma and Va is exactly 350 volt , when I let flow more current , the B- voltage drops down ofcourse.
        The low freq. are exelent but the middle and high are flat , I dont know how to say but not dynamic , not enough.
        The tubes I use plays good with another front tube , the ebc 81 ,
        thats a triode/ double diode , the two diode connected to the starground, plays verry good with a seperate power supply.
        Now I have make the Mu-stage with a 76 as triode and a 6688 as load/
        kathode folower , recommended by a friend , must be better , but I can't get it better.
        The Mu-stage is on :http://www.triodedick.com/
        Look by the "projecten" and then by "the General MK2 " , schematic.
        I'v ask him and he answer that the Mu-stage is superior to al kind of loads , all the voltages are good , the tubes I use are from Mullard
        or Sylvania for the 6688 , the 76 are from Kenrad, all new.

        In my other amps before was the B voltage 250 volt , loadresistor 100K , battery bias from 1,3 volt instead of a kathode resistor , next grid resistor 330 K ,input-stepatunuator 25 K , tube EBC 81 ,this tube have the minimal distortion of all tube I'v ever play with, plays verry good with this EL 34 , not full output but verry good with the Telefunken or Philips tubes

        I think the Mu-stage's have simply to much parts , I'v connected also (all) the 1 K gridstoppers , I never use them before , I always hear them and remove , but the amps are now a bit full with parts and cannot remove them easy , I think to take the solderiron and make all the sockets clear and start over again with a different input tube,
        I'v tryd before with a 76 with resistor and choke load ,good,but not enough gain to play direct out of the cd-player.
        Maybe someone have a good idea ?

        Thanks a lot;
        Best regards:
        Peter.

        
        
        
        

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        • Maybe Story can look at this.. . and have you tried this amp. . John PA 16:10:41 04/08/01 (2)
          In Reply to: Jhon , bias is 53 ma / 350 v. posted by Peter. on April 08, 2001 at 15:33:45:

          with another preamp?

          ja in sunny, warm, with a gentle breeze, Tucson, Arizona

          
          
          
          

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          • Re: Maybe Story can look at this.. . and have you tried this amp. . Peter. 16:23:52 04/08/01 (1)
            In Reply to: Maybe Story can look at this.. . and have you tried this amp. . posted by John PA on April 08, 2001 at 16:10:41:

            Hi ;

            
            No , I dont like preamps , I prefer only two tubes , most I like only one tube like the EL84 but the output is a little bit to low , but verry good. The level of my cd player , 2 v ,must be good enough to drive , more parts /Preamps give more distortion , I think.
            Thanks;

            Verry wet and cold here in the Netherlands , no summer yet.
            Brrrrrrrrrrrrr...........Brrrrrrrrrrrrrr.
            
            

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            • Why not go with a power transformer that puts out 400 . . John PA 15:36:34 04/10/01 (0)
              In Reply to: Re: Maybe Story can look at this.. . and have you tried this amp. . posted by Peter. on April 08, 2001 at 16:23:52:

              or 450 volts for the B+, bias around 50 to 55 with the rest of the circuit built around this?

              John in the rain is starting to clear, Tucson, AZ
              
              

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      • Re: What do you have the bias set at now? steven oda 02:36:33 04/08/01 (0)
        In Reply to: What do you have the bias set at now? posted by John PA on April 07, 2001 at 17:22:14:

        Not real familar with the amp---but the are the Svetlana old? Like did you buy them 4-5, or more years ago? These were not the the best sounding tubes---not like today's Svetlana EL34.

        Sorry I can't be of more help with the biasing. Are they set in triode mode? Or pentode?

        steve
        
        

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  • Re: I use the Svetlana 34's . . Story 12:21:08 04/07/01 (2)
    In Reply to: I use the Svetlana 34's . . posted by John PA on April 07, 2001 at 12:16:44:

    who told you this was true class A?
    
    

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    • Cary Audio. Talk to Dennis Had the owner and I guess . . John PA 14:42:51 04/07/01 (0)
      In Reply to: Re: I use the Svetlana 34's . . posted by Story on April 07, 2001 at 12:21:08:

      designer of the amp if incorrect please let me know. It seems there are differing ideas on what constitutes class A.
      ja in very sunny, and nice, Tucson, the flower of the west, AZ

      
      
      
      

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• Re: Svetlana EL34 steven oda 11:09:28 04/07/01 (0)
  In Reply to: Svetlana EL34 posted by steve on April 07, 2001 at 09:35:27:

  steve,

  Got a lot of variables to sort out. What is the plate voltage and idle bias set at? What are you driving these EL34 with? Svet EL34 that I've used in guitar amps seem to have good bass, though not as thunderous as the Type II Mullard's (dual getters, big brown base, mid-60's vintage, & expensive as all-get-out).

  steve
  
  

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