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Would A Matched Pair Of Electro Harmonix 6ca7 Tubes Be Ok In The Dt50 Head?


Best Answer radatats , 06 April 2014 - 11:53 AM

while they MAY be compatible, they may also be different. apparently original 6CA7's were identical to EL-3s but today's 6CA7 version is a beam tetrode whereas the EL-34 is a pentode.

 

Bottom line, I would not swap them out as too many other things can go wrong in that dark hole of mystery known as a DT amp... Stick with EL-34s...

 

Did you swap out the 12AX7s first?  It may just be the Phase Inverter tube... worth a shot and no biasing involved...

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#1 Brazzy

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Posted 06 April 2014 - 11:44 AM

Was wondering if it would be ok to use these tubes in my dt50 head permanently or at least to just test and see if my original power tubes are blown 'cause today the amp went cold. I have a new matched set of Electro Harminix 6CA7 tubes on hand.

 

DT50 Head output just went silent, any ideas why?


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#2 radatats

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Posted 06 April 2014 - 11:53 AM   Best Answer

while they MAY be compatible, they may also be different. apparently original 6CA7's were identical to EL-3s but today's 6CA7 version is a beam tetrode whereas the EL-34 is a pentode.

 

Bottom line, I would not swap them out as too many other things can go wrong in that dark hole of mystery known as a DT amp... Stick with EL-34s...

 

Did you swap out the 12AX7s first?  It may just be the Phase Inverter tube... worth a shot and no biasing involved...


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Quit complaining and DO something or help somebody with their issues...


#3 Brazzy

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Posted 06 April 2014 - 12:17 PM

while they MAY be compatible, they may also be different. apparently original 6CA7's were identical to EL-3s but today's 6CA7 version is a beam tetrode whereas the EL-34 is a pentode.

Bottom line, I would not swap them out as too many other things can go wrong in that dark hole of mystery known as a DT amp... Stick with EL-34s...

Did you swap out the 12AX7s first? It may just be the Phase Inverter tube... worth a shot and no biasing involved...

 

I'm going to heed your advice. I should've added to my previous post that when I bought these the description specifically said EL34/6CA7 and will fit in amps that use EL34 tubes but I also understand about the "DT's Mystery", lol.

 

  • FAT BOTTLE EL34/6CA7 - Rugged Construction Big Tone
  • Handles high voltage well - Works great in all EL34 amps, both guitar and tube hi-fi
  • Gold-Plated Control Grid and high vacuum for long life and great sound
  • Huge Dynamics and great bass control. Much better than other EL34s
  • Sold in Match Pairs

Edited by Brazzy, 06 April 2014 - 12:32 PM.

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#4 Brazzy

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Posted 06 April 2014 - 12:46 PM

Did you swap out the 12AX7s first?  It may just be the Phase Inverter tube... worth a shot and no biasing involved...

 

I replaced both 12AX7's with New Originals and still nothing/same way. Just 'cause I could, I used all the originals in a Jet City Picovalve Amp to see if they would work and they did work well indeed, but I also understand that this test may not be conclusive.


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#5 robyone

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Posted 06 April 2014 - 11:56 PM

take a look here;

http://www.thetubest...onix-EH6CA7-HPC

 

... i use Tung sol el34b,  love them....


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#6 Brazzy

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Posted 07 April 2014 - 07:07 AM

take a look here;

http://www.thetubest...onix-EH6CA7-HPC

 

... i use Tung sol el34b,  love them....

 

Now I that was more informative than the info I had, lol. Thumbs up !!!


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#7 Brazzy

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Posted 07 April 2014 - 07:17 AM

while they MAY be compatible, they may also be different. apparently original 6CA7's were identical to EL-3s but today's 6CA7 version is a beam tetrode whereas the EL-34 is a pentode.

 

Bottom line, I would not swap them out as too many other things can go wrong in that dark hole of mystery known as a DT amp... Stick with EL-34s...

 

Did you swap out the 12AX7s first?  It may just be the Phase Inverter tube... worth a shot and no biasing involved...

 

Sorry I never thanked ya for that info. they never left the box I'll save them for another application.


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#8 psarkissian

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Posted 03 March 2015 - 02:45 PM

radatats is right,...

"... while they MAY be compatible, they may also be different. apparently original 6CA7's were identical to EL-3s but today's 6CA7 version is a beam tetrode whereas the EL-34 is a pentode"----

 

The power tubes that come stock with these are "pentodes", that's how the circuitry is designed.

Don't mod these amps, use the specified tubes, you will have less problems.


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#9 Brazzy

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Posted 03 March 2015 - 02:54 PM

radatats is right,...

"... while they MAY be compatible, they may also be different. apparently original 6CA7's were identical to EL-3s but today's 6CA7 version is a beam tetrode whereas the EL-34 is a pentode"----

 

The power tubes that come stock with these are "pentodes", that's how the circuitry is designed.

Don't mod these amps, use the specified tubes, you will have less problems.

 

Fear not, those tubes are still in the box. Nothing but the Line 6 recommended tubes will be used in my DT50. Thanks!!

 

I've used one of these 6CA7's in the Jet City Picovalve I've got and it works great in there so I keep them for that.


Edited by Brazzy, 05 May 2015 - 08:54 AM.

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#10 James_Houston_Jr

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Posted 30 January 2016 - 09:53 PM

YOU CAN USE THE 6CA7 TUBES IN A DT50 I AM USING 2 MESA 12AX7 TUBES AND 2 JJ 6CA7 TUBES AND IS RUNNING FINE


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#11 Brazzy

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Posted 31 January 2016 - 07:23 AM

YOU CAN USE THE 6CA7 TUBES IN A DT50 I AM USING 2 MESA 12AX7 TUBES AND 2 JJ 6CA7 TUBES AND IS RUNNING FINE

 

They're working for you? Have you been using them for a long time? Thanks for the reply. I can't believe you found this thread man. Did you search for it or just stumble on it.

 

Have a Great Day.

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#12 psarkissian

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Posted 01 February 2016 - 08:49 AM

These are not the analog tube amps from the 1960's and 70's, where you can swap between tube types.

This is a hybrid amp with digital and analog sections.

 

"YOU CAN USE THE 6CA7 TUBES IN A DT50 I AM USING 2 MESA 12AX7 TUBES AND 2 JJ 6CA7 TUBES AND IS RUNNING FINE"---

I might be now, but I see way too many DT50's come across my bench just for that reason. Incorrect tubes and incorrect bias levels, I see this way too much. It will damage something eventually, running it like that. Do not use Mesa, JJ, Ruby Tubes or Groove Tubes in this amp. 

 

The characteristic curves between these tubes may be close, but not close enough.

These are Bogner hot rods, don't hot rod the hot rod or something will fail.

 

 

The characteristic curves are not close enough, and using the specified bias on these other tubes would be the wrong bias.

I see way too many DT50's come across my bench just for that reason. I'm trying to keep that from occurring. Please don't do that.

 

For those who say that EH's are just Sovteks with EH painted on it,... EH owns the Sovtek factory.

The EH labeled tubes go through extra scrutiny.

 

Use the specified Electro-Harmonix 12AX7's and EL34's. For those who ask soft, medium or hard,...

... I'm told by an EH person that we get the mediums.


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#13 psarkissian

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Posted 01 February 2016 - 08:54 AM

6CA7 is fine for a Pearlman Tube mic, but not in a Bogner tube amp section of a Line 6 DT50.

And radatats is right, don't go mixing pentodes with tetrodes,... the circuit isn't designed for that.


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#14 James_Houston_Jr

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Posted 02 February 2016 - 04:04 PM

WELL  SORRY BUT ITS HAS BEEN IN NOW FOR LITTLE OVER A YEAR NOW IT GETS WORMER THAN WITH THE EL34 WHEN IT GETS WORM I PUT A FAN BLOWING TO IT


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#15 psarkissian

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Posted 02 February 2016 - 04:56 PM

Then you've been extremely lucky up to this point.

 

Shouldn't use tetrodes in a pentode circuit. It's not designed for it.

It shouldn't get warm enough to require a fan like that. Not a good sign.


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