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Rolling Mullard 6DJ8 into GE 5670 Application

I have a Maverick Audio TubeMagic D2 DAC that has the three op amps upgraded to Sparkos Labs discrete SS3602 and I currently have a 1950s Western Electric 396A tube in it.  I just ordered an adapter that will allow me to install a 1960s Mullard 6DJ8.  I use the Mullard tubes in my Pathos Classic One MkIII and love the resulting sound, so I'm curious what the result will be in the DAC.  The Western Electric 396A replaced the GE 5670 that came with the DAC as an upgrade option.

Anyone have any idea what I might expect to hear?

mceljo
lewm
13,001 posts
 

Depends upon what the tube is doing in the DAC.  If it is supplying gain, then yes you'll hear "a difference". What sort of difference is impossible to say without knowing the circuit and even then it would be a guess.  If the tube is just acting as a cathode follower that drives the downstream linestage or amplifier, then the difference afforded by different tubes would be much less profound or maybe not noticeable.  Are you sure the 6DJ8 is electrically compatible with a WE396A and/ or a 5670?  I am totally unfamiliar with the latter two tube types.  There's more to tube replacements than just having a correct adapter.

petg60
1,486 posts
 

Are you sure the 6DJ8 is electrically compatible with a WE396A and/ or a 5670? 

https://www.radiomuseum.org/tubes/tube_5670.html

5670, premium model of 2C51, was introduced in 1946 and its successor was 6922 but it is not entirely the same tube. Some people though claim it sounds better than a 6922.

 

lewm
13,001 posts
 

The issue for me is not how either tube sounds, but whether or not the two tubes are comparable in terms of their transconductance, mu, and plate resistance, such that you could plug one into a circuit designed for the other and still get the most out of the substituted tube.

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