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Rectifier Tube Rolling in a Modwight LS 36.5DM

I was hoping to get advice, I have been rolling Rectifier tubes in my two box preamp I am blown away how different tubes change the sound ,I own two sets of Mullard GZ37/CV378 a set of GE 5U4GB both vintage early 1960's and a set of stock Sovtek 5AR4 also have a NOS set of 6H30 DR I am trying in the clean  box , both the Mullard's and Dr tubes only have about  five hours of run in time but the sound seems defused on the top end ok on the bass the GE Tubes are good in the mids but soft on the highs and bass so far the stock Sovtek seems to sound best ,Dan says try 5R4-GY Tubes, any one tell me about  the Mullard's in this preamp I am getting frustrated,  thanks 
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lowrider57's avatar
lowrider57
3,018 posts
 
No experience with rectifiers on a
 Modwright , but you cant judge the sonic effect of a tube with only 5 hours burn-in.
bdp24's avatar
bdp24
4,908 posts
 
@roberman, I love your making the point that what is commonly thought of as the "sound" of a tube is more a matter of it’s electrical characteristics and performance in any given circuit than some inherent subjective, "artistic" quality. That electrical performance is a result of its design and construction, which very much determines the sound it creates. I’m sure some will disagree with that assertion.
roberjerman
2,086 posts
 
@bdp24  Amen to that! Tubes do not possess some "magical" property that gives them a distinctive "sound"! An electronic circuit connected to a transducer (speaker or headphone) has a "sound". Not the individual parts! I expounded upon this topic at length some time ago in an earlier post.
roberjerman
2,086 posts
 
Tube brands DO NOT have distinctive tonal qualities! The "golden ear" crowd can throw stones at me! For the record, I have been around tubes and tube gear from young (the Fifties)!
roberjerman
2,086 posts
 
I have tried to give the OP some practical advice - and maybe save him from disaster! 
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