[eric343]

I swapped the GE roundplate EL84s and Tung Sol 5751 I had been using in the MG Head with some Ei Yugo EL84s and a Raytheon 5751 (windmill getter), let it warm up, and started listening... The sound had this choking, indescribable fog about it - it was not clear, it sounded as if someone had tossed a blanket over it! Also, the low-frequency background hum I had noticed with the GE/Tung Sol was not as prevalent. Still, though, this isn't what the Raytheon is supposed to sound like! So I replaced the Ei Yugo EL84s with the GEs and let that warmup overnight...

WHOA BABY!

No more background hum, no veil, no fog, just the clear, beautiful glory of the Raytheon! The muddying of the opening passage of the last movement of Dvorak's New World Symphony (zzz groans here) that I'd noticed with the Tung Sol 5751 isn't there anymore; while the HD600s have their characteristic veil/recession in the upper mids (which no amp I've ever met could remove) the Raytheon in conjunction with the GE EL84/6BQ5 manages to be very transparent indeed, revealing flaws in the recording that I've never noticed before while listening on the MG Head.

 

[Habib]

My experience with the JJs is not as obvious as yours. To me the JJs bring makes the amp sound more "even" with my Sylvania 5751 blackplate. It's definitely the supplimentary tubes to the Sylvania. Making the overall sound more balanced throughout the whole spectrum.

 

[eric343]

Keep in mind that I'm not using the JJ, I'm using NOS GE tubes...

 

[Habib]

I was just commenting on my own experience. Mine is not an obvious difference but still a preferrable change

I'd like to try to Mullard though, I heard they are pretty good too.

 

[dd3mon]

I have Ei Yugo's, JJ's and a pair of stock chinese tubes. They all sound much different from each other, especially the Ei's. IMO the Ei's just make everything fuzzy, similar to your experience. Both the JJ's and the chinese EL84's are far more detailed. The difference between EL84's is underrated IMO. They can change the sound as much as the signal tube.

-dd3mon

 

[Sean H]

I just picked up a pair of the Ei Elite Gold El84's and have had maybe 2-3 chances to listen to them and so far they seem pretty good. I swapped the stock Sovtek's back in last night and noticed that the Ei are definitely better but it's not a night and day difference. I'm wondering if I should give the JJ's a try?? It sounds like they have more detail, which might be nice, but the last thing I want is any addition of brightness or too much detail. Seems I'm very sensitive to the upper mids and treble and any added forward character at all in this area is something I would seemingly not like. Would it be fair to say the JJ's might be a good choice for someone looking for more detail, more focus, less tubey sound?

Also, anyone know how long it takes EL84's and 5751's to break in? I've been doing some searches here and at Audio Asylum but not finding any consistency in opinions.

I'm using a Sylvania 5751 black plate in the center right now. I also have an RCA Command series 5751 (cryo) but have it in my source- a Cal Sigma II tube DAC.