Review Notes - how we conducted the review Tube comparison table - reviews at a glance JJ Electronic 6L6GC Shuguang 5881 S.E.D. 6L6GC ("C" Logo) Electro Harmonix 6L6EH (6L6GC) Philips 6L6GC (used for reference) A second opinion: another 6L6 review Testing Conditions Not having access to the same gear as John Templeton (the author of the previous reviews), I delved high and low and came up with a Fender 4-10 cab and a SF Bassman that I promptly modded to the classic BF AB165 blueprint. The guitar was a Strat with a Gibson humbucker installed as the bridge pickup to give some comparison between Fender and Gibson tone. Tone controls were left at mid-point, nothing between the guitar and amp and the chassis was propped up to give access to the bias adjust. Plate B+ was measured at 450 vdc. In order to test the result of hotter and colder biasing, each pair of tubes was tested at 35 mA. and 50 mA of idle plate current. I wanted to see if some tubes needed to be run closer to that 70% of Plate Dissipation wattage figure, which is considered the safe maximum for Class AB1 in most circles. Some folks disagree and run them hotter. If they paid for 'em they can do as they please! I wanted to stay within a safe range for the typical user.
6L6 comparison at a glance 35 50 5 5 5 4 4 5 35 50 3 3 4 4 3 4 35 50 4 4 4 5 3 4 35 50 4 4 4 5 4 4 35 50 5 5 4 5 4 5 JJ 6L6GC - Beautifully constructed.
These tubes were totally quiet. The tone was rich and deep but with a noticeable
fast attack. If you like fast picked lead riffs these tubes are for you. Shuguang 5881 - Rather thin
sounding at first but improved noticeably when the bias was set on the hot side.
Showed some microphonics when gently tapped but not to excess. If you're on
a budget don't pass these up but be sure to bias at 65-70 % of the maximum plate
dissipation rating. S.E.D.
6L6GC ("C" Logo) - Rugged looking plates formed with a larger cooling fin
on the sides. They also like to be biased warmer than some to bring up the harmonic
content. Should be a good choice for either a classic Marshall tone in circuits
set up to accept the 6L6 or 5881 or the more traditional use in a Fender. I've
used this tube in a blackface Fender Super Reverb, 2 different Marshall style
Sovteks and several homebrew amps and it was amazing how the Svetlana's could
bring out either the British or American vintage sound, depending on the surrounding
circuit. I tried some humbucker pickups just for fun and was very pleased. Electro
Harmonix 6L6EH (6L6GC) - I've always found EH 6V6's to be extremely tough
and their 6L6 seems to be cut from the same cloth. Just peering through the
thick glass inspires confidence! If you want a road-worthy tube with great sound
then buy these - you won't lose as much sleep from worrying about bumps on the
highway on the way to your gig! Philips 6L6GC - American
made with the vintage sound! I switched between the other brands and even had
someone else do the switching and re-biasing while I closed my eyes to keep
the test "blind" yet my ears could always hear that little bit extra
that told me it was the Philips tubes driving the speakers. Even when biased
rather cold the tone still came through. It's a subtle difference that you may
not immediately appreciate but the more you play the more you smile. Treat yourself! Running at 50 mA clearly
makes all these tubes sound better. The Chinese 5881's needed it the most but
even with the Philips and the JJ brands it made a noticeable improvement. Of
course, this is all a matter of taste vs. cost. ALL of these tubes sounded acceptable.
It would be only fair to say that my own tastes tend to classic rock a la Jimmy
Page, Billy Gibbons and George Thorogood. For these tones I'd pay for rich harmonic
content. Other types of music or even an acoustic amp might find the Chinese
tubes just fine. |