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"Wild Bill" Costello 6L6 Review

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
Written by "Wild Bill" Costello of Busen Amps.

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 first tested at 35 mA/tube and then 50 mA/tube 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
Rated 0 - 5 where 0 is Poor and 5 is Excellent
Rows in gray are tubes used for reference

Mfg

Model

Bias (mA)

Noise / Microphonics

Detail

Harmonics

Comments

JJ

6L6GC

35

50

5

5

5

4

4

5

Great attack. Warmer with higher bias but some detail loss.

Shuguang

5881

35

50

3

3

4

4

3

4

Some microphonics.Very thin at 35 ma.Improved at 50 ma.

SED

6L6GC

35

50

4

4

4

5

3

4

Needed higher idle to bring up harmonics.

Electro Harmonix

6L6EH

35

50

4

4

4

5

4

4

Good, but not quite as thick as JJ. Great value. Looks like rugged construction inside.

JAN-Philips

6L6GC

35

50

5

5

4

5

4

5

At 50 ma., unquestionably the sweetest tone.

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!

SUMMARY

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.

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