Transformer Upgrade Kits

Midwest Amp Shootout --

Stock Blackheart BH-5 vs Mercury XLG Upgrade


Photo #1: We left the Mercury XLG Upgrade amp out of the case to make changing tubes easier. Photo #2: Eric Schatte, who owns a Mercury-equipped Pro Sonic, tries a few of his favorite county licks through the XLG Upgrade amp while Mike, Dave and Tom look on.
Photo #3: Tom Keating, tests the limits of his new XLG Upgrade amp as Dave and Kyle observe. Photo #4: L-R, Kyle Folger, soon to be the area's first Mean 13 Upgrade owner, Mike Dearth, Eric Schatte, Tom Keating and Dave Owens.

Tom Keating (owner of the newly modified Blackheart) summed it all up well when he said --

"Installing the Mercury XLG Upgrade in my Blackheart BH-5 was like giving it Lasik surgery. It gave new definition to the amp."

Whenever an amplifier is modified, technicians and players alike often find themselves wishing they had an extra unmodified amp so a true side-by-side (before and after) comparison could be done. Now, with the arrival of plentiful and inexpensive Valve Juniors and Blackheart BH-5s, we have the opportunity to take a real objective look at the results our work. We can finally experience in real time the change in performance that Mercury transformers provide.

The test rig for this clinic consisted of 2 (two) Blackheart BH-5 heads (one modified with the Mercury XLG Upgrade and one stock) playing through a Blackheart BH-112 speaker cabinet. We left the stock tubes in both amps for the comparison, but couldn't resist trying a few other tubes later on. Guitars used included an Anderson "Drop Top Classic" plus an assortment of Fender Stratocasters and Telecasters.

The first thing that struck us about the Mercury-equipped amp was a dramatic increase in volume level. I didn't think to setup the dB meter for some actual measurements but my impression was that the increase was on the order of 10 to12dB louder -- no small amount.

You could also hear a noticeable increase in touch sensitivity as well as the harmonic content (overtones) of single notes. Full chords were more clearly defined: individual notes were more distinct as they combined harmonically.

When driven into distortion, single notes and chords alike were much more musical and pleasing. Sustain was substantially increased as was the linearity of the feedback. Just as we experienced with the Mercury modified Epiphone Valve Jr., the XLG Upgrade amp could be coaxed into feedback over a much larger range: more than two octaves vs just a few notes with the stock amplifier.

Not being able to resist having a little harmless fun, we hooked-up a 4-12 cabinet and cranked all the volume controls. It was hard to believe that level of sound was coming from that single EL-84 tube. We had quite a time playing along with Mike Dearth's hot-rodded Fender Champ -- it's pretty loud too. I hope my neighbors enjoyed the music -- we sure did.

Submitted by:

Paul Anwiler
Paul Anwiler Tech Service

Toledo, Ohio

(419) 349-2207


For more information, assistance, quotes or inquiries:

9167 Independence Ave. • Chatsworth, CA 91311 • FAX (818) 998-7835

(818) 998-7791