Audio recorded with a Gibson Les Paul
Back in the mid-2000s, Marshall R&D
employees Ian Robinson and Bruce
Keir founded Blackstar Amplification as a
vehicle for their own design notions. Since
then, the company has enjoyed an admirable
run of success. Thanks to a line that ranges
from the HT stompbox series to Artisan
series handwired amps and the thunderous
Series One amps, Blackstar quickly found
fans among everyday guitarists and marquee
players like Ozzy Osbourne axeman Gus
G., Neal Schon, and such Britpop and New
Wave stalwarts as Echo and the Bunnymen’s
Will Sergeant, Ocean Colour Scene, and
Paul Weller sidekick Steve Craddock.
Though the company’s highest-profile
amps to date have primarily been mid- to
high-power amps with a distinctly British
flavor, Blackstar has more recently ventured
into small-amp territory to give low-watt-loving
studio artists and bedroom players
access to Blackstar tones. The HT-5R combo
is among the newest of these smaller offerings.
Featuring a very cool stereo digital
reverb, the amp uses a single ECC83 tube to
produce 5 watts of output power.
Compact But Capable
The HT-5R’s main controls are mounted
on the top panel. Its two channels, which
are selectable via the footswitch or the
overdrive switch on the control panel, give
you the ability to conjure everything from
snappy cleans to churning growls. The
Clean channel has just one Tone knob that
gives you everything from mellow warm
tones to a brighter sparkle when cranked in
the clockwise direction.
The Overdrive channel has a Gain and
Volume knob. The latter acts as a master
volume, adjusting the overall output of
the amplifier. The Gain knob increases the
crunch of the overdrive, which is capable
of everything from near-breakup to a wild,
hairy distortion. The Overdrive channel has
an expanded EQ with Bass, Middle, and
Treble knobs. There’s also Blackstar’s signature
ISF (Infinite Shape Feature) control,
which is also found on select HT pedals
and on most Blackstar amps. ISF lets you
blend characteristics typical of American
and English amplifiers. A counterclockwise
turn emphasizes American-flavored rock
tones—bass-heavy with exaggerated mids. A
clockwise turn summons a more Brit-hued
jangle. The reverb, meanwhile, ranges from
the subtlest color to dramatic washes.
The rear panel of the HT-5R is home to
some unexpected surprises. Aside from an
Effects Loop, Blackstar includes a Cabinet
Select feature, which can toggle between
the 12" Blackbird 50 speaker in the amp’s
open-back cabinet, or an emulattion of a
4x12 closed-back cabinet. Engaging the
4x12 gives a tighter response to the output,
which does sound remarkably close to the
character of a larger cabinet, albeit on a
much smaller scale.
You’ll also find a 1/4" MP3/Line Input
that allows you to hook up a portable audio
device (CD player, iPod, etc.) to jam along
with. The Emulated Output & Headphone
jack is another blessing for bedroom enthusiasts.
This output will give you the sonic
qualities of a guitar cabinet at noiseless
levels—perfect for recording or practice
without rousing the neighbors.
With its handsome black vinyl and
chrome knobs, the Blackstar HT-5R will
be comfortable at both black-tie events
and roadhouse saloons. Weighing in at 27
pounds and burnished with some hefty corner
brackets, this little beast looks and feels
rugged. But the sturdiness is more than skin
deep—the ECC83 and 12BH7 tubes, as well
as the rear panel controls, are all well recessed
and secure from jostling onstage or in transit.
You get the feeling that a lot of experienced
players had a hand in designing this amp.
Multiple Personalities
I gave the Blackstar HT-5R a workout with
my Fender Stratocaster, and started out on
the more aggressive end of the amp’s tonal
spectrum. After dialing up some medium-high
gain, adding a slight boost to the
Treble and ISF controls, and engaging the
4x12 cabinet emulation, I was treated to
a whiplash tone with a nasty bite that was
more than a little reminiscent of an early
Marshall. The meaty tube crunch remained
true and intact, even at lower volume levels,
thanks in no small part to the push-pull
design Blackstar implemented for the power
section. And even the quietest levels, my
Strat’s single-coils breathed with life I sometimes
don’t hear from much larger heads.
Turning off the 4x12 cabinet emulation
guided the tone into a rich and darker
zone. A counterclockwise tweak of the
ISF knob and drop in the gain yielded the
smoky sounds of Americana and Chess-style
electric blues. There’s real weight to
the low end that doesn’t suffer from the
amp’s small size, and the very responsive
EQ knobs are more than capable of adding
midrange heft and genuinely cutting
trebles when you need them.
With a Les Paul in hand, the Overdrive
channel off, and the Volume knob cranked
to maximum, the channel exhibited a sweet
combination of break-up and bark. The
darker humbuckers sounded a bit loose and
rubbery with the amp’s Tone knob set lower,
but higher settings brought out the Gibson’s
capacity for beautiful and crisp harmonics.
The Blackstar’s reverb is responsive and
lends a lot of flexibility to this amp. It has a
wide arc and a basic character that is brighter
than, say, a classic Fender reverb. But it’s
not at all harsh or “digital.” At the highest
settings, there’s a slightly aggressive slapback
quality in the echo that may be too much
for anyone other than experimentalists or
surf and psychobilly pickers. But in general,
the reverb is perfectly suited to the entire
range of the amp’s voices.
The Verdict
The Blackstar HT-5R is a uniquely crafted
amplifier that’s at home onstage, in studios
of every type and—provided you don’t
work with an aspiring Led Zeppelin rhythm
section—the practice space, as well. With
a responsive EQ, a wide range of clean-to-high-gain voices, and a booming reverb,
this little black box is well suited for recording
artists and bedroom pickers who are
looking for more refinement and warmth
than you get from a budget practice amp.
At about $450, this little guy may be more
than the average picker can justify for an
amp that probably isn’t powerful enough
for many gigging situations. But for home
pickers who consider tone paramount, this
little Blackstar does a lot for the price.
Buy if...
you’re looking for genuine valve tone in a small package.
Skip if...
you need super-sharp cleans at higher volume or the horsepower to gig with a rock combo.
Rating...
Street $450 - Blackstar Amplification - blackstaramps.co.uk |
DV Mark, based in Chieti, Italy, may not be a household name to American guitarists, but it’s a growing brand with a reputation for excellent tube guitar and bass amps, the latter of which are sold under the Markbass name. Players from jazz/fusion axeslinger Frank Gambale to rock studio stalwart Danny Kortchmar have made DV Mark amps part of their rigs over the last few years. Much of the company’s success may have to do with its ability to build tube amps that sound great while deviating from the classic tube-amp templates that dominate the market. The DV40 is fine example of that strategy.
Not Your Typical Tube Amp
The DV40 looks more like a 2x12 cabinet than a combo at first glance. Covered in an attractive, smooth black vinyl with black plastic corners, the DV Mark looks rugged and built for gigging guitarists—there’s no retro-minded fussing or overwrought concessions to the boutique crowd to be seen anywhere.
At slightly more than 37 pounds, the DV Mark is surprisingly light for a 2x12 combo. Its tube complement consists of a pair of EL34s and three 12AX7s, and it features cool, practical features—like a rear-mounted Pentode/Triode mode and a top-panel Continuous Power Control that dials up power settings ranging from .5 to 40 watts—that add flexibility to the power section. Another nice feature is the Advanced Tube Control System (ATCS) Interface, which features a USB jack for connecting the amp to your computer, where you can view data about tube performance. There’s also a Bias switch around back that changes the bias from high to low for even more tonal options.
In an unusual design move, DV Mark placed the DV40 chassis on the bottom of the cabinet and used a ribbon cable to connect the chassis, power section, and the top-mounted controls. The unique approach to weight distribution makes the amp feel solid, balanced, and relatively light. The 12" speakers feature custom neodymium magnets made specifically for the DV40.
From left to right, the control panel has high- and low-impedance inputs, a Norm/ Bright switch, Gain and Master controls for channel 1, Drive and Master for channel 2, and global Bass, Middle, High, Riverbero (reverb), and Presence knobs. The Continuous Power Control goes from 40 watts to 1 watt in pentode mode, or 15 to .5 watts in triode mode. As the control’s label indicates, about halfway through the knob’s throw, power switches from class AB to class A operation. The DV40 212’s Pre Out, Amp In, and Footswitch jacks, as well as the Power and Standby switches are conveniently placed on the top panel. Another very thoughtful touch is the red LED that flashes when you’re powering up to let you know the tubes are still warming up. When the tubes are ready to crank, the LED glows a solid red.
The bottom back panel has the standard IEC input for power, and in addition to the aforementioned USB jack, Pentode/Triode and Bias switches, there are speaker outputs for 16, 8, or 4 Ω.
Out on the Range
While the DV40 pumps out tones that run a wide gamut, it regularly—and impressively—evoked at least four of my favorite tones: a 1980s Jim Kelley combo, Ty Tabor’s Gretchen Goes to Nebraska tones, Sheer Heart Attack-era Brian May saturation and sustain, and the sounds of a cranked ’70s Orange OR120.
Channel 1 is a good clean channel, but a great gain channel. There isn’t a lot of headroom there, but with the Continuous Power Control set to full pentode power you can get syrupy cleans and really mean grind by playing with the guitar’s volume knob, which I did with a ’50s Tribute Les Paul Studio.
Channel 2 engages an extra 12AX7 stage to add more gain—which effectively makes it more like a single-channel amp with a boost. You have to be careful with the bright mode in this channel, though, because distorted sounds don’t work nearly as well with channel two’s added top end as they do for the cleaner channel one. Further, on channel 2 the bottom end has a compressed, crunchy character that’s simultaneously tight and loose—it’s almost as if there were a germanium boost engaged. Even with the drive at the lowest settings, there is an interesting grind in the distortion that separates notes and lends a compressed, sharp-edged attack. The flute-ish, chopping quality of notes with this setting were what reminded me of the previously mentioned Orange. It’s fat and juicy, with a spitty quality that’s simultaneously raging, sonorous, and billowing with sustain.
The Continuous Power Control is a great feature that works quite well with both channels. In pentode mode, it’s ideal for, say, a club situation where you have to bring the volume down at minimal expense to your tone. In triode mode, volume can be drastically reduced, but at the price of a more compressed sound that has some unpleasant artifacts as the sound decays. I didn’t hear a big difference in the two bias modes: There was a little more clarity in the high setting that many players would be hard-pressed to notice, but tubes will likely last significantly longer in low-bias mode.
No matter where you set the tone controls, the DV40 retains its voice—but the EQ is effective for refining it. Presence and High have great range, and Middle provides plenty of cut and boost—but it isn’t great for scooped hard-rock or metal sounds.
The Verdict
The DV40 inhabits a unique place among tube amps. It’s rich, even though it doesn’t have a lot of headroom, and there’s tons of gain on tap—though it comes at the cost of some low-end definition. However, sustain and harmonics are plentiful, and I found myself really enjoying the experience of playing it—in fact, I used it on a variety of projects to good effect. It isn’t a Marshall, Fender, or Mesa/Boogie, and it’s a better amp for that individuality.
Buy if...
you want a light, unique-sounding combo with smart new features and many tonal options.
Skip if...
you need more clean headroom.
Rating...
Street $1295 - DV Mark - dvmark.it |
Hi Jeff,
I have a Supro S6420 that I recently had serviced by a local
tech. I brought in the amp because the bottom end sounded
like mush. It broke up at low volume, and for a 35-watt amp,
it was not very loud. In fact, my ’66 Princeton Reverb has a lot
more volume and headroom.
So, my tech replaced the filter caps, removed a non-original
output cathode bypass cap, checked all power and plate-load
resistors, checked the transformers, and adjusted the bias (VP
425, 45 mA bias). All preamp and output tubes are good and
the speaker is good. Still, it has no volume. My Princeton
blows it away. What’s causing this lack of power?
—Bob,
Townsend, Tennessee
Hi Bob,
Thanks for writing. Well, it sounds like your very cool Supro S6420 is not living up to your expectations, and from your explanation of the servicing— most particularly removing a non-stock output cathode bypass cap—it seems likely that its previous owner may have felt the same way. However, I’m not necessarily agreeing there is something “wrong” with the amp. If you plug in a Tele, crank it up, and you suddenly sound like the first Led Zeppelin album, the amp may indeed be functioning properly! Comparing it to a Fender Princeton Reverb is quite honestly an apples-to-oranges scenario, but let’s see if there may be an explanation for your findings and better yet, a fix.
Regarding the Fender having a better bottom end, this may be due to a couple of factors. First: Most Fender amps, due to the type and position of the tone-stack circuitry, have a substantially reduced mid content. This results in the amps’ top and bottom end being more pronounced. Coupled with the substantially more closed-back design of the Fender cabinet, this may very well explain why the Princeton’s bottom end sounds fuller.
Even though the Supro has a 15" speaker, the fact that the baffle board and cabinet are not much larger than the speaker itself and the rear of the cabinet is virtually wide open, the enclosure is basically a baffle with sides. There’s not much low end being developed by the enclosure itself. If you’ve ever compared a 10" speaker mounted in a nice enclosure with a 15" speaker mounted on a piece of plywood, you’d know which one would win the battle of the bass.
Another consideration would be the speaker itself. Just because it “works” or doesn’t have any buzzing or tears in the cone, doesn’t necessarily mean it sounds good. Speakers get old and tired, and I can’t tell you how much a new speaker can completely change an amp for the better. A worn-out speaker along with the cabinet design could easily be responsible for the fact that the amp is not as loud as you believe a 35-watt amp should be.
You mentioned that the tubes are “good,” but didn’t explain how you determined this. Just because a tube checks well, does not necessarily mean that it sounds good. Substitution is always the best way to confirm how the tubes are holding up, so if you haven’t already done so, swap out the tubes for a quick check.
You also mentioned that the amp breaks up early and does not have much headroom. This too could be the result of a tired speaker, but it could also be design-related. Looking at the schematic, I see the final stage of the power supply— which supplies power for the first preamp stage—is fed by a 100k resistor. This is a far larger resistor than is typically used in such basic amps, and it would substantially reduce the voltage supplied to this stage. Though this is great for producing compression and overdrive, it reduces headroom. Decreasing the value of this resistor to 27k, or even 10k, should increase the headroom in this stage.
There is one other aspect of the comparison to your Princeton that I’ve not yet addressed: The Princeton has an extra gain stage in its basic amplification section. By contrast, this could easily make the Supro sound anemic. The good news is there’s an unused half of a 12AX7 in this Supro that you could press into service. Your tech would know how to turn this into a working gain stage. Placing this extra stage ahead of the existing first stage would yield more gain and saturation, while placing it after the volume control would yield more sensitivity.
If you’re not willing to go that far at this point, there are a couple of quick changes you can implement to make the amp more “full sounding.” Just be aware that the fuller the amp becomes, the more difficult it may be for it to stay clean at higher volumes. If you’re willing to give it a try, I’d suggest changing the input cap and resistor of the first gain stage. These are located immediately after the input-jack resistors. Currently, the capacitor has a .005 μF value and the resistor measures 270k Ω. Try changing the cap to a .01 μF or even a .047 μF, and the resistor to a 1M Ω. This should give the amp a fuller response, and the mod is easily reversible if you don’t like the result.
If all this fails to bring the amp to what you believe is an acceptable performance level, I’d recommend a quick substitution of a similar output transformer. Again, something may appear to be good, but a quick, temporary substitution is the best way to know for sure. I hope you get your Thunderbolt thundering!
Jeff Bober is one of
the godfathers of the
low-wattage amp revolution,
co-founded and was
the principal designer for
Budda Amplification. Jeff recently launched EAST
Amplification, and he can be reached at
pgampman@gmail.com.
