McGary Audio

Monday, September 19, 2011

Home Recording Review!
ADK Audiophile Series TC 47-AU
Large Diaphragm Tube Microphone



Brevis...
Base Price: $1,499 retail;
Likes: vintage tube smoothness, build, price;
Dislikes: not a thing;
More info: ADK TC 47-AU


by Jackson Macinnis

When the Beatles recorded at Abbey Road in the 1960s, they used the venerable Telefunken U47 microphone, which began its run in the 1940s, on almost all the drums and most vocals. They had a ton of those multi-pound microphones. Today, it’s nearly impossible to find working original microphones because of a shortage of the older tubes from the WWII era. If you do find one, it could be as much as $20,000. Thankfully, there have been some companies lately that have taken up this cause of renewing the “vintage” sound — as closely as possible to those historic microphones. ADK is one of the companies that achieves its “vintage” marks at very affordable prices.
Although known for its budget, Chinese made microphones, ADK’s Custom Shop has been designing and building really good high-end mics for a while. These USA-assembled microphones have a Belgian/Australian designed, Asian-built capsule and are every bit as good as the current European mics on the market (sometimes better). They offer sonic signatures of various vintages — without the bad stuff (noise, hiss, exaggerated response, etc.)
The TC 47-AU tested here is a typical example of a good-performing, modern tube microphone that is designed with a vintage flavor, but is not many thousands of dollars. In fact, the price is only $1,499 retail, compared to the recently resurrected Telefunken U47 that sells for $10,000, or an original at $20,000 — if you can find one.

Features
The ADK audiophile series microphone Model TC 47-AU is a class-A tube, hand-graded (6072), fixed-cardioid pattern, 1-inch diaphragm condenser mic. It comes complete with a large flight case, 115V/230v “turbo” tube high-voltage power supply, dual cables, T-ring and basket mounts, and a pop filter.
ADK states that the best applications for the TC 47-AU are: vocals, acoustic and electric guitars, reed instruments, strings, drum overheads and applications where you would want a vintage tube microphone sound. The power supply is extremely heavy duty and well made, mainly to protect the fragile tube inside. The maximum SPL is listed at 125 dB, which allows it to work with all sorts of instruments including drums; self noise is 18 dB.
As mentioned, the ADK comes standard with a lot of accessories: a rugged ATA flight case, two mounts, and a pop screen. Suspension shock mounts are extra when you buy most German microphones, so it’s great to see them included in the TC47-AU kit. Overall, this mic is well priced and equipped for professionals and home studio recordists who want that vintage tone.

The audition
Here at Sirius-XM studios in DC, it’s all about drums and guitars today. Some of the best recording techniques often involve innovative microphone setups. Since the 47 style of mic was used for drums by numerous studios, I thought I would try that technique here.
As chief engineer and director of the Sirius|XM, I was going to directly compare an original 1951 U47 that we have in our mic closet, but the tube was too noisy to make it a fair comparison. For general comparison purposes, I decided to use a recent Neumann U87, which is one of the more popular, high-end large diaphragm microphones on the market.
I used one U87, two feet from the bass drum at 45 degrees. The TC 47-AU was set at the same distance and angle. For the hi-hat and tom, I placed the U87 and TC 47 one foot away between the two drum components. I ran both mics through Focusrite 110A reissue preamps and then into the A/D converters of our Sony Oxford Console. The resultant audio was imported into Pro-Tools for metering and tracking. I monitored on custom, active midfield monitors.

These USA-assembled microphones have a Belgian/Australian designed, Asian-built capsule and are every bit as good as the current European mics on the market (sometimes better).

On the ADK tracks, the ADK instantly revealed an open, roomy, but very nice, low-end sound. You can hear a single, clear low note ringing in the room, and it seems as if the tube mic is rounding off some of that hard tightness that digital recording often adds to the drum kit sound. That slight smoothing effect is a good thing in recording — as the precision in digital is often a hindrance to get a good mix of all the instruments.
The fact that the ADK’s organic sound is from the tube microphone, and not the result of a fancy computer plug-in, also is refreshing. So much of the recorded sound today is the result of processing plug-ins in the “box” (computer), but with the ADK, you have the vintage signature transmitted through the mic, just like in the old days.
I liked hearing the ADK TC 47-AU on today’s rock music drumming. Think White Stripes, Beck and other room-heavy drum sounds with that analog old school sound. In heavy duty listening, the drum’s room sound was pulsing and energetic, as if the tube itself was a live element in the recording.
I switched over to the Neumann U87 set of tracks. I heard the blurred low end in the room as well, but with a slightly different emphasis on the high end of the drums frequency response. There was a drop in the ADK’s high-end response that replicates the old U47, but I liked it; for my drum application, the TC 47-AU had more character than the U87.


ADK TC 47-AU on the drum kit

On a Martin acoustic guitar recording session, I placed the U87 and ADK one foot from the twelfth fret. The guitar playback revealed a similar character, but the ADK was smoother — especially when playing slide. And unlike 60-year old tube mics, the ADK’s newer tube electronics and hand-graded tubes revealed no extraneous hiss or tube sonic artifacts. The mic was very quiet.
I also noticed that the ADK recorded tracks produced a nice, thick midrange tone from our big body acoustic. If you had two of the ADKs, it would be an ultimate “vintage” stereo setup for acoustic guitar. Maybe capture the flavor of the early-to-mid 60s folk era with that pervasive small body guitar sound.
On a male-vocal session, the ADK mic had a really rich middle with just the right amount of top end. It definitely had that old vintage signature. If the vocalist is too bassy, you might want to use a different mic or some EQ, but for our applications, it really nailed it. And the mic’s lack of noise makes it ideal for recording 24-bit.

The verdict
There are low-cost imported microphones and pricy USA- and European-made microphones that claim authentic replication of vintage U47 microphone sound. The ADK actually delivers the essence of the classic microphone sound — with less noise and grit, than the original — and for a whole lot less money than the expensive new ones.
The ADK TC 47-AU is a great way to upgrade your overhead drum, acoustic or electric guitar, or your vocal microphone (keyboards and horns as well) to an iconic sound for way less money than buying an original. I also recommend it for an Everything Audio Network Stellar Sound Award.

Jackson Macinnis is chief engineer and director of the Sirius|XM recording studios in Washington, DC. He also is a multi-instrumentalist musician and home audio recordist who composes music for TV and film at his home studio. He can be reached via the Everything Audio Network.


©All original articles on this site are the intellectual property of the Everything Audio Network. Any unauthorized use, via print or Internet, without written permission is prohibited.


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Thursday, September 1, 2011

Dynamic Duo Review!
An Enlightened Warmth From
Rogue Audio’s Model 99 Preamp,
Stereo 90 Super Magnum Amp




Brevis...
Base Price: $2,595 (99); $2,595 (90)
Likes: luscious sound, bias adjust, USA build
Dislikes: internal speaker load adjust
More info: Rogue Audio

by John Gatski
From time to time, I like to do these Dynamic Duo reviews, where I pair two audio components that complement each other. The reviews can be from the same manufacturer, or sometimes from different companies. For this review, I picked the USA-designed and manufactured Rogue Audio Model 99 Magnum Tube preamp and Stereo 90 tube amplifier. Both have been on the market for a few years.
As a longtime audio enthusiast and reviewer, I have always held an appreciation for the designers who make tube-based gear. Nearly a hundred years after the first tube-based gear made its way into the electricity age, manufacturers continue to build, and customers continue to enjoy, the virtues of “valve”-based audio.
Rogue Audio’s Mark O'Brien and company have consistently introduced new tube audio products since the late 1990s. I like their approach of merging the essence of the tube sound — with modern internal components and signal flow designs — that complement the latest digital sources, as well as the stalwart analog sources.

The Magnum 99 Preamp
I have owned my Rogue Model 99 since 2001, and had it upgraded to “Magnum” status in 2005, which is now the standard configuration. It is my go-to tube preamp for review and personal audio listening. The 6SN7 tube used in the line stage exhibits a wonderfully smooth quality that, in the right design, also is quite accurate with fairly tight bass performance. Soundstage is wide and deep.
The Rogue Ninety-Nine ($2,595 base price) utilizes four hand-selected 6SN7 tubes, configured in a mu-follower circuit topology that enable that wonderful, smooth tube quality. Yet the high-quality capacitors, resistors and high-grade wiring enable the tube pre to match well with modern digital sources, such as high-end DACS and universal players. The external power supply — connected by a two retro-looking cloth-covered power umbilical cords, includes a toroidal transformer with high-speed HEXFRED diodes, seven separate regulators and a toroidal high voltage transformer.

The Rogue Ninety-Nine ($2,595 retail) utilizes four hand-selected 6SN7 tubes, configured in a mu-follower circuit topology that enables that wonderful, smooth tube quality.

My version contains the excellent-sounding phono preamp option (which adds $600 to the retail price), which utilizes four 12AU7 Russian tubes. The preamp also has a nice-sounding, headphone amplifier that taps into the line output stage, though the 1/4-inch connector is inconveniently located on the back panel.
The substantial Model 99 Magnum chassis sports a nice-looking, logically laid-out front panel with seven controls: an on/off switch, mute switch, multiple gain selector, volume, source selector, mono switch and record loop switch. The front panel is heavy duty billet aluminum and gives the preamp a classy, upscale appearance that belies its modest audiophile price.
The rear panel includes an array of input and output premium jacks for the four line components and the phono preamp. There are two twist-on connectors for the power supply cords. The preamp comes with a remote control, which is for volume only.

The Stereo 90
The Rogue Stereo 90 is a 90 wpc, KT-88/KT-90 based amplifier, designed in Class A/B push-pull topology. The tube complement also includes a 12AX7 phase inverter tube and 6SN7 signal tube per channel. The Stereo 90’s versatility is enhanced by its “mode selectability.” It can be operated in triode or ultra-linear mode via a rear panel switch. The Stereo 90 is a hefty amp, thanks to its heavy duty build, including the massive power supply and output transformers.
The Stereo 90‘s standard version retails for $2,595 and the Super Magnum version retails for $2,995. The Super Magnum version, which I tested, includes the following upgrades: KT-90 output tubes, HEXFRED bias supply diodes, screen-grid resistors upgrade, polypropylene bypass filter capacitors, bypass coupling cap upgrade, PRP audio path resistors, Cardas binding posts, Cardas RCA jacks, upgraded wiring, and upgraded signal tubes.

Four classic 6SN7 tubes
Removing the cover reveals the tidy, high-end assembly of the Stereo 90, and one of my favorite features, the manual adjustment of the tubes’ bias current. This feature allows the end-user to use unmatched tubes, yet still get optimum performance. The feature consists of a current meter, a switch that selects each tube and four mini-potentiometers (one for each tube) for adjusting the current. An included screw driver is used to turn the pots until the correct bias current is displayed via the meter for each tube.
While you are inside setting up the bias, you can also configure the speaker load for 4 or 8 ohm operation, via the internal speaker-tap wires. Dimension-wise, the Stereo 90 measures 18-inches wide, 15.75 inches front-to-back and 7 inches tall. It weighs in at 60 pounds.

The set up
I used the Stereo 90 and Model 99 preamplifier with a multitude of components and peripherals, including Alpha-Core solid-silver interconnects and speaker cables, Oppo BDP-83SE universal audio player, Esoteric DV-50 universal player, Benchmark Dac1 Pre D/A, Rotel RP-955 turntable, and TASCAM DVRA-1000 PCM-DSD recorder/player. Speakers included Legacy Focus 20/20s, Westlake LC8.1s and Legacy Studio HDs. AKG K701s were used for headphone listening via the 99’s headphone amp. Both the Model 99 preamp and the Stereo 90 were plugged into the AC using Essential Sound Products Essence cables and power strip.

The audition
In audiophile terms, $6,200 is a modest amount of money for made-in-USA audio gear, yet, there is nothing modest about the Rogue Audio tandem’s sound quality. The sonic signature of the two components relay a sense of tube warmth, smoothing digital’s sometimes rough edges in the midrange and treble, but showcasing the essential accuracy that solid state preamps and amps can deliver. The bass performance of the Stereo 90 in the ultra-linear mode is amazing; you could drive a subwoofer with this amp and not be disappointed.
On the Groove Note SACD Anthony Wilson Trio — Our Gang, the warm-toned, hollow body jazz guitar, Hammond organ and drums recorded direct-to DSD was comfortingly analog in its presentation through the Rogues. That nice drum cymbal sheen and rich, organic Hammond organ overtones were there in force. Some tube systems sound overly bloomy on this recording — not the 99/90 combo; they projected the recording’s high-res warmth — without descending into the dark side.

The Super Magnum version, which I tested, includes the following upgrades: KT-90 output tubes, HEXFRED bias supply diodes, screen-grid resistors upgrade, polypropylene bypass filter capacitors, bypass coupling cap upgrade, PRP audio path resistors, Cardas binding posts, Cardas RCA jacks, upgraded wiring, and upgraded signal tubes.

In listening to Genre Bertoncini — Body and Soul (an Ambient Recordings SACD) masterful nylon string guitar recording of notable pop and jazz standards, the delivered sonics were even more impressive. The dynamic energy of the classical guitar was clearly evident with an expansive soundstage and nice transient energy to the string plucks. These tracks also revealed the Rogues’ excellent signal-to-noise performance and tube selection.
Speaking of tube selection, Rogue Audio’s Mark O’Brien told me that his technicians pay close attention in selecting tubes for the Model 99 preamp because 6SN7 tubes can get noisy as they gain hours of use. I have also noted this characteristic with the 6SN7. Even premium NOS USA tubes often get noisy. But the Chinese-based, hand-selected signal tubes picked by Rogue Audio stayed quiet and microphonic free for my testing. I have one set that dates back to 2005 — and not a hint of extra hiss or thermal noise.
On pop music, the 99/90 tandem was impressive on music that has good dynamic range. The Talking Heads — Little Creatures 24/96 PCM Dual-Disc sounded great on this system, with a nice, open analog recording feel — with multiple layers of guitars, vocals and a little pedal steel guitar sprinkled in. The Elton John — Captain Fantastic and the Brown Dirt Cowboy SACD was a sonic showcase for the duo. Lots of detail from the analog tape-to-DSD transfer was clearly heard through the Rogues.
On really dense, modern power pop/rap/dance kinds of music (the kind mixed for the Ipod generation), the slight “warming” of the already hyped midbass and compressed dynamics of the music does not lend itself to the best sound with the Rogues; even some of the most expensive audio gear has trouble with such sonic “mud.” I usually avoid that kind of new music, though some of the earlier analog recorded and mixed rap music, (Public Enemy — Fear of A Black Planet, for example), did sound pretty good via the Rogue siblings.

Handy bias adjust in the Stereo 90
I played a few LP records from my trusty Rotel RP-955/AT150ML cartridge setup to test the phono stage. The 99’s phono circuit is one of the best integrated designs that I have ever heard in a tube pre. In more than ten years of use, I would rank the phono stage’s lack of noise and dynamic quotient up there with much-costlier separates. Multiple plays of the latest remastered LP of Wes Montgomery — Full House and some old direct-to-discs LPs from Crystal Clear and other labels revealed the music, sweet music of well-mastered vinyl.
Ergonomically speaking, the Rogue tandem worked perfectly. All the controls and buttons were solid — without any noise. The tubes were hiss free and free of microphonics. Recommendations? Maybe putting the headphone jack on the front for the 99, and a speaker load switch on the 90‘s back panel, instead of having to change the wire jumpers from the inside.

The verdict
If you are shopping for an new amp/preamp, and want accuracy and that soothing quality of tubes, I recommend the Rogue Audio Model 99 preamp and the Stereo 90 amplifier as a matched set. Based on their performance and price, the pair receives our Everything Audio Stellar Sound Award — as a duo or as separates. You get great sound, relatively low cost, and plenty of functionality. Even as separates, you cannot go wrong when matching these components into a tube or solid state system.
And as a bonus, you get to support a USA audio company; Rogue Audio components are hand assembled in Brodheadsville, Pennsylvania.

©All original articles on this site are the intellectual property of the Everything Audio Network. Any unauthorized use, via print or Internet, without written permission is prohibited.


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