The GT Brick tube mic pre and direct box. By Kurt Foster

"The Brick"

As a producer of POP music, I generally prefer the sound of mic pres that have “attitude". These are usually (although not confined to) pres comprised of Class A, discreet construction with robust power supplies and transformers employed on the ins and outs. This is not to say I think that this is the best design for all uses or that the approach and resulting sonic signatures are the ideal. Instead, I have arrived at the conclusion that it is what I have been conditioned to think of as "That Sound".

Until recently, there has not been anything available, which could be by any stretch of the imagination could be considered as "affordable" from any manufacturer that fit that description. The cost of design, construction and parts was prohibitive and other than a few DIY kits that required more than a bit of technical knowledge to construct, there was really nothing to fill the vacuum in the marketplace. The offerings that were available, in my evaluations all fell short of the mark. Many had had a pleasant sonic signature that often led many to believe they offered a good "bang for the Buck" but in my trials I found them to gag, choke or puke when presented with anything resembling a full bass wave or extended high end and none of them offered any sense of front to rear dimension that high end designs provided. We all know nature abhors a vacuum and the design gurus at the well known and respected manufacturer Groove Tubes, were listening to the clamor from the market and responded with an offering they decide to call “The Brick".

It appears in order to save on new tooling and design, the team at GT, opted to begin with their well loved “Ditto Box" tube direct box and expanded its capabilities with the inclusion XLR mic level inputs and phantom power to create "The Brick", without incurring the bottom line expense of developing a completely new product. This is often a recipe for disaster but this time the team at GT with their wealth of knowledge in tube mic pres implementation with products like the VIPER, succeeded admirably creating in my view the first truly "affordable" single channel mic pre that will really hold its own against any of the offerings from vintage, high end and boutique manufactures around.

The Brick is housed in a sturdy all steel case, painted off white and screened with black markings that make it look more like a cinder block than a brick. I was expecting something colored red (uhh, like a brick) but the off white color scheme fits in the putty colored "desktop" environment, which I assume this was the reason for the choice.

“The Brick" weighs a ton and I can absolutely guarantee it will not be pulled off the top of your desk or rack by the weight of the connecting cables like some other "affordable" light weight pres I have used. When you plant this baby on top of something, between the rubber feet and its own weight, it stays put!

Front panel controls are no nonsense and straight ahead with XLR mic input rated at 3-megohm impedance and balanced 150-ohm line-level XLR out and a pair of 1/4" 3-megohm impedance phone jacks labeled "inst input" and "inst thru" to accommodate keyboards and guitar and bass instruments, a signal ground lift rocker switch and the GAIN control which provides +25dB to +55dB for mics and +0dB to +30dB for instruments. The Gain pot has a very cool retro touch employing an old school mushroom knob that makes me feel like Bill Putnam every time I reach for it. If I had my druthers I would have either these mushroom or chicken head knobs on every piece of gear I own! Power on and off and phantom power are on rocker switches located on the rear panel of "The Brick" along with two very bright LEDs which are so bright they cast a visible light on any wall or object behind the pre, preventing you from leaving "The Brick" running inadvertently unless of course, you are blind.

The power on / off lamp is a bright azure blue and the phantom power indicator is standard red. The unit runs on 120 / 240 volts @ 50Hz. / 60Hz. and pulls 22 Watts AC via an IEC receptacle that also houses the fuse, which is rated @ 500 mA slow blow @ 115V/110V or 250 mA @ 220V. When I pulled the fuse receptacle open I was pleasantly surprised to discover a spare fuse included. No line lump, wall wart or external power supply is required. KEWL!

I opened the Brick by removing the Phillips screws that hold the four rubber feet ON THE BOTTOM and took note of the clean and well laid out build quality utilizing “through the board" construction. There are two transformers and three tubes (6205, 12AX7 and 12AU7) that run in cascade Class-A mode. All connectors and controls are nutted to the case and connected to the board via wires just like the “Big Boys"! This is a pre that will be serviceable by anyone in the field as long as there are parts available for it. I would prefer to see the on off and phantom power switches on the front panel and the XLR’s on the rear but I found the configuration posed no serious issues in use. I also wish the XLR (f) input connecter was of the latching type however through my trials the connectors maintained a perfect connection.

IN USE
The first thing I ran through “The Brick" was bass guitar. Using both a Dano Longhorn reissue and a Fender ’54 P Bass reissue, the sound was full and fat with not hint of head room limitation regardless of how hard I pushed the level. “The Brick" provided plenty of gain even at lower settings. The sound was clean and punchy with just a hint of what I would term as “grunt". I moved on trying my MIJ Strat and Tele and found the sound to be as I expected at lower settings. Increasing the gain adds some crunch and again, “grunt" to the sound. As a direct box, “The Brick" behaves just like one would expect it to, comparable to many other high end DI’s I have used in the past, reasonably transparent with no hint of loading. There are no separate input and output gain controls so you cannot overdrive the gain stage and then attenuate it at the output to prevent overs on your digital converter as you can with some other pres but if you run “The Brick" into a compressor, channel strip on your mixer or use an inline pad on the output you can drive the snot out of “The Brick" achieving a very pleasant distortion; More on that later.

I next used “The Brick" on an overdub session recording electric guitars. We ran the guitar into both vintage ‘62 Bassman and ’64 Ampeg Jet and mic’ed them up using a matched pair of KEL HM-1’s. The resulting sound was vintage warm with plenty of high end sparkle. The dimension and depth “The Brick" rendered was phenomenal and while I would not term it as a dark sounding pre, it’s full and round sound / sonic balance is well done with plenty of smooth tube high end, making it through to the recorder. For me paired with the HM-1, “The Brick" has become my “go to" set up for recording electric guitar amps. My friends and clients have all concurred with this observation so far.

My final test for “The Brick" was on some vocals for a Punk Rock CD I recently recorded. The artist / producer I was working for wanted a distorted sound and was adamant about using an old ASTATIC 200S crystal mic, which I usually employ on harmonica through a guitar amp. I personally felt that was not the best mic choice so as a safety I also put up an ATM 4033 and ran both mics through a very well known boutique / high end transformer balanced solid state pre based on early Neve designs, that offers impedance and loading switching and pre post gain control that lists well over $2000 and through my UREI 1178 stereo limiter but in spite of all the bells and whistles, the sound of the tracks really did not excite either the client or myself. We decided to replace the pres with “The Brick" and the result was a pair of tracks the client and I were very satisfied with. Using the UREI I was able to push “The Brick" as hard as I wished and found the sound to be quite acceptable no matter how hard I drove the tubes. Of course at full gain the sound gets quite “crunchy" but not in a nasty inharmonic way (like that achieved with solid state topology) but instead a warm fuzzy tube crunch that never made the vocals intelligible no matter how hard I pushed the pres. In the end, I wound up blending the ASTATIC and 4033 tracks to achieve that distorted sound you get from crystal mics but still with some body and “oomph" from the ATM to help the vocals top out over the guitars and bass just right!

IN CONCLUSION
After using “The Brick" for some time now, I have concluded that it is a great pre for vocals and instruments. I would venture a guess that The Brick" will find it’s way into a lot of Rap and Hip Hop producers studios as it provides a very “in your face" vocal sound at less than a quarter the expense of the more popular mic pre / channel strip commonly in use for that application. As a DI for bass and guitar the Brick works as it should and as a pre for mics on loud guitar amps it shines. Unfortunately I didn’t get an opportunity to use the Brick on drums but I have heard and read comments from satisfied users that it works very well in that application. I am looking forward to trying “The Brick" for both kick and snare on my next drum tracking date.

I would prefer to see a latching XLR connectors for the mic input and I don’t like the in and outs XLR’s on the front panel and the power and phantom switches on the rear but all in all, other than those few small complaints, I can find nothing negative to say in regards to “The Brick". The sound is as good as it gets at any price. At last there is something in the under $500 category I can recommend to newbies and small studios on a tight budget that really qualifies in my book as a “real" mic pre. The folks at Groove Tubes have hit it waaay out of the park with “The Brick".

The Brick lists at $499 but “streets" for considerably less. You can learn more at; www.grovetubes.com.


© 2005 Kurt Foster
(p) 2005 Kurt Foster

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