REVEIW EQP-KT UPGRADED WITH FULLY TESTED MULLARD MODERN PRODUCTION TUBES

Does swapping tubes really make a difference? 

Is it worth extra $$ to buy fancy tested tubes?

Inside the EQP-KT, click to enlarge

We have an ongoing long term vacuum tube comparison going on in the High on Technology lab and some exciting early results are rolling in. Fully tested, graded and matched sets of 12AX7 and 12AU7 were installed in a pair of EQP-KT equalizers, replacing the stock Chinese “Bugera Selected” tubes (don’t you just love tube marketing). The results were shocking and impressive.

REVIEW: Tubes for Microphones, Preamps and Guitar Amps

12AX7A Super-Star of Guitar Amps

Are you curious about what tubes are, when they were invented, why they sound different and how they work? If the sound coming out of different tubes makes such a BIG difference, how come no music is marketed as “using it” or “game changing”? Let’s unpack the mystery around 9-pin miniature vacuum tubes used in guitar amps, tube-EQ, microphones and mic preamps.

REVIEW PULTEC® STYLE EQP SHOWDOWN - AudioScape vs Klark Teknik vs Warm Audio

L. Stereo Pair AudioScape EQP, R. Klark Teknik and Warm Audio EQP

Stereo pairs of all three of these Pultec-style EQs are sitting right here in the High on Technology studio. I currently have a pair of brand-new Klark Teknik EQP-KTs next to me with fresh sets of Tube Depot premium-sorted Mullard 12AX7s and 12AU7s going through a 24-hour burn-in before we start serious listening. Tube rolling is fully underway across all three pairs of EQ, the AudioScape pair, the Warm Audio pair, and the two KT units. Lets dig in and compare features and sound.

RIP WEIGHT TANK WT-72 MIC PREAMP - Locomotive Audio confirms the Weight Tank Preamp is discontinued

The very-beefy Weight Tank microphone preamp built by Locomotive Audio in St. Louis, Missouri, is now discontinued. Eric, the designer builder has confirmed the preamp will no longer be offered due to availability of acceptable low noise tubes for the unit and it is gone from their web site. 

MANLEY LABS ACQUIRED

Manley Labs, makers of iconic tube gear like the Massive Passive and one of the most expensive Variable Mu tube compressors, has been acquired in what is described as an all-cash transaction, by entrepreneur and industry veteran Dirk Ulrich, who is best known for iZotope.

REVIEW: Jim Marshall’s JCM2000 TSL100: The Misunderstood Masterpiece of Tube Tone

Jim Marshall

When you think of Marshall Amplification, you think of Jim Marshall—the "Father of Loud," whose vision gave us the iconic stacks that defined rock ‘n’ roll. From the JTM45 that powered the British Invasion to the JCM800 that roared through the ‘80s, Jim’s legacy is synonymous with pure, tube-driven tone. In 1997, under his watchful eye, Marshall released the JCM2000 TSL100, a 100-watt, all-tube amplifier that marked a triumphant return to the company’s valve roots. Yet, this amp remains one of the most misunderstood in Marshall’s storied catalog—criticized by some players but cherished by those who uncover its magic. 

REVIEW AUDIOSCAPE OPTO COMPRESSOR: A hand-built, modern tribute to the LA-2A

For vintage gear enthusiasts, the Teletronix LA-2A optical limiter remains a studio legend, and its magic lies in a quirky component: the electroluminescent panel inside the T4 optical attenuator. This glowing heart of the LA-2A isn’t your typical light bulb—it’s a retro luminescent panel that pulses with the audio signal’s intensity. As the input signal surges, the panel lights up, casting its glow on a cadmium-sulfide photocell, which adjusts resistance to smoothly tame the signal’s gain. This interplay delivers the LA-2A’s iconic warm, musical compression, beloved on vocals and beyond. It’s a shining example of 1960s tech still stealing the show in modern mixes and it’s so important that AudioScape MAKES THEIR OWN!

REVIEW AUDIOSCAPE EQP-A, VINTAGE PULTEC-STYLE VACUUM TUBE EQUALIZER

I’ve had this pair of AudioScape EQP-A in the studio for just over a year now and they’ve been used on various individual tracks during mixing and on the stereo buss -- trying to hear if they are capable of improving my mixes -- better than other options? I’ve compared them with several plugin recreations and against other affordably priced hardware which is available through retail stores, rather than — Factory-Direct — all products from AudioScape are sold direct and are not available in stores. These equalizers are hand built in Daytona, Florida, but are they Good?

REVIEW AUDIOSCAPE V-COMP+ 6386 DELUXE EDITION, WHAT IS GATES STA-LEVEL?

Original 1950s Gates Sta-Level

The Gates Sta-Level was a vacuum tube compressor/limiter designed in the early 1950’s (like me :-). It used a variable-mu tube to achieve gain reduction (the same remote-cutoff tube type as used in the famous Fairchild compressors).

Now AudioScape in Daytona, Florida has brought the original circuits back to life, complete with “Sonic Truth”, vacuum tube power supply and the all important, “6386”, remote cutoff, variable-mu tube that does all the gain control. I started on this review over a year ago, there were some BIG surprises along the way.

REVIEW LOCOMOTIVE AUDIO 14B VARI-MU VACUUM TUBE COMPRESSOR, MODERN VINTAGE DESIGN WITH HUGE TONE

Locomotive Audio is a boutique audio equipment builder in St Louis, Missouri (my old home town :-). Their products are hand made in very small numbers so they can deliver old-school quality, beauty and ultra-high performance.

The 14B Vari-Mu by Locomotive Audio

The 14B is a 2U, vacuum tube powered vari-mu compressor which incorporates original design features with vintage design elements. If you mix outside the box, you'd better put seat belts on your ears because this compressor inserted on the lead vocal track will blow your mind. 

FINDING BOWIE AKA CHRISTIAN WHITMORE AKA PRO AUDIO TUBES

The Legend, the Man and the Tubes. The TUBES? What?

REVIEW WARM AUDIO WA-MPX TUBE PREAMPLIFIER, IS IT GOOD?

 

CLICK TO ENLARGE

I was dead wrong about this piece of gear. When I first saw pictures of the Warm Audio WA-MPX preamplifier I was put off by some of the obvious marketing moves. In this review we'll be looking at the single channel model of this vacuum tube powered microphone and instrument preamplifier.

CLICK TO ENLARGE

The big VU meter on the front is actually the same budget meter they use in the WA-76 compressor with a black plastic shroud to make it look like an ancient Ampex component. It has a switch controlled function called “Tape Saturation” but no recording tape is involved (so why call it tape?). 

If these things bothered you at all, the only thing I have to say after buying and trying the WA-MPX is put any preconceived ideas away because this piece of hardware rocks!

REVIEW WARM AUDIO WA-73 VS LOCOMOTIVE AUDIO WT-72, OUTSIDE THE BOX

SOLID STATE VS TUBE, MASS PRODUCED VS BOUTIQUE

Weight Tank WT-72 single channel preamplifier with minimalist features

The WT-72 is one sweet sounding tube mic preamp. It is designed and built in St. Louis, Missouri by Locomotive Audio.

The WA-273 is a two channel version of the WA-73. This solid state preamplifier was designed with the Neve 1073 as a guide for the appearance, controls and sonics. 

One channel of Warm Audio WA-73 preamplifier

In this review I'll be comparing the sound of a single channel of the WA-273 to the single channel Weight Tank 72-style tube preamp. Can the budget-reproduction of the classic Neve design keep up with the tubular bliss of the Weight Tank 72?    

REVIEW WHAT IS WEIGHT TANK VARI-MU COMPRESSOR BY LOCOMOTIVE AUDIO?

CLICK TO ENLARGE

The internet has provided an alternative path for smaller boutique gear manufacturers to deliver their wares directly to the discriminating buyer, years ago we called this “Factory Direct”. 

I was totally unfamiliar with “Locomotive Audio” who manufactures the “Weight Tank” vari-mu tube compressor, but a fortuitous click on a banner ad took me to the Locomotive web site where I started reading about this unique processor. Everything I read about the WT-COMP made me want it, finally I could stand it no more, I ordered it. Was it worth the wait?

REVIEW WARM AUDIO EQP-WA vs KLARK TEKNIK EQP-KT, PULTEC-STYLE TUBE EQ SHOOTOUT

by Mark King for proworkshop.com

We've been using the Warm Audio EQP-WA since they first hit the market, as early adopters we purchased two from the very first batch, we've since added a second pair because we liked the first pair so much.

Several months after the release of the Warm Audio EQP, British designer Klark Teknik announced they were also going to release an EQP-KT model for the same price as the Warm Audio product.

The KT model made an uneventful entry in the market place and after a very short time Klark Teknik reduced the price, first to $499 and then to the unbelievable price of $299 each. This low price combined with encouraging threads on various audio forums like Gearslutz caused a run on these units. Almost overnight dealers went from some on the shelves to triple digit backorders of the unit.

User reports about the EQP-KT have been very positive so we ordered a pair for the Proworkshop studio in July, 2017. They finally arrived September 16. Were they worth the wait?

REVIEW WARM AUDIO EQP-WA TUBE EQUALIZER

WARM AUDIO EQP-WA 

TUBE EQUALIZER REVIEW

by Mark King for Proworkshop.com

WHAT IS IT?

The EQP-WA is an equalizer based on a 1960's design by Pultec Audio. The original units are some of the holiest of grail in professional recording studios and fetch astronomical prices. For years mere mortals like me could who could not afford to drop 4000-7000 dollars on a single vintage piece (provided you could even locate one) were doomed to not know the magic of the Pultec EQ.

DIY BUILD THE STEREO MASTERING PRECISION BALANCED-LINE VARIABLE ATTENUATOR

BUILDING THE 600 OHM BALANCED-LINE VARIABLE ATTENUATOR

by Mark King for Proworkshop.com

TWO CHANNEL BALANCED-LINE VARIABLE ATTENUATOR

RACK MOUNTED DIRECTLY BELOW API 2500

THE PROBLEM

I am a big fan of the Warm Audio EQP equalizers. The Proworkshop studio has a pair from the first production run which we bought for tracking use in the studio. Once I heard them in the mastering-loop of our Neve mixer I knew this pair was doomed to stay there because they added so much power and tone to the stereo mix.

Newer production units from Warm Audio include a variable-gain trim-pot control on the back of the unit so you can match two pieces for stereo use. The pair we're using in the Proworkshop mastering system does not have these gain controls.

With the gain control located on the rear of the new Warm models the options for adjustment are still limited unless it's very easy to get to the rear of your rack to tweak the screwdriver-adjustable trim pots. 

THE ATTENUATOR SOLUTION