Editor's Note: This is part 2 in an ongoing series by Fletcher, Rec Pit forum moderator extraordinaire and head of Mercenary Audio in Boston. Click here to review part 1, talking about the nature of "vintage" gear and mic preamps.

The next step in my signal path is usually compression. As we are limiting (no pun intended) the scope of this article to things that are old, I will omit the half dozen or so new products that in many cases do what these do only better.

Again, I'll emphasize that not all new things claiming to be as cool as old things are cool at all; some are real dogs and should be avoided like the plague. Try as many things as you can before deciding what will work best for your style of engineering.

The world leader in cost and performance is the exalted Fairchild 670. Testing for this 2-channel, 70-pound mutha was performed in Les Paul's living room. Serial numbers 1-6 were production prototypes and sound slightly better than the subsequent production models.

Those subsequent production models (fetching more than $20,000 these days) must be heard to be believed! It's like adding the in-your-face fatness you have always craved with the thickest, most controlled bottom you have ever experienced, and with a high end that just shimmers and dances to your delight.

When I don't have one around, I go to Georgetown Masters in Nashville to have Denny Purcell master my record. Besides being one of the finest mastering engineers on the planet, he has his "Fairchildren" (a pair of 660s, the mono version of the 670) that always make my recordings sound like I almost have a clue.

It seems that many of the West Coast engineers prefer Attack/Release constant #4. I prefer #2 and #3, faster release times than preset 4. According to the manual, numbers 5 and 6 are user presets, but you have to go inside with a schematic and soldering iron to change these. (By the way, #1 doesn't suck, it's just really fast).

The 670 was originally built for disc cutting and has Lateral/Vertical controls to limit the movements of disc cutter heads. I've found that on stereo percussion tracks (congas and the like) you can use this setting as an almost psychoacoustic device. It seems to push the congas out about a foot to either side of the speakers. Way cool effect.

(Click here to go to an interesting site on the Fairchild 670.)

The RCA BA-6A is another serious favorite. I have no idea how it accomplishes this, but anything run through it gets ten times larger than when it went in. They are also amazing mic amps--they have enough gain so you can plug a mic directly into the input and go straight to tape.

They can put out as much as 95 volts at the output, so when using it on line-level sources I generally find the need to pad the input and output 20 dB each. This seems to get you closer to the optimal operating range for the unit.

RCA BA-6A

These are not low-maintenance units; they require careful care and feeding. This should not be performed by anyone not intimately familiar with the unit. The folks at RCA seemed to be aware of this and incorporated a tube tester in the unit. The setup is critical, or you might find yourself spending many hours dealing with a loud hum.

(Click here to view a schematic of the RCA BA-6A.)

The Teletronix LA-2A is perhaps the most popular (and badly copied) of all tube limiters. The original LA-2s were made in Sunnyvale, Calif., and are identifiable by their gray painted face plate.

Teletronix LA-2A, now under the Universal Audio umbrella.

The most commonly seen models were made in North Hollywood and feature a brushed aluminum face. These later models (post-serial #383) featured a switch on the back to give you limiting as well as compression functions. In the earlier models, this was accomplished through jumpers on an octal socket. Through their evolution, they went from a T4-A opto attenuator to the T4-B. While several folks swear they can tell the difference, I cannot.

(Click here for more on the Teletronix LA-2A, including info on building your own!)

In my travels, I have run into an ITA LA-1 and and LA-1B. They seem to be rarer than hen's teeth. Ambient Recording near Stamford, Conn., has an LA-1B, and it sounds amazing. (I have one also, and I hope to convince Mark at Ambient to fix mine for me.)

While we're on the subject of hen's teeth, MCI (Music Concepts Inc.) from Jeep Harned, the same dude who manufactured consoles and tape machines in the '70s and '80s, made a tube mastering limiter that can do some very cool things for guitars.

It has the ability to keep the guitar sound as big is it can be, but through some special powers it seems to possess, it makes them get out of the way of the vocals. How does it know?