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[macca]

Hi,

I will soon be able to play with one of the old RCA limiters (an earlier version of the BA6A) and was wondering if any of you are familiar with these units and, if so, could give me some pointers or tips on getting the most out of these boat-anchors. For example, what kind of controls do these units have, and what does each control do? I've seem some photos, and not much is readily apparent to me other than they don't have any of the slope/ratio, threshold, attack, or release type of knobs that I am used to. Rather, all I see are an "INPUT" knob, an "OUTPUT" knob, something called an "IN/OUT" knob, and something called a "METER" knob.  Any idea what these are or what they do?  Also, any favorite starting points for vocals? bass?

thanks

[vernier]

It's a limiter designed to smooth-out radio broadcasts in the 50's ..made to be set, and left alone under the broadcast tower. There's mostly two ways to use it (I think). Either by adding a tad of limiting to whatever you want (when tracking or mixing), or crank up the input to really squash whatever it is you want to squash (usually at mixdwon). Thats about it. I'm guessing the pre-set ratio is at least 12.1 if not more.

[wwittman]

Basically you have input level which acts as threshold, and output level (or make-up gain)... that's it.

I love the Ba6a on acoustic guitars and it's nice on a vocal once in a while, more for its colour than its actual compression.

I also sometimes use the 86-1a's on electric guitars for a softer, spongier sound than an La2a.

[Fletcher]

An earlier version of a BA-6 would be a BA-86... the input is the input, the output is the output... the meter is both a level meter and a tube tester.

Seeing as those things were called upon to drive signal like a 1/4 mile from the broadcast studio to the tower, they have enough gain to light a small town, or at least operate a power tool.

I would highly recommend a 20-40db pad on the front and a 20-40db pad on the output so you can actually get into the range of the input and output knobs... otherwise you're going to end up leaving them on the first click and probably still have too much horsepower on the back end and possibly not the level of compression you might desire.

This is all based on the assumption that the thing is working somewhat properly... which is a pretty damn big assumption.

Best of luck with it.

[macca]

yes, it is in fact a BA-86, and supposedly in good condition.

Thanks for the info, everyone.  Someone else als osuggested that I might need pads on the input and output, so I'll be sure to try that.

[Larrchild]

I use my BA6-a to de-burr and round off the edges on grainy synths and other things with Digitalis.

It's slow and it's a little dull but it has it's place.

The tube bal "a" and "b"  pots behind the trap door are uber-important to set properly, or they get ragged sounding real fast.

Best case, tune em for minimum THD if ya can.
http://www.sowter.co.uk/schematics/rca_ba6a.jpg   ba6a schematic  (54 db gain! Fletcher, yer right..you could just bring the xlr connectors near each other!)

[maxdimario]

Quote:

It's slow and it's a little dull but it has it's place.

You'd be surprised at what a new set of tubes and new caps (paper or otherwise) can do to the 'softness' of an old compressor.

would you drive around in a 50 year old car without changing the tires, oil, spark plugs and shock absorbers etc..?

those old cars can be real 'soft' too when not maintained.

[Larrchild]

Thanks, I'm gonna try that.  


I meant the coffee-can sized audio transformers lack modern frequency response. They start to roll at about 12k.

[vernier]

I'll take slow and dull over fast and ice-picky any day.

[Larrchild]

me too, actually. i use it for synths a lot. stuff that dosn't need 12+k, and is brittle and grainy.

It comes out nice.  release times are old school, which was the slow comment.

[toobiesnack]

hi new memdber here..
can yo post a pic and/or schematic of this ba-86 unit?
i have a ba-25

it would be cool if you have the scematic so i can compare it to the 6a and the 25 schemo's

later
ts

[rob schnapf]

i have a Ba 86.
it has so much gain it can start a fire.
i recapped it.
i killed myself tracking down those tubes
to retube it.
i've spent money on it with various experts.
and still it sounds like friggin hell.
but it does weigh a metric shitload.

[vernier]

BA6A's are kill-factor 10,000.

[Tim Gilles]

The RCA BA-6a is immensely useful piece of equipment if it is in working shape.

Enough gain to drive a lotta mics WITHOUT a preamp, so you might consider moving your mind in that direction.

Fletcher is spot on regarding the simple gain mods.

One of the best 'rock and roll' room mic squishers EVER, IMHO.

Go ahead.... smash 20dB common.... you may love it.

Works wonderfully in tandam with other(faster) compression units either before or after it for a myriad of other tasks. Be prepared to hear a whole bunch of "fi" dissapear from the signal path if you drop the wrong thing in after this beauty, she passes a wonderfully shaped signal.

One of my favorite boxes of all time.

Best regards,

Tim "Rumblefish" Gilles