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Holy Moly... RCA BA-31
Old 22nd May 2008
  #1
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bdmctear's Avatar
 

Holy Moly... RCA BA-31

So I must have bought these about 10 years ago. I used them occasionally over the years then they just sat there.

Plugged them in this week. Killer on Kick and Snare. Padded 15dB on the way in using Sure pads. Actually, they sounded very very cool before I used the pad, it just wasn't right for the project the way they distorted. I will definitely try it in the future.

Then yesterday we used them on guitars and they sounded amazing.

Does anyone else use their BA-31s? Am I just gushing and will I wake up having come to my senses? They really sound super cool!
Old 23rd May 2008
  #2
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bdmctear's Avatar
 

Woke up today. They still sound kinda like Neves... Class AB Neves.

Guess I'm just talking to myself.

How are you doing, Brian?
I am okay. You?
Doing well.
I think you are very talented.
That's really nice of you to say.
Old 23rd May 2008
  #3
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Zep Dude's Avatar
 

I have a pair of Ba-73a's (similar but with external power supply) and they're world class. All this germanium people are talking about these days? The RCA's are the real thing.

I also have a pair of Ba31's I haven't fired up yet but I expect they'll be in the same ballpark.

Ssshhhhhh, we don't want to send the prices on these soaring.
Old 23rd May 2008
  #4
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bdmctear's Avatar
 

Quote:
Originally Posted by Zep Dude View Post
I have a pair of Ba71's (similar but with external power supply) and they're world class. All this germanium people are talking about these days? The RCA's are the real thing.

I also have a pair of Ba31's I haven't fired up yet but I expect they'll be in the same ballpark.

Ssshhhhhh, we don't want to send the prices on these soaring.
Quick! How do I delete this thread? Ha!
Old 23rd May 2008
  #5
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And where does one find these little sleepers?

(I promise I won't tell anyone)
Old 29th May 2008
  #6
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emrr's Avatar
they are really cool for rock records, and for the life of me I can't understand why they are still so cheap. I have restored and racked up 8 of them, and use them all the time. sorry......
Old 29th May 2008
  #7
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bdmctear's Avatar
 

Agreed. I think they are just as cool as an API on guitar any day of the week.

Do you have your hands on a pair for sale right now?
Old 28th December 2008
  #8
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Matty Muir's Avatar
 

I know I'm a little late to this thread but, BA-31's are truly great. I've got 4 of them and I've used them on everything. I just sent some emails out trying to find someone to rack them up with Gain, Pad, Phase, and Phantom. I've almost sold them so many times. I'm so glad I didn't. I love them. Anyone know a good source for racking?
Old 28th December 2008
  #9
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Ha! Hey Matty. I bet I know where you got your BA-31s! And you know who could rack them up, too!

Since Paul Hammond is probably too occupied, you may want to find who racked Jeff Ziglers? I'll email you his address. I think his roommate did a bang up job on his.

B
Old 28th December 2008
  #10
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emrr's Avatar
If you have the mounting trays, I have spares of the proper RCA rack.
Old 28th December 2008
  #11
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Matty Muir's Avatar
 

Crazy!! I just spoke with him and he told me his old roommate is out of contact apparently. His one channel rack job is really nice. He's selling it on Ebay. That's how this all started!! I hope this message finds everyone out there well and having a great Holiday Season!!

Matty Muir
Old 28th December 2008
  #12
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Matty Muir's Avatar
 

Thanks Doug for the offer. I may be takin you up on that. That stuff is impossible to find. Cheers!!

Matt Muir
Old 23rd February 2009
  #13
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jlaber's Avatar
 

I got my hands on a BA71 a few years ago, paid less than 100 for it. I also have some BA73 modules, which are higher-output line amps (line amp with 80 dB gain?).

I did a shootout comparing the BA71 with a Neve preamp I built out of genuine 1272/1091 components. I also compared the BA73 and some other less-colored preamps like John Hardy, SSL and a transformerless NE5534 op-amp pre that I use for a no-color reference.

Using a Rode K2, all I had at the time for vocals, I connected all to an A-B-C-D-E switch box, normalized all the gains, and fed into a EQP-1A clone I built, then to an LA-2A to complete a typical vintage vocal chain.

On male vocals I found the Neve and BA71 very similar, especially in the "air" produced with a 12 or 16 K boost on the passive EQ. The main difference is the illusion of a gently-sloping mid-boost curve in the BA71. I would say that the BA71 is reminiscent of a late 60s Frank Sinatra recording. There's a chance that the BA71 or a similar RCA preamp would have been used for this vintage of Sinatra.

I also did the same shootout with Avantone ribbon mics in front of my Sano guitar amp (another killer deal) , and in line with transformer-coupled DI Synclavier, Drum machines and E-Mu samplers.

In every case I felt the BA71 was on par with the Neve, a real tone monster.

The BA73 on the other hand is a bit electric sounding as-is, so I modified it by tapping the preamp section output (insert) of the Neve and feeding the last 2 stages of the BA73. This combo is quite another tone monster, and for lack of better words, Frankenstein sounding. Less midrange-centric and very big and bouncy on the low end with subdued details on the high end. For whatever reason, Herman Munster comes to mind.

I feel the BA71 is a top contender where you want vintage transformer-colored sound for pop/rock close miking. These days I see them go between 200-300 on eBay, and they crop up more often now than I noticed a few years ago. I never re-capped mine, but I am sure they all could benefit from quality replacement aluminum or copper foil electrolytic caps.

If you're handy with the soldering iron, or have access to a tech I can almost guarantee long-term gratification with the BA71, at any price. It does, however, require an attenuator at its input to be versatile, does not have a ton of gain (about 40 dB I think) and there is no provision for insert or fader, like the Neve. Regardless, the BA71, IMHO, is one killer underground piece! BTW, I didn't verify yet, but while the BA73 is all-germanium, I would not personally claim the BA71 to be all-germanium.

If you like this kind of stuff, I also highly recommend some of the RCA passive eq sets. I have a bass-mid-treble trio that is smooth and versatile, +/- 6 dB or so, but requires about 20 dB makeup gain. These are extremely rare, but you can often get a big bargain on them since they were often found in school auditorium PA systems and the like.

thumbsup
Old 24th February 2009
  #14
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emrr's Avatar
I wrote a full breakdown over here:

the real RCA ba71?
Old 24th February 2009
  #15
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Linus's Avatar
 

I've had a pair of BA-31a's racked for a long time. They sound great. They aren't clean/transparent at all. When pushed they get a nice grind to them.

Not particularly high gain either. Someone once told me that there is a simple mod to the circuit that will significantly boost gain but I didn't bother to try it as I am mainly recording rock and roll.

I originally got 10 modules, 2 BA-31a and 8 BA 31c modules. I kept the 2 BA-31a modules (germanium based I believe) and sold the BA-31c modules.

What a lot of people unfamiliar with them don't realise is that they have their own powersupply built into every module.

Mine were racked up by the tech at Smart Studios (Butch Vig's studio in Madison WI) when I lived nearby.

I still have the original product literature (including the schematic) somewhere.

Very cool sound.
Old 24th February 2009
  #16
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emrr's Avatar
The simple answer regarding the all germanium versions is that they are 6 transistor, and the other type only 4.
Old 24th February 2009
  #17
Ahh!

Quote:
Originally Posted by emrr View Post
The simple answer regarding the all germanium versions is that they are 6 transistor, and the other type only 4.
Shhush! Which is almost as good as 3 pentodes a rectifier tube and a huge amount of UTC iron, but don't tell any one, none of the kiddies has heard of RCA so far, lets keep it that way.
Old 24th February 2009
  #18
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I've been taking about this stuff for a decade now, while trying to sell it, and the kiddies still haven't heard of it. It's all still a real bargain.
Old 24th February 2009
  #19
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chet.d's Avatar
 

Quote:
Originally Posted by bdmctear View Post
Woke up today. They still sound kinda like Neves... Class AB Neves.

Guess I'm just talking to myself.

How are you doing, Brian?
I am okay. You?
Doing well.
I think you are very talented.
That's really nice of you to say.

Lots of us think you're really talented Brian. thumbsup
Old 18th March 2009
  #20
Gear Nut
 
Matty Muir's Avatar
 

Update: Tomorrow I'm going to be receiving my 4 RCA BA31s in a new rack with PSU, Gain, Phase, Pad, and Phantom. The guy who racked them even put an original RCA badge on the front. Check it out in the picture.

I'll let you know how they sound.

MM
[IMG]file:///Users/matthewmuir/Desktop/Matty%20****/rcaba31a.jpg[/IMG]
Attached Thumbnails
Holy Moly... RCA BA-31-rcaba31a.jpg  
Old 18th March 2009
  #21
i had 11 Ba-71a modules.. they are supposed to be the same as the Ba-31 but without the power supply, i have a racked matched pair of these and they are my "go to" overheads preamps, sometimes they are cutting vocals pretty great also. the thing is there are two kinds of input transforers used for them, i had 8 modules with UTC and 3 others which was WAY better with different input transformers, i don't know what it is, probably a different UTC but I'm not sure. it's not a flat sounding preamp at all.. very hyped high end and very saturated (in a great way). the UTC ones are darker
Old 19th March 2009
  #22
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VoiceManMike's Avatar
 

Here's my 31 I racked last year "Thanks Doug for your help on this."


I still need to get 48v in it.
This little magic box is my daily VO mic pre, it's just scrumptious sounding.

Last night I picked up a RCA BA-43 for my ribbon, I might need your help on this too Doug.
Old 19th March 2009
  #23
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imacgreg's Avatar
Quote:
Originally Posted by VoiceManMike View Post
Here's my 31 I racked last year "Thanks Doug for you help on this."


I still need to get 48v in it.
This little magic box is my daily VO mic pre, it's just scrumptious sounding.

Last night I picked up a RCA BA-43 for my ribbon, I might need your help on this too Doug.
OT here...

Love the output gain knob... you didn't get that from Luky's hardware in Burbank did you? I found a similar knob there and used it on a mastering matrix I made for a friend...
Attached Thumbnails
Holy Moly... RCA BA-31-n3609345_39757673_4207.jpg  
Old 19th March 2009
  #24
Here for the gear
 

i have a chance to get 7 BA-71's. im borrowing one right now to check it out. there's one more that isn't racked. the other 5 are in an awesome, rather large, console. im way excited about it. by the way, my band just mixed a record i at Matty Muir's place and it was a real good time. all kinds of rightous gear.

if anyone has a schematic for a BA-71B it would be greatly appreciated.
Old 21st March 2009
  #25
Gear Nut
 
VoiceManMike's Avatar
 

Quote:
Love the output gain knob... you didn't get that from Luky's hardware in Burbank did you? I found a similar knob there and used it on a mastering matrix I made for a friend...
I picked that up at Apex a few years back when they had a great selection of knobs --must of been 10 years ago.
Old 21st March 2009
  #26
Gear Nut
 
VoiceManMike's Avatar
 

Quote:
Originally Posted by heavyhand View Post
if anyone has a schematic for a BA-71B it would be greatly appreciated.
It's the same as the 31 except without the PSU.
RCA BA-31A Preamp Schematic
Old 27th March 2009
  #27
Gear Nut
 
jlaber's Avatar
 

Quote:
Originally Posted by Bassmec View Post
Shhush! Which is almost as good as 3 pentodes a rectifier tube and a huge amount of UTC iron, but don't tell any one, none of the kiddies has heard of RCA so far, lets keep it that way.
Funny you say that. I've been tweaking a prototype tube pre for the last week or so, and I ended up using 3 pentodes and some juicy UTC LS series iron. I looked to RCA schematics for inspiration. The 5879 makes a great input tube. I'm waiting for a pair of GE ***** 5686 tubes to try on the output. With enough headroom, gain and the right amount of feedback a good tube pre is right up there with the best of solid state. And if you want a transformerless hi-z input for bass a tube pre is ready with the addition of only a jack and mic/di switch.
Old 27th March 2009
  #28
Gear Nut
 
jlaber's Avatar
 

Quote:
Originally Posted by heavyhand View Post
if anyone has a schematic for a BA-71B it would be greatly appreciated.

I looked for a BA-71B schematic but didn't have one. I have one for the BA-73 line amp.

However I found the cut sheet for the passive EQs I mentioned which suggest using a BA-31A for makeup gain. I bought a set of these on eBay for dirt cheap ($35 or so) yet the sound quality is at the level of the RCA preamps. Gentle slopes, transparent EQ with inductors. More than just a bargain. Hard to find though.
Attached Thumbnails
Holy Moly... RCA BA-31-001.jpg  
Old 3rd April 2009
  #29
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RCA BA-31a vs. BA-31c

I got a BA-31c, it's the only preamp i got, so I can't really compare.
But I'm interested to know what is the difference between the Ba-31a and the BA-31c. Anyone?

Linus wrote he sold all of his 8 31c module and kept the 31a's. why?

Hepi.
Old 17th April 2009
  #30
Here for the gear
 

I have a pair of the BA-31C's racked up here. I've had them for about five years. A few months ago I considered selling them because I wasn't using them as much. Today I fired them up to cut guitars for a record I'm working on and they were perfect! I guess I'm not going to sell them after all.
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