Categories
Custom Fabrication Gold Coast Recorders Technical

RCA OP-6/BA-2 Hybrid Mic Pre Amp: Listening Test/Shootout

Alright!  So earlier this week I described the successful completion of the RCA OP-6/BA-2 microphone preamp.  Check out this previous post for all the construction and technical details.   The short story is: the RCA OP-6 is one of the most fetishized vintage mic preamps out there; I have always wanted to try one out; the easiest/cheapest way for me to do this was to build one (or at least as close as I could get).  The problem is that the input stage requires a special attenuator device, exact values unknown; therefore I had to substitute an input stage from another device.  I chose the input stage from the RCA BA-2, as I have built many of these and they always work great.  The result: a hybrid of the OP-6 and the BA-2.

OK so there it is.  Anyway, the very helpful+generous TW came by to help me out on this one.  I wanted to try the OP-6/BA-2 Hybrid (hf. OBH) on a couple of different sources with a couple different types of mics. We a/b’d the OBH with an API 512.  I use the API 512 as a benchmark for mic-pre shootouts because it’s a high-quality unit that many people own and use regularly.  What you are about to hear are identical mics tracked through the two different preamps, direct to Pro Tools via a Lynx Aurora.  Levels were matched. No other processing, level adjustment, or manipulation was done.  You are hearing exactly what came out of the preamps.  To appreciate the differences between the units, you will need to listen to these files on good headphones or a full-range speaker system.   If you listen on a system with a subwoofer (we used the Blue Sky system at Gold Cost Recorders), you will hear some dramatic differences.

OK.  So first up: let’s listen to the drum kit above.  These are vintage ludwig drums, 30″ kick, 12″ and 14″ toms, 14×5 wood snare.  Cymbals are fairly dark old Zildjans.    You are hearing two identical Shure SM-81s placed right next to each other, approx 8 feet in front of the kit, pointed directly at the kit.  The 10db pads on the SM81s are engaged.  The SM81 is not the prettiest sounding mic, but they have a very flat frequency response.

First: here’s the API 512:

LISTEN: Drums_API

…and here’s the OBH:

LISTEN: Drums_RCA_hybrid

Our impressions were as follows: the OBH has more low end extension.  On the Blue Sky system, the kick drum in the OBH signal moved the room in a way that the API simply could not.  The API seemed to move the kit a little closer to the plane of the speakers, but at the same time the top end was not as in-focus.  There is a definite low-midrange boost going on with the API.  I can say this with relative confidence because I measured the frequency response of the OBH and it is totally flat from 15Hz – 10K, with only a very slight raise above 10K.  In terms of operation: the API gain control was at 3 o’clock; the OBH was at 9 o’clock.  WOW that is a lot of gain.

Next, let’s listen to some acoustic guitar.  TW played an old Martin D-19 (same as a D-18) that i mic’d with a well-matched old pair of Beyer M260s ribbon mics. The M260 has a built-in gentle roll off that starts at around 200hz

Alright so take a listen.  First, the API 512:

LISTEN: AcGtr_API

…and now the OBH:

LISTEN: AcGtr_RCA_Hybrid

Our impressions were that the OBH had more low bass but less low mids; it had a more ‘mellow’ feeling.  The OBH also had better high-end extension.   This also resulted in slightly more HVAC (air conditioning) room noise in the OBH.  Although I like the sound of the OBH again here, it is less of a clear-cut choice.  The mid-boost that API seems to deliver is very welcome in this particular setup.

In summary: TW put it this way: ‘(the OBH) is like a pair of gentle shelves (shelving EQs) on the very highs a lows.’  I think this is very accurate.  The OBH seems to give what I think of as an English sound: that sort of larger-than-life, hyper-real sound that UK records have always aspired to.  I highly encourage your DIY’ers out there to give this project a shot; you will find it to be a very useful tool.

Thanks again to TW for his help with this listening test; T’s band THE STEPKIDS is just back from LA where they did a direct-to-vinyl (!) live set in front of a studio audience (!!!) at Capsule Mastering Labs.  Check out the details of this very cool endeavor here and here.

 

 

 

Categories
Gold Coast Recorders Technical

Ward Beck Console Preamps: History, Preservation, Listening Test

Tom Gruning with one of his Ward Beck ‘lunchboxes’

I came across Tom Gruning’s work on eBay and I was drawn to the level of craftsmanship that he put into these largely unheralded Ward Beck pieces.  What’s/Who’s a Ward Beck you say? Well,  today on Preservation Sound we will learn a little about Ward Beck, the Canadian broadcast-audio-equipment manufacturer; take a look at some of Gruning’s work reinvigorating and preserving these pieces for use in the modern music studio; and we will conduct a listening/recording test of his pieces in comparison with some studio-standards.

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TG work in the Shop

PS: Tell us about Ward Beck, the audio-equipment manufacturer.

TG:  As far as WBS history…their consoles were/are broadcast consoles that were/are very, very high quality. I seem to recall reading that Neve was their primary competition in that market during the 1970s and ’80s. Neve moved over into recording consoles and WBS stayed with the broadcast market. There is a really wonderful on-going WBS history thread in the forum at the Ward Beck Preservation Society website. I suggest all your readers go there and tune in as it is an absolutely fascinating first person account of that history.

PS: How did you get involved with converting old Ward Beck console modules into stand-along ‘plug-and-play’ rack units?

TG: I got interested in WBS equipment about five years ago. I was putting together my personal ProTools project studio and simply couldn’t afford excellent quality store bought mic pre-amps. Being a research guy, I spent inordinate amounts of time reading what people had to say about any and all console strips. These were, after all, considerably cheaper to come by than the plug and play Neves, APIs, Chandlers, and on and on. The Ward Beck stuff sounded like the best of the bunch in that first and foremost, people thought they sounded excellent and were built like tanks. There was also a really knowledgeable and helpful community of folks willing to help newbies like me: that is, the gang at the Ward Beck Preservation Society.

As I wound up learning more about making these things work, I started investigating different modules when I could afford them. At this point I have 460s, 461s, 462 and 472 EQs, a 466 compressor, 470s, and 490s in my personal stash. Eventually I’ll add some 441s and a few others I have my eye on.

PS: Tell me about the mic preamps that you sent me.

TG: The 49o pres I sent you started life as line level modules in a small, fourteen channel broadcast mixer. ….I pulled the first module and found the Hammond 6012 input transformer so I set about the task of turning these into mic-level units. It really didn’t take too much modification to turn them into mic level units and I wound up bypassing the logic circuitry in many of the racked pairs. Besides simplifying the signal path and eliminating the possibility of ICs crapping out, the mod (which I credit to legendary WBS guru Dave Thomas) gives the pre a pleasingly accentuated mid-range presence that really jumps out in a mix. They are great sounding pre-amps and prices on them are still very reasonable.

PS: Tell us about some of the different vintage Ward Beck pieces out there in the world.  What should folks look for?  What to avoid?

TG: I like the sound of all the WBS modules with input transformers. Bypassing the logic on the 490, the signal path is essentially the same as that of the 470. These sound really good on snare/high hat, electric guitars, and various other sources. The 460 series has a bunch of different designations: 460A; 460B; 460M; 460L,;460LA; etc. My favorites are the ‘L’ and ‘LA’ models simply because they are, as I recall, the most recent of the 460s and they have the really nice sealed pots, fully parametric EQ, and so forth. However, there really isn’t a hell of a lot of difference between the sound of an ‘A’ or ‘B’ and any of the others. The 460s have a big black custom made Hammond input transformer that really gives them a yummy, big, fat, round presence that is at the same time clear and nicely balanced. And they really are built like tanks. I’ve only run across two WBS modules that I couldn’t get up and running: a 466 compressor that I sent to Tristan Miller, a very talented Canadian tech who whipped it into shape, and a 461 mic-pre that I’m still banging on and eventually will get working. Most of the time, cleaning and radically exercising the switches, which are the only really weak link in the WBS chain, will get them passing signal.

PS: What Ward Beck ‘rack-conversions’ do you have available in-stock at present?

TG: I still have a few of the 490H rack boxes in stock (like the one I sent you). I also have a slanted front maple eight pack wired for six slightly modified 460 modules and two 470s. That one has a separate 1U rack mountable power supply. At present the box contains the two 470s, one 460L, and one 460LA. Oh yeah, I also have several 2U pairs of Yamaha PM1000 modules in my GruningAudioworks boxes. I have pictures of all these things on my website tomgruning.com. I also build custom-made hardwood cabinetry for WBS modules and various other things including exotic wood cabinets that house powered “picnic baskets” for API 500 series compatible modules.

Also, just as an aside: If any of your readers decide to rack up some WBS (or Auditronics, or PM1000) modules and would like some help, please feel free to contact me. In learning how to do these, I ran across a number of people who have been very helpful and generous with advice and instruction. If I can do the the same that would be good.

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The Ward-Beck 490A input module in its ‘just-harvested’ state

(image source)

Alright.  Now on to the listening test.  TG sent me a pair of 490A modules which he had racked up, adding phantom power and system power in a very nicely fabricated black steel chassis.

I mounted them in a pre-amp rack at our new studio, Gold Coast Recorders (more on GCR to come…).    I have heard folks compare these Ward Beck preamps to API 512s.  I decided that this would make as good a comparison as any.  Especially since many of you are probably familiar with the sound of the API 512.

Our friend Tim W., recordist and drummer of the excellent band The Stepkids, came by GCR to help in this listening test.   Here’s what we did.  And it ain’t scientific.

Tim got behind a 20/14/12 circa ’64 ludwig kit that I had mic’d up with 4 mics:

-two Sennheiser 441s on the kick, and two Neumann 103s in front of the kit.

The mic pairs were spaced as close as possible.  One kick mic/Front mic pair went into the Tom Gruning-racked Ward Beck 490s; the other kick mic/front mic pair went into a pair of AP1 512s.  The outputs of the mic preamps went directly into pro tools.  no other processing was used, and the signals were played back and bounced with the faders at zero.

I asked Tim to play a beat inspired by this chestnut.  And here’s what we got.

Here is Tim’s performance as recorded thru the Ward Beck M490A pair:

LISTEN: WardBeck_M490A

…And as a reference, here is the exact same performance, recorded at the same peak level, but recorded thru the pair of API 512 preamps:

LISTEN: API_512

Here is a screen shot of the Pro Tools session.

You can see clearly that the Ward Beck kick channel (Kk) is limited in comparison to the API kick channel.  It’s also more symmetrical.  The room mics (OH), on the other hand, have similar dynamic range except on the strong peaks.  Perhaps this greater dynamic range  was due to the fact I used the pads (on both the API and the Wbecks) for the room mics but not the kick mics.  In case you are wondering about phase: yes I did try reversing the phase relationships on both sets of mics, and i can confidently say that what you here in these mono bounces is the correct phase relationship.

Tim and I listened back in the control room at GCR.  The room is outfitted with a Blue Sky monitoring system with their 12″ sub; the low-end extension and clarity is very good.  And this was very helpful for this particular evaluation.

TIM W: ‘The signal from the Ward Becks really moves the room.  It’s much deeper in the bass but not as punchy (as the APIs).  I can really hear the articulation of the Toms in particular (with the WBecks).  There’s less presence of the hi-hats and the cymbals in general.  The bass is really deep – there’s more length to the kick drum sound.

PS: The APIs are a lot more focused, but there seems to be an entire octave of additional bass extension to the kick drum with the Ward Becks.  I feel like it is unusual to hear mic preamps that have this much ‘attitude’ but actually have deeper bass than a high-end preamp like an API.  The low mids feel scooped on the Ward Beck; the high extension is not as good.  I imagine the Ward Beck would be great on rock bass guitar or maybe room mics for a kit.

TW: The API is giving me more low mids in the snare and toms, but i am not hearing that real low end in the bass drum.  (the API pair) is more ‘punchy’ rather than really bassy’

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I encourage you to listen to the audio examples above and draw your own conclusions.  I feel like the Ward Becks are good addition to the rack; I am definitely excited to try them on an SVT cabinet, and some loud rock vocals too.  It’s definitely a very coloured sound – both in terms of the compression and the scooped low-mids and slightly rolled-of highs.  I will also give em a go on kick drum for sure.   Check em’ out on Gruning’s site; you might be pleasantly surprised how affordable they are.