Tag Archives: reverb

Highlights from the 1971 AES Convention

AES_1971,,,and today, perhaps unsurprisingly: some of the new kit unveiled in 1971 at the NYC AES show, also via DB mag.  Of note: Auto-Tec, Scully, Ampex and 3M intro’d new 16-track machines, Neve made a push for a new console (would this have been the series 80?), AKG introduced the BX-20 reverb, Melcor showed its model 5001 electronic reverb (anyone???), and a new company called Eventide introduced a digital pitch-shift device!  The Neumann U47-fet and Sennheiser MHK-815 mics were introduced, as were the Marantz 500 and Crown M2000 power amplifiers.

Click here to DL a pdf of the proceedings: AES_1971_DBmag


There is just a shit-tonne more of this stuff, so click the link below to READ ON;;;;;

Continue reading Highlights from the 1971 AES Convention

The EMT 250 and 244 Digital Reverbs

EMT_250Download the original product-sheets for the EMT 250 Digital Reverb and its baby bro the 244:

DOWNLOAD: EMT_244_250_reverb

That giant 99-lb star-wars-lookin thing above is an EMT 250.  Ten years ago I was working on a session at Ocean Way Nashville and they still had one of these things right next to the console.  Anyone out there still using a 250 in the studio?  The 250 uses 12-bit, 24k convertors, which means that both input and output are low-passed at 11Khz.

EMT_250_flowThis brings up a good point about reverb in general: you don’t need a lot of hi-end to create good-sounding reverb for most applications…  I always keep some sort of low-pass filter active in my reverb returns to trim off anything that’s not contributing in a meaningful way.  Luckily, even the most basic reverb plug-ins tend to have a low-pass adjustment built in.  My $0.02: use it!

250_reverb_diaVery interesting to read this: so apparently the 250 uses 19 different taps, with feedback only on some of them.

EMT_244The lesser-known 244 (i’ve personally never seen one, FWIW) uses 13 bit convertors; no sampling rate is specified, but given that the frequency response is stated between 30hz and 8khz, it’s likely around 20k.

To you veteran engineers out there: was the 250 the first high-quality digital reverb? Were there any earlier units that you have used?  Let us know,,,

The Sound Of 23.5 Karat Gold

EMT_240Download not one but two circa ’72 brochures for the EMT 240 ‘Gold Foil’ reverb system:

DOWNLOAD: EMT_240_reverb

The 240 was apparently intended not to replace the 140 so much as provide a smaller, portable (132 lbs haha) alternative.  I’ve provided y’all with 10 pages of documentation here, it’s worth reading..  this thing really is an engineering marvel.  Rather than a ‘plate,’  the reverberant surface is a tensioned sheet of gold-foil 18 microns thick.  This gold-foil material, btw, was a completely in-house-made material…  fkkn crazy.  Anyhow, check it out…   those of you who have had experience working with both a 140 and 240, pls weigh in on the relative merits thereof.


EMT 140 TS Plate : King Of The Mechanical Reverbs

EMT_140_TS_1971Got a pretty good one for y’all today… download the complete 8pp 1971 brochure for the EMT 140 TS reverb system:

DOWNLOAD: EMT_140_ts_1971

I was recently given a large collection of 1970s EMT documentation, so get ready for detailed info on pretty much every EMT reverberation product ever made.

I met a studio owner recently,  it was a very nice place, some excellent gear and instruments, mentioned that he was in the market for a plate; he felt that a good plate reverb is a piece of kit that can actually be a significant factor in a producer or engineer choosing one facility over another for a project.    Those of you who regularly hire facilities for projects: agree?  As a studio owner, I’ve personally been planning on skipping the plate and going directly to building a chamber, but who fkkn knows when/if this will happen.  Plate would sure be nice… here’s what EMT had to say about the 140 back in ’71:


EMT_140_frontEMT_140_TS EMT_140_block_diagram*************



For previous plate reverb coverage on PD dot com, click here…

The Black Box

BlackBoxLet’s just say hypothetically that you had to write+ record a tremendous amount of guitar-based music very quickly.  And even though you work at a recording studio filled with numerous custom and vintage-modified tube amps and great microphones, this music needed to be recorded in a modest home-studio using the not-awful but not-awesome Line 6 POD Pro XT.  Could there be some device that might bridge this gap in audio aesthetics, if even a bit?

NameplateI’ve used the Line 6 ‘POD’ series of devices for a decade; they are not very good for recording prominently-featured electric guitar parts, but they definitely have their uses in the studio; the Bass Pod Pro has actually worked out well a few times, and the Pod Pro is often good to add grit to synths.   When music must be recorded in a domestic environment, though, a POD can be very helpful, at least logistically.  I recently bought the newer POD ‘PRO XT’ version for around $200 on eBay.  Aside from an annoying but sonically inconsequential mechanical-hum given off by the power transformer it seems to work fine.  It even has the ability to user-adjust the blend between close mics and far mics on the ‘Amps.’   Does it sound just like a good tube amp, well-mic’d, in a great sounding room?  No.  At best, it sounds rather like playback from a 16-bit ADAT, if any of y’all can remember that sound.  Not bad, but not very detailed and overall sterile.   I knew that some tubes, transformers, and real mechanical reverb could help transform the POD sound to something that I would be a little more comfortable with.  So when I found a Fisher Space Expander for $10 at the flea market last fall, this little project went up near the top of the list.

On_PanelThe Fisher is an old home HiFi reverb system with unbalanced -10 input and outputs; I need +4 balanced.  But I did not want to modify the Fisher unit in anyway (other than adding a grounded AC lead), since they are highly sought-after and i might want to sell it someday.  So i rigged it up inside this old salvaged DIY ham-receiver case with one of those MCM electronics balancing amps, and two inexpensive Jensen MOD series 9″ reverb chambers with medium-impedance inputs (around 300 ohms, I believe).  One tank is short decay, the other is long decay.  I realize that the 17″ larger tanks do sound better, but since this box was destined for my tiny home-studio, size is a real issue; I needed everything to fit inside the 14×8″ steel box.   I’ve already enjoyed the benefits of being able to select two different tanks; on tracks that feature two electric guitar parts I am easily able to situate each in its own ‘space.’

RearHere’s a rear-view of the whole fandango.  Balancing amp is on the right; note that it is stereo, and the unit is fully wired for stereo; that being said, the fisher only generates a mono reverb signal which is then blended into the stereo direct output path; since I am using the unit for mono guitar tracks, I just use one pair of the XLRs at the moment.

PotSwitchAt left: the ‘blend’ knob, and below that a DPDT on/on switch that selects one tank versus the other.

Someone very helpfully scanned and uploaded the manual and schematic for this device; click here to download the PDF directly from them.    There are not too many surprises in the schematic, other than that  the first reverb recovery stage has a 330k plate-load resistor; this is the highest value that I have ever seen, and it failed almost immediately.  Twice.  I eventually put a 2-watt CC in place of the original 1/2 watt, and changed the adjacent coupling cap as well.   I had to replace pretty much all the B+ resistors in the unit (and several coupling and bypass caps) in order to get rid of some nasty intermittent noises; now the unit is working fine and it sounds really good!  A word of advice if you get one of these things: run the input hot, and back off on the return level.  It takes A LOT of signal before it distorts or smacks the tank, and you will be rewarded with a much-improved signal-to-noise ratio.   The MCM balancing amp has handy gain-trims that make it easy to achieve overall unity gain on the direct signal while accomplishing this goal.

Click here for some previous tube-reverb system action on PS dot com

Pioneer SR101 ‘Reverbe’ Unit

PioneerSR101_inCaseI picked up the above-depicted Pioneer SR-101 all-tube Stereo Reverb unit for a few dollars at the final flea of ’12.  It worked after some minor repairs and I am happy to report that it’s actually a pretty fine lil box.  I made a few modifications and added some hardware to adapt it to studio use.  I’ll describe the whole fandango here in case any of y’all are thinking of going down the hardware-analog-reverb path.  There are plenty of these things on eBay, often closing in the $50 – $200 range. Even if you have to spend a lil time or money on some repairs, it could still be a lot cheaper than the roughly comparable Orban 111B or the Sound Workshop 242, both of which we also have + love at Gold Coast Recorders.

frayedWiresAbove: the ‘pickup,’ AKA ‘output’ side of the twin tanks.  Unlike the Fisher Space Expander (which I also just picked up… deets on that one soon…), the Pioneer is a true stereo machine.  Each input feeds its own physical reverb tank.  This is a big, big benefit over the mono-summing of the Fisher.  My SR101 unit was passing direct signal, but not reverb, on one side; the culprit was actual just the output lead of the tank (above), which was over-heated during manufacture and had a signal-leak-to-ground on the coaxial cable.  A quick snip-n-solder and we’ve got SOUND.

GroundBecause this is 60’s piece, the AC mains are not grounded.  So I hacked up a nice long IEC cable and added that.  Above: I connected the ground (green) wire to the common lug of the multi-cap cap.  Seemed to be the most convenient option…       The only other repair was of a more mechanical nature.  The tanks are suspended from steel risers via small springs, with foam rubber pressed between the tanks+chassis.  45 years of tiiiiiiiiiiiime marching-on had turned much of the foam suspension into sticky goo; I replaced the rotted foam with some generic foam road-case-material.

PioneerSR101_SchemAbove: the schematic of the SR-101, courtesy of this handy web forum.  Notice the two red wires: the fellow who originally posted this schem was kind enough to highlight them.   Here’s why.  When I originally got the unit, it was a little tricky to troubleshoot; the left input came out of the left dry output, but the left channel reverb emerged from the right out.  WTF?  Turns out that this was a gimmick that Pioneer used in order to ‘widen’ the stereo effect.  And it does work, but that would just be confusing as hell in the studio.  So I re-reversed (versed?) the direct-signal wires and then reversed the leads going to the RCA output jacks.

swtichWhile I was at it, I drilled a hole in the front panel and added a DPDT on-on switch that cuts the direct signal fully out-of the signal path.  So now the left channel input and its associated reverb both emerge from the left output, as one would expect, and vice-versa for the right channel.  PLUS, now I can flick the switch up and  get reverb-only in the outputs.    Easy enough…

case_rearAbove: the rear of the rack-case.  That lil silver box on the right is a bi-directional stereo balancing amp designed to interface consumer audio gear with studio (or broadcast) audio systems.  Basically, it takes a stereo balanced +4 input signal and drops it to -10 unbalanced output, and simultaneously takes a -10 stereo input signal and boosts it to a +4 balanced output.   I own many of these sorta things, but the unit above is notable in that it is really, really, really fukkin cheap.  These things are generally in the $70 – $200 price range, but my fav purveyor of dirt-cheap electronic crap MCM electronics has em now for $39.  There are often sales too; I think I paid $35 for this one and $30 for the last one I bought.  Both worked fine BTW.  Anyway, I wouldn’t recommend that you mix a record thru the thing, but I can’t imagine it doing any harm to the signal coming from a 45-year-old box of tubes and springs and carbon-comp resistors.

balance_AmpAbove: the front of the balancing amp as seen from front of the rack-case.  The knobs set the send and return levels to and from the SR-101.  This is super-handy in terms of setting the right nominal level to ensure a good signal-to-noise ratio without creaming the tanks too hard (wow that sounds gross).  Unlike the reverb tank in a fender guitar amp, for instance, the SR-101 hits the tanks with power amp tubes (around 2 watts, as opposed to maybe 100 milliwatts in a fender).  So it is possible to get a pretty good signal level out of them without too much objectionable noise in the tank return circuit, provided that you hit the tank input hard enough.  I might be repeating myself now, sorry, it’s late…

ReverbeAnd above: the sole audio control on the unit, charmingly labeled ‘REVERBE TIME’  Yes Reverbe.  Love it.  As the schematic reveals, this is simply a passive gain control in the tank pickup amps.  So yeah it’s a one-sound box.  But it’s a glorious sound.  This dusty gem just got put in GCR today, so once I get a chance to try it on a mix I’ll post the results.

More outboard gear of the early 60’s

The Pultec range of 1961: the Pultec EQP-1S program equalizer, EQH-2 program equalizer, HLF-3C high and low pass filter set, MB-1 mic and booster amp, and Mavec micpre/EQ unit.

Pultec equalizers have enjoyed fifty-plus years of popularity among recording professionals.  Much like the first several compressors released by Universal Audio/UREI, they have never really gone out of style.  And if vintage Pultecs seem expensive these days (and they no doubt are…), remember that there is an inflation factor of 11x from 1961 to 2012.  So the value of these pieces has more or less simply risen with inflation.

Download catalog data on the EQP 1, shown above: Pultec_EQP-1

Download catalog data on the EQH 2, shown above: Pultec_EQH

Download catalog data on the HLF, shown above: Pultec_HLF-3

The Pultec MEQ-5 and SP-3 Stereo Panner of 1962.  As unlikely as it might seem, the ‘pan’ knob was, at one time, a new and novel concept. 





Ok so these are not outboard so much as inboard but you get the connection.  The Langevin EQ-252A, EQ-251-A, and EQ-255 filters of 1961.





Above: the Universal Audio 175B limiter is announced.  The 175B is quite similar in operational principle to the Altec 436/8 and the Gates Sta-Level but the UA is far more sophisticated.  Just a really smartly designed piece of AFAIK, it was sold like shown, with no top cover.   gear.  Retro Instruments currently makes a reissue of this classic piece (but with a top cover).

Above: an inexpensive studio echo unit of the early 1960s: the Telefunken Echo Mixer. It is a spring-reverb unit.  Click this link for an audio demo.   Apparently used by Klaus Schulze on his “Irrlicht,” which is one of my favorite records.

Sound Workshop Reverbs of the 1980s

Download the four-page catalog for the Sound Workshop 242C and 262 stereo reverberation devices:

DOWNLOAD: SoundworkshopReverbs

I’ve been using a 242C in the studio for years; it’s ok for signals that don’t need much high or low end.  It’s pretty boing-y and a little bit noisy.  It does have a cool dense, gritty texture that give backing vocals a nice old-school character.  At this point, i have learned to always use it in the following way:  usually I pre-delay the input 10 or 20 ms; then run the input signal through a gentle compressor (usually DBX 160); and cut the highs and lows on the return to remove hiss and hum that the spring pickups introduce.  Oh yeah and the 242C is not really intended for +4 studio use; so i also use a Peavey stereo +4/-10 converter in order to best gain-stage it.   So yeah… a lot of support equipment around this humble box.   It does get a lot of use tho.  Hey at least it has overload LEDs and and a very-useful ‘input mix’ switch with combines both inputs – great for creating pseudo-stereo from a mono source.