Category: Uncategorized

When folks learn that I build and service vacuum-tube based audio equipment, some of the first questions they ask are: Is it hard to find those old tubes?  Where do you find them?  As it turns out, lots of different places.

The RelaxAcizor was, depending on who you ask, either a quack-medical/exercise device or a sex toy that was marketed clandestinely to women in the 1950s.  It consists of a voltage amplifier in a chassis with a series of electrodes that attach to the (female) body on numerous pads.

Looks fairly horrifying.  Anyhow, using dials on the amplifier-unit, the user can vary the amount of voltage that the various muscles experience.  The result?  The manufacturer claimed that it would lead to ‘effortless weight loss.’  But as Peggy Olson experienced in episode 1.11 of MADMEN, it is more likely to lead to orgasm.

(Peggy Olson, noted audiophile.  WEB SOURCE)

Anyways… I bought a partially-disassembled RelaxAcizor for a few dollars at the flea market yesterday.  It was oddly missing its case, so the rear of the chassis was exposed.  This is a crucial point.  Because the innards of the unit were visible, I was able to see that it contained a VT-52 tube.

The VT-52 is a very valuable and useful audio tube.  It’s basically (BASICALLY..) a 2A3 designed for 6.3v through 7v filament voltage rather than 2.5 volts.    This tube has a huge cult following.  Check out this deep website dedicated solely to the VT52. I love the sound of the 2A3.  My main home-music listening amplifier for the past 5 years is a stereo 6SL7/2A3 amp that I built based on a schematic from Angela dot com.  There are a ton of great, simple schematics for Single-Ended high-fi amps that use the VT52 as the output tube; and unlike the 2A3, which requires an unusual filament voltage and requires an unusually low output transformer primary, it appears that the Vt52 will work fine with normal ‘guitar-amp’ type 5K Output transformer.  Directly-heated Fender Champ?  Yes I think so.  I am inclined to recommend this schematic over the others.  The 2A3 likes to be fed by a low-impedance signal and I would bet that the VT52 is similar in this regard.

Carving up the RelaxAcizor also resulted in this nice wrinkle-finish chassis, which will find a good home someday in a a future project.  E commented that perhaps I cut up the unit because I felt threatened by it.  Well, either that, or the fact that VT52 tubes go for upwards of $100 on eBay.  $300 if they are W.E. branded.

Alright so what’s the point?  Search web forums and you will be told that the VT-52 is a very rare, mysterious tube.  OK.  But consider that over 400,000 RelaxAcizors were sold in the US.  That’s a lot of expensive directly-heated triodes sitting, hidden, in junk piles throughout this country.  So get digging folks.

One warning:  you might have a hard time prying the R/Z from the hands of this lady.

Scully was one of the main US makers of professional multi-track tape machines through the 1970s.  Scully was based in our fair city of Bridgeport CT.  Wikipedia has no information on this classic manufacturer; in fact, they incorrectly identify it being from ‘bridgewater connecticut.’  I’ve been slowly accumulating archival material on this company and hope to have a comprehensive treatment together at some point.

Earlier this week I bought a full truck load of old Scully and Ampex tape machines for a few bucks (no joke).  I think that there were about four Scully 280 2-track machines, several Ampex 351s and PR10s, a 16-track scully 2″ machine, and a few other odds and ends.  My truck is currently out-of-commission awaiting some parts, so I was limited to taking just the stuff that would fit in my VW.  This meant leaving the transports behind and just taking the electronics portions of a few of the machines.

The most exciting piece is this Ampex 3761.  It needs a complete restoration (nearly every part and connector is rotten), but the chassis/faceplate and UTC transformers are intact, so I think I will give it another life.  The 3761 is not a particularly useful device, but it does have an incredible pedigree.   It is a four-into-one microphone level mixer which uses the excellent 5879 pentode tube, and some of the best input transformers that UTC (or anyone else) ever made.  The 3761 was used in order to mix four microphones onto one track of an Ampex tape machine (in fact, it gets its power from the tape machine).  And what recordings were made using these devices?  How about most of the classic STAX recordings.  Good God.

Anyhow, seems like this thing deserves another chance.

How about the rest of that stuff though?  It all dates to around 1965-1970.  None of it seems to have been maintained since 1990, and everything was generally filled with dog hair, dead bugs, and bits of food that (presumably) mice secreted away in there.  Yes it was really that nasty. So i was not about to risk a major biohazzard restoring this stuff.  The only other option:  Chop it up.

Each of the 280 chassis contain a number of excellent hermetically-sealed transformers: a UTC A18, UTC A39, and a very large Freed 600:600 (split) transformer. I have yet to find a UTC A-series transformer that did not work, so I am reasonably optimistic.

Three of the 280s also had a UTC 0-1 500:50K input transformer.  Many of the 280s also had clean XLR jacks, lamp holders, and API VU meters.  So it was a good harvest in general.

I do feel a little guilty about chopping up these classic units, made with care here in BPT; but I have a plan to earn back the audio karma.  Once I can track down the schematic for the 280, I will clone the mic pre-amp circuit, and build a few stand-alone 280 clone pre-amps using the original transformers, meters, and whatever other cosmetic parts that I salvaged.  I have been waiting for the right solid-state pro-audio project to present itself, and I think it found me.

It was a little painful to dumpster the carcasses; I felt a little better after K told me that someone shortly thereafter pulled them from the dumpster, shouting excitedly that they were brass, and therefore valuable for salvage.  One person’s junk…

Damn that dude was funny.  Heard he became/was-always a major reactionary.  Anyhow, PS was not updated this weekend because…  this weekend was ‘open studios’ in scenic Bridgeport CT.  My shop is located in an Arts-Space building, and we opened the doors to all comers this weekend. As always, met some real characters, and got to know the other folks in the bldg a little better.    If you came by and rapped with me…  thank you.  Hope you enjoyed the event.

E and I like to ‘work-through’ these open-studio events; keep it productive while taking the time to speak to anyone interested in our arcane activities.  You likely know that I am involved in the creation and servicing of tube-based audio equipment; E is a letterpress printer.  During these open-studio working-sessions, E refers to our spot as ‘Sturbridge Village‘, and I find this hilariously accurate.

(This is from Sturbridge Village, not our shop.  But u get the idea)

ANYhow… point is…  I actually got a lot done this weekend due to the fact that I was forced to be in the shop for two entire days straight.  This week, we will look in-depth at…

..the Premier 88. Which is finally F’ING DONE!  and oh my god does it sound killer.  Also….

…Repaired/Restored a Magnecord PT-6 all-tube pro reel-to-reel recorder (circa 1950).  This was a great find that turned out really well.  It is up and running 100% after a little attention and…  114db mic pre amp?  What the F?  But it sounds great.  Also….

…the Mic PreAmp saga continues.  Completed my 3-stage Pentode pre-amp.  This is the culmination of years of experimenting with various ancient broadcast preamp ideas, and… so far, so good.  It works well. Next step…  frequency sweep tests.

I hope to cover all of this (and more…) this week.

Tomorrow marks the first day of what we expect to be a 3-month period of intense construction work to create a new recording studio-space here in historic Bridgeport CT.

Since this process will have me very… occupied, I am going to take the opportunity to focus this site for the next three months on my collection of catalogs, manuals, schematics, and product sheets relating to older+antique audio.  Everyday I will post full scans of a new document hitherto unavailable on the WWW.  Expect some very interesting and very unusual stuff, with daily updates.

If anyone out there has any requests for scans from a certain manufacturer, product, or product type, just drop me a line and if I have it (and it’s not already on the web), I will scan and post it.

During this 3-month period I will continue to write posts similar to the existing content, but these will come on more a weekly basis rather than daily.

Starting in February I will resume the daily-updates of the more broad nature that is the goal of this website.

I wrote briefly about Cairo Egypt in an earlier post. As usually happens on our vacations, I try to seek out whatever regional audio-oddities I can.  Cairo did not offer much in this regard, but I managed to find a few items of interest.

Most of what I came across was public-address equipment and rudimentary recording gear.  This caught my eye in a shop beneath a highway overpass in the center of the city.

It was a new microphone in a shopworn box.  It cost me about $15.  Meet the Shour Beta 57.

Look familiar?  Yes it does.  Today we will take a listen to this marvel of copyright infringement and see how it compares to it’s Shure-brand inspiration.

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When is an object a copy?  What defines a fake versus an imitation?  Deception, or the desire to deceive, is certainly a factor.  I think that our friends as Shour INC probably had deception in mind, especially since Roman characters are likely as inscrutable to most Egyptian residents as Arabic is to me.

There is no Shour dot com, btw.  And there is absolutely nothing on Google relating to Shour Microphones.  It’s not a bad attempt at a name, though.  Sort of suggests ‘Shure’ (the world’s best-known microphone manufacturer) and ‘Shout’ (the most basic of spoken signals) combined into one convenient brand.

I think the fact that they actually go so far as to tout (highly doubtful) Mexican manufacture (as actual Shure mics are made in Mexico) is pretty telling. I am going to assume that the Shour was birthed in China, but I have no way of knowing.  Oh and no word on the availability of the rest of the Shour line.  OK!  On to the sound.

I did not have a Shure Beta 57 in the house today, so I used a regular Shure SM57, which I imagine sounds pretty similar…  I think the polar pattern rather than frequency response is more of a factor in distinguishing an SM 57 from a Shure Beta 57 (Cardiod vs Hypercardiod).

Despite having an XLR-M output jack, the Shour is a high-Z, unbalanced mic.  Connecting it to the DI input of the MBOX and cranking the gain resulted in audible digital inteference noise (sounded similar to iPhone interference), so in order to nullify this, I instead used a direct-box inline.  This DI is one of my own, from a series that I built using 1970’s AKG UT-330 matching transformers.

OK here’s the sound clips.  Have a listen.  First, the SM57.

Shure_SM57

…and now the Shour (through the Direct-Inject box):

Shour_Beta_57A

A few things are obvious:  The Shure 57 has much better low-end response evident, even with the signal being an acoustic guitar mic’d at 2-feet.  I would imagine that if you stuck these mics on a bass guitar amp or floor tom, the difference would be much more dramatic.  On the other hand, this could be due to the Direct Inject box, and not the mic itself.  I have never measured the response of this DI box.

The other clear difference is the noise level.  Since I am using the DI box, I needed to boost the gain on the Shour input to 100%.  Anyone who has used an M-Box will know that this basically creates a White-Noise-Generator.  Those preamps are terrible.

Overall, though, the basic sound is similar.  I was surprised.  Of course, there are a whole wealth of other characteristics that distinguish microphone quality, such as feedback resistance, durability, and SPL handling ability, but I think it’s safe to say that I got my full $15 worth of microphone here.

Anyone have a similar knock-off mic story?

The Advent 300 FM stereo receiver was introduced in 1976.  In audio-speak, ‘Receiver’ indicates a device which combines a tuner (radio receiver), a pre-amplifier (a device which governs audio control functions such as level, source selection, etc), and a power amplifier (a device with high current output in order to drive speakers to a listening level).

I have always admired the design of this piece, and I was excited to pick one up today (in the box, no less) at an Estate Sale for a few dollars.

The ‘industrial’ styling of the piece is striking considering the era.  It almost looks like a piece of industrial paging-equipment.  IT stands to reason that the design was motivated by the fact that the major selling point of the unit was a sort of ‘less-is-more’ attitude.  This unit sacrifices high-wattage-output (which few people ever use anyway) in order to devote more dollar-value to a higher-quality signal path throughout, and more R+D efforts.  Advent clearly knew that the design was stellar; they even included a graphic representation on the box of the unit.

Here is a scan of the entire manual, in case you want to check out the details.  I really like the way that this manual is written.  The writing is very much in-line with the electronic philosophy of the unit.  For instance, there is basically no ‘instruction’ to it – the unit is so simple that it hardly needs any explanation.  Instead, the manual focuses on the ‘why’ of the unit.

Manual: Advent300_Manual

There is a schematic printed on the bottom of the unit, which is a good thing, because my 300 did not work when i hooked it up.  The schematic revealed a likely culprit, and after opening the unit and replacing a few internal fuses (located AFTER the power lamp!), it was cooking.  And it works well, especially the tuner.

The best part of the manual is the ‘in-situation’ ‘serving suggestions’ that Advent offers.  Enjoy a trip to Tasteful Contemporary Home c. 1976:

Been recording today.

We spent last evening setting up, running cables, tuning the drum kit, and getting some basic drum sounds going.

Trying to get drums down for 6 songs today.  The material has a loose, laid-back feel, so it’s not too tall an order.

One of my all-time favorite TV shows is The Rockford Files.  James Garner plays a laid-back ex-con private eye.  He’s an old-fashioned guy kinda coasting around half-confused amid all the far-out hippies and irresponsible bon vivants of mid-seventies Los Angeles.

He’s kinda like If Johnny Cash Was A Detective.  He drives a gold Firebird (NOT a Trans-Am – too tarty-) and he’s generally pretty alright.

Since our show is set in mid-seventies LA, there is plenty of music-biz shenanigans throughout the series.  In one of my favorite scenes, Rockford impersonates (oh-btw- his general workflow consists of 70% impersonating fictional people and 30% fast driving) an A+R guy who proposes remixing an ex-con’s old record with new string overdubs ETC…  another one has him head-to-head with a squirrelly label head with a payola/coke/murder problem.  it’s all pretty great.  ANYHOW.  in the scene below, Gandolf Finch (played by issac hayes) describes doing something that no one really does anymore…  he BUYS USED STEREO COMPONENTS thru the classifieds.  IN THE PAPER.

Wow.  people used to actually needed to buy an amp, a tape deck, a tuner, a record player, speakers…  crazy.  Nowadays it’s an ipod dock with a lil amp built in.  Would a 12 yr old kid even understand WTF Gandy is talking about here?   Components?  Furthermore, the whole plot of this episode hinges on the fact that the used speakers turn out to contain a shit ton of stolen money/drugs ETC.  What could u fit in one of those ipod docks?  a few roaches and a coupla nickels?  Certainly not enough to get Rockford out of his trailer.  (oh yeah- Rockford lives in a mobile home on the beach).  Check out the clip below, and check out The Rockford Files streaming on Netflix. Season 2 is the best season, IMO.

GandyGetsAUsedStereo-desktop

This is a website about audio.  More specifically, the history of audio, and our relationship to audio.  Audio, broadly defined, is the electrical representation of sound.  Sound has existed for at least as long as anyone has been around to hear it, but audio is a relatively new technology.  The ability to ‘capture’ sound and then ‘play it back’ divorced from its origin in time and/or space is the most basic function of audio technology.   In addition to this role, audio technology can also be an instrument; a tool to create unique sounds that do not originate as acoustic sound.  I do not mean to imply that these are separate functions; capturing and playing back sound will always change the sound, regardless of the intent of the audio operator.   There is always a grey area between documentation and manipulation; every audio operation creates the potential for a new sound.  We have developed a great many audio tools and technologies to maintain the ‘fidelity’ of audio: that is to say, maintain a ‘true-to-the-original-sound’ quality in our audio signals.  We have also developed a great number of tools and technologies to enhance, distort, combine, separate, and generally manipulate audio.  It is these tools and technologies that I am interested in exploring.  I am interested in their effects, their methods, and their development.  Most of all, I am interested in their potential to create meaning for the people who experience these new sounds.  Sounds that have been brought across great distances, through spans of time, bearing the artifacts of the particular tools that have crafted them.

I will not be presenting a chronological narrative.  I am not attempting to offer a comprehensive or thorough treatment of audio history.  Instead I will focus each post on a particular subject: a technology, a technique, an individual, a recording, a piece of hardware.  I will provide historical context, and offer my thoughts about what significance the subject may have.  Some posts will be very broad in nature, and some will be fairly technical.  Much of what I write about will stem from my own experiments with audio hardware and techniques.  I hope you find the information useful.