by Phil Taylor
In my quest for better tone I frequently scour Ebay for NOS (new old stock) vacuum tubes in the hope of finding a bargain Mullard ECC83, Telefunken E82CC or some, as yet, undiscovered (by me) equivalent that might be used as a substitute with perhaps improved performance or reliability. Over the years stocks of the more commonly utilised NOS tubes have inevitably dwindled and their prices steadily climbed. At the time of writing this article Mullard ECC83s (12AX7s) are exchanging hands for over £40-00 each. These old tubes are an irreplaceable resource and we’ll almost certainly never see the likes of companies like Amperex, Mullard, Telefunken and Siemens again. The expertise and quality materials to manufacture true intrumentation grade tubes is gone. – it’s decades since these companies ceased manufacturing tubes and supplies of the more widely used NOS types are finally drying up – there are no more bargains to be had.
It’s these escalating prices that make the search for unplundered supplies of NOS tube equivalents such an alluring prospect.However this search is a frustratingly fruitless pursuit
A staggering array of thermionic devices were developed and manufactured From the early 1900s up until the late 1980s including triodes, tetrodes, pentodes, thyratrons and numerous other specialised tubes. The legacy is unimaginably vast and today there are still enormous quantites of these tubes around – dealers and tube amp manufacturers have taken a share, however there are still military warehouses scattered around the world containing boxes of tubes – a time capsule containing tubes sealed and untouched since the day they were manufactured and packed. They’ve not seen the light of day for decades let alone been used – prefectly mint. This not some urban myth like Area 51 or the Roswell Incident. I’ve purchased NOS tubes. They typically come in brown cardboard boxes of 100 with each tube in it’s own individual white box. The 50s and 60s were the zenith for audio where hi-fidelity sound reproduction equipment was built to be the best it feasibly could be. Companies like Quad (Quality Unit Amplified Domestic) and H.J.Leak & Co researched, experimented, innovated, made genuine contributions to the art and set new standards for domestic hi-fi sound reproduction equipment. Of course, these (privately) owned companies were also driven by profit margins, however hi-fi had yet to be devalued in the name of shareholder profits and short-term gain – it was still early days for the free market. Those capitialistic gremlins (mainly accountants, middle management and marketing gurus) that would eventually be responsible for ear buds, er…ahum waveguide speaker technology (TM) and other cheap and nasty ‘plastic’ gizmos marketed at a price point had yet to hatch and take over. Engineers still had the time and space to dream and build the best that physics and the state of manufacturing would allow.
Audio signal and power amplification were just one application of tubes, however the World War II effort demanded tubes for other applications including modulators/demodulator circuits for radio, proximity fuses for guided missiles and logic circuits for digital computers (enemy message decryption). This means there are plenty of NOS tubes out there however there are plenty that are not suitable for audio circuits. So the search for for audio tubes is not straightforward – there are many different types NOS tubes some being fit for audio applications and others that are not duitable for use in audio circuits
The first time I saw the 5963 in an RCA catalog was 1956, and they
were marketed for VT digital computers, mostly, such as the UNIVAC.
NORAD used these by the boxcar full in their early UNIVACs that were
used in the NORAD system in the ’50s through the ’70s. Many of the
used 5963s on the market now are probably part-outs from the old NORAD
machines, which would occupy large buildings and need 100s of tons of
refrigeration to cool.
The big difference here is that most “computer rated” tubes are not screened or spec’d for noise. The 5963 is notorious for having a large percentage of examples being noisy. then the beginning of production for the 5963 might be 1949 or 1950.Me too, I asked an old timer about it once at a auction and he told me that folks get excited about special purpose tubes, but they were just that, and if the purpose didn’t require them to be silent, you would likely get lots of noisy ones. The 5963 is a great tube though, if you do find a quiet one.These tubes are intended for digital circuit designs (it explicitly states this in the datasheet), hence the poor microphonic performance (if the tube is hard-on or hard-off then some sensitivity to vibration certainly isn’t that critical in a digtial switching application – unless it so terrible it is at the logic switching threshold). If you do happen to convince someone to purchase these 5963 tubes for hi-fi audio applications then they will be serverely disappointed and not a happy customer. “I don’t see anyting in the datasheet about higher microphonics.” – Of course not – the manufacturer is not going to bother to specify a parameter which is pretty much irrelevant for digital applications (switching, frequency division, counters, etc). That would be like specifying the gain of a CMOS ripple counter – it’s just not relevant to the way the device is used.
Probably if you audio test and hand select these tubes for low microphony (have you tested any?) or they’re used in a low gain application, then the microphonics won’t be an issue. But if you think JJ are tubes are poor for audio, then these computer tubes will be worse. They’re simply not appropriate for use as an audio tube let alone an audiophile tube.
We are fortunate to live in a time where, although past its zenith, the hi-fi audio industry still exists in tubes are still manufactured by companies such as JJ Tubes. there are valid reasons that audiophiles seek They’re. As audio electronics engineer I count myself fortunate to still be able to obtain these tube are fortunate to inherit this legacy. – the years between them from their date of manufacture are bringing them closer and closer to being valuable antiques rather than vintageIt seems to me we’re not too far away from a time where it may be considered foolhardy or even bad taste to actually use NOS tubes in amplifer – they will be coveted by an elite of wealthy collectors who use them only on special occasions or ultimately strive merely to preserve them in their original cardboard boxes as rare and fragile museum pieces of a bygone, golden age.
These beautiful guitar effects pedalboards and cases with leather handles and tweed fabric covering are hand-crafted by Heath Verrall, Stratford-upon-Avon, Warwickshire, United Kingdom. Heath builds several standard pedalboard designs and will also build custom sizes to your specification. For more information check out his website
Sorry I’ve not given a progress report on the Effectrode delay for sometime. This year I’ve been busy getting other pedals into production (Helios, new Tube Drive and Blackbird), however I’m hoping to dedicate more time to the Effectrode delay project next year once the Delta-Trem tube tremolo is completed in spring. Some of the work I’m doing on the Delta-Trem will be used in the forthcoming delay – for instance, the Tap-Tempo control circuitry. So I kind of am working on it already! Also there’s something to be said for taking one’s time with a design as it allows me to take a more considered approach, explore different avenues, get other opinions and let ideas ferment – and nothing good is done in a hurry.
In the three years or so I’ve been researching this and planning, I’ve talked to several knowlegable engineers, musicians and enthuisasts, some of which have had personel contact with engineers from Binson. For instance, David Bozzoni knew Dr Bini and several original Binson engineers and has been invaluable in providing technical and historical info. It’s important to me to have sense of the history and the people involved in the creation of the original Echorec – or it could be described as a sense of nostalgia. Anyway the spirit of this project is also very important – I want to create a product which reflects the obsessive detail that Dr Bini (Mr Binson) lavished on his products.
I’m also privilaged to have had a few meetings with Steve Rothery (Marillion) and he has been kind enough to advise on what features should be inlcuded on the design. Additionally, Phil Taylor (Gilmour Music) who has been extremely invaluable in Beta testing and fine tuning many of my pedal designs will also have some input on this design. So I feel fortunate to be in such company, standing among giants of engineers and musicians. I cannot overemphasise the significance of having advice from such seasoned professionals in the design stage of a pedal. It really is a great reaasurance to be able to talk to these guys. The devil (or God, depending how you look at it) really is in the detail and it is impossible to get all the details right without some help.
As usual, with all my other designs, I’m way behind schedule, but watch this space. It is happening!
Thankyou to Steve Rothery! – it’s a real honour to be mentioned in the credits list on the new Marillion album, ‘Sounds that Can’t Be Made’. This album is well worth a listen as it is exceptionally well preoduced and has a sophisticated, almost filmscore quality with some beautifully arranged compositions – my personal favourite is the emotive track ‘Sky above th Rain’. Steve uses the Effectrode Fire Bottle, PC-2A compressor, Tube-Vibe, Delta-Trem, Tube Drive and Blackbird pedals throughout the album. More info about the recording process for this album can be found on the Marillion website.
This picture of me was taken a while back at the Dr Who exhibition in exhibition in Llangollen, Wales. Sadly the Dr Who Experience closed back in 2003.
I’ve been building circuits – vacuum tube buffered ring modulator with neon relaxation oscillators to be exact – for the BBC. Tune in to Radio 3 on Saturday evening at 9.30PM to hear weird and wonderful tube circuits sparking, burning and screaming as they are pushed to their limits in an attempt to recreate some of the sounds from the 1950s movie ‘Forbidden Planet’! More info can be found on the BBC website
First shipment of authentic Daka-Ware – Chicago chicken head knobs has just arrived today. These knobs are manufactured using the original moulds made by the Daka-Ware Company back in the 1940s and I can’t say enough good things about their quality. They are moulded from phenolic resin – this is the real thing no plastic reproduction. If it’s not marked it’s not Daka-ware!
A batch of 100 new design TUBE DRIVE pedals are almost complete. I’m just waiting on chickenhead knobs (authentic U.S.A. manufactured Dakaware, not the Chinese copies) to be delivered. If you’d like to get on the wait list please contact us direct via email to reserve one. The TUBE DRIVE is designed for flexibility, ease of use and outstanding guitar tone. Three thermionic vacuum tubes make up a cascaded symmetrical clipping circuit and active ‘Baxandall’ tonestack. The clipping stages operate in single-ended class A at real amp plate voltages to deliver exceptionally natural and musical overdrive.
A long overdue trip to Bletchley Park to see the ‘Colossus’ digital computer – containing 1500 triodes, pentodes and thyratron tubes. It was an utterly incredible engineering achievement for it’s time, to design and build this machine back in the 1940s to help decipher German radio messages during WWII and also a staggering achievement by the late Tony Sale to rebuild this replica of one of the original Colossi machines from just a few black and white pictures, some scribbled notes and old telephone exchange parts. When we visited the machine was fully powered up – the 8KW power dissipation plus a hot and humid August afternoon made it uncomfortably hot inside the hut where Colossus is situated. More info can be found on the Bletchley Park website. A great day out!
The picture above shows a close of the new old stock pencil tube used in the Effectrode PC-2A photo-optical tube compressor. You can see the frame-grid construction and the grid is made from 22 carat gold plated wire that is thinner than a human hair – a work of precision engineering and art in its own right. You’ll notice a big improvement in tone when playing through the PC-2A when compared to solid-state and VCA compressors. The tube circuitry delivers stacks of head-room and low noise floor for outstanding dynamics, preserving the attack characteristics while creating musical and natural compression. It wraps your signal in velvet.
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