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SPEAKING OF TUBES.....


A series of articles appearing on this page from time to time, tossing my two cents worth in about those glowing bottles.


WHO ARE YOU AND WHAT CAN YOU TELL ME ABOUT TUBES?

A little bit about Brent Jessee Recording & Supply, Inc. and some our most often heard questions about tubes in general.


OK, who the heck is Brent Jessee?

Brent Jessee Recording & Supply is truly a labor of love, and Brent Jessee is the guy lovin' it!

We started out as simply Brent Jessee Recording. We were initially only a location audio recording and editing service. Yours truly, Brent Jessee, had been recording church and school band and choir concerts since 1970. We used to lug open reel tape decks, microphones, cables, headphones, and all the other trappings of location recording around Northern Illinois as a hobby for years. Professionally, I am a trained audio-visual repair technician who, during my 25 year stint in the ranks of "the day job", repaired everything from VHS recorders to 1 and 2 inch broadcast videotape recorders, to professional audio recorders, to amps and CD players, and just about everything else in between. Later in the career, I managed three different service shops, two doing broadcast and pro equipment repair, and the last repairing consumer electronics. Anyway, I had the recording bug bad, and got more and more professional equipment. Finally, I decided that it was high time this hobby paid for itself. I remember the first gig that actually made some money selling cassette copies of the performance: a church Christmas choral concert about 1984. I think I made about $40 profit and decided there might be something to this business! We got our first paying gig about a year later, and needed a name for the new-found recording company. After toying with "Digilog", "Sound & Vision", "Digital Audio Services" and "Brent Jessee Sound", we settled on "Brent Jessee Recording". The name stuck, and we didn't add the "& Supply, Inc." until we incorporated in 2003. We progressed from open reel tape, through the evolution of digital audio with the first PCM video based recording systems, to Digital Audio Tape (DAT), to computer audio editing and hard disk based recording. I was the sound engineer of the professional choral group The Chicago Master Singers for ten years, and have several Compact Discs they have released to my credit. We continue our tradition in audio recording with our present offerings of audio archival services, analog to digital transfers, audio sweetening and restoration, and post production editing and duplication services. Got a tape you want put onto a CD? Got a recording of any kind that you have nothing to play it back on? Drop me an e-mail, this stuff is our specialty.

So where do the tubes come in? I had been collecting antique radio sets since 1974, and had been buying vacuum tubes wherever I could find them, just to keep the radio sets running. It got to the point where I had enough tubes to retube an entire museum of old radios, and storage was becoming a problem (or so I thought). About 1994 I took a tube caddy of tubes to an antique radio swap meet, and was surprised when I sold a good number of them. I put my entire inventory onto a computer database (Microsoft Works v3.0......this was 1994 remember!) and got an idea of their worth from some tube vendors who had price lists at the swap meets, and also from that newfangled online database, the Internet.

The Internet was the big awakening. I was online and put up my own webpage, for fun. One day in September 1996 I decided, just for fun, I would put my entire tube inventory with the prices on one of my Webpages. The rest, as they say, is history. I started getting e-mail inquiries from tube fans from as far away as Japan, Hong Kong, and Brazil. The tubes started to sell. I sent my Web address to Yahoo! to get listed on their search engine, and they listed me as having information on vacuum tubes and "other geek stuff." It worked. More e-mails came my way, and I made a cool $800 by the end of 1996!! By 2002 the business had grown to the point that I was literally working two jobs......the day job and the tube job. When corporate downsizing struck me a fatal blow, it was more or less a relief. I dived right into my tube and recording business full time. It was the best thing that could have happened, and I am just loving this gig now!

I have seriously devoted much of my time to learning the nuances of tubes, their uses in various circuits, their differences in sound, which tubes are better, which tubes are best in antique and modern tube equipment, and how to help clients find the best tubes for their particular use. I became a regular at all of the local antique radio meets, ham radio festivals, and all types of electronics sales. I learned which tubes were in favor, which tubes were rare and in constant demand, and which tubes were not worth stocking. I obtained some of the best tube test equipment, and taught myself the ins and outs of tube testing, measurement, and matching. I had always loved repairing tube radio sets, and now began collecting and repairing tube amplifiers and preamps. I remember the first tube amp I had repaired, an Eico ST70, that I hooked up to my main system to test it for possible resale. This was a number of years ago, and I had never seriously listened to a good tube amp. While the Eico is by no means a top flight amp, I remember being AMAZED at hearing that first CD through those glowing tubes. It put my Harmon-Kardon transistorized system to absolute shame. The warmth, the soundstage, the presence, the airy top end and solid bass, and the stereo image literally left me with my jaw dropped to the floor. I stayed up most of that night, playing all of my favorite CDs, and hearing stuff on them I had never heard before. Needless to say, I now have four tube stereo systems, and a fifth in the works!

I have basically dedicated myself and my business to bringing that awe I felt with that first tube amp, to every client I possibly can. I find that with a simple e-mail or phone call, I can ask a few detailed questions, and guide my clients to the tubes that will give them the same jaw-dropping sound that I enjoy here. Tube rolling is so much fun, and it's fun to help first time customers discover it for themselves!

OK, what is the million-dollar question? It's probably "how will this certain tube sound in my amp or sytem?" It's a tough question, a loaded question, and how I answer it can make the difference between a satisfied customer or a customer who is still searching for the holy grail of good sound. Generally, this is an unanswerable question except in the most general of terms. Here is the skinny on tube sound basics: many vintage tubes can be classed into two categories, specifically those with a very neutral sound bandwidth, and those with a boost in the midrange spectrum and a touch of 2nd order harmonics which tends to sound like the proverbial "tube warmth". The vintage tubes from Germany and some USA types usually fall into the neutral sound category. The best of these have a wide bandwidth, a nice open airy top end, good bass, and excellent stereo imaging. The Telefunken tubes immediately come to mind, and in the right system and listening room can sound like heaven. I use them myself and love 'em. However, in a bright room or a system with a bit of treble emphasis, they can sound "lean" or cold. In a guitar amp this type of tube can play very clean, but don't usually saturate very well if you want that "phat" sound.

In the midrange warmth camp, we have vintage tubes from Holland, Great Britain, and many from RCA in the USA. Amperex, Mullard, Brimar, Philips and RCA will all inject a little warmth in the mids and vocal frequencies. These tubes will do the trick to a thin-sounding system, a bright listening room, or a shrill guitar amp. These tubes will play clean in a guitar amp, but will saturate better when overdriven. The RCA 12AX7 tubes are wonderful for this, and get a gritty, hugely phat sound when driven to distortion. Hear this tube at the opening bars of Steely Dan's "Reeling in The Years" in all their gritty glory. In a hi-fi system, these tubes have the same airy top end, great bass, picture perfect imaging, but have that warm "tube sound" which is usually just the right tweak to some systems.

"Do I need matched tubes, and can you match them for me?" This is another biggie. Matching means basically testing two or more tubes for their transconductance (Gm, or the change in plate voltage with respect to the change in grid voltage) and the amount of plate current draw while the tube is under load. There is much hype and actual mis-information on the Internet about tube matching, including some claims from some vendors that are really just wishful thinking. First of all, matching of linestage tubes (like the 12AX7s or 6DJ8 tubes found in a preamp) is a good idea, but is NOT critical. A matched pair will give you basically even gain from tube to tube, and the tubes are likely (but not guaranteed) to age at the same rate. With some preamps, especially in phono stages, matched pairs of preamp tubes are very important, so check with your owner's manual or manufacturer of your equipment first. Actually, a good linestage or phono stage design should be able to work just fine with tubes that vary by 20 percent, especially since tubes will drift in their characteristics over their lifespan. I know, I know, it's my humble opinion, so refrain from the heated e-mails if you dissent. Put it this way: you will never go wrong with matched sets of preamp tubes, but you will not damage your equipment or totally ruin your sound if you don't get tightly matched sets.

In the case of power output tubes, it's a different story. These tubes, when used in pairs or quads, SHOULD be matched whenever possible. Most amps using two or four power tubes use them in "push-pull" configuration, with one providing the muscle for the positive halves of the audio waveform, and the other pumping out the negative half of the waveform. First off, you want them to be working at the same gain, and properly aligned to avoid such issues as crossover distortion and excessive plate current draw. The closer the tubes match, the easier it is to adjust the bias and put the tubes in the center of their ideal operating states. Some amps are "self-biasing" and really are depending on you plugging in nicely matched sets. Again, a well-designed amp will usually operate just fine with a slight mis-match, as tubes will usually drift from their ideal match as they age. I can match any power tube or preamp tube to your specifications if I don't already offer that particular tube in a matched set.

"Are your tubes new?" Probably asked right after the other questions listed above, most of the time! For all the technical details, please see my page on NOS tubes: http://www.audiotubes.com/nosnote.htm In a nutshell, if a tube is not listed as used, then it is tested and meets the specifications of an unused tube. Vintage tubes I sell are all at least 25-30 year old, and many are much older. These tubes don't often look sparkling new and perfect, but rest assured they have passed the tests and measure up to the manufacturer requirements of a new tube of that type.

We have an unconditional 30 day guarantee on every tube we sell. I would like to be your tube guru and help you find those jaw-dropping tubes for yourself. It's important to know that you are buying tubes from a guy that has done his homework, and who will work with you to find the best combination of tubes for your particular application. Then comes the security of knowing that if there is any problem, even if you just don't like the sound of a certain tube, your purchase is protected and fully guaranteed. My basic premise is to offer tubes for sale at a competitive price, and at a quality level that I would want to use myself in my own system. Try to get this level of service from an online auction site!!!

I'm running out of space and time. I'll toss in another two cents worth next time. In the meantime, let me know if I can help you find some really fine-sounding vintage tubes! Send me e-mail with some ideas for the next article!


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Copyright © 2004, Brent Jessee Recording & Supply, Inc.