|Smart Tube Buyers Guide |
WHEN TO CHANGE TUBES
> > > For Organ players, Musicians, and Audio Connoisseurs > > >
Ok so your organ or guitar tube preamp or amplifier is sounding like a sick dog in the middle of the night and you want to fix it without spending a lot of money, huh?
Well changing the tubes can make a major difference and get your favorite amplifier or organ back to sounding like it should so you can impress all your friends with that great vintage tube sound.
So how do you know when to change the tubes and which ones to change? Here are some suggestions that have been helpful to others over the years
Symptoms that you may have a tube problem:
1. Your amp/preamp is DEAD! – no sound at all and the tubes are not glowing. Check that your power cord is plugged in and your amp is turned on and the fuse is good. All tubes don’t go out at once unless they all have no power.
2. You have sudden changes in output levels, loss of highs or perhaps mushy lows or muddy chords and some notes may sound weird, you have poor or no balance between notes or the amp makes “funny” noises like popping or crackling.
3. Your power tubes (the big ones) may become microphonic and sound like a big echo or a torn speaker. This can also happen to preamp tubes like the 12AU7 or 12AX7 when they go bad, but usually the output gets low if the preamp tubes are deteriorating.
4. The power output (sound level) isn’t as high as it used to be because you have to turn the volume up higher to get the same level of output. The cause is simple, output tubes deteriorate gradually over time along with a loss in both bass and treble responses.
5. You have a tube that is not glowing or lit up but others are ok. This usually means one has prematurely burned out and the rest will shortly follow – better to get a whole new set and keep the old ones as backup (throw the bad ones away – recycle them as glass please!)
6. Remember bad tubes can cause premature failure of other parts, such as the output transformer, speaker, and other vital components and these may already be bad if you didn’t change the tubes in time or regularly.
OK you have some of the symptom described, now what do you do?
Most musicians should change their tubes once a year if they play moderately loud and fairly often (like church organs or concerts). For Hammond organ players the power tubes in the tone cabinets often get very hot and lose power over time. You should also remember to check the tubes in the organ console as they are often the preamplifier which feeds the signal to the tone cabinet amplifier. Sometimes there is a separate reverb or vibrato amplifier or power amplifier (Like Hammond A-100, D-100, L-100, and M-100 series) in the tone cabinet (or console) and you will need to change these tubes also if you sense or hear a problem like I mentioned above.
In the old days, you could take out your tubes (mark which holes they came from) and take them down to the corner drugstore ands test them. Unfortunately tube testers are no longer conveniently available to do this and the test only lit up the tube and rarely tested it to the same conditions as in your amplifier with the correct voltage and bias conditions (That’s how we test them). So even if the tube was “OK” on the tester it still may be weak in your amplifier. So testing your own tubes is not a convenient option.
The most reliable alternative is tube- for-tube replacement and a before-and-after comparison. You can do this one tube at a time (like changing spark plugs one at a time) until your amp sounds better or just replace them all at once (easiest) and start to enjoy the great sound your amp put out when it was new to you.
When you do replace the tubes (and most people can do this), remember to turn off the amplifier (or organ console and tone cabinet), unplug the cord, let the tubes cool down if they were turned on and replace one tube at a time with the new tube (remove the old tube and put in the new tube and go to the next one, etc).
DON’T TAKE OUT ALL THE TUBES AND PUT THE NEW ONES IN WITHOUT MARKING THE HOLES THEY CAME FROM! Many tubes have the same pin configuration and will fit in several places they are not electrically compatible and may cause a major problem. But if you are careful this won’t be a problem and you amp will be happy with its new tubes and so will you!
Good luck and may all your notes bring happiness to their listeners!
< < < For Hams, CBer’s, Radio Jocks, and RF Experimenters (you know who you are!): > > >
Ok so you’ve got a vintage piece of gear that has low power output from the transmitter or a sick receiver that has low sensitivity, cracks or pops when first turned on or has low audio output. A new tube set would probably help that ole receiver and a new set of final amplifier tubes (and driver tube!) can certainly bring new life to your treasure.
We stock several Complete Premium tube sets for Collins and Heath gear as well as RF Finals and driver tube combinations for 6146, 6HF5, 6JS6C, 6GE5, etc that have been very popular with owners all over the world.
Here’s the Smart Buyer’s Scoop on RF tubes: Get a gain matched set of tubes AND a new driver tube to go with them. We gain match, manufacturer match, and size match all our sets so you will be satisfied every time! You should check you transmitter manual for any neutralization needed and perform the necessary steps for best operation. I have links to many pieces of equipment in the Tech Support section of the website or you can do an internet search and probably find one.
A quick note on 6146’s if you use these tubes. Some old 6146W have a problem neutralizing in older circuits designed for 6146 or 6146A radios. The newer 6146W’s are actually ruggedized 6146B tubes that work well in most Collins gear and many others that were originally designed for 6146B. I have had very good customer response to 646 or 6146A in Collins gear and some people have also used 6146B and W’s – you milage may vary but I generally ship the 6146/A with Collins as indicated in my auctions. For the full 6146 story search for the many articles by K9STH or click the link on the Ham Radio Premium Tubes page.
Are Chinese and Russian tubes any good?
Quick Answer: For audio applications the Russian and Chinese tubes work fine and some are better than others. I sell a lot of Svetlana and Sovtek for preamps and audio amplifiers (6550, 6CA7, 6L6, 6V6/6N6S) with excellent results. I also like the 1940-60’s American 6V6 which has a great sound.
Many tubes are ONLY MADE by Russian and Chinese manufacturers today so you have no choice other than tested Vintage tubes that meet new tube minimums (like ours).
For RF amplifiers, I usually have better results with US/European made tubes but have had good reports on some Chinese Shuguang tubes for 6146B/W applications. For 6146B applications, use the 6146W or 6293 for longer life. If you want to cheap out and rewire your filaments to 12V you can use the 6883 which was a 12 volt filament 6146B used in mobile two way radio service. Get Matched Premium (see definition below) sets if possible, otherwise match the tubes for gain and plate current even if from different manufacturers. ALWAYS replace the Driver tube when you replace the final tubes.
Simplifying the Jargon and Hype of Tube Descriptions
PLEASE READ THE FOLLING CAREFULLY AS IT DESCRIBES SOME OF THE COMMON TERMS USED IN DESCRIBING THE TUBES FOR SALE IN MY AUCTIONS
The number in parenthesis (x) after the tube number in the title is the number of tubes in the lot of that type. No parenthesis means only 1 tube of that type. a "/" in the title indicates and equivalent tube designation like 6HQ5 is the same as a 6HA5 or 6HM5.
Here is a guide to some of the other terms used in my tube auctions:
NIB means New In original Box. The tube ID number and brand match the box brand, the tube is not used, not tested (unless specified) and is physically new looking. These tubes usually sell at a premium price and may include the newer tubes made in Asia or Russia.
NOS means New Old Stock. The tube is new but may NOT be in the original box or may be in an unlabeled white box with the printed tube number on outside for ease of identification. Tube is NOT tested unless specified. These tubes are usually out of production and are old stock from past manufacturing. They are generally a good value.
Tested means that the tubes have been tested and meet the minimum acceptable requirements for emission and/or gain as determined on my Hickok 539B or 580 tube tester (great tester) roll charts or reference tables. Each tube section is individually tested with separate grid bias setting and plate and screen (if applicable) voltages(if applicable) and plate current (if specified) to ensure that the tube meets minimum NEW standards. I generally do not do LIFE TESTS on the tester and do not warranty the tested tubes to pass a life test on your tube tester or to meet the minimum requirements of your tester. Tested tubes may be new, used, NIB or NOS (see description) and all meet or exceed minimum NEW requirements. These tubes are an excellent value depending on brand, when made, and physical characteristics such as black plates, halo getter, chrome tops, etc.
Vintage means USED, probably untested and with or without a box (original or relabeled).
Matched Set means that the tubes in the set (more than one) all match within 10% of transconductance readings or plate current (if measured). This standard ensures that the tubes will be electrically equivalent in the installed circuit and perform as a matched set in a push-pull or parallel application.
Premium Matched Set means that the tubes are matched electrically (see above) AND that they are from the same manufacturer and are physically similar in shape.
I try to describe the items accurately using the above guidelines for the key words. However I do not warranty any tube for use in a particular application, or how it sounds in an audio amplifier and I am not responsible for your use of the tube for any purpose or if it causes any direct or consequential damages like burning down your house because it got to hot in your 1960’s amplifier.
However I strive to have happy customers and have a return rate of less than one percent of all tubes sold so feel good about buying from Captain Bob.I have over 2,200 auctions under my wing and a very high satisfaction rate. If you have a major problem, email me and I am sure we can work it out.
See more tubes in my store for all types of applications including Hammond Organ, Fender Guitar and various tube testers. Check them out!