bmusic - Tech Tips

Care and feeding of your Valve Amplifier
by Bob Charman

In the second instalment of our 'Valve Head' article series, Bob gives some 'sound' advice on how to properly look after your prized valve gear, and how to get the most out of it. Some elementary precautions and applications can make a huge difference to your tone.

As you will be aware, a lot of money is spent by guitar players both "rich and famous" and "poor and unknown" in an attempt to achieve the sound that each one hears in their head. Valve amplifiers, which are preferred by most players, are becoming more expensive and some of the vintage classics are almost unobtainable. So, I think we need to achieve the maximum performance from the equipment we have available. I have to say that I have seen and heard examples of expensive amplifiers that sound bad, just because they are not being cared for and fed properly. If that can happen with an expensive amplifier, you can be sure that it will be more so with budget priced units.

So, what are the important things a guitarist needs to know about the care and feeding of his valve amplifier?

First and foremost, this is a piece of electronics and just like any other electronics it doesn't like liquids. Every time I see someone playing with a beer, coke, coffee or whatever, sitting on top of their amplifier I cringe, and then smile, because I know that there is a repair job coming up sometime in the future. In particular, valve amplifiers use very high voltages and the insertion of a liquid will instantaneously vapourise any components that it comes in contact with.

Next, smoking is bad for your health, and if you use your amplifier as an ashtray, it's bad for your amplifier's health too. I've seen many vintage amplifiers with a line of cigarette burns along the tolex. It's a fire hazard and seriously reduces the resale price of the equipment.

Speaking of valves, they do not last forever. If you are regularly gigging, say once a week plus a practice or two, and you use your amplifier above 3 on the volume control, then you should be changing your power amplifier valves every one to two years. The pre-amplifier valves are not as heavily stressed, but they should be replaced after five years or so and if you have a valve rectifier then that should be replaced with the pre-amplifier valves. I constantly get comments from guitar players that their amplifier sounds so much better with a new set of valves, and Shane at bMusic has the best value valves around. Remember, though, most amplifiers will require re-biasing to achieve the best results out of new power amplifier valves, refer to my first instalment, Notes On Replacing Power Amplifier Valves, for details about valve biasing, or speak to Shane and arrange for me to re-bias your amplifier for you.

OK, that's the care part, now the feeding. Why is it that a guitarist will spend several thousand dollars on a valve amplifier and speakers, plus more thousands on a Les Paul® or a Stratocaster®, then connect it all up with $10.00 leads? The sound that comes out has to pass through the leads from the guitar to the pedals, pedals to the amplifier and finally from the amplifier to the speakers. You may have seen articles about the trouble audiophiles go to when it comes to speaker leads, oxygen free copper, large diameter, fine stranded wire etc etc. Well, the same applies to an electric guitar- Good quality leads are essential to a good sound, and they have to be the correct lead for the job. DO NOT use guitar leads for speakers and DO NOT use speaker leads for guitar. They have quite different construction and each is optimised for it's particular purpose. A guitar lead has to carry very low level signals without reducing the level or altering the sound and they also have to protect the signal from external electrical noise sources. Speaker leads, on the other hand, have to deal with much higher voltages and currents. A 100 watt amplifier connected to an 8 ohm speaker can deliver almost thirty volts at three and a half amps. Compare this to a guitar signal of about one tenth of a volt at two millionths of one amp and you get the picture. Buy the best leads that you can afford, and take good care of them. They will last longer and sound better, and when you pay more for them you will, most likely, look after them better. Don't put kinks in leads, don't tie knots in them to keep them coiled up. There are a number of cable tie products that will keep a coiled lead neat without doing any damage to the internals, once again, speak to Shane at bMusic. He is also the man to see for all the correct leads that you need to get the very best out of your guitar and amplifier.

From the land of big crocs, hard rocks and dirty socks keep rocking.

Bob is available for all valve needs, from repairs and servicing to finding you those elusive components. Bob is also a wealth of information and would love to be tested with your curly valve questions. Based in South Australia, Bob can be contacted by clicking HERE.
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