Just finished writing this up for Shredaholic.com:
NOS Valve/Tube Guide
Generally speaking, pretty much any NOS or used tube made around 20 years ago or more will sound better than any current production tubes that you can buy. The reasons for this are varied, but most are due to the fact that tubes just aren't in demand anymore.
Manufacturers can't afford to make the metals used in construction of the tube as pure, and the vacuum in the tubes isn't as tight because tighter vacuums cost more time and therefore money. That's why you will often find complaints today of certain manufacturers' tubes being unreliable (eg. power tubes 'red plating' soon after they've been installed). Certain chemicals can't be used for tube production because they are toxic, and the ones that are still allowed to be used today tend to be only legal in countries where workers have less rights, and they don't cost as much to employ either (eg. China, countries formerly in the Soviet Union). That's why old factories in those countries are mostly the only ones still making tubes today, as opposed to old factories in England or USA.
Why go for old tubes?
What should I buy?
NOS Valve/Tube Guide
Generally speaking, pretty much any NOS or used tube made around 20 years ago or more will sound better than any current production tubes that you can buy. The reasons for this are varied, but most are due to the fact that tubes just aren't in demand anymore.
Manufacturers can't afford to make the metals used in construction of the tube as pure, and the vacuum in the tubes isn't as tight because tighter vacuums cost more time and therefore money. That's why you will often find complaints today of certain manufacturers' tubes being unreliable (eg. power tubes 'red plating' soon after they've been installed). Certain chemicals can't be used for tube production because they are toxic, and the ones that are still allowed to be used today tend to be only legal in countries where workers have less rights, and they don't cost as much to employ either (eg. China, countries formerly in the Soviet Union). That's why old factories in those countries are mostly the only ones still making tubes today, as opposed to old factories in England or USA.
Why go for old tubes?
- Old tubes were made so well that they last much longer than current production tubes. Preamp tubes have been known to last around 30 years, or around 20,000 hours. That's practically a lifetime for a tube amp.
- In most cases, vintage tubes sound better than their modern counterparts. The quality in manufacture of these tubes has a large effect on the sound, particularly in preamp valves. You really have to try some vintage tubes instead of modern production ones to experience just how better they sound, they make your amp come to life. The more gain your amp uses the less noticeable this effect may be, as in some high gain amps, transistors or diodes are used to get more gain instead of tubes, so the tubes will be less important.
- Get them while you can - since these tubes are obviously no longer being made, once they're gone they're gone - and prices are always going up.
What should I buy?
- Different manufactures produced tubes which sound different - a tube made in a different plant or by a different manufacturer will probably sound different.
- Many tubes were relabelled, so they may not necessarily sound like you'd expect by looking at the manufacturer name. The best way to know who made your tube or where it was made is to learn how to recognise the internal construction of tubes, and learn how to interpret the codes printed or moulded on the tube. For example, today from eBay I received a Tungsram 12AX7 that I won for £3, yet the valve said "Made In England". Tungsram 12AX7's were made in Hungary, and by looking at the location of manufacture, the date codes, the sound of the tube and the internal construction, I know that this was a tube actually manufactured in Britain by Mullard in their Blackburn factory.
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