Northern Electric Tubes

[Zer09]

Well, Radio Shack sold RCA 12ax7's for $2.55 ea in 1960.......These old catalog archives are great to look up old equipment retail prices....
1960 Radio Shack Catalog Low-res page 171 of 318
And from an online inflation calculator...."What cost $2.55 in 1960 would cost $18.56 in 2010. " The calc wouldn't go to 2012.
So tubes are priced about that I guess....

It's actually better than that because the net price for 1-10 tubes is $1.43 dropping to $1.12 when you buy 50+. The telling part of that catalog page is the guaranty...1 year from date of purchase. Truth be told, i will most likely never have to buy a tube again because I have Rubbermaid totes full of American and British tubes as it was the addiction that led me to the amp building addiction. Amassing power and preamp tubes was my gateway drug to building my own amps. But if someone was selling $20 12ax7's with 1 year guaranty I wouldn't think twice about trying them. As it is now I occasionally try them out of curiosity.

[Chuck H]

Well, as Stan pointed out, preamp tubes should last for years. I never trouble with shock mounting or isolation and I get about a year out of NOS as V1 in my high gainer. In a moderate gain amp with shock mounting and isolation I could forcast five years easy. IMHE that translates into two years for the Chinese tubes. Which sound fine but... Already covered.

Ever since I've been playing tube amps, which is longer than I've been making them, the standard preamp tube failure is V1 becomes microphonic in some way. Sometimes it's a wierd sound that acts percussively on the attack. In that case the tube is usually toast. Most of the time the tube just starts to whistle a little when the gain and/or treble is turned up. In that case I can usually just swap tubes around and find a quiet one for V1. The "whistle" tube is still capable of service in less sensitive circuits. I might need a new preamp tube just for V1 because of it's extreme sensitivity. I can count the number of times a preamp tube failed in a spot other than V1 on one hand. Point is, preamp tubes can last a really long time. With shock mounting and isolation I might be surprised at how long even V1 can last in a high gainer.

[überfuzz]

Anyone here that actually have some flight hours with these tubes? I'm planning to buy some Full Music 12ax7 to see if they fly. Thoughts on that?