2. tech-talk
  3. 1132765469

Please educate me on tubes

Since I know nothing about tubes, I have a few questions:

Vintage, re-issuem NOS, modern production (or if there are other types)? What do these types mean?

Is it safe to buy used? If so, what do you look for?

Should I buy as sets (pairs, quads, matched)?

Where do you get the most, least or doesn’t make a difference? Input, rectifier, output, etc.?

Thanks!
vman71

Showing 2 responses by jea48

jea48
4,266 posts
 
Mike, I found this on Google, lots of info on the Eico FH-81.
http://www.google.com/search?hl=en&q=Eico+hf-81+&btnG=Google+Search

Jim
jea48
4,266 posts
 
Here is some info to get you started.
http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html

From my experience and others early 60s NOS tubes are the best sounding tubes and the most expensive. I have bought tubes from members here on Agon and off of ebay.
The tubes I have bought from members here on Agon most were new NOS tubes. I did buy some used NOS tubes from Sam here on Agon about a year ago and they still test strong.

Most of the tubes I have bought off of ebay were used. Of about six pairs, half have gone bad, mostly due to grid emissions.

Buying tubes on ebay is about like shooting craps, throw the dice and take a chance.
Two pairs that I just bought recently only lasted about 50 hours. One pair of early 60s Siemens E88cc tubes, and a early 60s pair of Amperex PQ 6922 USA tubes.

About a month ago I won a bid on ebay for a pair of 60s Siemens CCa tubes from a gentleman in Germany. In his ad he said both tubes tested strong. He even gave the test results. When I received them the first thing I did was to test them. Both tubes failed on shorts and grid emissions. I filed a claim with paypal, now the waiting game.

If you are going to buy new or used NOS I would highly recommend you buy a mutual conductance tube tester.

As for new production tubes I have had good results with EH, Electro Harmonix, tubes. I run them in my Audio Research VT50 power amp.
Even new tubes you have to be careful who you buy them from.
The last set of EH 6922 tubes I bought from Jim McShane, great guy to deal with.
http://pages.prodigy.net/jimmcshane/.

One of the biggest mistake I made early in the tube game was on a pair of new NOS Siemens CCa 6922 tubes. I bought them here on Agon. The ad said they were from the 60s, turns out they were from the 70s. Learn what to look for before you buy.

Here is a great picture of the early 60s and later 60s Siemens CCa tube.
http://gon8.audiogon.com/i/c/f/1115367414.jpg

Jim
More to discover