Coytee Posted February 17, 2005 Share Posted February 17, 2005 If you have an amp and buy matched tubes for it (as I have done), and you have one of them replaced (as I have had done), how do you know the replacement tube "matches" the first ones? Obviously one can not know that absent measuring all the tubes (right?). So, is there a test one can give with a multi meter, or is the only way to really test, done with a tube tester? Is there perhaps some other way to get an inkling of their matchfulness? Am I making a mountain out of a mosquito bite? Inquiring minds wanna know Quote Link to comment Share on other sites More sharing options...
Ritz Posted February 17, 2005 Share Posted February 17, 2005 I can't respond to your specific request because I don't know how to 'match' tubes either by knowledge or equipment. However, I understand that they should be matched for better performance. I just bought new tubes for my Music Reference RM-10. It takes 4 EL84 and 2 12ax7's if I recall. One of the 84 flamed bright and the vendor asked for that one and the one next to it (V3 and V5 as noted on the amp) in return and they will forward a separate matched set for replacement. I deduct therefore that at least some deem it important to keep them matched. Can I tell the difference? That remains to be seen. It seems like others are more able to do so than I. Gerry Ritzert Quote Link to comment Share on other sites More sharing options...
Deang Posted February 17, 2005 Share Posted February 17, 2005 If you are talking about your Jolida, which I believe is cathode biased -- then what you have to do is buy two matched tubes if you lose one. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted February 17, 2005 Share Posted February 17, 2005 or get your self a true mutual transductance tube tester...you can match the tubes yourself then. tony Quote Link to comment Share on other sites More sharing options...
Coytee Posted February 17, 2005 Author Share Posted February 17, 2005 ---------------- On 2/17/2005 2:40:12 PM sunnysal wrote: or get your self a true mutual transductance tube tester...you can match the tubes yourself then. tony ---------------- Is that what is otherwise known as a "tube tester", like a Hickock brand? (if I got my memory right) Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 17, 2005 Share Posted February 17, 2005 ---------------- On 2/17/2005 2:24:32 PM DeanG wrote: If you are talking about your Jolida, which I believe is cathode biased -- then what you have to do is buy two matched tubes if you lose one. ---------------- The 502 has "fixed bias". When you adjust the bias with your multimeter you are in effect "matching" the tubes. That is the advantage of fixed, adjustable bias and is why Craig recommends the "bias mod" on his Scott rebuilds. Rick Quote Link to comment Share on other sites More sharing options...
JJkizak Posted February 17, 2005 Share Posted February 17, 2005 Using the tube tester of course assumes that all of the components in the amplifier are totally the same value, which they are not, that's why they adjust the bias in the amplifier. Then again how close is close on the tube checker? Might be better to adjust for minimum distortion. Then again if you junked the tubes and got a good solid state amp you would never have to worry about balancing or for that matter replacing a final. OK tube guy's, you can commence the attack now. JJK Quote Link to comment Share on other sites More sharing options...
sunnysal Posted February 17, 2005 Share Posted February 17, 2005 hickok made nice tube testers, but you need to identify which specific models would meet your needs. I use a Hickok 600a which allows me to match my 2A3 and EL34 output tubes...regards, tony Quote Link to comment Share on other sites More sharing options...
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