Tubes Asylum Questions about tubes and gear that glows. FAQ

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ Tubes Asylum ]

---

[ Alert Moderator ]

---

Re: "Matched pairs" vs. "test new": what's your thinking

Posted by Mechans (A) on January 11, 2007 at 02:16:37

In Reply to: Re: "Matched pairs" vs. "test new": what's your thinking posted by Sondek on January 10, 2007 at 20:10:51:

Matched pair means from from the same company same cosmetics and to many simply matched to some extent for gain. Given as rule from some source? as 10%.
On my tester a typical small MTC Hickok 800 (very much a 600 if you know that) it measures MTC. More imporantly does the "match" refer to the average "gain", a misnomer for amplification capacity in micohmos at a given operatering point in an MTC tester. For dual triodes which is a very common tube type indeed. Does it mean all sections match with in 10%, or just each tube's everage of it's two sections compared to the other tube's sections?
Think of a pair of tubes with weak output. A simple example -My nominal value is 2600 microhomos for a 6SN7GT. What if I find 2100 microhmos 2000 in tube 1 in sections 1 and 2 respectively, that = only %2.5 off mean for each section.
Tube Number two has sections that measure 1800 and 1900, 50 is the deviation from average thus for 1800 its only 2.7% and curiously it doesn't seem significantly different from 1900 at 2.62%.
The average MTC for tube 1 is 2050 the average of for tube 2 is 1850 the average sum of the 2 tubes in toto is 3900/2 = is 1950 micohmos. Racall that the average output tube #1 is 2050. The average output of tube # 2 = 1850 wich is 200 microhmos which is 200 micohmos different from the of 2050, the difference being 200/2050 = 9 %. Therefore one could argue if they look identical, they do in fact "match". Granted all sectons do not meet matching criteria across tubes with a spread of 2100-1800. But who amongst us would want to shell out $280 for such weak tubes.

Test strong is meaningless, it is a mereley a subjective comment. It seems it is used when actual test conditions and the results are not available.
In the end niether descrption is terribly helpful with out some kind of test results to verify what they mean.

This post is made possible by the generous support of people like you and our sponsors:

Signature Sound

[ Signature Sound Lounge ]

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---