Tube Basics 101: What is a rectifier tube for?


In laymans terms please:

What is the function of a Rectifier tube (such as the 5AR4/GZ34 found in my tube preamp)?

Why/How would the Rectifier tube affect the sound created?

How would this differ from the function of a typtical Driver tube (such as a 6SN7, 12AX7, 12AU7)? Also, would a driver tube typically have more affect on the overall sound (i.e. Which tubes would you roll out first if you wanted to change the sound of your preamp?)

Also, what is a "Getter" tube?
nnck

Showing 3 responses by rodman99999

A power supply's rectifier(and it's quality) is VERY important to the sound of any amplifying circuit(phono, mic, preamp, power amp, etc). Anyone that has taken the time to install, say a Mullard Blackburn GZ34/5AR4, in the place of most other tube rectifiers(of the same family), or Fast/Soft Recovery Epitaxial Diodes, in the place of standard SS rectifiers, will likely attest to the improvements of presentation(across the board). Generally speaking; the sound will open up, have greater dynamics and a smoother(less grainy) high end. What you are listening to, through your speakers IS(in actuality) your house current, as prepared by your power supply. Your speakers are connected to your power supply, through your output devices(tubed or SS), and the DC output of said power supply is modulated(YES- the correct term) by those devices(basically switches), as directed by the musical signal. Is that the WHOLE story? NO! Every gain stage is important. Phase splitters and driver tubes BOTH contribute tremendously to one's final sound. BUT- to ignore the importance of the power supply's rectifiers, is to rob yourself of MUCH musical pleasure. I didn't stay at a Holiday Inn, but I have been modding audio equipment, and pro gear, for over 30 years and have made many a discerning ear happy, in that time.
Hello Mr N- While it is certainly true that everyones' aural accuity, and system resolutions vary; tubes in circuit make a dramatic difference, and one must be nearly deaf to miss their impact. Since you mentioned the 6SN7 family, I'll start there, as the driver will have an effect on ALL your inputs. This tube: (http://cgi.ebay.com/2-MATCHED-Sylvania-BAD-BOY-VT-231-6SN7-GT-6SN7GT-Tubes-/300532799867?pt=Vintage_Electronics_R2&hash=item45f926997b) is an excellent performer, that won't break the bank(like my faves; the TungSol round plates, and Sylvania 6SN7W, tall bottles). They are easy to find(right now anyway). Whatever you buy; be certain the triodes are balanced, and the pair also(if more than one is used in that stage). When you replace the phono tubes; once more, balance is important, but also- get CERTIFIED LOW NOISE tubes, as the gain there is much higher, and any noise will be amplified(http://www.upscaleaudio.com/testing-signal-tubes). After you've gotten accustomed to the new flavor of your system; find a NOS Mullard(Blackburn Plant) GZ34(http://www.tubeworld.com/5ar4.htm), and enjoy! OH, BTW: The Mullard rectifier will probably outlast you, and your preamp. Here is a site that will give you an idea of what presentation to expect from some of the difference NOS tubes in the 6SN7 family. I've tried all the top contenders listed, and can vouch for the veracity of the opinions given(http://www.avclub.gr/forum/archive/index.php/t-4376.html).
I based my comment on what you said about having a 12AX7 and 12AU7 in the phono circuit. Both are, "dual triode" tubes, and(as you have one each for both channels), if the two triodes(WITHIN EACH TUBE) are not balanced, neither will the sound be, from that stage of your system. Of course: that will bother some, more than others. Did you look at the Upscale Audio page, on grading tubes? The better the grade, the closer the triode balance(from most sellers). Personally- I've never heard a Chinese tube that I wanted to listen to again. But- who am I to say what's right in someone else's listening room? Happy listening!