6au6wa triode connected as a line amp?
Anyone had any experience with this combination? Thanks a whole heap! Ray
Anyone had any experience with this combination? Thanks a whole heap! Ray
6AU6? no - but I've used the EF86 triode-connected for the past couple of years... I've built three preamps around it and have been very happy. My latest creation with it is the best so far... EF86 dc coupled to a 6922 White Cathode Follower, onboard regulation, tube rectifier...
I've been meaning to try the 6AU6 and/or the 6SJ7/6J7 family... but right now I have a bunch of parts to build a C3m linestage
I've been meaning to try the 6AU6 and/or the 6SJ7/6J7 family... but right now I have a bunch of parts to build a C3m linestage
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Several manufacturers are using the 6au6 as a triode in first stage of condenser microphones I guess for the low capacitance and high plate resistance. Gona try it as a bottom tube in a cascode. Thanks Ray
6AU6 has often been used in triode mode and is quite linear. The biggest problem is that quality varies quite a lot , so you need to select a tube that is not noisy or microphonic. I found GE to be very microphonic but RCA were OK.
I've used 6AU6A successfully in triode mode. For line amp use, where the signal is in the order of 1v RMS or more, it's best to strap suppressor and screen grids to plate, in the usual way for triode mode (using dropper resistors). It works well with plate current of around 6 to 10mA. Mu is abot 36 and maximum dissipation is about 3.5w.
If the signal is small, as in a preamp (say less than 100mv), you could try strapping both suppressor and plate to ground and using the screen grid alone as the anode. You get about the same mu but maximum dissipation is now only 0.65w, so a low current is called for. This arrangement offers good shielding, due to the plate being grounded. It is quite linear for low-level signals but not for large signals.
P.S. I have a pdf file about using the 6AU6 with the plate grounded, if anyone wants a copy.
I've used 6AU6A successfully in triode mode. For line amp use, where the signal is in the order of 1v RMS or more, it's best to strap suppressor and screen grids to plate, in the usual way for triode mode (using dropper resistors). It works well with plate current of around 6 to 10mA. Mu is abot 36 and maximum dissipation is about 3.5w.
If the signal is small, as in a preamp (say less than 100mv), you could try strapping both suppressor and plate to ground and using the screen grid alone as the anode. You get about the same mu but maximum dissipation is now only 0.65w, so a low current is called for. This arrangement offers good shielding, due to the plate being grounded. It is quite linear for low-level signals but not for large signals.
P.S. I have a pdf file about using the 6AU6 with the plate grounded, if anyone wants a copy.
I built a 6AU6 triode Aikido line stage. I am very happy with it. Very good all the way thru. Bass is good as is the midrange and high frequency. I did have to hunt thru a bunch of 6Au6's untill I found some quiet ones.
I tried a 6SJ7 triode line stage and wasn't pleased with the results.
I tried a 6SJ7 triode line stage and wasn't pleased with the results.
I would think that the 6AU6 WA or WB would be more resistant to microphonics than the consumer grade tubes, as they are specified and constructed to resist shock and vibration. Correct me if I'm wrong...
I have tried some of most all of them. They tend to come in 3 flavors, ones that sound great, ones that are microphonic, and ones that are noisy. The noisy ones have a background noise that can come and go. It can be a hiss (common) a rumbling sound, or a random snap, crackle, pop. Some of the old Japanese ones (Fujitsu Ten comes to mind) are often noisy, and some sound great. I have found some military surplus ones that are noisy also.
Too much gain; Mu of 36.
Least gain, without bypass cap in the cathode circuit, about 16. Too much.
Look for a lower Mu device.
Aloha,
Poinz
Least gain, without bypass cap in the cathode circuit, about 16. Too much.
Look for a lower Mu device.
Aloha,
Poinz
Hi , 6AU6 was used as output line amp on the vintage recording systems of the former ORTF . ALCATEL loved this as Cathode follower with 40Hys inductor under 160v on Va/Vg2/Vg3 (also triode connected) . A 2,2uF cap serial loaded with 9k allowed driving a 600ohm line amp . A VERY VERY NICE solution ! 😉
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