|
OTL Asylum OTL, Output Transformerless Amplifier User Group. |
|
|
|
OTL Asylum OTL, Output Transformerless Amplifier User Group. |
|
In Reply to: Re: what Ralph said, plus posted by Slick on December 6, 2005 at 08:02:42:
We used the 6DJ8 many years ago. It is a terrible tube for audio, although quite linear. They were designed for high frequency and instrumentation purposes but are too microphonic for audio (although that has not stopped them from being used!).When constructing cascode circuits, Valley and Wallman point out that the resulting circuit has good characteristics that belie the rather low currents that the tubes otherwise see. In particular linearity and gain tend to be better than expected.
Gain is the important thing to a differential amplifier so a cascode differential amplifier will have better differential effect than a simple differential amplifier will. The resulting mu is much higher than that of the 6SN7 by itself. This is enhanced by the CCS circuit that the amp already has. Prior experimentation has shown that adding semiconductors tends to also add semiconductor artifacts.
So for most applications the circuit works out quite well. In the old days the 12AT7 was used. Although it has less gain, the 6SN7 sounds better!- in fact better than *any* miniature tube in production. We have what we call the 20-year rule which prevents us from using out of production tube types. The 6SN7 is thus the best thing out there for our applications.
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Re: what Ralph said, plus - Ralph 12:49:22 12/06/05 (1)
- Re: what Ralph said, plus - Slick 04:04:57 12/07/05 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
