Jake,
That's an interesting question here. In many cases, you could drop in lower gain 12au7 and in those cases, it would probably work fine, if not under optimum conditions.
However, in what looks like a direct coupled phono stage with the equalisation wrapped around the tube in question, I would imagine that it's probably not a good idea. The operating point wont be exactly right for direct coupling and the different tube would likely change up the equalization some... how much, I don't know... it might not matter, it might change it quite a bit.
In this case, I would think it much smarter to spend $10 or so on a 12AT7 from somewhere and avoid the headache all together. Yeah?
That's an interesting question here. In many cases, you could drop in lower gain 12au7 and in those cases, it would probably work fine, if not under optimum conditions.
However, in what looks like a direct coupled phono stage with the equalisation wrapped around the tube in question, I would imagine that it's probably not a good idea. The operating point wont be exactly right for direct coupling and the different tube would likely change up the equalization some... how much, I don't know... it might not matter, it might change it quite a bit.
In this case, I would think it much smarter to spend $10 or so on a 12AT7 from somewhere and avoid the headache all together. Yeah?
Re: 12at7 vs 12au7 (interchangeable?)
No. That's a feedback amp, and using a 12AU7 instead of a 12AT7 will change the open loop gain, and thus, the performance under NFB. You'd have to redesign the feedback network to compensate for the lower Avol.
jn2630 said:Will it work in my application?
No. That's a feedback amp, and using a 12AU7 instead of a 12AT7 will change the open loop gain, and thus, the performance under NFB. You'd have to redesign the feedback network to compensate for the lower Avol.
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