A 12BH7 output stage

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NewYorkDave

Well-known member
Joined
Jun 4, 2004
Messages
4,378
Location
New York (Hudson Valley)
I've been using the following line output with good results in recent experiments. Perhaps it can be adapted to your own designs.
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If you can tolerate a higher insertion loss--on the order of 12 to 14 dB--try using the entire primary of the transformer. This will provide a lighter load for the 12BH7 to drive, and will likely result in improved performance and slightly higher maximum output.

The Edcor is rated for +27dBM maximum, but I'll bet it could handle peaks of +30dBM without peril. It's a pretty hefty little transformer.

The figures quoted on the drawing assume a 600 ohm load. Maximum output will doubtless be higher into a higher impedance load, but the transformer might ring. Try it and see.
 
Kick ass Dave! :thumb: :shock: :grin: :green:

And to think the NE5532 designer thought his chip could replace that... tsk tsk.. :roll:
 
Well, the 5532 will beat this circuit any day of the week as far as distortion goes; but on the other hand, I don't think it can pump half a watt or more into 600 ohms... :wink:
 
Thanks for the compliments.

Most of you know this already, but I'll state for the benefit of those who don't: this circuit does not provide voltage gain. It's an output buffer only.
 
To be able to interface with the outside world.. you never know what's out there :green: and it may be far away, so you'll need to drive long cables..
 
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