[CJ]

I was wondering what this DC threshold does on the 670.
Also, there was some mention that the 12AX might be seeing class B and possibly C operation.
Explain.

Thanks!

The DC Threshold is the single pot in the middle.

[bcarso]

What's the voltage on the fat line at the bottom?

[CJ]

sorry for the crop job, but the file is huge.
Thats ground. Also, I added more to the top of the pic.
Let me know if you want the whole schematic.

cj

[CJ]

Having problems getting the big file to download.
My site wants an FTP type  deal.

I can email it if you want.

[Larrchild]

Assuming the grids are essentially grounded to DC, the cathodes are being shifted by that 100k pot to change their operating point from class a for compression to class b or c for peak limiting.

The effect is that in class b, only the tips of the waveform get amplified.
Hence, Peak Limiter via smaller conduction cycle.

fat line is ground .... top line is reg b+

[bcarso]

Having problems getting the big file to download.
My site wants an FTP type  deal.

I can email it if you want.

I'll PM you with the addy.  I believe Larrchild would also appreciate a nice clean copy.

[PRR]

> what this DC threshold does

I'm sure I explained that once. Probably here.

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