London Power ad

[-]
Search the Forum








(Advanced Search)

Precision Power Scale Circuit
#8
Hi Guys

Precision Power Scaling: part H.

Can't see the forest for the trees.

During the development of the Precision Power Scalers, I added an offset to the voltage divider so there would be a minimum output voltage. Of course, with the Z-core there is no need for this, but did I remove it from the circuit? No.

The redundant circuit elements are D3 and R3, which are in parallel to each other. These should be left out and a wire link installed in one of their positions - it does not matter which one. Use a cut-off resistor lead bent into a U shape and insert it into one of the component positions. Splay the ends on the solder side, trim with flush cutters and solder.

I install this jumper on the PCB when SV1 or SV2 are ordered. BUT... just in case you receive a board without this jumper, you know what to do. The kit notes show this replacement.

So... the next boards will be perfect but I'm not getting them until the present inventory is used up.
Reply


Messages In This Thread
Precision Power Scale Circuit - by K O'Connor - 12-11-2025, 01:53 PM
RE: Precision Power Scale Circuit - by K O'Connor - 01-23-2026, 01:39 PM
RE: Precision Power Scale Circuit - by K O'Connor - 01-23-2026, 02:21 PM
RE: Precision Power Scale Circuit - by K O'Connor - 02-25-2026, 01:38 PM
RE: Precision Power Scale Circuit - by K O'Connor - 02-28-2026, 02:57 PM
RE: Precision Power Scale Circuit - by K O'Connor - 03-04-2026, 08:08 PM
RE: Precision Power Scale Circuit - by K O'Connor - 04-15-2026, 10:09 PM
RE: Precision Power Scale Circuit - by K O'Connor - 07-28-2026, 02:01 PM

Forum Jump:

[-]
Come in where it's warm!
A warm welcome to tube amp modding fans and those interested in hi-fi audio! Readers of Kevin O'Connor's The Ultimate Tone (TUT) book series form a part of our population. Kevin O'Connor is the creator of the popular Power Scaling methodology for amplifiers.
Please remember these three principles: respect, sharing, community.
Not familiar with The Ultimate Tone book series? See discussion topics, or click here to visit London Power/Power Press Publishing.

[-]
Tube Amp Forum Hosted by London Power
London Power logo