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London Power's Power Supply for Preamps (PSU-PRE) - Printable Version

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London Power's Power Supply for Preamps (PSU-PRE) - London Power - 04-14-2020

Have you tried the PSU-PRE Power Supply Kit for Preamps? Post your comments or questions here!

[Image: psu-pre-new-1-297x300.jpg]

The PSU-PRE power supply kit for preamps is low-profile and will fit inside a 1U rack chassis. It uses a pair of DC, well-filtered, standard Hammond 229-series transformers to create the heater and plate supplies. The plate supply has two nodes that can be individually tapped with paired wiring. The heater supply can be wired for either 6V or 12V; 12Vr is preferred for use with London Power preamp kits and for using the ERK Electronic Relay Kit for channel switching. The heater supply also supports the switching circuits.

The regulated heater output can support up to two/four 300mA heaters at 6Vac or up to two/four 150mA heaters at 12Vac. There are three Links on-board that set the heater transformer wiring and regulator output to "6V" or "12V". The regulator keeps the heater voltage hum free.

There are two basic versions:
PSU-PRE-12 can support up to two 12A_7 tubes - enough for a 2-channel preamp
PSU-PRE-24 can support up to four 12A_7 tubes - enough for a 3-channel preamp

Read more about the PSU-PRE at .

If you're interested in London Power's tube preamp kits, see this page: .

RE: London Power's Power Supply for Preamps (PSU-PRE) - K O'Connor - 04-19-2020

Hi Guys

Note that both versions of the PSU-PRE come with the same number of regulator BJTs, which means that in the 2-tube version these can be stood up on the PCB rather than being bolted to the chassis. For the 4-tube version, the BJTs should be mounted as the photo shows and bolted to the chassis. The kit notes show how to align everything.

PSU-PRE includes mounting hardware for the board and BJTs.

Have fun