London Power ad

Search the Forum

(Advanced Search)

Kits needed to build an LP-PRE?

Greetings. I have a question for you and/or the Community.

I would like to build a complete LP-PRE in a 1U or 2U rack unit.

As I see it I need the following kits:

And a chassis kit.

Am I missing anything to complete this?

Can you tell me whereabouts I can secure the pieces/parts to mount cards in vertical orientation in the Hammond chassis?

Many thanks,
Jim Gale
Roanoke,VA USA
Hi Jim

Always best to go with a larger chassis for more air for the components, and for more space for your hands to work in.

PSA is actually PSW, Panel Switch.

PU-PRE-24 is heavily filtered and BFX and LP-PRE follow Galactic Grounding principles, so QS-LV is not really needed unless it appeals to you for "ultimate quieting".

If you use the 2U chassis, then mounting of the boards is greatly simplified, using a nut or two as spacers on each bolt.

Have fun

Thank you. PSA just slips off the fingers too much these days what with abbreviations all the rage...

2U works for me. I tried a preliminary layout, PSU off to the side and back, LP along the front panel. It looks like I could get away with an 8" chassis depth given the size of the PCBs.

I could see a use for the remaining space to infill a power section later, but a separate power amp has been the plan all along.

I'm gearing up now to point to point wire a Soma84 from TUT5 in an Epiphone Valve Jr. shell. I expect it to be quite a sleeper. Tongue
Greetings Kevin, et al.

Hard reset! A recent encounter with a Fuchs ODS has me craving the D-PRE in place of the LP-PRE.

BFX ships with a panel switch for parallel/series.

I would like to foot/panel switch the channels.

My order now looks like this;


2 x RLY

Is this everything I need to make this?

Many thanks.
Hi Jim

Switching D-PRE requires relays not ERK.We sell relays as RLY - wouldn't you know...

Do you need to switch the effect on/off? Use a relay for that. If BFX is in series mode for the effect you use, then "bypasing" requires two relays and a rewire of the series switch. Q-MINI has the control interface required, as well as channel switching control for a 2-ch preamp - maybe a bit of overkill here unless you want to add Q-LATCH to have direct, random access from any channel/FX combination to any other with a single switch transaction.

If you you are content with a channel select button and an FX button, i.e. it suits your playing style, then just the switches and relays suffice.

Have fun

Thank you. I'm still a bit confused by all the switching options, so I'm going to chose simple: a foot switch (FSW) and a panel switch (PSW) for A or B channel switching, wired so FSW overides PSW when plugged in. For the loop: a S/P switch and send/recieve level control.

So for the switching I need to order two RLYs, a PSW and FSW. BFX kit is self contained for my needs. Order up!

Book 6 is in da house! Both literally and figuratively.

Woo hoo!

Is it my imagination or have the References to chapters in previous Books for further information on a subject increased? If so, yea!

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