PAIA Stak In A Box Tube Preamp Kit Build.

[DrNomis_44]

Hey Everyone,

I've got a new diy project to work on over the next few weeks, recently, I ordered online a new PAIA Stak In A Box Tube Preamp kit from PAIA in the US, it arrived in the post this afternoon.

Okay, so, what is the PAIA Stak In A Box Tube Preamp?

It's a preamp that uses a single 12AX7 tube, plus some extra solid-state circuitry to get that "Tube Stack" sound, but here's the interesting part, it gets the "Tube Stack" sound by deliberately running a 12AX7 Tube at lower voltages than what a 12AX7 would typically be run at in, say an old Fender Twin, or a Marshall amp, according to the kit's manual, the 12AX7 is run at +42V DC at low current, it uses a special circuit based on a CD4049 Hex Inverter IC and a "Voltage Multiplier" made up of some diodes and capacitors to generate the +42V DC, it runs off a standard 12V AC plugpack adaptor, so, no need for dangerous 240V AC wiring.

The PAIA Stak In A Box includes an FX loop, as well as two built-in speaker simulation circuits which can be bypassed, there's also a Crunch, Drive, and Output control as well as a balanced XLR out which you can connect up to a studio or PA mixer.

The kit comes with all the necessary parts and mounting hardware and etc, but the 12V AC plugpack adaptor and front panel are not included, for some reason the front panels for a lot of the kits PAIA sell aren't currently available, so, I have two choices, either make a front panel using a 3U 19-inch rackmount front panel, or a case, both bought from my local Jaycar Electronics store.

The Tube that PAIA supply in the Stak In A Box kit is a brand-new Sovtek 12AX7WA high mu (100) twin triode tube.

The kit looks easy enough to build, and since it doesn't use dangerous voltages, I'd recommend building one for those wanting to get started in building Valve/Tube amplifiers.

I decided to start this thread so I could document the build-process just in case others may be interested in building one for themselves.

Will include some pics and scope screenshots.....stay tuned.

Here's a link to the PAIA Stak In A Box Tube Preamp kit on the PAIA website for those interested in building one: https://paia.com/dp/9210KP_Stack-In-...%29%3C%2Fa%3E/

[Trevor Davies]

This looks really cool. I love the idea that it works off 12 V.

[fender3x]

The kit looks easy enough to build, and since it doesn't use dangerous voltages, I'd recommend building one for those wanting to get started in building Valve/Tube amplifiers.

I decided to start this thread so I could document the build-process just in case others may be interested in building one for themselves.

This is a big part of the reason I have never attempted things with amps...and the reason I sold my old Sunn head to a collector. I am afraid of those voltages. Will look forward watching this build!