Drip Pultec EQP1A
I have been working in the lab to bring Some custom drip pultec eqp1as to life.
Check out the time-lapse:
Sowter Transformers and inductors (The absolute best audio transformers available.)
Panasonic Film Caps in EQ filter section.
Metal Film Resistors
Original Daka-ware Knobs
JJ Gold Pin ECC88 & Electro Harmonix 12AX7 tubes
These Drip Pultec Eqp1a equalizers are the latest installment to the studio. By building them myself, I have an appreciation for the circuit, can hand pick the components, and I can truly ensure that the units are matched. I believe that this is one of Drip’s best board kits yet as Greg @ Drip is finally designing front panel boards which makes the builds much cleaner!. The unique thing about these is that they are a passive eq that uses a really nice tube amplifier for make up gain. By using high quality film resistors, and the best tubes and transformers around, we are able to build vintage gear that is absolutely amazing sounding and highly sought after.
Most of the original Pultecs that I have played with have had noise issues, or have not been matched. By building these from the ground up and hand selecting the parts, I have been able to control what goes into the units and ensure that the units are truly matched and amazing.
I wouldn’t recommend tackling a build like this unless you have Electrical Engineering skills and tools at your disposal. Although these Drip pultec eqp1as are an easier Drip build, they are still complicated and require a lot of soldering. I also think that an oscilloscope is mandatory if you are going to be building any electronic gear beyond simple circuits. Other important EE tools are a variac, isolation transformer, good soldering rig, and good clippers/strippers. These amps operate at 500VAC and it is essential that safety is considered above anything else when building these amplifiers.
One reason that I have an issue with Drip’s stuff is that they don’t provide any schematics for their boards and on top of that, the power supply circuits on the boards do not usually follow the original schematics.
The purpose of this page is not to instruct you how to build this, but rather show you my process for building. If you have any questions about it please head over to the forum at Drip Electronics to post there.
The Eqs are in phase as you can see in the video, and they are matched. You can see the sine wave on the scope here and the top wave is a 1khz test tone going into the unit, and the lower wave is coming out of the unit with a flat eq. It looks good and is in phase.
I will be adding some sound samples here soon so stay tuned.