Blog Pages

11/21/18

PULTEC EQ PROTOTYPE

Revision "A" PCB's for 2 out of 3 sections of my Pultec EQP-1A are now completed.  The 3U enclosure is from Collective Cases.com.

6X4 POWER SUPPLY

The power supply PCB was the first section to be built and tested. The DC output from the 6X4 rectifier tube is good and clean. I purchased my 6X4's from Tube Depot.com. I purchased the Hammond 270FX power transformer from Mouser Electronics.


BALANCED AMPLIFIER

The output stage of a Pultec EQP-1A is a "Balanced Amplifier Topology". A balanced amplifier operates with a "balanced input signal" and the signal remains "balanced" throughout the entire amplifier. Theoretically, a "perfectly balanced" Balanced Amplifier can significantly reduce Even-Order distortion.


TRANSFORMERS

One of the challenges of building your own Pultec EQ is deciding which transformers you would like to use. Quality transformers are not cheap. So, getting it right the first time is important. For this build, I chose a Sowter 1475e input transformer and a Cinemag CM-S217D output transformer.


PASSIVE EQ STAGE

The passive EQ stage is currently being breadboarded on my bench. I will need to create a PCB layout for it once I am finished testing. Stay tuned.

Thanks for reading,
Trenton

11/11/18

SKRM AUDIO DSP PROTOTYPE

I just recently finished a prototype design for an audio circuit that integrates a SKRM DSP module with analog processing. If you've never messed with DSP audio effects before, the folks at SpinSemiconductor make it pretty easy. They offer small modules with built in DSP effects.
Trenton Blizzard Audio DSP SpinSemiconductor SKRM Module
For my design, the SKRM module will install on the bottom side of this prototype PCB. The header-socket isn't installed in this image. Getting DSP effects into your audio designs is a fairly straight forward process when using these modules. However, coding your own DSP will require a great commitment in time in order to master your own effects.

According to Experimental Noize, the FV-1 IC's are available individually and come pre-programmed with effects. You will need to include external memory if you want to create your own effects. Find out more at Experimental Noize.

SKRM MODULE

Trenton Blizzard SKRM DSP Module
Shown above is 1 of 3 SKRM modules available mounted in my BB-SK breadboard adapter. BB-SK adapters make it really easy to prototype audio circuits with these cool little DSP modules by bringing out all of the double row pins into a single row that you can plug into a standard electronics breadboard. All pin functions are labeled on the PCB for easy hookup.

Thanks for reading,
Trenton

11/3/18

How To Design A 12AU7 Gain Stage Part-2

Part 2 of my "How To Design A 12AU7 Gain Stage" video series on YouTube.
In this video I demonstrate:
  • Breadboard Assembly
  • DC Plate Voltage
  • AC Voltage Gain
  • Frequency Sweep



Thanks for watching,
Trenton