Brown Audio Labs

09/04/2026

Well I'm adding a pretty crucial piece of test equipment to my lab, and may even market it. It is a precision ripple voltage meter.
For testing power supplies, 150-300VDC, with options for greater range in the future. The specs are as follows.

Meter Range: mode 1 - 500mV max, 50mV min.
mode 2 - 50mV max, 0.5mV min.
PS Loads:. 30 and 60mA @ 300VDC, selectable.
Accuracy:. ~ +/-1%, haven't tested yet.
Power Supply: 12VAC ac-to-ac convertor, 2.5mm connector.
Devices: 3- OPA134 ,op amps
1- 16F1827, microcontroller
Microcontroller is programed using MPLABSX.

Curcuit Description: The DC voltage first passes through an RC filter where the DC component is removed, it then preceeds to the first op amp stage which amplifies the ripple, output is then filtered again, and proceeds to a second op amp, which brings the signal to a voltage that the Analog-to-Digital convertor can process, this voltage is then rectified, to obtain an RMS reading, which then passes onto the ADC contained in a microcontroller, the software will then calculate the RMS reading of the ripple, this is then sent to an LCD screen to display reading.

08/28/2026

Many don't know I had a loudspeaker company before I ventured into audio electronics,The pictures shown are the model Piano Forte floor standing speaker system, a reflex enclosure system, using a 6" Planar Magnetic Tweeter paired with the infamous 6 1/2" Dynavox woofer, a really great combination! I sold 3 or 4 pair of these with great results!!

08/23/2026

Some MC-3 action, and just some laid back music. It's hard to tell it's in the mix, no noise, hum or hiss at the moment.

08/21/2026

I want to give my current assessment of tube based audio gear right now! I don't know of any main stream company that still does all tube designs, maybe Jadis? But much of this downturn is do to the loss of many great tube gear designers, in the last 20 years or so, William Johnson of ARC, David Hafler, Gary Dodd, Roger Modjeski, I don't know if Mike Elliott of Counterpoint is still with us.

The company I really want to highlight is Audio Research, when William Johnson had the helm, they made some phenomenal products, He of course was working off David Haflers designs at Dynaco, mainly perfecting the Dynaco PAS-3 and the infamous ST-70, the SP-3 was the first endeavour, perfecting the PAS3, it was a great design, David Wilson converted the phono stage into a microphone preamp, by bypassing the RIAA, and made some fabulous recordings!! But after Johnson passed away the company went way off course on it's products, sacraficing the sound of tubes for a more solid state approach to audio, wanting perfect low noise curcuits instead! I hope to revive what is being lost in tube audio,please help Me in that endeavour.

Send a message to learn more

08/20/2026

The MC-3 is up and running, it sounds great and is quiet for an all tube pre-pre, except for the MOSFET source follower outputs. The big take away is Mr. John Broskie's Aikido Cascode in the audio stages I believe. I'll post a video DEMO fairly soon!!

Tube Compliment:

3 - Apex tested JJ Gold Pin 6922, audio stages
1 - 12AT7 Voltage Amplifier(power supply)
1 - 12BH7 Pass Tube(power supply)

08/10/2026

The MC-3 is being assembled now, it's a classy looking piece of gear, it should sound great! the basic topology is an Akido style cascode of 6922's, I am using JJ Apex tested gold pin tubes, there is a primary and secondary ps regulator, all tube heaters are regulated including PS tubes, dual channel coupling buffers. This preamp is for both low level MC cartridges(.25mV) and high level MC(.5mV), it has front panel load and gain adjustments.

07/27/2026

My MC-3 is just about ready for assembly, boards will be in soon, I thought I would share my topology, and I'm using the MCP-33 by AR for comparison, one main change is that instead of taking feedback from the cathode follower, like in AR's schematic, for the cascode, I'm using an Aikido style setup, Mr. John Broskie revelutionized tube audio with this setup. Its basically a noise cancelling arrangement in a typical cascode configuration, I also did away with the cathode follower and used this amazing MOSFET for my output device, it comes in a TO-92 package but has over a 2W rating, and comes with all the safe guards that a MOSFET needs. I'm doing a little more gain with this setup also for lower output MC's, I'm using very heavy regulation and ripple killers. and a good grounding setup.

07/27/2026

Here's a 3D of my newest amp board, I've basically taken the ST-70 to a whole new level, going all toroidals with great specs, this will be named the ST-80, nearly a full 40watts per channel, fully regulated front end, extra current to spare. The output transformer specs are below.

Output power 100 Watt
Turn Ratio 25:1
Ultra Linear tap 40%
Primary impedance 5.0K ohm
Primary DC resistance 112 ohm
Output impedance 4 & 8 ohm
Output DC resistance 0.3 & 0.5 ohm
Max DC plate current 300mA
Frequency response 10Hz - 20KHz
Weight 7.3lb.
Dimensions 5" d x 2.8" h

07/22/2026

Would anyone like some tone controls(defeatable) to go with Their preamp? Many of You probably remember the Dynaco PAS preamp, and when Hafler quit building tube gear, Audio Research Corp, pickup where Dynaco left off, with Their signature product the SP-3, it was good enough that Wilson Audio Loudspeakers, took the preamp bypassed the RIAA, and made a microphone pre, from the phono stage, My preamp will have that same ability, to use as both a phono stage or microphone pre. The line preamp is a two stage triode, that employs bootstrapping for greater linearity. The preamp will have both primary and secondary voltage regulators, for the lowest possible noise, and improved specs. I Need some input from You folks, good or bad idea?

07/19/2026

https://positive-feedback.com/show-reports/lone-star-audio-fest-2018/

This event didn't seem long ago, like yesterday, I've been too busy with my other work to make it to any other shows in the past, I hope that will change. There aren't many brick-n-mortar stores left around anymore, the internet changed that. It was a great time, and met some really great people, lots of fun!

Lone Star Audio Fest 2018 Show Report