Contact Info

The Upgrade Company

+1 269-352-7609

This email address is being protected from spambots. You need JavaScript enabled to view it.

 (6) of David J. Schulte's patents




Payments & Shipping










The Upgrade Company, AudioVisual Equipment  Dealers, Harbor Springs, MI 











Contact Info

The Upgrade Company

+1 269-352-7609

This email address is being protected from spambots. You need JavaScript enabled to view it.

 (5) of David J. Schulte's patents



+ 30 Day In Home 100% Refund Period

+ 5 Year Parts & Labor Warranty with Every Signature Edition Upgrade

+ 100% GUARANTEED to beat ANYTHING else on the market!


Nothing we sell ever comes back.  

We don't even have to advertise.  Once our clients experience for themselves the extreme high performance & "bang for the buck" we deliver, they keep coming back as funds permit.  

The Upgrade Company would not continue to be A+ rated on the nationwide BBB algorithm month after month unless we were delivering on our promises.

Please call +1 269-352-7609 to place order

CAT Testimonials

Unsolicited Testimonials sent to David J. Schulte and The Upgrade Company LLC

Every client has paid The Upgrade Company LLC in full.   No kickbacks, no commissions, no fees of any kind for recommending our products and services.


TimePortal Cables, Mark Levinson No. 532H amp, CAT SL-1 Signature tubed pre, ZESTO balanced tubed phono preamp all with our Signature Edition Upgrade & RFI EMI RIDDANCE technology installed.

Dear Audio Addict (this is in fact a term of endearment as I also am one by definition).  
I have been asked by David to comment on some recent work and purchases that I had requested so I’m doing so. 

First assuming most persons reading this are truly interested in the reproduction of music in the home (regardless if vinyl, yeah! or digital, boo!) are in fact intelligent, have enough monies to pursue this ‘expensive’ hobby. So why are we addicts?  Because stock gear and cabling isn’t satisfying there’s A LOT of music missing and A LOT  of distortion you don’t know you are hearing until you experience a fully RFI EMI Ridded system with the new unique technology by Upgrade Co.

Despite being told consistently that the ability to reproduce  ‘live’ music in the home is not realistic, we keep spending on the hottest new amp/pre-amp/CD player etc. seeking that impossible goal, only to be told 3 months later by magazines that the $10,000 piece of equipment you just bought is already out dated so off we go to buy this new product. Odds are as we move up this equipment carousel we do start to notice boxes are checked(more airy highs/ wider deeper soundstage/more powerful deeper lows) and my favorite— it was like many veils were removed.

Now how does this rambling tie in to my products from The Upgrade Company? I started a few years ago changing various cables to David’s TimePortal products to include all interconnects (except turntable & digital) speaker cables and power cords. These replaced various top of the line cables of a well respected USA high end cable company. With each cable change there was always a marked improvement in sound, all the boxes were checked and no purchase regretted plus I still have no desire to rush out and ‘upgrade’. But something was still missing. But no more. Recently bought new midlevel USA made turntable with a lower level British tonearm. Mounted a well known moving coil cartridge gave me a really nice but not fully satisfying sound. As usual turned to David. Replaced entire tonearm wires and most importantly replaced the tonearm wires to silver and the interconnects with TimePortal Cable Statement RCA’s. Got the arm remounted & table set back up, mounted the same cartridge, put on familiar record and for first time in 40 years was completely drawn into the music. Clearly all the boxes were checked but that didn’t matter. I went to my vinyl collection and have been listening to records I know and bunches I didn’t even know I had. The TimePortal Ground cable was a real surprise also and I can't explain it.  Sucks out RF apparently.

Equipment wise only change was TimePortal Statement interconnects & a TimePortal turntable/tonearm ground cable from the SOTA table to to the SE Upgraded RFI EMI RIDDED ZESTO Balanced tubed phono stage. Believe that this final ground cable change added to my otherwise complete TimePortal Statement pre-power amp cables & power cords & speaker cables.  Synergistic.  Exponentially better.  This final missing link of RFI EMI extracting cabling has lifted me to audio nirvana. Night & Day over Cardas Golden Reference in every way.

As we can’t achieve reproduction of live performances in your home don’t be an idiot and rush out and throw money at the hottest new piece of equipment that will be obsolete in 3 months.  Buy pieces you are happy with yo begin with then get serious about the SE Upgrades & unique TimePortal cabling.  Getting rid of RF is the key! Made a big difference on my ZESTO tube phono stage.

Hope this not too bizarre but I now know that having all TimePortal RFI EMI Ridded cabling is what’s gotton my system to where it is today even after the SE Upgrades to my CAT SL-1 Signature tubed preamp & Mark Levinson No.532H power amp SE upgrades  Same system with top of line Cardas Golden Reference cables - Not even close.

Cannot praise TimePortal Cables enough. They have brought my system to new heights but more importantly my listening pleasure up many levels of enjoyment. I thought I had good stuff to begin with.

Very highly recommended.                            

Pictures to follow.

Dr. Ronald Stroud MD   Voted Alabama's #1 Internist


Our "Signature Edition" upgrade we performed to Dr. Stroud's Convergent Audio Technology SL-1 Signature Version vacuum tubed stereo preamplifier

The CAT arrived. The sound is AWESOME! Great job! More later...

UPDATE #1 03/03/14 Already with just a few hours of use the CAT's sound has further improved a lot.  I am a true believer in what The Upgrade Company does.  Keep up the great work!


Dr Ron Stroud MD

Page information last updated: 20/04/2017

Disclaimer: We believe but do not guarantee that the information on this website is correct at the time of publication.

Our Clients Say...

November 2019

Dr. Ronald Stroud MD, Alabama

October 2019

Dr John Read
Jim Wojno
Jim Wojno
Jack Paris

September 2019

Rick Frye

August 2019

Dennis Binda
Dr. John M. Read

July 2019

Dr. Ron Stroud MD
Seth S.

May 2019

Dr John Read
Bob Lanser
Jay English, Illinois

April 2019

Sahr Abu, Wilmington, DE
Robert Kemper, Miami, Florida

March 2019

Dave Allison

February 2019

Ken Volk, AZ

January 2019

Rick Gallos, Canada

December 2018

Brian Breslin

November 2018

Dave Allison

September 2018

Don K, VA

July 2018

Seth S.

June 2018

Warren "happy ears" Hingst

May 2018

Rick Gallos, Winnepeg Canada

April 2018

Paul, CA

March 2018

David Berger, CA
Marc A., Illinois

February 2018




David Berger, CA

January 2018


December 2017

Dr John Read, Saudi Arabia
Phil Ho, Sacramento, CA

November 2017

Ronald S Stroud, M.D.
Don Fleming, North Carolina

October 2017

Dave Allison, Texas

September 2017

Ron D, Illinois

August 2017

Doc John

July 2017

Sam Disney

June 2017

Don Kaplan, Virginia

May 2017


April 2017

Phil Ho, California

March 2017

Tom Drummond

February 2017

Phil Ho, California

January 2017

Paul E. Minnesota
Seth S.

December 2016

Chip Stern

November 2016

Dr John Read, Riyadh, Saudi Arabia

October 2016

Rich H, Colorado

September 2016

Fred Laury
Fred Laury

August 2016

Erick Perry
Erick Perry

July 2016

Rob Gallos

June 2016

Chris Sanabria PhD, Texas

May 2016

David Donohue, PA

March 2016

Pete Stumberg

February 2016

Manuel Ortiz

January 2016

Brent Brisco, Canada

December 2015

Jim Wojno
Jim Wojno

November 2015

Dr. Bob Baker, FL
Neil, Texas

September 2015

Alfredo, Texas
Paul Elliott, New Prague

August 2015

Manuel Ortiz

July 2015

Seth Shabo

June 2015

Gary L. Peeke, Chicago
Gary L. Peeke, Chicago

May 2015

Jeff & Joann Goldberg, Michigan
Pete Stumberg, New York
Ben Hayes, Australia

April 2015

Tom Drummond

March 2015

Tom Mathews, Georgia
Tom Mathews, Georgia
Tom Mathews, Georgia

February 2015

Mike R, FL

January 2015

Jim Wojno
<span style="font-family: a

The Upgrade Company LLC © ®™

Phone +1 269-352-7609 EST • Email This email address is being protected from spambots. You need JavaScript enabled to view it.