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The Upgrade Company

Customer support and communication is an issue taken very seriously by The Upgrade Company. We strive to exceed your expectations. 
Please drop us an email or voicemail today.  We promise to reply to your inquiry as fast as possible.
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 (6) of David J. Schulte's patents




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











Contact Info

The Upgrade Company

Customer support and communication is an issue taken very seriously by The Upgrade Company. We strive to exceed your expectations. 
Please drop us an email or voicemail today.  We promise to reply to your inquiry as fast as possible.
Contact Information
Office Hours: Monday-Friday 10am-6pm, PST


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

+1 702 708-4378

 (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 Email Us on This email address is being protected from spambots. You need JavaScript enabled to view it.  to place order

Parasound Testimonials

Unsolicited Customer Testimonials for David J. Schulte and The Upgrade Company
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. 

Parasound Signature Edition Upgrade and TimePortal Cable Upgrade

Hi David,

Hope all is well. The gear arrived today. I’m so glad I took this route. Luckily, my power conditioner is a universal version. So, the main TimePortal power cord snugged in perfectly.
To say “I’m impressed “ is an understatement. Familiar songs have taken on new meaning. Now I know what the artist and sound engineer wanted the listener to hear.
It’s quite a surreal experience.  A bit like opening up your window curtains to see the sunlight for the first time. It’s like the music is free to express itself. To me, the energy is quite uplifting.  It’s a dramatic change. 
And the gear is not even broken in yet.

Thank you David for sharing your passion. It’s the sound quality I couldn’t afford without your Signature Edition upgrades & TimePortal Cables. 
Blessings from Sydney Australia!

Eddie Silva


Parasound A51 5 channel power amplifier with SE Upgrade 

Wow!  Big changes heard on my A51.
Way better bass!  Deeper bass with more pitch definition more punch & faster & cleaner.  Lower mids really fleshed out & live, mid/highs sparkle now really clean sounding, very organic and live more air bigger stage hearing stuff not noticed before. Kudos!  By the way my Oppo and Emotiva AV Controller are getting even better then a month after I first reported. This RFI EMI ridding technology is amazing it just keeps getting better! 
Jay English, ILL


Parasound JC-2 BP Upgrade with Signature Edition Upgrade

For those interested in the bottom line of this review, you may skip to the bottom of the second page.  Those interested in context….

Anyone who orders a new piece of audio gear has high hopes that it will be as good or better than expectations; that is, it will make a clearly audible improvement, one worth the dollars paid for it. 

When I received my new Parasound JC-2 BP preamp, rated among the best according to most of the reviews (Stereophile Class A, TAS), I had all kinds of expectations that it would substantially improve on my tube based preamp.  My old preamp had been modified with Teflon and foil caps in the signal path, all the power supply electrolytics replaced with plastic caps bypassed with Mundorf Caps, etc, and most importantly substantial circuit modifications by the late Harvey Rosenthal.  I really liked the tube preamp, but with my new Tekton Double Impact speakers (another great find), I thought that perhaps more was possible.   The stock JC2 gave me a whole lot more detail, and the musical colors seemed a bit more natural. However, I wasn’t getting that often elusive  “body” of singers and instruments that I had heard with my tube gear.  

I started to question myself about the decision I’d made.  Surely such a top rated preamp as is the JC-2, was capable of more, wasn’t it?

There are those audio engineers and others who don’t believe in “break-in,” but after ~50 years of listening to audio equipment, I am not among them.  I decided to reserve judgement until I had some serious hours on the new preamp.  Gradually, Things started to sound more relaxed, and especially more dynamic.  There were dynamics that made things sound more natural.  And yet, it still did not,  as the saying goes,  allow me to suspend disbelief, and vocalists were still not all there.


I should mention that I am using a fairly new DAC, the Chinese assembled LKS 004 DAC, with the upgrade (itself an amazing piece that blew away my Lavry)  (, that itself took some time to break in. 

I am using the bi-amp wired version of the Tekton Double impacts, driving them with single ended tube monoblocks on top and the Parasound A21 for the bass. The JC2 has output jacks that allow me to drive them both simultaneously, and both amps have gain controls allowing me to match the bass and treble volumes.  The worst remaining weakness, IMO, is the Oppo 980 that I am using as a transport, although I do use the amazing IFI digital pulse straighter-outer that, to my surprise, does make a huge difference.  

I have also spent lots of $$$ on power supply cleanup, between filters and power cords of various manufacture.  So, basically, I am one of those wacko audio nuts.  BTW, I love music of most kinds.  

I see that I’ve written a rather long introduction, but this upgrade is worthy of it. 

Perusing some audio blogs, I came across some folks who had had their equipment upgraded, to what is usually referred to as an SE edition, by David Schulte of The Upgrade Company.  

Most of the equipment in my system, except the Parasound A21 had been upgraded, some several times, by my friend, the late Harvey Rosenthal.  A great amateur photographer, Harvey was one of those guys who knew just about about every vacuum tube circuit that had ever been tried.  He also knew that circuits depended on a mix of the right parts to achieve the sound. 

Like the Japanese, Harvey was a fan of the old McIntosh tube equipment, that is now selling for a fortune.  He did not like what electrolytic capacitors did to the sound of most equipment, and wherever possible either eliminated or bypassed them with plastic caps.  My vacuum tube preamp had no ‘lytics in the power supply.  Instead he installed large plastic caps.  While those caps did not store the same amount of energy, they have a much faster response.  We also used teflon and foil caps (boy do they take time to break in!), wherever possible in the signal path.  The main advantage in working with Harvey, was that we could together listen to what he had wrought, undoing it if a change did not make improvements.

However, in the absence of Harvey (RIP my friend), having read some great owner reviews, and after speaking to David and trying to understand his theory about the pernicious effects of RFI/EMI interference, I decided to ship him my shiny new preamp.  I took a leap of faith, not so risky as it might have been given his generous guarantee.


It is not that David does not believe in using high quality replacement parts when doing upgrades, he does.  However, he also does things that, to my knowledge, no other upgrader and I suspect very few manufacturers do.  I won’t give away any of his secrets, primarily because I don’t know any of them, but he does focus on relieving the equipment from both outside and self generated high frequency interference, the effects of which stress amplification and inter-modulate with signals.  I hope I have that right.  In any case, I’ll leave it to him to explain further.

The cost of the upgrade was not insignificant. David told me that there is a lot of hands on, down in the circuits and wiring work, as well as the cost of the high quality parts he uses.  Anyone who has bought a teflon or exotic Mundorf, etc. cap these days knows what those babies cost. 

Obviously, the cost of an upgrade is based on what equipment you are upgrading. As I understand him, David works on almost any high quality gear (no point in putting money into less than good gear).

Given the cost, when I plugged in the JC2, I expected improvements over what I had previously,  I did not expect what sounded like an entirely new, more sophisticated preamp. 


You all have your favorite test recordings, so take with a grain of salt what I am describing.  Morton Gould’s “Jungle Drums,” a 1950’s early stereo recording was a revelation.  I like it because it is a great stereo recording showing excellent dimensionality left to right and front to back. Orchestral weight and timber sound right to these old ears.  Astonishing since they were just learning how to do stereo.  Another favorite of mine is a compilation of Ella Fitzgerald’s hits. Most are in mono; a few in stereo. Ella had a body!  Still not quite what it was, but a body, nonetheless.  

Recall my comments about of break in.  In the case of this upgrade I have had both small day-to-day improvements, and three major jumps. It was great to come home, turn on the system, and after waiting a bit for warm up, hearing a bit more transparency/clarity, better tonality, more “liveness.”  

I can’t explain it, but three times I’ve heard what I considered to be more than incremental improvements, a performance jump.  They occurred at about 100 hours, 250 hours and ~400 hours (the last is an approximation since I stopped keeping track).  Aside from improved openness, the biggest change was with the dynamics.  The bass, particularly became significantly more transparent and deeper sounding. With certain recordings, show music became near live.  And Ella! She’s all there now.  Some of the cuts that I felt were not well recorded opened up.  Other vocalists now show their full range.  Some opera cuts are  amazing.  

The modification has resulted in nothing less than a system transformation.

I also obtained one of David’s power cords.  It is more that the size of a garden hose, with all the shielding that David uses.  It, too made a nice incremental improvement over the other high end cord it replaced. Most of the listening described above was done using it.

David tells me that I ain’t heard nothin’ yet.  I believe him.  IMO, if you are reading this, you should, too.

He will get more of my gear as my budget allows.  I want to upgrade my transport and do the DAC.  

But I do have a budget, and my wife has this idea that we must eat from time to time.


Robert Kemper,

Miami, Florida

Number of Signature Upgrades

I hired The Upgrade Company to upgrade my Emotiva XPR-5 amp, my Emotiva XPR-2 amp, my 4 Emotiva XPA-100 mono’s, my Marantz 7701 A/V Processor, my Marantz 7007 Universal player and in each case the sound became fantastic in every way.  Each time the unit came back it was far more musical and smoother yet more refined more detailed greater bass weight and heft and extension and speed, kids really organic and fleshed out and clear like a real human voiced sounds, piano spot on.  Highs lost all the grain and glare and grit, sparkling and shimmering and airy.  I know some of you think video cannot be improved but you are dead wrong: the Marantz A/V Controller and Marantz 7007 player each exhibited a banishing of grain and washout, looked much clearer with inky deeply saturated but not blooming colors the way they should be I could go on but you get the idea a true Genius that makes other shops I've dealt with in the last 52 years look like amateur's.  Upgrade Co. has true solutions for all brands and a treasure trove of knowledge. I have been obsessed with high end audio and now video too since 1965. Well I can tell you their RFI EMI RIDDANCE technology makes a gigantic improvement in sound and picture. Not just a little bit. The Improvements are astounding. Combined with their exclusive TimePortal power cords, XLR’s and HDMI cables, the results are State of the Art nothing in any one else's system or showroom comports not even close.  A single TimePortal power cord doubles or quadruples the sound quality depending on high up in cost you go.  Even the video was further improved by my Timeportal power cords.  Oh and the Richard Gray 400 Pro's once SE upgraded and fitted with Furutech NCF outlets and 20 amp IEC inlet made  real big improvement on sound and just as much on picture quality on my 8' screen. Everything got much better. Even the bass and black levels were really improved.  You won't even BEGIN to get the most out of your gear without their cab els and the tips and tricks they can explain to you if you call them. Most of you Ill bet do not have your stuff setup properly. Hire Upgrade Co for personal setup that'll literally will blow you away and that by it’s itself is worth the price of admission. How many Installers and sellers will drive four hundred miles too help get things right. Too show my commitment here is what else I had upgraded:  My Marantz PM11S2 Integrated amp, my Parasound P3,  little bit to my Phase Linear 700 S2 in my other systems so far. --


Yours truly  

Tom Drummond 


Parasound A21 Signature Edition Upgrade


Bert Hennessy






I have the big Dynaudio C4's on my front channels. Very revealing & large speakers. 

After hooking up my Marantz UD 7006 Bluray DVD CD Universal player that received Upgrade Co's Signature Edition Upgrade, I finally heard timbre and decay in my system. The sound stage is now so much more life- like and engaging.

I then hooked up my new Parasound A21 Signature Edition upgraded power amp from Upgrade Co that arrived about the same time my Marantz UD-7006 SE player did.

NO WAY!! With the SE'd Parasound in my system, I got way more warmth, detail and depth, much larger soundstage, much more clarity & ease & liquidity. How can this be?? These units aren't even burned in yet.

So today, Sunday February 23rd 2014, with a little burn in time, I decided to A-B compare the Signature Edition upgraded Parasound A21 to my stock McIntosh MC302 power amp I've been using on the big Dynaudio's.

Plain and simple: The Parasound A21 SE kicks it butt. Totally embarrasses the stock McIntosh MC-302. This A-21 SE is much better. It's also far better than an $8300.00 tube integrated (can;t mention the name) I'd borrowed recently. The bass is so much more full and in my chest. Sound overall is so much more real, live, and engaging and musical even at the highest volume levels.

Bert Hennessy, TN

Page information last updated: 06/05/2020

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