In design for more than a year, Underwood Hifi has decided to begin to import their own cables under the Core Power Tech AV brand. Designed by some of the best Engineers in the world – these cables like all Underwood owned products represent unparalleled value at prices that bring sanity to the cable segment.  


The new Core Power Tech AV cables were designed for ease of use, long life, and most importantly – incredible performance for the money. Each cable will be class-leading in their price category represented. Super high-end materials and manufacturing processes have been utilized throughout. Underwood, Core Power was able to negotiate directly with the makers (extruders) and with their buying power, develop a direct relationship with some of the finest makers of audio cables in the world. 


Our lineup is easy to understand.

We will start with 4 cable types. Each cable type will have a Silver, Gold and Diamond version

1) Power Cables are under the moniker Valiant

2) USB Cables are the Conduit

3) Line Level Cables (interconnects) shall be known as Linx

4) And finally, Speaker cables are appropriately named Defiant


Core Power cable customer feedback

1)  Sorry it took me a few days to get back with you since the cables arrived. My thoughts on the cables, damn man. You know your shit. Those work perfectly fine with the Auralic and made a difference in detail on the sound. A noticeable difference. Man I appreciate you more than you know. You did way more than most people today do for customers. Dead serious. Rare breed man but I’m so happy we hooked up. 

I also am thinking about buying some of your power cables. Not the $750 version right now. I have Pangea. They are huge and thick but that doesn’t necessarily mean they are good. Their cables didn’t sound like yours. I think the most inexpensive version of your power cables are light years better than these. 

Thanks again, Shane

2) By the way, I received the Diamond speaker cable yesterday.  While I was at work, I burned the cable in all day.  Although I’m sure it’s not close to being at its best, I can tell you that your cable definitely improved the sound over some XLO speaker cable I’ve been using for 10+ years. It sounded more open and dynamic, yet even smoother.  Really happy with it!   Tom

3) Hi Walter!  Just a note to give you my impressions of the Core Power Diamond cables.

In a word, excellent! I have a very transparent system, and I had been using Audience Au 24 SX cables (RCA interconnects and speaker cables). I swapped in the Diamond XLRs first, then started breaking them in. Even out of the box, they were very good, only a small veiling. At the 12 hour point (where I usually hear the worst of cable break in), I was starting to wonder if they were going to make it, but around 20 hours they really started opening up. The speaker cables were even more stable during break in. The combination kept steadily improving.

Now I have more than 60 hours on the interconnects and nearly 40 hours on the speaker cables. The sound is very clean and transparent, better than the Audience cables. Imaging is precise and truly holographic, with loads of fine detail. I'm definitely getting more of a sense of performers being in the same room. At times it's almost creepy how real things sound!

I hate to sound like a stereo critic, but these really are great cables. Listening to music is more fun than ever!

If you're wondering, I have a 2.0 system:  USB drive to Auralic Aries G2, Auralic USB cable to DSPeaker Anti-Mode X4, Diamond XLRs to Bel Canto Ref 600 M monoblocks, Diamond speaker cables to GoldenEar Triton Reference speakers. Power is via dedicated 20 A line to PS Audio P20, with Nordost Heimdall 2 power cord to the X4, Nordost Red Dawn PCs to the Auralic and Bel Cantos. Charlie H.

4) Aloha Walter, I received the Deep Core and more recently received the Core Diamond AC cable.  Today, I received the receipt - thank you. I could not wait, I connected the Deep Core to the wall via the Diamond AC cable and turned the system back on.  I played music.  Wow!   The outstanding system I had before became even better.  Deeper more detailed bass was my initial response.  After a while a female vocalist began singing and I was drawn into the room where the system resides.  Incredible detail and vocal nuances became evident in such intimate detail.  My system sounded good before but now, Grandiose!!!!

5) By the way, the 8 foot pair of the Core Power speaker cables I purchased from you are the best I have ever heard on my system, mirroring the same high quality as your other Deep Core products.  They have transformed my system from very good to magical!

Thanks for everything and your professional mannerism and expertice,    JS

6)  Subject: Lynx Diamond XLR IC’s Message: Wally, these Lynx Diamonds are superb interconnects. They are doing everything that I hoped for when I took a chance on them. Smooth, detailed, full frequency balance, revealing. Thanks.

7) Hi! Walter, I connected your Diamond speaker cables on my system. wow! It’s fantastic! My 800D2 are sounding much more expressed! You are right: it’s performance like 10 times price brands!   Thank you!   SZ 

8) Wally, Yet another "Oh My Goodness", what have I been missing all these long years!

I thought the Mac 601 mono-blocks were just hyped old tech with pretty blue dials.

After getting the new Diamond Xtreme cords, it was as if a window opened and the heavy curtains were pulled back, and the sun, the birds, the whisper of the wind in the leaves, and the neighbors arguing 4 blocks away could now be heard in extreme detail.

What I difference!  Really, really big change. Its like taking the cotton out of your ears and hearing why you spent so much $$$$ on this addiction in the first place.  Like audio heroin!  I'm glad I've already paid for my daughter's education!

And, all this time I thought I knew what good stereo was.  I'm already in audio heaven!  How much better do it get?   Bruce S.

9) Walter, These Gold power cables are great and not just for the price.   I put one in the office system and was blown away so i replaced the $1000 dollar one on the Mcintosh in the main system and the Core is better.   I will try the interconnects this week.   Thanks, Rick

10) Walter, I have been in this hobby since 1970 and a dealer for certain products since the late 1990's. I have had many different power cords with great results, but I never thought I could get the performance that are offered by your cords at the prices you offer. I feel they are equal to cords costing at least 5 or more times. I have not had the opportunity to try all that is out there and could not afford some even at dealer pricing. I have done preliminary listening with all of your cords in my system and I am utterly amazed. I do not know how you do it, but I am a believer. At this point I do not need to go to any other cords. Cannot wait to hear what the Equi=Core and Deep=Core will offer. I will talk to my customers and local audio friends. Deryl

11) “I swapped my Nordost Baldur for the Power Core Diamond Speaker cable about three weeks ago.  I try to take note of my equipment performance (for my own memory) - this is the first time I send an email with my notes to someone else. I thought Walter deserved it.  I had the Nordost for the last 10 years, after a love affair with Audioquest. I tried cables from other brands but ultimately went back to the Baldur. My system is comprised of Sonus Faber Guarnieri, two subs Syzygy 10”, Odyssey Stratos Monoblocks SE, PS Audio PW DAC and Transport and Bluesound Node 2i. I spend money wisely - I have three teenager kids and college is looming ahead.  For example, I kept the SF Guarnieri for over 20 years, because all my listening sessions with other speakers did not bring substantial improvements unless I would have to spend two-three times what I had spent on the SF.  I love music, but I avoid spending money for what I would only consider “marginal improvements”.

In come the Diamond Speaker Cables.  I bought them at about half the price of what I had spent on my Baldurs years back - Walter’s claim of providing a high multiple of their value tempted me.

Once swapped I was hit by initial strong microdinamics that impressed me (in my definition: ability in the reproduction of music to change rapidly to changes in the recorded performance tone, e.g. going from PPP to FF and viceversa), but the sense of stage width and depth was not better than my Baldurs, nor was I convincer of details retrieval.  I swapped back to the Baldurs, which confirmed my initial impressions.  I decided to persevere and let the Diamond break in for two weeks.  This weekend I gave it a serious listen:

Microdynamics were better than the Baldur’s - confirming my initial impression - but now: details pulled out much more vividly than the original listen, most importantly, there was an overall sense of presence and scale that took me to a heightened level of performance.  No matter what the music. Billie Eilish “was in the room” with her young sultry/rasping voice, Pink FLoyd Wish you Were Here guitar attack popped out from the center right of the soundstage, the dynamics of Bach’s Goldberg Variations were more present and “lifelike” - one step closer to a real close up performance - Gould was humming along passionately.  The 2nd movement of Abbado’s Van B’s 3rd symphony was more present than I heard before in my system, the sense of scale of the orchestra was stretching outside the back wall of my listening room.  Enough said.  Can a cable make such a difference in a system?  It did in mine.  I am keeping the Diamond and my Baldur’s will soon hit e-bay - anybody’s interested?”  Angelo

12) Walter, These Core Power power cables are great and not just for the price.   I put one in the office system and was blown away so i replaced the $1000 dollar one on the Mcintosh in the main system and the Core is better.   I will try the interconnects this week.  Rick

13) Walter, just a few words on the C/P Diamonds.  I now have 2 Diamond Power Cables, and 1 Diamond XLR Interconnect. I will be buying more!  As you have said, they are THE BEST.  Nothing but music, black background, WIDE--TALL--DEEP soundstage. Treble, bass, and mids are perfect!  Layering 2 die 4!

I am hearing technicolor sound like never before! Each additional cable has been like an expensive upgrade in hardware.  And their ability to convey the emotion of the music is magical.  Just one final note...I had been using some (HFC) High Fidelity Cables, ridiculously priced, you know, the ones with the silly-ass magnets?  Core Power Diamonds crushed 'em.  Now I feel like a dummy having wasted my money on them---NEVER AGAIN.  From now on its Core Power, baby, YOU BETCHA! Thank you, Walter, for bringing out another sensational deal.

14) Hi Walter, Thank you.

I’ve been thinking that needs to be said. The past few of days have been a new step up in my listening experience, and are very much in line with what I’ve been pursuing for years and years with one upgrade after another. With the Equi=Core and Diamond power cables, the really telling part is how much clarity there is even at the very lowest levels of listening; there’s real bass coming from my 15” woofers at whisper-quiet levels! And of course there’s even greater detail when the volume is higher. Yesterday I stopped in my tracks when a classical harp piece was playing and between movements I heard the harpist’s feet change pedals. Stunning.

I have absolutely no idea how upgrading the power feed to my system can have such a dramatic effect on the quality of the sound, but there’s no denying what my wife and I are both hearing.

As I ponder that while we both sit wordlessly stuck in our seats listening to one piece of music after another, I realize it’s because of you and what a remarkable business you have. Your passion for great sound is obvious, but also how much you want to share it with everyone possible by making it as affordable as possible. Your website features brands I’ve only seen mentioned in the high-end audio press, or that I’ve never heard of, but all of which are clearly top-notch in the world of audio, at price points that are much more accessible to those of us who might not be as well-heeled as others. Emerald Physics? Wyred4Sound? Deep=Core? Wywires? Wireworld cables? I certainly would have never known any of these first-hand without Underwood Hi-Fi.

I know that I could have put together a pretty good system from other vendors, both local and online, but to get to where we are now would easily cost double or triple what you charge. And for that I thank you.

Oftentimes in the world of business too many good things are treated as expected, and not recognized for how good they really are. I felt this is my opportunity to rectify that at least just this once, and to let you know how much I appreciate you and your company.

Cheers, Daniel

15) The Gold XLR interconnects sits right in there, big and bold and thick and rich - without slowing things down. This is so much better than the Audioquest RCA's I was using that it feels like a new system. 

I will save my pennies and get the Golds in RCA form for my source components. I'm so pleased that you decided to go into this crazy part of the HiFi world.  DT

16) Finally got round to trying the Gold power cables and I gotta say they are are amazing. Mind thoroughly blown! I might have to find some cash for a few more.  Pierre

17) Your new Diamond USB cable made a substantial difference. I had to toss my USB line cleaner accessory. Your cable works great alone with the DAC5 in many ways. Thank you.

18) Right on WALTER, The Gold speaker cables with 100 hrs in sound incredible



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