How was the sound of your TDSS upgrade to your Nuforce Ref 9 amps?

I'm very excited at the prospect of improved sound that will come from the TDSS level 3 upgrade to my Nuforce Ref 9 V3 SE mono amps.  Bob Smith will be doing my amp upgrades in the next couple days.  The biggest change will come from the much more powerful power supplies he's putting in.  My system already sounds fantastic but he says it will be THE finest amp sound he has ever heard and thus will transform the Ref 9's into something few have ever heard.  I have VMPS RM40 BCSE ribbon speakers with the MLS cabinets--in other words among the finest speakers Brian Cheney ever made.  They are already on Sistrum SP-101 platforms with RTS couplers clamping them down--a fantastic combo in sound.  I really can't imagine sound with more clarity with dynamics that are off the charts and extremely organic bass than I already have.  

Tune in next week when I have the radically improved Ref 9's and I won't be able to wipe the grin off my face if all Bob says is actually true.  The rest of my system is the TRL DUDE preamp, Whest 3.0 RDT SE phono, Modwright 5400 Signature Truth CD/SACD w/Bybees on the rails and Audio Magic Pulse Gen ZX, super Lenco 78 with most of JTN's mods included, Trans-Fi Terminator, Benz Micro Ruby 3, wires by Cerious Technologies Graphene Extreme SC, Teo GC ICs, JW Reference ICs, Amadi Maddie Signature ICs, power cables from WyWires Juice II, Amadi Phil Reference, Mojo Enigma, TRL Silver, and Core Power Technologies Equi=Core 150, and Star Sound Sistrum racks with RTS couplers clamping each component.  I have Synergistic Research Blue fuses in the Nuforce amps, Whest, and Modwright 5400.
I look forward to your impressions. I have a Nuprime IDA-16 that I really enjoy that I might have TDSS upgrade someday.


Hi Scott,
I'll let you know soon.  Bob just got my amps today.  I talked with him for quite a while before leaving.
I had him do the full monty for a pair about 1.5 years ago. His communication, care and work was A+. They are driving a modified pair of Maggie 3a's and sound wonderful. Full spectrum, with excellent drive. Absolutely no complaints. You should be very pleased.
Thanks Raymond,
I'm looking forward to what's in store with Bob's mods.  It should be great.  Bob says they will be like having a 600 watt per channel amp driving speakers that really like power, especially in the bass.  He also says the amps will have much better micro details and really just better in all ways.
Just got my Nuforce Ref 9 V3 SE's with TDSS level 3 upgrades back.  On first listen, the sound is now better in all aspects.  Hearing many sounds I couldn't hear as well or at all previously.  Very dynamic, lucid, and beautiful sound on CDs so far.  Every CD has been a new treat to enjoy.  Will play considerably louder in addition to the improved sound quality also.  The soundstage is very accurate, deep and delineated.  Singers are dead center.  Dynamics just jump at times.  Thank you, Bob!!!
Now 3 weeks of mostly continuous 24/7 play.  I've turned it off and back on twice in that time.  The amps have 350-400 hours of break-in with music playing.  The sound is very beautiful, more transparent, and the bass is extremely clear and dynamic.  I've been working on the new plinth for my Lenco 78 turntable so I haven't been able to hear records in the past 2 weeks.  Should be done with this in about 2 weeks--hopefully this is not the movie Money Pit and this turns into many more months.  It is my second plinth build.  It will require me to wire a new switch and put an IEC in the back of it.  Should not be a big deal.  The sound should be much better as I'm using a new chassis from Artisan Fidelity which will improve the speed stability and mechanical stability also.  I'll report on the analog sound when I get finished.  CDs and cassettes are much better sounding than before the TDSS mods.

Thanks for the update. Sounds like you are really enjoying the upgraded amps. 

I've had the my IDA-16 since April and I'm really enjoying my system for the first time in many years. It makes me nervous to think about changing things but the TDSS upgrades are very tempting.



I had Bob do the most extensive level 3 upgrade as it would also make the amps much more reliable in addition to the improved sound. Everyone that has had Bob at TDSS upgrade their amps has been very impressed with the sound afterwards. Compared to upgrading your ICs, PCs or SCs, or putting in high end fuses, the TDSS upgrades make a bigger difference in SQ. I would most definitely think about giving Bob a chance to make your IDA-16 an even better component than it already is. The sound will not get away from the stock Nuforce or Nuprime sound, it will just be better in all areas--or in the case of a level 3 upgrade, a lot better!

TDSS's shop is in Indiana, correct? If it is I might take a drive there, check it out and talk to Mr. Smith (if he's available to do so). Do they have a listening area set up?


Bob's shop is in his home in NW Indiana just off 80 a few miles south.  He has a pair of his SP Tech monitor speakers there that could be set up.  He used my amps but he probably has some amps to listen to--I'm not sure of that, however.

Good luck,
Thanks, Bob. Might have to take a road trip; could be interesting.

Enjoy that amp.


Bob did the TDSS mods to my Ref-9 V2se, they're substantially better across the board, while retaining the inherent qualities that put them on the map originally.

I can’t recommend Bob highly enough, he knows his stuff about what makes NuForce/NuPrime what they are, his prices are reasonable, and he’s a friendly and accessible guy.

I'll try and give a complete follow-up from my brief post above the best I can:

    It has been a while since I had Bob at TDSS upgrade my Ref-9 V2s. TDSS has been doing the upgrades for a while now, but I guess they are really starting to catch on because I’ve had a number of guys contact me lately wanting to know my impressions. In fact, rather than repeatedly writing pretty much the same thing in emails and PM’s, I figured it would be easier to post this and then I can just send guys the link to it.

Just so everybody knows, back when I had the upgrade done TDSS only had one level available that, back then, they called their “Custom Upgrade.” Since then Bob discovered that further improvements were possible by replacing the power supplies too. As it stands the upgrade in my amps is what they are now calling their Level-1/D.R.R.T. Upgrade, so they don’t have either of the new power supplies installed that make up the TDSS Level-2 and Level-3 upgrades. 

can only imagine if they did! In fact, maybe after Christmas I’ll be able to allocate some funds and have those installed too, because from the reviews I’ve been reading on the TDSS website, guys that have gotten the Level-3 installed are just blown away.  

   The amps have had something like a year or so to break in, so from what I’ve been able to
tell they are done as I haven’t really noticed any new changes for a while now. That said, the results are everything that I was expected, and more. Way more. As most of us, I have been tweaking my system for a number of years now by trying different cables, equipment feet, damping blocks, etc., and NOTHING I have done has ever made nearly as much improvement as Bob’s upgrades. So from that standpoint I can say that at least the Level-1 upgrade was worth every penny and then some, and a super good deal in comparison to all the other stuff I’ve tried over the years. I can’t speak to the Level-2 or Level-3 upgrades as I have never heard them, but knowing Bob he doesn’t get into doing “gray area” stuff, so I have little doubt that they would add even further improvements, just like everybody seems to be saying. 

As far as the sound goes, it’s not exactly easy to put into words. 
First of all, the stock sound or
“signature” of the amps hasn’t changed a bit. The same highly detailed yet almost “tube-like” "liquid" quality that I have always loved about the Ref-9s is still there, but now seemingly more so. It’s as if I can hear those qualities even better now. Beyond that though these puppies have really opened up, as I am hearing fine details that I was never able to hear before. A lot of times I have found with other equipment changes that result in added detail, the sound can seem to become a bit too bright and maybe even a bit “edgy” and fatiguing, but not with the Level-1 TDSS upgrade. In fact, the sound is even smoother, more relaxed and more natural now. Brushed cymbals sound like real metal and gently fade away into a totally black background. And unlike before the upgrade, there is not a hint of hiss whatsoever, even with no music playing and listening within inches of the tweeter. As I said, the original tube-like signature in the midrange is still there, but even better than before. I hate to use the words “warm” or “harmonic bloom” because they seem to imply that harmonics are being added, which they are not. Not from what I can tell anyway. I guess you’d say the subtle harmonics that were always there in the first place come to the forefront more now, as the sound has taken on a richer texture. The effect is pretty cool too because my system is kind-a “luxurious” sounding now, as if it cost a LOT more than what I have invested in it. 

reminds me of going to a real upscale high-end shop and listening to a system that sounds so good you’re afraid to even ask how much it all costs. Oh, imaging and soundstage? Man, instrument localization is on a whole other level. You close your eyes and you can almost smell the alcohol and cigarette smoke of a nightclub. Diana Krall is right there in front of you, and you just want to reach out and grab her! Well, I guess that would be the case regardless, but you get my point. Then with the right recordings the sound emanates from well beyond my speakers now more than ever. Before the upgrade I always had really good imaging and soundstage, but now its like there was a hidden control for that somewhere and somebody came along and turned it up several notches for me. The stage is even deeper now with a better sense of height and everything is truly holographic. Well, unless the recording sucks. You can’t expect any piece of gear to fix that. Then finally there is the “speed” aspect. Percussive sounds have a “live-ness” now that really grabs your attention. Plucked acoustic guitars, piano, drums, etc. all sound more like they are real and palpable, as opposed to just being good recordings. I guess you’d say the same thing applies to the bass as well. 

     The upgrade hasn’t really allowed me to “turn up the wick” any more than
before, because I can begin to hear the amps start to distort at the same preamp volume setting as before the upgrade. I suppose that is partly because I didn’t get the Level-3 upgrade with the new power supply, which in retrospect (had it been available at the time) would have been nice to have. So anyway, from a technical standpoint I don’t suppose there would be any measurable increase in power output, yet the bass authority and overall peak dynamics have improved in such a way as that you might be tempted to think so. THAT was a real surprise. 

I could go on, but I don’t think I can really add that much more that would make it worth the trouble for you all to read. The only way to know is to hear for yourself anyway. In my opinion, the TDSS upgrade was the best system tweak I have ever experienced and was well worth the price. Oh, and Bob really knows his stuff and is a great guy to deal with too. I also like the fact that his upgrades don’t involve tampering with the actual amplifier circuitry either. He’ll tell you that he won’t touch it, so don’t even think of asking him to start replacing parts like capacitors and such. He’ll upgrade everything else outside the main amp circuits if you want, but that’s it. For me, that’s good to know because you don’t have to worry that the guy is gonna go in and start changing stuff, as if he thinks he knows more than the engineers that designed the amp. According to Bob, these new Switching amps are so complex that nobody should mess with them other than the engineers that designed them, and I agree. Knowing that I have confidence that he didn’t screw something up that will maybe cause the amp to blow up or whatever later on down the road. I’m not made of money and can’t afford to be buying new amps whenever I feel like it, so now after the upgrade I expect that I’ll have these puppies for a good long time to come. That’s good because now with the way everything is sounding I have absolutely no desire to keep shopping for a better amp. Although, I have to admit that I am REAL curious to know what the Level-3 upgrade would do? Oh well, maybe after the first of the year at tax time!!! I hope this helps anybody that’s thinking about taking the plunge. I don’t think you’ll be sorry if you do. I know I’m not, and lately there seems to be more and more guys out there that agree. 

Got to give an update on the TDSS level 3 upgrade to my Nuforce Ref 9 SE V3 monos. The amp module on my left amp went dead so Bob S. at TDSS replaced it while adding a different damping material between the module and the chassis on both amps. All I know is when they went back in the system, the sound was even better, The soundstage was much better developed, deeper, more stable and wider and the overall sound was smoother yet had just as much, if not more information. It is now VERY difficult to stop listening--a real joy. The upgrade is not cheap, but you will gain in reliability, and the sound quality is a BIG perk. I use the amps with a TRL DUDE tube preamp that is very ballsy, dynamic, and yet refined and detailed. I can’t wait to get my TT plinth rebuild done so I can see how far the Lenco parts upgrades have taken it. Will give another report soon.

The rods of my Sistrum rack are being cut and retooled as I write so I will have 2 much shorter racks that will allow the soundstage to bloom even further and be much more stable physically.

Will be adding Perfect Path contact enhancer after all this happens which should have a dramatic improvement with a cumulative effect at 3 different times. That should be the cat’s meow.

Latest sound of the TDSS Level 3 upgrades of the Nuforce Ref 9 monos is now phenomenal. I took the amps to a friend’s house so he could hear what they sounded like with the pair of Tekton Double Impacts with Bill Dion’s fantastic parts upgrades including new Dueland wiring direct to each driver from the individual crossover parts, many large and expensive caps in the all new crossover, and some of the drivers were upgraded. He used a very highly reviewed tube integrated amp, and then a parts upgraded and other mods done Threshold 400 amp. The 400 sounded a little deeper and tighter in the bass, but both sounded a little lacking in the presence region. We listened for about 1 hour to the 2 amps.

Then we inserted the Bob Smith upgraded Ref 9’s. Immediately, the sound was much more live and involving. The bass was now incredible in all ways, and no matter how much more information was easily present, the sound NEVER got harsh in any way. We gave the amps the power test and turned them up very loud and the sound just scaled upward. There was no irritation on the ears and the amps just kept on going. The dynamics with this combination were just off the charts--drum hits, guitar picks, horns sections all popped. We listened for the better part of 3 1/2 hours straight until I figured I overstayed my welcome. My friend wanted me to leave the amps there for awhile, like 3-4 months. However, I wanted to see if the amps would do the same in my system. Bob A., my friend, had plugged the amps into 2 different outlets side by side, with all his other stuff plugged into the bottom 2 outlets. At my house, I had plugged the amps into the same outlet with just the DUDE preamp on the other. All my front end stuff was plugged into an SR QLS-6 strip and then to its own 3rd outlet. In my system with VMPS RM40 speakers, the volume would shut down on one channel when I tried to turn the volume up. Would this be the same if I plugged them in the same as Bob did?

The sound of my system was now unbelievable, and I have all my components stacked on the floor temporarily while the rods of my Sistrum rack are getting cut and retooled. The clarity, dynamics, soundstage, etc. became even better than before I took the amps to Bob A.’s house. I then took the volume up to where it was when one amp would temporarily shut down and a couple notches higher. It was now LOUD and I kept it that high or higher for over 2 hours. Never had the problem of overloading the amps. The sound just soared and again there was no listener fatigue. I really can’t wait until the Sistrum rods are retuned and I will now have 2 much shorter racks with the wonderful sound the Sistrums bring. These amps are world class and I’ve now heard them in 4 different systems. Unlimited volume with live dynamics and transparent, detailed sound yet organic. Thank you Bob Smith of TDSS for an unbelievable amp upgrade and thank you Bob A. for letting me see a better way of getting my power from the amps. Needless to say, Bob A. is having some serious thought about getting his own pair or TDSS Level 3 Ref 9’s SE V3. He has been looking for an amp that would put the life into his wonderful speakers and he has found it.  If you have a Nuforce or Nuprime amp(s), and you are thinking how can I make this even better sounding, RUN, don't walk, and talk to Bob Smith about his upgrade.  By the way, the amps will become much more reliable with the improved power supplies put in--an added benefit!

After reassembling my system following an extensive rebuild of my basement including the listening room, I found that the low woofer on one of my VMPS RM40 BCSE speakers had a fairly loose connection from the clip that was crimped over 2 joined sets of wires running to the woofer.  I crimped the 2 wires firmly with a HD needle nosed pliers so the wires were of similar width from the connection to the clip.  Then I crimped the clip on securely and soldered it for good measure.  After reinstalling the woofer, I played music and the problem noted about one channel shutting down at about 11:00 on the dial, now had no problem with more volume as I was able to play my system at 1:00+ with no issues.  Took awhile to discover the problem, but all is well in all areas now.

Couple months ago, Bob Smith at TDSS did what he calls the CapCellBar upgrade to both of my Nuforce Ref 9 V3 SE mono amps. He replaced the large bank of 20+ capacitors with larger, but fewer caps that were as much as needed, added his Smith Cell Vortex, and added solid copper bus bars to each amp. He had upgraded the power supplies to 500 watt/channel from the 350 watt/channel that were part of the level 3 upgrades that had been done a couple years ago. This upgrade allowed the amps to scale volume more efficiently and improved the sound over the already great Ref 9 with level 3 in all ways. BUT...the CapCellBar upgrade made an even bigger difference in SQ than the entire level 3 upgrade in these ways--the dynamics were now much more noticeable; the bass was both deeper and had great texture that allowed one to hear the different types of bass being playing very easily; there was much more detail to the sound at all frequencies allowing you to hear things that were never heard before or were less audible prior. The soundstage info was wider, deeper and more solid in where each instrument or singer was located. IMO the new upgrade is an even larger upgrade from the level 3 than the level 3 was from the standard mono amps. You should contact Bob at Ozark Mountain Audio or at TDSS--the Nuforce and Nuprime authorized upgrade place.

Hi all. Recently, one of my reference 9 v3SE amps died. I assume it’s the common power supply failure. I’ve been following bob smith for a couple of years in case this ever happened.. and now that it has, unfortunately  tdss and bob smith have vanished. I was able to find someone’s invoice online for the upgrades which listed the parts used for the power supply swap. I was wondering/hoping someone somewhere had a picture of the upgraded internals of their v3 SE that they could send me so I can get an idea of how these replacement parts have been integrated. 
many thanks. Nick.