What amp did you have before the UFO25? And what is your front end? Are you using the Decware stock tubes?

Certainly your new amp will sound better after dozens of hours but even right out of the box mine did not seem "bass enemic." But I didn't get the Decware tubes, I used my own well broken in tubes. A quick check of your speakers indicate the minimum recommended power is 25 watts, so it is possible the speakers aren't a good match. But at this point I would wait until you had at least 30 or 40 hours and then re-evaluate.

I received my UFO25 not too long ago. I did not have the bass issue you describe, even at the very start. I do have high efficiency speakers though: Floor standers with 101db efficiency, Full Range Driver, high pass filter for tweeter, down to 30hz, and no crossover. In fact, for my smallish room (12x14) I get more bass than I need.

It may be that the combination of a crossover and the 90db efficiency are enough to hinder the UFO25 and not provide a good enough match and synergy. Those look like nice speakers though and may be a better match for higher power tube or solid-state amps.

However, as CAJames mentioned, maybe more time on the UFO25 is needed.

Thanks all for the advise and messages. It seems that burn-in and a change of tubes to one that is 6N5P and OA3/VR75 gave a more solid feel to the sound. The sound difference is really substantial from less than 4 hours to today's less than 10 hours of burn-in. It's already sounding great! I'm surprise you guys didn't experience how lumpy it sounded just out of the box. It is comparable to my previous Hegel H120 with just so slight burn-in. I can't wait to hear how it sounds going forward.

I'm really in love with the looks of this tube amp, the photos don't do justice to how beautiful it looks. It feels like it's Christmas in a few days with this vibe the amp is giving me.

All is good again, I'll surely report back my findings especially if it's able to awe me despite not having the most perfect speakers of a match.

@mrchipster was the bass issue ever solved? while the bass has improved it's still feeling rather anemic.  :'( It'd take quite a bit of improvement to the bass for it to sound better, it's like they lowered the volume of the whole mid-bass and bass section.

That's good to hear, thank you.

Sorry to hear that your lack of bass issue isn't getting much better.

Unlike your case, I've had great bass from day one with my UFO25 and speaker pairing. What the burn-in process did do in my case was to tighten it up, solidify it, and deepen it to some point. During burn-in it was mostly overall sound quality that would come and go and then eventually get better and better. Consistency in fullness, richness, articulation of mids and highs mostly, with the bass enhanced as I described.

CAJames has mentioned some very good points. You may have already tried but changing the VR tube, trying different positions of the impedance switch and the bias switch can make a reasonable difference.

My gut tells me that the synergy between amp and speakers may not be there. Unless there is something wrong with the amp (a very low probability) then the wisdom here also says to give it more time and good things may come.

Obviously, you may not have another set of speakers otherwise you may have already tried, but using a different set with higher efficiency may shed some light.

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I hate to say it, but if I had to bet this is where I'd put my money as well. Speakers like your Triangles typically need most of their rated power for the bottom octaves. Certainly the Totems I had before Decware/Omega were like that. If you don't have enough watts you can still get plenty of volume, but the speakers essentially become a high pass filter that rolls off the low frequencies.

But, you've still got to break in the amp and a lot can change with some more time.

Nice!

Glad a simple change made a big difference. Goes to show how the amp/speaker pairings can produce different results with certain changes in the lineup. As I cycled the VR tubes with my pairing, it didn't affect the bass much (always had good bass) but it did tame the highs. So, for me going from the OA3 to the OC3 made a good difference in highs and then going to the OD3 tamed the highs even more. When I use the OD3 I also find I like the bias switch in the high position. The high bias surprised me since I was wanting to diminish the highs a little and the bias increases it somewhat, but it gave a better sound stage with more air around instruments in my configuration. I plan on getting upgraded tubes to replace the original ones, so I expect to go through this all again and probably settle on a different outcome, who knows.

I'm relatively new to tubes and still experimenting with all the combinations of tube types and switches. As the amp is burning in it's going through its own changes regardless of what the tubes are doing. You'll probably find that there are more changes coming for the better with your amp and sound. Glad you're enjoying it more now.

Indeed.  This is the price for resolution.  You have to understand that the resolution of an amplifier signal path derived from two resistors and 1 capacitor without feedback, circuit boards, or any solid state parts and real linear power supplies -- class A operation, hand soldered with solder that penetrates deep into the parts leads... will be shockingly magnified over conventional hi-end audio gear.  Give yourself 500 hours before you make any concrete observations.

Once that happens, and you will be in another room most likely -- suddenly you will hear it just lock into warp drive and go.  It will make you walk into the room to hear what is actually happening.

This is Decware.  Until you have a tape machine with a all tube signal path and no negative feedback, you will never hear how good the amp is, even after 1000's. of hours.  

Btw, an amp with 1000's of hours on it, or even better 10's of thousands of hours on it, sounds simply unbelievably good.  Every is seasoned like a fine wine.

The  worse thing you can do is let the amp sit for several months or years.  It then has to be re-burned in when it is finally put into service.  Granted it takes less than half as long, but it still happens.

And frankly it's not even the amplifier that we are talking about here, it is the signal capacitor.  The capacitor is what breaks-in more than any other part.  Everything else just seasons.  Specifically, the dielectric in the capacitor has to firmly seat with the foil or film that is used. This is as much about electrons carving a path over the dielectric as it is about temperature expansion and contraction seating the film/foil in the cap.  

Solder also breaks in and depending on how good the artist who soldered it was determines how long the solder node takes to break in.  

Once you have 500 hours on this amplifier, anything you don't like about the sound is the amplifier showing you the weak links in your audio chain which includes the acoustics of your listening room.

Getting back to your relief about the bass, you will never grow tired of musing over how 2 watts (that can drive nearly a dead short) can have any bass control whatsoever...  

Wait until you get some more efficient speakers.  The ZF15M or ZF15L at 100 db have a moving mass of 17 grams and are crossoverlesss.  In these heavy baffles they redefine what is possible in bass articulation and control... it is other worldly.  17 grams of moving mass is 5 to 10 times faster than all modern day loudspeakers.

Speed is how fast a driver can stop and change directions without overshoot or distortions in time.

You can easily spend the rest of your life eliminating handicaps before and after the amplifier because it is impossible for it to become the weak link in the audio chain in todays world.  You will see this in the next 400 hours and after.  We will all look forward to your feedback.