[wushuliu]

The amp seems to play about 25 hours or so on a charge, it is very efficient.

Thanks. I ordered one. Will compare with my CDA254 amp. FYI, the OFR-1 is no longer available.

[wcvb]

The amp takes about 100 hours to fully break in. The amp never sounds harsh, but it will open up as it beaks in.

I have two SLA 12v scooter batteries hooked in series for 24V and a 24V smart charger. I forget the brand.

With the battery, the noise floor drops and you hear more detail. This results in more tranpaency, more depth, and a bigger soundstage. Small background details are also more noticeable.

The 24V is going to give you 32 watts per channel, the 12 V will probably give you about half of that.

Cardas posts improved the amp by about 30% fom top to bottom. It also added more magic with a bigger soundstage.

I have never heard it clip, even when I had the 88db Classico 3's here. But I never play my system much past the 95-98db levels. I don't want to lose my hearing.

Thanks for the reply.

I'm breaking in my Millennia now while I try to figure our what batteries and what capacitors to use.

Need to choose type and capacity of the batteries and the type, capacity and number of the caps.

Even stock, with the AC supply the amp sounds very impressive indeed.


Regards,
wcvb

[OzarkTom]

My buddy Rex called tonight. He hooked two of the amps up today as monos. Rex said there was another 20-30% improvement in smoothness and even sounded more tubelike.

[wushuliu]

So we're waiting for feedback from Occam, correct?

[Occam]

Yup....

[wushuliu]

Yup....

Sorry. Was a passive aggressive nudge. Totally wasted on a new yorker, I know. 

[Occam]

Its been an interesting few days. The amp arrived Friday.  I set it up, driving the amp directly from my EAR Acute III CD player with the amp powered via the supplied 24 volt battery pack. As the Acute has its own remote volume control, I used it rather than the Millenia's volume control which I turned all the way up to remove it as much as possible from the circuit. I left it on repeat until Sunday afternoon. The battery recharges very quickly.The amp drove my Marten Miles II speakers.
From the last 3 days of listening, I'm very impressed. It really goes quite loud while maintaining composure. But with my tube complement on the EAR, 2 Siemens PCC88s the Germanic clarity of the Siemens, along with my GSII interconnects, gave a more analytic presentation that the TBI needed, resulting in a subjective lack of midrange warmth and density that I prefer. As I didn't have a pair of Amperex or Valvo Dutch produced ECC88/PCC88s to swap for the Siemens, I changed the GS II interconnects for my HE interconnects. The net result was more warmth and the requisite midrange density, but the downside was a slight loss of resolution, as expected of a lesser interconnect. Regardless, the imaging was wonderful, precise, with appropriate depth and height when on the recording. This is not a characteristic I find in many amps, regardless of price. But given the limited power available to my Martens, it couldn't produce the size and solidity of soundstage available from a similar quality amp with substantially more power.
While the bass extension and control was good, the limited power couldn't offer the control of either my Aksa Lifeforce or Ncore 400.

The amp acquitted itself quite well on tambourine and bells, which IMO, is very difficult. I think the supplied punched metal RCA female chassis connectors are a limiting factor and might be responsible for the grain I heard in the treble, so I think it needs an upgrade like the one Tom did on the binding posts. Dunno, but while this might be called 'polishing a turd' by the cynical, one really can't get top notch performance with compromised connections. [nevertheless, as configured, the system had sufficient resolution to verify the differences I'd previously heard among LS cable connectors, WBT vs Furutech vs DH Lab vs etc.... And that does speak quite well for the amp.]
As I've mentioned previously, its been more than 2 months of playing slap and tickle with my Ncores to get it to the point where it bears comparison to my beloved Aksa Lifeforce. After a progression of changing signal and speaker internal wiring, realizing I had to leave the Ncores on all the time (at least 6 hours), I finally changed the internal ac wiring on the supplied wiring harness to my own cable and am close to satisfied. Also, both of the wall powered amps sit on brass cones on a mdf shelf,  which couple to my rack via upward facing points. I demoed the TBI with it sitting on a wood floor decoupled with the 2 supplied little drum dampening squishy pads. Heck, there isn't any component, cable, or cord in my system, that doesn't cost substantially more than this charming amp.
Do I consider the amp a giant killer? Not really, I doesn't 'kill' my Ncores, which in turn, didn't 'kill' my Aksa Lifeforce. [ I'll also add that I'm not familiar with similar products from Virtue or RWA ] But for $500 plus the cost of batteries and charger, along with connector upgrades, its a mighty fine amp. Driving near-field a pair of LS3/5a s, the worlds greatest and most pleasurable headphones, it could be glorious. It might work wonderfully driving more efficient speakers, or powering a satellite / powered sub-woofer system. YMMV

FWIW,
Paul

my system -
http://www.audiocircle.com/index.php?action=systems;area=browse;system=771

[Rclark]

seems like pretty high praise, other than the limited power output. A lot of tripath amps (Virtue) put out more power, some I've seen put out many times more. I wonder if part of their secret is keeping output low.

[wushuliu]

Thanks Paul. Those Martens look like a tall order for the TBI (guessing the Miles also dip down to 4 ohms on the low end?), so that's a great review all things considered.

Did I read someone is going to use it with their Maggies? 

[OzarkTom]

Thank you Paul to take time out of your busy schedule and do a review on this amplifier. I knew that this would be one of the toughest comparisons on the tour for the TBI amp. I am pretty sure that these Martens and the Maggies will be the toughest speakers for the TBI to drive on the tour.

BTW Paul, do you think some of that grain that you heard could have been eliminated by setting the amp on your pro stand instead of sitting it on your hardwood floor?

[Freo-1]

Thanks for a most excellent and well written review, Paul.   
 
 
I’m looking forward to giving the amp a spin with a couple of different speakers.   

[Rclark]

 Yeah, I'm going to put them on my Magnestand mmg's, but out of all the Maggie's, they're the easiest to drive I would think. I get good output (somewhere in the 90dB range) with 57 watts per side before with the Virtue, but that's pushing the amp awfully hard.

 At 32 watts, this TBI should at least be able to drive normal listening levels and should be comparable to the Virtue. Well it will be comparable, it's going to be compared 

[wushuliu]

Yeah, I'm going to put them on my Magnestand mmg's, but out of all the Maggie's, they're the easiest to drive I would think. I get good output (somewhere in the 90dB range) with 57 watts per side before with the Virtue, but that's pushing the amp awfully hard.

 At 32 watts, this TBI should at least be able to drive normal listening levels and should be comparable to the Virtue. Well it will be comparable, it's going to be compared 

Should be interesting. The MMGs are 4 ohm nominal with medium (86db) sensitivity. That's asking a lot from the TBI. Given what I have read about Paul's (Accuton=drool btw) speakers in terms of specs, I am really surprised the TBI acquitted itself so well. On the TBI site it states the amp is optimized for 8 ohm and only 12v should be used for low impedances...

[Occam]

....
BTW Paul, do you think some of that grain that you heard could have been eliminated by setting the amp on your pro stand instead of sitting it on your hardwood floor?

Tom,

Dunno, I didn't (and couldn't) spend enough time with the amp to experiment with its coupling/isolation. From previous experience, amps really do benefit in both resolution throughout the spectrum as well as bass control from optimizing their physical environment.

Regards,
Paul

[OzarkTom]

The amp is on the way to Freo-1. He might not receive it until Monday.

[Freo-1]

I’ve started listening to the amp.  With the supplied AC power supply, the amp sounds nice, but nothing special.  However, with the battery power supply, this little guy really delivers the goods.  I only got about an hour of listening out of it before the battery was too low (started making popping noises).  So, I’m charging up the battery, and will report back after some listening.
 
Too early to tell, but so far, on the battery, this amp sounds MUCH better than I would have thought.   
 
Makes me wonder if a dedicated outboard linear power supply would also work well?

[wushuliu]

I’ve started listening to the amp.  With the supplied AC power supply, the amp sounds nice, but nothing special.  However, with the battery power supply, this little guy really delivers the goods.  I only got about an hour of listening out of it before the battery was too low (started making popping noises).  So, I’m charging up the battery, and will report back after some listening.
 
Too early to tell, but so far, on the battery, this amp sounds MUCH better than I would have thought.   
 
Makes me wonder if a dedicated outboard linear power supply would also work well?

What kind of power supply does it come with, is it a switching one?

[OzarkTom]

I forgot to mention that one thing about the popping. The battery needs charging.

[Freo-1]

What kind of power supply does it come with, is it a switching one?

Yes. It looks like one you get with a laptop computer.

[Freo-1]

I forgot to mention that one thing about the popping. The battery needs charging.

How long does it take to charge?  Do you happen to know how many amp hours does the supplied pack have?
 
Also, are there 24 vdc battery packs with more amp hours you are aware of off the  cuff?  Thanks!