New Sensation M901 finally here, burning it in...

antonio · « **Reply #40 on:** 31 Mar 2010, 10:19 pm »

wow! exciting start!!!
finally bullet-to-4pin din adapter is arrived and i could connect the wires and check all product:
10A/30V jt dynamic antec, sensation m901, couple of nirvana cable and both remote control (plastic and alu).
all work perfectly.

of course after i payed attention to music.
my stereo system is: cd player NAD C454BEE, KEF Q7 (90 DB sensitivity) and above virtueaudio products.
my old ampli is a TA10.1.

first of all, the noise of jt dynamic (seems the tipical 50hz of a transformer) is also audible at normal music listening distance, but is very low and does not damage music listening.

of course, at beginning the sound was harsh, the medium frequency glassy and bass incredibly strong but dark.

but after only 1 hour, sound become more soft and pleasant, all musical instruments are incredibly detailed
and alive...as if the old TA10.1 had removed a layer of a couple of mattresses. the bass became very deep (i never imagined that my kef could sound so deeply..) and have start to be more clean and controlled.
in fact, already so I'm very much satisfied, but everything suggests that with another 99 hours of burning I will end up hopelessly fall in love with my new sensation...

PSB Guy · « **Reply #41 on:** 31 Mar 2010, 10:35 pm »

I must be lucky or something, I've yet to hear any sort of power supply related noise through my speakers. And that's with any of the power supplies that I've used, from 24v/65w to JT Dynamic Power monster (love it!). My PSB Image B5s are rated 87dB anechoic chamber/89 dB typical listening room by the company...maybe they're being generous with their numbers, don't know, but PSB speakers have always been highly regarded. Plus, it's nice to support fellow Canucks.

antonio · « **Reply #42 on:** 31 Mar 2010, 10:57 pm »

perhaps due to the fact that the dynamic JT is optimized for 60HZ USA power, and not for 50HZ Italian and could be a small audible resonance. still nothing problematic.
i play my old ta10.1 with an EU (50hz) 12v 5A power supply and i never heard any noise from speakers. however i'm very very satisfied because quality of sound of sensation is improving every passing moment and with music, noise is not audibly.

Jason T · « **Reply #43 on:** 1 Apr 2010, 11:18 pm »

Antonio
lets see what other 220volt users say.
when tested I dont here any noise from my 220V PSU's (with a step up transformer) and don't think you should either.
we might have to address that.

littletree76 · « **Reply #44 on:** 2 Apr 2010, 02:45 pm »

I use the JT Dynamic linear power supply with 230V/50Hz AC main and 92dB sensitive bookshelf speakers. Comparing with previous 30V/130W switch mode power supply, the noise level has been reduced.

Since the JT Dynamic linear power supply does not have regulator built in, ripple level is determined by the low pass filter (capacitance network) immediately after the rectifier. The ripple frequency should be twice of AC power line frequency after rectification. So I wonder how the ripple eventually affect output of the linear power supply.

Initially I was looking for regulator module to improve output of the linear power supply, but on second thought regulator will lower conversion efficiency of the linear power supply (95%) and increase heat generation, thus I decided to leave it as it is as the Virtue One amplifier must be left on most of the time.

antonio · « **Reply #45 on:** 14 Apr 2010, 06:04 pm »

is the power performance of sensation with 24v battery 10A as like as with jt dinamic 30V 10A?

Jason T · « **Reply #46 on:** 15 Apr 2010, 03:54 am »

I'm running mine on a 24V 7.2AH batteries and I like it allot.
I can tell that I'm missing 6 volts worth of power but other than that I'm not sure if I like it better or not (coming from the guy that builds the power supplies

)

I've gone back and forth a few times and dont hear an obvious difference in my system.
My speakers are a 3 way and are 4ohm 87db 150watt so their not highly efficient but kick butt none the less

Light-Echo · « **Reply #47 on:** 15 Apr 2010, 12:39 pm »

Jason

So...stick another 6v in there? It's apparent people have been running the V's at more than 30 volts no?
I'm running (will be running) 2 x 12. Why not 5 x 6? I realize the real voltage is better than 30 but is this really an issue?

KFD

virtue · « **Reply #48 on:** 15 Apr 2010, 02:29 pm »

The issue is that fully charged 12v = 14.4v. The risk is yours. Those traces are fairly small and we've blown up units using test tones @34v. Will your music ever have the power of a test tone? Probably not. But be warned!

cynan · « **Reply #49 on:** 15 Apr 2010, 09:40 pm »

This was discussed in an earlier thread here at length. 2 fully charged 12V batteries will give you up to 27V (my system measures closer to 26.6V, but I digress) - which is not that far off from 30V. Therefore it stands to reason that 5 6V batteries in series may generate up to around 33.5 volts. You might get by with this, but as mentioned above, it could be risky depending on music and volume levels.

To further complicate matters, if wanting to set up a simple DIY battery system with a charger connected in parallel while the circuit is connected to the amp, you will likely introduce even higher voltages (my 24V charger puts out about 28V to 29V when in charge mode). A 30V charger would therefore put out somewhere in the neighborhood of 36V - which could definitely damage the amp.

To add to this is the increased likelihood for voltage balance headaches if attempting to charge 5 batteries in series (resulting in wearing out some batteries faster than others, perpetually augmenting charge/drain imbalances down the road).

As an aside, I cannot say that I notice a difference in volume when the charger switches on, even though the circuit reads 2 extra volts at the batteries (and to be honest, cannot really notice any difference in background noise either). Also, switching to the 30V 130W PSU does not seem any louder than the batteries at the same pot setting.

Light-Echo · « **Reply #50 on:** 15 Apr 2010, 11:26 pm »

My remarks were more rhetorical than anything. I will stick with my 2 x12v and I don't have a JT Dynamic unit to compare it with anyways. I don't even have my speakers built yet so it's all just speculation on my behalf for now.

Dave

dunlapk · « **Reply #51 on:** 16 Apr 2010, 01:34 am »

PSB Guy,

How is the burn-in going? Have the sonics improved? Have you tried speakers other than your B5's?

Hope things are going well

K

PSB Guy · « **Reply #52 on:** 16 Apr 2010, 12:05 pm »

One thing that really impresses me about this little amp, especially paired with the JT Dynamics power supply, is it's resolution. I recently purchased a Promitheus NOS DAC, and even through my well regarded but decidedly budget speakers, the differences in sound quality between the Promitheus and the Devilsound DAC it replaced was IMMEDIATELY noticable. Last week, I started having issues with the Promitheus and had to switch back to the Devilsound (looooong story, more about it on the Promitheus circle) and the change was jarring, to say the least. Funny you should ask if I've tried any other speakers, because this little amp has got me wondering what is possible with more up-scale speakers, maybe PSB Imagines or Synchronys, or Totems...but that's for the future, got a mortgage to pay. Anybody in the Toronto area have a pair of expensive speakers they want to lend me?
And yeah, the sonics have improved considerably since I got the amp. It now has that characteristic Tripath sound that I love, laid back in a tube kind of way, no fatique, with power and slam when there needs to be. The sound hasn't changed as much lately as it did in the beginning, I suspect that's because the Auricaps have finally burned in, they have well over 300 hours on them. Now if I can just get a DAC that works and does justice to the amp...

virtue · « **Reply #53 on:** 20 Apr 2010, 06:24 am »

I got this nice note from a customer today... worth passing along... I thought.

"Seth, I know you've had a busy few weeks with the soft-start issue, so I've
held off on submitting my thoughts on the Sensation M901. It's burned in
for about 250 hours at this point, and I've probably listened for well over
a hundred hours, so I think I have a handle on it's sound and many virtues
at this point.

First, my office system includes the Sensation, a Wadia 170i IPod
transport, various Ipods, an Audio-gd DAC-200, a Rega Jupiter CDP and Usher
Be-718s. When I bought the Ushers I had an Onix Sp3 tube amp, completely
retubed with vintage and NOS tubes. I felt the Ushers needed a little more
power in my setup and I bought a Cambridge 840A, version 1. I was
completely unhappy with the sound of the 840A - dry, flat and lifeless. I
went back to the Onix, but kept my eye out for used equipment on Audiogon
and other sites. After months of failing to see anything in my price range
(about $1000) that I felt would be a significant upgrade from the Onix,
(it does sound pretty good), I was ready to give up. I had been watching
your efforts to bring the Sensation to market for more than a year, but I
had decided to wait until you were ready to ship before I bought. When I
saw you were ready to ship, I ordered mine. It arrived a week after being
ordered.

My music tastes are pretty wide ranging - chamber music, traditional jazz,
world music and tons of pop/rock. Much of my listening at work is, of
necessity, at fairly low to moderate volumes, but I do listen at louder
volumes after everyone else has left for the day. For me, the keys to an
enjoyable listening experience are separation of instruments, a pleasing
treble (glare drives me crazy), an engaging midrange and the ability to
reproduce the human voice and stringed instruments (violin or guitar) in a
life-like way, with realistic decay and nuance. I love to hear a realistic
drum sound, too, with the ability to distinguish different drums and
techniques. Deep bass and width/depth/height of sound stage are less
important. The system has to be able to give me most of the musical detail
at low volume, even if it loses some of the dynamics you hear at higher
volume levels. While most of my downloads are 256 or higher, the system
also has to be forgiving of less than perfect downloads and use warmth and
musicality in these instances to make up for some loss of detail.

Can I just say the Sensation fulfills all of my requirements for an
amplifier? It is equally at home with classical and contemporary music and
produces a realistic soundscape at all volume levels. It is deeply
resolving, but never at the cost of losing a sense of the musical whole.
Glare and glassiness are nonexistent. Vocals are fully formed. Stringed
instruments - cello, violin, guitar - have an in-room presence. Drumming
is fun to hear - listen to any of the Jack Johnson or remastered Beatles
album or the kettle drum on "Amy" from Ryan Adams' Heartbreaker album, and
you'll hear what I mean. Plenty of snap, the ability to hear sticks on
drumheads, even the rattling of the drum sidewalls. The amp is very
forgiving of less-than-stellar recordings and squeezes out whatever detail
and soundstage exists in them. Well-recorded pieces can be spooky, with
lifelike detail and shifts in dynamics.

Over the years I've had lots of amps, beginning with the old Marantz 1060.
In terms of today's dollar, I imagine that the Sensation is similar in
price to what I paid for that Marantz in 1971. Like that old Marantz, I
think the Sensation will be a classic, with styling that will never go out
of fashion and sonic goodness way above its price point.

I can't imagine there's a better value out there than your amps.

Michael G."

mikeeastman · « **Reply #54 on:** 20 Apr 2010, 06:34 pm »

I'm doing same thing with exact same amp , we both must have good timing and
good taste.ha ha
I'll be running mine off a 210 aph battery bank ,charged by my solar system.after 12hrs of burn in it already has better staging than my present system and I'm just got it hooked to my Olive,no dac or tube buffer.Can hardly wait to hear whole system.
I have one question who do I hook up the high pass ?

virtue · « **Reply #55 on:** 20 Apr 2010, 06:45 pm »

Mike -
Here's a picture showing the jumpers. They both must be moved one position to make the 0.1 uF caps (smaller) active in the circuit, and take the 2.2uF (bigger) caps out.
In this circuit, the smaller ones don't let the LF pass through... so the pre-outs remain full-range but the mains don't get anything below 80hz, first-order (gentle slope).

Seth

Light-Echo · « **Reply #56 on:** 21 Apr 2010, 02:38 am »

Okee dokee. I posted somewhere else about burning the M-901 in with an 8 ohm resistor load.

Any thoughts (or perhaps warnings) on a particular volume setting? Should I maybe change it up every so often, 'louder' for a stretch and then a little 'quieter' others? I have the Roger Waters Love It To Death CD playing on repeat at the moment. Nice dynamics.

Regards
Dave

OzarkTom · « **Reply #57 on:** 21 Apr 2010, 04:09 am »

Quote from: virtue on 20 Apr 2010, 06:24 am

I can't imagine there's a better value out there than your amps.

Michael G."

And here is another that has found the Sensation is better than tube amps. I still say it will beat any tube amp with transformers, Cary, VTL, Manley, Audio Research, Conrad Johnson, etc...So what will beat it? Just might some OTL's. The David Berning will probably do it at $9800 plus a pre-amp. I first met David in 1978 at Chicago CES, and if transformers were good for tube amps, he would still be building them. He gave up long ago. David actually had the best transformer driven tube amps of the 80's, the EA 230 and 2100.

Like Michael said, this amp is very revealing, yet makes almost any song sound great. If you a rocker from the 60's like I am, The Doors, Donovan, Boston, and others all sound unbelievable. Then put on Norah Jones, Diana Krall, or some good recorded Jazz, and then hear how well recorded it is. This is a whale of a buy.

Light-Echo · « **Reply #58 on:** 21 Apr 2010, 04:20 am »

Zman

How about some Dream Theater? Perhaps some Umphries Mcgee Live? (The only way to do UM).
I chose the Waters disc because it has some awesome dynamics and I had this little epiphany: that the dynamics would be like feeding the body a good multi-vitamin, as opposed to a strictly a steroid diet.

Dave

marvda1 · « **Reply #59 on:** 21 Apr 2010, 06:56 am »

how about putting the jt power supply in a sensation case to match the amp