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Elekit TU-882 Vacuum Tube (5670W x 2) Headphone Amp - Page 3  

post #31 of 61
Thread Starter 
Could we see some test results proving that awfully low noise level?
Answer, The ripple filter circuit, used with the MOSFET, is built-in with the power supply circuit. This filter, used in our higher-end amplifier models(TU-873LE 300B, TU-879S 6L6GC and TU-882), helps to reduce humming noise.

How is that measured?
For all the various headphone jacks? Is it an average?
IEC weighting (SN ratio, 102dB)
It is for a standard headphone jack, around 32 ohm.

What's the voltage swing? Is it capable of 4V for a 600ohm headphone?
Yes. But please note that the amplifier is basically for head-phone.

We do not know why the voltageswing is the problem.
If you know the electric power the answer comes out naturally.
The electric power is indicated on Page 11 of the manual - 200mW.
Therefore the swing voltage for this case is 31Vp-p.

post #32 of 61
Has anyone actually gottrn their hands on one of these? Any comments? Has me intrigued...
post #33 of 61
Me too .. what tube rolling options do I have if I get this? I am a tube noob.
post #34 of 61
Thread Starter 
2 x GE 5670W included.
post #35 of 61
Originally Posted by Solitary1 View Post
Has anyone actually gottrn their hands on one of these? Any comments? Has me intrigued...
Originally Posted by eugenius View Post
Me too .. what tube rolling options do I have if I get this? I am a tube noob.
Hi guys, like you I am very interested in trying out this unit. Victor has agreed to send one test sample which I should be receiving by the end of June. I thank him for the opportunity and will post my hearing impressions.
post #36 of 61
Thread Starter 
will ship this week

Have Fun!!
post #37 of 61
yeah enjoy, I want it shipped to Canada to test sooner or later....or at least get some impressions!
post #38 of 61
Originally Posted by vkung View Post
will ship this week

Have Fun!!
Thanks and I will report back.
post #39 of 61
I received my Elekit TU-882AS headphone amp and a matched pair of WE 396A tubes today.

It took about one-and-one-half hours to assemble the amp. I treated all the electrical contacts with Caig ProGold GXL.

I started with the medium impedance setting at the 1/4 inch connection and the Sennheiser HD 650 headphones. Voice sounded a tad thin. The high impedance setting yields better dynamics and a more true to life midrange. Voices are heavenly. The small amount of self-noise at the high impedance setting is faintly audible and negligible.
This amplifier is fast and without overhang.
I've never found it easier to follow lyrics and to place background vocalists than it is with this amp.
All this is basically out of the box. I will report if the sound changes with break-in time.
I have to think that there are changes that could be made to this circuitry that would yield no noise at the high impedance setting and allow for the rotation of the volume control beyond about 9:30.
Tube rolling candidates include JAN 5670W, 2C51 and 396A valves.
Further observations June 26, 2009.
I contacted the North American importer, Victor Kung, and another enthusiast who owns the amp about the trace noise at the high impedance settitng. I should note that this noise is not intrusive, but being a perfectionist I would like to see it banished. I explained that the noise occurred only at the high impedance position and that I felt the gain was excessive there. The response was unsatisfactory. At a minimum Elekit should be concerned that HD 650 cans at the High Impedance setting play loudly at less than 9 o'clock rotation of the volume control. Further research and prompting is needed.
After 50 hours of break-in voices are stunningly fine. The bass, at first strong but somewhat less than perfectly defined, has become powerful and articulate. Particularly, tracks from Raising Sand by Plant and Krauss were most involving. The sense of the recording space is improved, as is localization of voices and instruments. The highest frequencies are now easily appreciated without any heightened projection.
post #40 of 61
Too bad you don't have some Grados or Denons, this amp seems ideal for them.
post #41 of 61
My local electronics shop stocks Elekit kits, but not the headphone amp. Makes it very tempting to try and order one. It does, as commented elsewhere, look like it would benefit from a few minor upgrades.
post #42 of 61
I have posted the first part of my review/impressions at: BTW I started w/ Grado RS-1 cans.
post #43 of 61
Thread Starter 
Here is the comment from TU-882 designer Mr.Fujita :

The first TU Series product launched in 1986. Mr. Fujita has been one of the engineers instrumental in driving developments of these vacuum tube kits for the past many years.

Mr. Fujita was born in Osaka in 1956 and raised in Fukuoka. He became interested in electronics in his higher elementary school grades and began to construct germanium radios and transistor radios. His first love with classical music was The Blue Danube sung by the Vienna Boys' Choir he heard in his junior high days. He eventually fell under the spell of music and audio. Soon he found himself gathering vacuum tubes from abandoned TVs and with humble parts permitted by his limited pocket money, he began building simple amplifiers or transceivers on aluminum lunch boxes or steel cookie cans. At the same time, he indulged in railroad models and made HO gauge trains of his own. It was during these junior high school days also that he obtained his HAM operator's amateur radio license.

In 1980 when a university student, he bought the first-gen Sony Walkman, then a revolutionary product. From then onwards, he became interested in portable audio in general. The car audio in his first set of wheels was this Walkman plus a DIY IC amplifier. Busy schedules filled up with lectures and studies prevented him from building his home hifi amps and he settled for Marantz and a pair of Diatone DS-25B 2-way monitor, with the speakers still in use today. Then he discovered Dixieland jazz at a club and it became one of his favorite music genres.

After graduating from Tokai University with a communication engineering degree, Mr. Fujita landed a job designing electronic systems for an automobile manufacturer before joining Elekit. In his present position, Mr. Fujita's life-long passion for audio electronics, model making and electro-mechanical engineering have finally found perfect solace and satisfaction. The solid DIY term of his youth helps him conceptualize, design and develop the TU series of amplifiers and CD player among many other Elekit products.

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permitting the volume control to be advanced to somewhere between the 10 and 12 o'clock positions where pots generally yield superior sound which may have the additional beneficial effect of lowering the apparent self-noise of the amp. This really does not make sense.

In his opinion, the gain of TU-882R/AS is designed perfect.

Matching the impedance is important only to convey the power of the amplifier to the headset in most effective manner.

However, having the best sound quality is another story.

Matching the impedance could cause distortion and low damping. You need to see the balance of the impedance matching and good sound quality.

As the said headphone, Senn HD650, seems to convey the power very effectively, it no longer has to be connected to high impedance. Connect it to low impedance and get the best sound out of it. Low distortion and high damping.

As you know, the vacuum tube amplifier has very low damping, 5 or 10 at most, compared to a semiconductor amplifier having 100-200 damping. Connecting it to low impedance could lead to high damping and low distortion, a better sound quality, which must be something that all users want to achieve.

Also, TU-882R/AS is designed to best match commonly used headsets, and focusing only on those high-impedance headsets is not a good idea.

Could this explanation help the situation? I hope so...

post #44 of 61
Thread Starter 
Thank you Marroyo and Skylab

mrarroyo's review

Skylab's Review

REVIEW SUMMARY: A ranking of 22 tube and tube/hybrid headphone amps
post #45 of 61
Burning in my new TU-882 now. I'll write up a detailed review in a few days. First impression are really good.
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