Elekit TU-879S 6L6GC

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G

Gobble

Member
Joined 2010
bdbender said:
So I tried the combination of Tung Sol KT120 plus Sovtek long plate 12ax7 and I love it in this setting. The KT120s are hard to describe, but full and balanced and extended bass and nice midrange and treble. There is no downside that I can hear (again, this is a fairly noisy setting), and the 12ax7lps drives them well.
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From what little I know these KT120s need much more current. It also seems to be the case that different tubes may not shine and sound their best if the correct current/voltage/bias is not applied when a tube is dropped in to a circuit.

How does this self-biasing circuit work in this kit? Can it be tweaked with a potentiometer like (screwdriver) knob to fine tune the current voltage for a tube type if required?

--G
 
G

Gobble

Member
Joined 2010
Just FYI for the community members, I ordered the kit today along with the coupling caps from Vitamin-Q.I figured I would rather not spend another $14 on shipping just the caps - that money can be spend on tube rolling.

I will update on the build progress as it happens.

After procrastinating for a full year and wondering what kit to acquire, I am finally glad to have made this decision within days of having discovered the Elekit all by chance on the net. :)

Thanks Victor.

--G
 
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J

Jeephead

Member
Joined 2011
New to tube.

I am considering this kit as my 1st entry into tube amps. I have always heard how much nicer the sound is out of a tube amp is compared to SS. This seems to be a great value after looking at the prices of other non kit amps. My musical taste cover everything from classical to Nine Inch Nails. I plan on using a set of Bose AM5s with this or a pair of Boston Acoustics shelf speakers. I am not sure if this amp would handle my Polk RT55's. Could anyone tell me if this amp could run the AM5s or even the Polks? I could not find the sensitivity specs on the Bose.
Thanks
-David
 
vkung

vkung

Member
Joined 2005
DSC_4735.jpg


2011_06_25_14_34_00.jpg


TU-879S with RCA 807
 
B

bdbender

Member
Joined 2010
Gobble said:
From what little I know these KT120s need much more current. It also seems to be the case that different tubes may not shine and sound their best if the correct current/voltage/bias is not applied when a tube is dropped in to a circuit.

How does this self-biasing circuit work in this kit? Can it be tweaked with a potentiometer like (screwdriver) knob to fine tune the current voltage for a tube type if required?

--G
Click to expand...
Self-biasing does not allow or need adjustments. Some folks don't like it for just that reason, but this amp works just fine within its range of tubes. You can get into changing cathode resistors and so forth, but that is tough with a printed circuit board.

I had run a set of KT88s for a while with no problems, and if they weren't in storage due to my move I probably would have just put them back in, but this is supposed to be about fun, eh, so why not try the KT120s, since people really seem to like them. The specs are not all that different, either, except maybe for plate resistance. I was more worried about the available heater current, but there's a fuse for that and no problems have showed up.
 
G

Gobble

Member
Joined 2010
Thanks bdbender.

One more question. I plan to purchase an REL T3 sub (avaialble at a really nice discount) to add the presence of lower harmonics missing in my fullrange setup. These subs use speaker level inputs into the sub amp in parallel with the speaker cables (from the speaker terminals of the amp) in order to blend more effectively with the main speakers.

Q: Will this place an extra load on the TU-879S amp? Or will this little thing cope with the load effortlessly?

Victor?

--Gobble
 
vkung

vkung

Member
Joined 2005
rimian said:
I purchased this kit from tubedepot a few weeks back. They were very helpful. I really enjoyed putting it together and it sounds great. Whoever claims you can put it together in 2 nights probably doesn't have kids :). Either that or I am a total n00b.
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Sorry Your TU-879S from Tube Depot has an aftermarket R-core. Your aftermarket R-core is not supported by ELekit. The cost of Original R-core is few times more than your aftremarket R-core. Each 230V R-core is worth JPY 8,800.00 from Phoenix.

Elekit wrote:http://diyaudioprojects.com/Forum/v...sid=08de6153cb831a520b744fa90022b4de&start=30

TU-879S is originally designed for domestic market, and basically comes with 100V power transformer. However, for use in USA and other countries with 120V or 230V specification, our dealer in USA decided to source a power transformer with the said specification on their own. As we cannot test the transformer they sourced on their own, we explicitly mentioned that we are not liable for any trouble caused by their transformers


The original R-core of TU-879S does not have the coloured tabs for multi voltages; they have either 100V , 120V, or 230V custom made for the specific area by Phoenix, Japanese R-core transformer maker. ‚R-CORE_TRANSFORMER

When purchasing your TU-879S kit, please ensure that you are getting the original R-Core transformer made by Phoenix, Japan to maintain optimum quality output (see pic without coloured tabs for voltage). A lot of clone R-core transformers use inferior (poor quality) iron and of course the sound quality will be downgraded. The clones are not up to the standard of quality of the original R-Core invented and licensed by Kitamura Kiden Japan. Be wise and go with the original R-Core and not the reproduction.

Extracted from 6moons
Untitled Document
Consumer Alert (July 11, 2011):

Consumer Alert (July 11, 2011): The only thing better than free advertising is a good review. But if the manufacturer changed parts or allowed third party to change parts after the review was published, what do we do? Victor Kung of VK music was the first importer to introduce and successfully promoted Elekit to North America in 2008. Without any English literature and printing support from the factory, Victor translated all the kit building instructions into English and prepared printing artwork for the TU-882R, TU-870R, TU-875, TU-884CD and TU-879S. He invested tremendous time and money building up brand image and consumer loyalty by providing after-sales services and maintaining an active forum for Elekit. Thanks to Victor’s perseverance, the Japanese factory agreed to provide North American shipments of the TU-879S with the same Japanese made high-quality R-core transformer suitable for North American voltage. Victor accepted the fact that these transformers would jack up his cost and was willing to lower his already very humble profit margin. It’s shocking that the manufacturer could later turn around and flush all his hard work down the drain.


How so you ask? VK Music being a small enterprise short on capital could not meet the high volume the manufacturer demanded to grant him exclusive distribution rights. An American-based tube trading online store was attracted to take a piece of the TU-879S success. Since all the ground work had been done and the language barrier removed (a instruction manual being crucial to kit DIYers), the manufacturer gladly accepted. Anxious to push more sales in America and Europe, the American online store had their own dual-tap dual-voltage transformer manufactured in India.

Now I have nothing against lowering costs to benefit the masses but quality must be guaranteed. If I were Elekit, I would test these Indian transformers, then either endorse them if up to standard or reject them if not. I would not allow my products to be associated with unknown or untested parts. Yet Elekit has chosen to bow down to profit and do just that by supplying TU-879S sans R-core to the American company. In an Elekit forum on DIY Audio Projects, the manufacturer stated that "...as we cannot test the transformer they sourced on their own, we explicitly mentioned that we are not liable for any trouble caused by their transformers."


Pilate’s washing hands might have ridden him of guilt but not crime. Even more ridiculous in this case is that the manufacturer undercuts one loyal importer who pays a premium for factory-warrantied products and at the same time undermines the other importer’s credibility by legitimising their “grey-market” products yet claiming innocence and not being liable. It must be clarified that the review item here was fitted with the original Japanese made R-core transformer meeting Elekit specifications, which I believe has contributed significantly to the sonic performance of the kit. The American online store has a trustworthy and reputable name in the business and they’re a good company I have purchased tubes from. I truthfully wish they would send their transformers to Elekit for appraisal and endorsement.
 
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R

rittb001

Member
Joined 2006
Help needed TU-879

I just completed a tu-879 kit. One channel has about 25% of the output than the other. I switched output tubes and replaced the 12AX7 without benefit. Used input 1 and input 2 without change. Checked my computer soundcard outputs which feed the amp. No deal. Reversed the inputs and even switched the speakers which did nothing. No matter what I change, one channel is down about 6 dB. Before I start tearing my hair out and tearing the amp apart, anyone have an idea as to where to look?
 
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