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The "Lovely Cube" Headphone Amp (Lehmann Black Cube Linear Clone) - Page 85

post #1261 of 1427

Stephen seem´s to give wrong information, as he also send me a second mail:

 

"Talema Toroid 30VA 2x15V has 2 version,  input 220V and input 115/230V version.  When using input 115/230V version for 220V input, the 2 primary coils must be connected in series : Brown ,(Violet-Grey), Blue.  for 2 secondary coils , connect them in series as red , (black-yellow), orange , to become 15-0-0-15V.  As I remember, the DC resistance across each secondary coil is about 1.5 ohms."

 

But I do not see any difference, still it will be black-yellow as 0V for secondary.

post #1262 of 1427
Just follow the wiring diagram.



Mains to PRIMARY:
Brown and Blue connect to your mains AC 220V (fused)
Violet and Grey shorted together.

SECONDARY to Lovely Cube:
Red to AC 15V (top screw connector)
Orange to AC 15V (bottom screw connector)
Black and Yellow shorted together and connected to 0V (middle screw connector)

Simple!

Now, wear your protective suit and plug it in... popcorn.gif
[joking]
Edited by Tribbs - 3/28/15 at 10:40am
post #1263 of 1427
Quote:
Originally Posted by mikaelmark View Post

I have now asked a friend at my work about this project, as he is an old men with good know how in electrical - and he said it should be fine to drive the LC with battery connected after the rectifier diod´s. It will also be fine if connect the battery before the diod´s, but preferrable after (to 15VDC in).

But the two big 4700uF (or in my case 10000uF) filter cap´s should be used.

Something I recently came across http://tangentsoft.net/elec/vgrounds.html
Edited by Tribbs - 3/16/15 at 3:37pm
post #1264 of 1427
Quote:
Originally Posted by Tribbs View Post


Something I recently came across http://tangentsoft.net/elec/vgrounds.html

Yes, tangentsoft is a useful site about some portable amp´s like Chu Moy and Pimeta and some OpAmp´s.

 

Thank´s for the link - I´m gonna read that!

 

Now, back to the "standard" LC with OPA627AU

 

and 200VA 15-0-15VAC toroid: I just soldered the last few things and connect it to the wall outlet with 230VAC. On the secondary, there was 2x16,7VAC and all three led´s was litting and LM317/LM337 getting hot (as they should do).

 

So in the evening today, I´m gonna connect a DAC to it and try with HD600 (I do´nt dare trying my HD800 at first attempt). Will report my impressions tomorrow.

post #1265 of 1427

And here´s my impressions: First off, I connected my Squueezebox Touch to a china WM8740 DAC, then to the Lovely Cube with the HD600. Connected the AC wall outlet plugs and all LEDs litted up. Putted on the phones to my head; Was there something wrong? Could´nt hear anything. So I turned up the volume on the SB Touch and LC – Voila! There was music. I set the SB to pause, and now I could hear some background noise. -No, it was the wind outside the window blowing. Listening some more to the music, and all I can say is that the sound is really good!

 

Then again I paused the music, and this time I again tought I could hear some noise. -No, now it was the neighbour vacuum cleaning!:blink:

 

So my fear about using a lot of big caps seemed to be meaningless.

 

After I unplugged the wall outlet plugs, I touched the LM317/337 heat sink´s, and could not hold them for any long time. But I assume it should be that way.

 

Now I could not wait until I´m gonna test with my HD800 after some ”burn in”.:L3000:

post #1266 of 1427
My LC is dead quiet at full volume and no input. If it wasn't for the LED light you would think it was turned off.
Edited by Tribbs - 3/22/15 at 4:20pm
post #1267 of 1427

Ditto here, my LC is completely silent and I can hear how some tracks has noise while others are completely silent - usually for low bitrate and/or vinyl rips.

post #1268 of 1427
I'm thinking about building a second one with all the trimmings. Already ordered a PCB and a few boutique components. I need to find a clone case compatible with the clone PCB.
post #1269 of 1427

I'm on the verge of tears.

 

I visited an unfamiliar subforum in my local forum to ask about my replica watch, and I had nothing but condescending replies, snide remarks, and snarky responses, and most of them made fun of how "If you cannot afford to get a nice watch then take what you can get".

I'm no rich man, I have little money. It hit too close to home.

 

And then I came here, and there's nothing but positivity.

 

Thanks everyone, stay awesome. Though you people are strangers so far away, I feel welcomed as one of your own.

 

Sorry for the off topic post, but my chest is too heavy.

post #1270 of 1427

Guess you have not met some of the Lehmann Linear fans when the Lovely Cube just came out.

post #1271 of 1427
Quote:
Originally Posted by mikaelmark View Post

Whoaa, now I´ve found something very interesting!!L3000.gif

DT9205A is an multimeter that can also measure capacitors by capacitance (2nf - 200uF/ not sure about up to 2000uF) and measure transistors by hFE.

So this little marvelous thing can be just fine for matching those BD139, BD140 and BC550C, BC560C. And the price will only be about $10. You have to pay a LOT more, about $400 for a Fluke, but even soit can not measure hFE!

People selling those transistors matched at ebay, will have a lot more payed for them then unmatched.

http://www.head-fi.org/t/249447/what-dmm-you-use-to-match-transistors-hfe


Mikael Markstrom

Mikael, do you use this DT9205A meter for hFE? Does it work for matching the transistor?
post #1272 of 1427

I once had owned it.  顶。。。

post #1273 of 1427
Quote:
Originally Posted by Tribbs View Post


Mikael, do you use this DT9205A meter for hFE? Does it work for matching the transistor?

Yes, the DT9205A works really well for measure and pairing the hFE values for the BC55/60C and BD139/40-16, so do also several of my small cheap DVM´s I´m having.

 

The values differed quite a lot, especially for the BD139/40-16. Just be careful when measuring, as the hFE value will differ by temperature. It´s advise to using some (ESD) gloves or just wait for a while after touchind them before measuring - or just hold them equally long, it should be fine.

 

But I´m disappionted about the capacitor measuring with the DT9205A, as it did not work. Have compared with Fluke 177, 187 and also more expensive Fluke´s, and they do fine. When I did a claim for the DT9205A to the eBay-seller, I then payed for a new unit, and when that one did´nt arrived, the seller shipped two more units after i claimed. But I did´nt get those either. So, the seller promised me to repay me, but I does´nt get any money. But eBay costumer service helped me get my money back for the second payment I did.

Then I bought one more from another eBay-seller, but I was telled this unit was shipped back to the seller, and once again I get my money back.

 

Also, the DT9205A is´nt really accurate when measuring for example resistance or voltages.

post #1274 of 1427
Quote:
Originally Posted by kkaky37t View Post
 

I once had owned it.  顶。。。

Did your DT9205A measuring capcitance for capacitors? (see my earlier post I just did)

 

And why do´nt you have it now? Did it broke or have you sell it?

post #1275 of 1427
Quote:
Originally Posted by penmarker View Post
 

I'm on the verge of tears.

 

I visited an unfamiliar subforum in my local forum to ask about my replica watch, and I had nothing but condescending replies, snide remarks, and snarky responses, and most of them made fun of how "If you cannot afford to get a nice watch then take what you can get".

I'm no rich man, I have little money. It hit too close to home.

 

And then I came here, and there's nothing but positivity.

 

Thanks everyone, stay awesome. Though you people are strangers so far away, I feel welcomed as one of your own.

 

Sorry for the off topic post, but my chest is too heavy.

Clones/copies are often much cheaper and use to be made in China or equal. And for the price, the manufactures use to save as much as the can in the components using for the item. And therefore, clones are usually not at the same grade as the original product - and so is this headphone amp. You the eBay clones for about $40 will not be comparable with the original for about $1200. And that´s what this forum is for, to helping and get each other tips and recommendation and it´s to everyone to decide how much to spend and acknowlede how the final product will end up. For me, I´ve spend about $300 for each of my LC, and now it´s of an higher grade than the original. And it´s more enjoying to assemble for yourself, and then have that in your mind when listening to it!

 

So, you should feel very welcome to this forum - and why not build one for yourself? It must´nt cost so much to get a decent amp. for your headphones.

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