[Tribbs]

Regarding the gain setting of the DIP switches:
 
If the above photo accurately depicts the settings.
White should designate the toggle and black should be interpreted as the void.
 
And, they are binary!  <D'oh!>
 
  0 dB = Down|Down = Off|Off = "00" binary = "zero" decimal
10 dB =     Up|Down = On|Off = "10" binary = "two" decimal
18 dB = Down|Up     = Off|On = "01" binary = "one" decimal
20 dB =     Up|Up     = On|On = "11" binary = "three" decimal
  [size=medium]=[/size] Down | Down = Off | Off = 0 dB
 

 

[miky2011]

Hi Francisdemarte,

0db = lovely cube only pass the sound without amplification?

Its that true?

I have doubts about that ...

 

[francisdemarte]

Gain by definition is "an increase in"
 
Technical definition of gain:
 
http://whatis.techtarget.com/definition/0,,sid9_gci499581,00.html
 
 
The amplification factor, also called gain , is the extent to which an [size=10pt]analog[/size][size=10pt]amplifier[/size] boosts the strength of a [size=10pt]signal[/size] . Amplification factors are usually expressed in terms of [size=10pt]power[/size] .
 
The [size=10pt]decibel[/size] (dB), a [size=10pt]logarithmic[/size] unit, is the most common way of quantifying the gain of an amplifier. For power, doubling the signal strength (an output-to-input power ratio of 2:1) translates into a gain of 3 dB; a tenfold increase in power (output-to-input ratio of 10:1) equals a gain of 10 dB; a hundredfold increase in power (output-to-input ratio of 100:1) represents 20 dB gain. If the output power is less than the input power, the amplification factor in decibels is negative. If the output-to-input signal power ratio is 1:1, then the amplification factor is 0 dB

 

[miky2011]

 
I still have the problem.
 
With the gain at 0db. I have not amplification. I have to put the volume to maximum to hear the same volume as I listen to my Sansa Clip + directly. Even a little less with "lovely". 
 
With the gain to 10, 18 and 20dB I have changes in the output sound. I have SOME LITTLE amplification but I have yet to set the volume to maximum to have enough volume to hear worthily.
 
I have to say that I don't have hearing problems. ! My Lovely does not amplify the input signal !!!
 
Attached photos of my PCB front and bottom.
 
https://www.dropbox.com/gallery/2747771/1/Lovely?h=53f1a2
 
 
* Will note that I've made ​changes of components for originals equivalents. All changes with same capacity in the case of capacitors and the same resistance in the case of resistors ( I've only changed the value of the four 1K2 resistances by 1K5).
 
* I changed the LM317 and LM337 by originals 337T and 317T with bigger heatsinks.
* I changed BD139 and BD140 by BD139-16S and BD140-16S.
* I changed BC550 and BC560 by BC550CG and BC560CG.
* Input bigger capacitors have different format but are same capacity and voltage that stock lovely clone. Smaller input capacitors are MKP 22nF/1000V. (i had tested with originals and i had the same problem).
* 22nF opamp capacitors are KP1837.
* 100pF opamp capacitors are LCR FSC (100pF/160V./2,5%)
* Opamp is original 2134 . With 2134 and 2111AM lovely stock i have the same problem.
 
 
I'm pretty worried. I do not understand what is happening. Any suggestions.???
 

 

[Tribbs]

Miky,
 
Did you try another source other then your Sansa Clip?

 

[francisdemarte]

Take your time and go over and reflow all your solder joints. Including the ones to your RCA sockets.
 
Make sure the components you replaced are solder in the right way. Especially the regulators, the 3 legs, Vin Vout and G are in the right way
 
Your Fuze should be set to max volume. 
 
Set that gain to something above 0. I suggest 10 or 18 since it's easier to notice 1 up and 1 down switch.

Use the stock opamp.
 
Do you have a digital multi-meter? You might need to make sure the voltages are correct. I'm not sure where all the test points are try emailing stephen for some tips, and/or PM BlaBlaBla.
 
 
 
 

 

[miky2011]

 
Hello,
      here I am with my problem.
      I have reviewed all solders. I have tested dip switches for gain function properly off and on.
      All components are in place. I have measured voltages with digital multimeter:
 
     - BD140 BD139:              collector-base .- 14v.
                                           collector-emitter .- 14v.
                                           base-emitter .- 0.6v.
 
 
     - BC550C BC560C:         collector-base .- 15v.
                                          base-emitter .- 0.6v.
 
     - LM317T LM337T :          Adj .- 13.8 v.
                                           Input .- 21.6 v.
                                          Output .- 15.0 v. (-15.0 for LM337T)
 
     - OPAMP 2134 is receiving 14.7 v. 
 
    I have replaced the opamp with the stock. I have changed the sound source by putting my phone even the maximum volume.
    Despite all this I still have to put the volume to maximum to hear the music. Even on 20db. gain !!.
    With 0dB. even I noticed that the sound is attenuated.
    
    HELP !!  

    
 
    

 

[francisdemarte]

Sorry for  your troubles, I know your pain, the it took me a month to get my first DIY DAC working correctly.
 
You've hit my limit on technical expertise. Try posting to the DIY forum or email the seller at seaipoju@yahoo.com.
 
Another quick test is to make sure the cable you are using between your Fuze and amp is good.
 
Have you tried another source, like a cd or dvd player something with more output voltage than your Fuze.
 
Is there a way you can check if the opamps have been damaged?
 
Maybe your volume control may be defective. Unforunately, the only way I know of testing one is to remove it from the board test the resistances when you turn it.
 
 

 

[francisdemarte]

PS also try the matrix m stage thread.

 

[BlackstoneJD]

Does the Lovely Cube Premium even hold a candle to the original Lehmann? Has anyone done an actual sonic comparison?

 

[francisdemarte]

BlackstoneJD:
 
Very few people have heard both, the few impressions that I've read they indicated that they do sound different. It's impossible to judge audio equipment by someone's opinion over the internet. You have to judge for yourself.
 
Are you in Chicago? There is a head fi meet coming up in a few weeks in Northbrook. I went to one last year, my first ever, and there is a lot of amazing equipment to try out. Details here: http://www.head-fi.org/t/574527/chiunifi-5-the-official-and-annual-chicago-area-headphone-get-together-november-12th-2011 Unless my wife schedule me for something else, I'll probably show up this year too.
 
If you want PM me and I'll lend you my cheap plastic box build of the Lovely Cube so  you can get an idea of what it sounds like.
 
 

 

[Tribbs]

You started this thread Matrix Vs Lehmann 18 months ago.
 
Also check out the arguments here: [size=x-small]http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures[/size]
 
[size=10pt]If you are seeking a comparison in your consideration of purchasing a Lehmann BCL why not buy both, make the comparison yourself and sell one?[/size]
 
[size=10pt]Personally I'd rather spend my cash on another set of cans.  [size=10pt]I just can't justify what, if any, added value the price of the BCL brings over a Matrix/Lovely clone.[/size][/size]

 

[francisdemarte]

Here is probably the best comparison post I've seen between the Lehmann and the Lovely Cube:
 
http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures#post_7364890
 
 

 

[Maverickmonk]

Looking at assembling a Lovely cube to mod and play around with, but I was wondering: If I wanted to be able to use it as a pre-amp, would I just reroute the leads to one of the headphone jacks to RCA's on the back panel (twisted and shielded, maybe coaxial pairs)? If so, which jack should I use for the preamp? (I read that one is line out-muted and the other is line-out?).  Also, would it be adventagous to create a simple grounded-shield to cover the transformer?

 

[chetlanin]

How are things, miky?
 
 If the good advices from francisdemarte has not brought a solution, I think it might be an idea to check if the signal is present at the output of the opamp. You could use at 1k sinus wave at the input (and turn up the volume a bit). A multimeter should show the AC signal at the points shown in the picture (which are directly connected to the output pins of the opamp). You should easily be able to get lots of Volt out of the chip.
 
For that matter you send music into it and take the signal from here,  and (together with a ground lead) connect to a pre-amp input).
Preferably connect through a 100-1000 Ohm resistor close to the output, in this case).
 
I strongly suspect that something is wrong with the op amp or its connections.
 
A pair of completely wrong resistor values is theoretically also a possibility, in a case like this.
 
 
 

 
 
P.S.
In principle this should be a very easy case! The fault showing in both channels, so it must be something very fundamental or simple, and one will always get to the root of it with a few checks or measurements. (more difficult are often faults which are appearing sporadically).