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The "Lovely Cube" Headphone Amp (Lehmann Black Cube Linear Clone) - Page 7

post #91 of 1171

Quick comparison with the Little Dot MK VII+. 

 

At about $100 cheaper than the LD with shipping (complete cost of my build), the option of op amp rolling is what makes this amp so great.  Not just the cost.  With the two ICs, stock and the LM4562, this amp's sound quality is very close to the LD.  When biasing the LM4562 into class A, the Balance Lovely Cube "BLC" I think is quite equal to the LD.  There is some give and take.  Little differences between the two but I am very happy with either one.  With this quick comparison I won't be getting into the specifics of the sound but I can say that either one of these amps is easily worth more than what they cost.

 

Running the BLC with the Burson dual op amps will put it's cost close the the LD but the sound is better.  It may not be apparent at first listen but then you begin to pick up things like better micro detail, sound stage, headroom, separation and placement.  From  what I'm hearing, the LD might end up on the for sale forum.

 

post #92 of 1171


 

Quote:
Originally Posted by sunneebear View Post

 

Anyone with this amp or the M-Stage think it runs kind of hot?


I agree - received my M-Stage early in the week, and have been doing burn in and preliminary listens...

 

It definitely runs very warm - the buffer stage is a nice and toasty class A clearly!

 

I have yet to fit Purrin's class A mod - and I have a collection of opamps to try out.... would love to bias them further into class A than the initial adapter (provided very handily by JTAM along with the M-Stage) - but I can now see why he was being conservative, given the warmth of the sealed case without the class A mod.

 

I have spare heatsinks and such lying around - but given a sealed case, already running warm - benefit is likely to be limited

 

I will be looking on to see what your cooling solution looks like - and am thinking about how to let air in and out of the M-Stage case without destructive alterations

post #93 of 1171
Thread Starter 
Quote:
Originally Posted by sunneebear View Post

Finally put the finishing touches on my balance Lovely Cube.  It's a cheap case but hey it works.

 

Face.jpg

 

 

 

Where did you get the case? Looks like the perfect size for my planned balanced LC and Opus DAC.

 

My Lovely Cube doesn't get very hot at all, and it's running off the 18V AC power supply from my EF5 driving a pair of 300ohm HD650's...

 

 

 

post #94 of 1171


 

Quote:
Originally Posted by francisdemarte View Post



 

Where did you get the case? Looks like the perfect size for my planned balanced LC and Opus DAC.

 

My Lovely Cube doesn't get very hot at all, and it's running off the 18V AC power supply from my EF5 driving a pair of 300ohm HD650's...

 

 

 

http://www.customaluminumboxes.com/  Really great company to deal with.  Yes my case is custom made.  You select the type, size, thickness and some other things and you get a quote.  Mine only cost $32 shipped.  Much much better than those cheap project boxes that are quite expensive.  I chose the medium thickness option and it's very sturdy, no flex at all.  I may try the thickest option if I order again.  The face plate is a 3/8 acrylic scrap I had lying around.

 

Could it the Burson op amps that's making it hot.  Let me try the stock ones tonight.

post #95 of 1171
Quote:
Originally Posted by dlaloum View Post
I will be looking on to see what your cooling solution looks like - and am thinking about how to let air in and out of the M-Stage case without destructive alterations


One option is to put holes in like http://www.head-fi.org/forum/thread/513379/diy-charity-raffle-twisted-pear-ventus but larger holes.  The other is to cut out the whole area and attach a grill of some sort inside.

post #96 of 1171

I ran the stock IC and the LM4562 for about an hour.  The amp runs just as hot with them as the Burson.

post #97 of 1171

Anyone tried the bias mod? Wich one do you think is the best?

post #98 of 1171

Lookup purrin's posts....

 

I have the mod ready to go but am currently listening stock to get to know the base sound before I go changing it!

post #99 of 1171

I cannot find it.

But is the 3.49 bias better than default? If so should i go for it to have a balance between performance/safety?

post #100 of 1171

The opamps I've tried so far sound better when biased to Class A. Albeit in varying degrees.

post #101 of 1171

Hello

I greet all here in forum
sorry for bad english I only had three years of the language at school and I was not the best :-)

I have "lovely" before getting two days
I bought everything including: alluminum box, connections, everything

after 13 days, it was super na Germany

the supplier as I said super packed, everything was great and so nice fast objectively

I have connected it directly to NAD CD player, analog output

12 hours I hear it and tell me everything is wonderful! The wide, airy, accuracy, better than Matrix M-Stage (I immediately sold)

my headphones hifman HE5 works very well with "Lovely"

I write more on this later

post #102 of 1171
Quote:
Originally Posted by Cya|\| View Post

I cannot find it.

But is the 3.49 bias better than default? If so should i go for it to have a balance between performance/safety?


Honestly, running with a 3.0mA or even 2.0mA bias is probably good enough to have the op-amp be in class A (and have its corresponding positive traits) considering its feeding a diamond buffer output stage.  The only reason to go above that is to tweak the sound balance, depending upon op-amp.  LM4562 / LME49720 get warmer with more current.  OPA2107 gets bright until 5mA, then it starts to get darker (6-7mA which is a lot).  I use the touch-test to check for how hot the chip gets, although I should mention it's not reliable since the transistors generator a lot more heat which tends to spread throughout.  The class A biasing only affects the chip, not the output stage (transistors).

 

I'm am currently running 3.3k resistors with LM4562.  I'm now tending to run with higher value resistors (less current) because it seems going the other way tends to reduce dynamics and make things sound flat.  I'm seriously considering the use of 1N5xxx series CRDs instead of resistors - if I don't just grab the latest Burson's first.

post #103 of 1171

Noooo - don't do that! I want a comparative report on the crd option!

post #104 of 1171
Quote:
Originally Posted by stau View Post


12 hours I hear it and tell me everything is wonderful! The wide, airy, accuracy, better than Matrix M-Stage (I immediately sold)
 


Welcome to Head-Fi stau.  Good to hear a M-Stage and Lovely Cube comparison. 

post #105 of 1171
Quote:
Originally Posted by purrin View Post


 if I don't just grab the latest Burson's first.


I emailed Burson about the the safety of class A biasing.  The reply I got is that not only is it safe but I should get the same benefits as a IC.  Not so.  I am using 3.9 resistors on a adapter and the Bursons became extremely airy.  Focus and definition are lost.  I have not tried other values but direct seems to be more than good enough for now.


Edited by sunneebear - 9/26/10 at 4:51am
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