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The "Lovely Cube" Headphone Amp (Lehmann Black Cube Linear Clone) - Page 78

post #1156 of 1168

Now I found a store autemashop.com here in Sweden selling BD139/140-16 (ST) and BC550/560C (ON Semi) at ebay:

 

http://www.ebay.com/itm/111310652096?_trksid=p2055120.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

The prices are really affordable and they will ship to Europe and US.

 

I just bought 40 pcs BD1xx-16 and 100 pcs BC5x0C.

 

And I also have to say, when I upgraded my first Lovely Cube with RK27 volume pot, some polystyrenes and "snubbers" (0,1uF caps) to bypass the rectifier diods BYV27, the sound was getting much quiter.

 

So now I´m just waiting to start building my two new amp´s, just a few things left to get.

post #1157 of 1168

I have just received the transistors, BC550C and BC560C is On Semi and BD139-16 and BD140-16 is Fairchild (not ST Microelectronics).

 

But the BD´s do not have any metal survace at the back of them, please see pictures below. Do the Fairchild not have metal surface on their transistors? Will the heat dissipation for the heatsink be equally good?

 

 

 

/ Mikael Markstrom

post #1158 of 1168

I see that Fairchild warn for counterfeits: http://www.fairchildsemi.com/includes/sharedText/counterfeitPartsPolicyStatement.html

 

Here are also a picture of some LM337 that I have. May all those be genuine Fairchild, or are any of them maybe counterfeits?

 

/ Mikael Markström

post #1159 of 1168
Citação:
Postado Originalmente por DeGato Ver Post
 


Não existe o melhor ou o pior. Cada grau de seleção tem a sua finalidade. Geralmente -10 -16 ou B, a seleção C não tem nada em comum com o áudio. Ele vem das fabricantes e descreve apenas limites dentro dos quais um transistor especial de toda a massa terá sua hfe.

 

Quando se trata de BC5 ** no tampão sua hfe afecta a impedância de entrada do tampão. É importante se você usar OPA que não consegue lidar com carga pesada com um relativamente pequeno de impedância. Neste caso hfe do BC5 ** deve ser bastante elevada. Por outro lado, demasiado elevada hfe tem os seus inconvenientes. Outra coisa importante é hfe diagrama / atual. Dependendo da quantidade de corrente passa através de um transistor ou a sua temperatura a hfe irá variar. No melhor dos casos o desvio de hfe deve ser o menos possível em um determinado intervalo.

Também vale a pena considerar a deriva térmica ea capacidade interna de um bipolar entre seus pinos, se você quiser obter um resultado estável e previsível.

 

O PCB verde tem layout um pouco diferente no outro lado da moeda. Mas ainda não é o melhor. Eu estou trabalhando em minha própria revisão de um PCB com canais completamente separados com proteção de ouvido e filtros separados, reguladores de tensão, retificadores e para cada canal otimizado para componentes de áudio.

http://www.mightything.com/lc/images/BCLv2_alpha.jpg

 

Felicidades.

Olá 

Esta versão parece interessante, 
já tentei essa versão da dupla mono? 
joga bem, melhor do que Lehmann?

post #1160 of 1168
Quote:
Originally Posted by aneker View Post
 

Olá 

Esta versão parece interessante, 
já tentei essa versão da dupla mono? 
joga bem, melhor do que Lehmann?

It measures a bit better. More space and the overall performance is better. Personally, I prefer it over the original one. It also has important protection circuit for headphones. It's important in case if you have expensive or rare headphones :)

post #1161 of 1168

Plastic body is ok in some cases. I've seen genuine parts made like that.

In case if you are not sure about the origin it's better to send an e-mail with some photos to the company which produce those chips.

The same for Fairchild.

Quote:
Originally Posted by mikaelmark View Post
 

I have just received the transistors, BC550C and BC560C is On Semi and BD139-16 and BD140-16 is Fairchild (not ST Microelectronics).

 

But the BD´s do not have any metal survace at the back of them, please see pictures below. Do the Fairchild not have metal surface on their transistors? Will the heat dissipation for the heatsink be equally good?

 

 

 

/ Mikael Markstrom

post #1162 of 1168

What the OPAMP originally found in the Lehmann Black Cube Linear?

post #1163 of 1168

opa2134

post #1164 of 1168
Quote:
Originally Posted by DeGato View Post
 

It measures a bit better. More space and the overall performance is better. Personally, I prefer it over the original one. It also has important protection circuit for headphones. It's important in case if you have expensive or rare headphones :)

 

Could put some pictures so we can enjoy?

 

At the moment I am also building a version identical to the original with PRP resistors. I do not know what this is going but I've read somewhere that these resistors have a cooler and shrill sound!

post #1165 of 1168

I purchased the amp today, works well with the DT880. 

 

Which OPAMP recommended with this amp? 


Edited by FOXY - 6/16/14 at 2:42pm
post #1166 of 1168

The lower economy class: NJM2068 NE5532, OPA2134, OPA2604

 

 

Middle class: AD8620, OPA1612, LM741 (never used)

 

 

Top class: OPA627, LM4562 or LME49600/ 49720/ 49860, AD8066, OPA2227, THS4032 (my favourite, need´s 100nF cap between pin 4 & 8 for stabilization)

 

 

Those are dual OpAmp´s and ready for use directly at the board. If using single ones, such as AD797, you will need 2 of them and a Brown dog adapter. Also have in mind if they are DIL/ DIP or for survace mounting. Surface mounting are more tricky to solder, and you will need an adapter also (if you´re not a solution handy man like me and MacGyver :) see pictures below of some of my mod project´s)

 

http://tangentsoft.net/audio/opamps.html

 

It´s also possible to use a discrete OpAmp, such as Burson, John Hardy or Audio GD, but they´re very costy and bulky!

 

 

/ Mikael Markstrom

 

 

post #1167 of 1168

Edit: Sorry, also the OPA627 is single and will ned an adapter for using 2 IC´s.

 

Also, have in mind there are some single version OpAmp´s of those I listed, such as: OPA134 (instead for dual OPA2134), AD8610 (AD8620), THS4031 (THS4032) OPA1611 (OPA1612). There is some advantage, such as a bit better channel separation if using two single OpAmp´s, but the cost is a bit higher, it need´s more space at the board and more work to solder.

 

 

/ Mikael Markstrom

post #1168 of 1168

Arriva il mio ...


Edited by Laybar - Today at 2:27 pm
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