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The "Lovely Cube" Headphone Amp (Lehmann Black Cube Linear Clone) - Page 77

post #1141 of 1171

The CDIL BD139-25 and BD140-25 will have about 60% higher hFE than the -16 (original standard), and they are about 60% better then -10 (cheap ebay clones). And I think hFE will be important when used in audio.

 

I know there are some expensier voltage regulators for about $100, but the LM317 (negative) and LM317 (positive) are popular and used in many cirsuits - but be shure they are from known manufacturers, like Fairchild, ST Microelectronics etc, and not cheap china-clones.

 

For myself, I´m gonna use thermal compound for regulators and transistors heatsinks.

 

 

Best regards: Mikael Markstrom

post #1142 of 1171
Quote:
Originally Posted by mikaelmark View Post
 

The CDIL BD139-25 and BD140-25 will have about 60% higher hFE than the -16 (original standard), and they are about 60% better then -10 (cheap ebay clones). And I think hFE will be important when used in audio.

 

I know there are some expensier voltage regulators for about $100 I think discussed earlier in this post, but the LM317 (negative) and LM317 (positive) are popular and used in many cirsuits - but be shure they are from known manufacturers, like Fairchild, ST Microelectronics etc, and not cheap china-clones.

 

For myself, I´m gonna use thermal compound for regulators and transistors heatsinks.

 

 

Best regards: Mikael Markstrom

post #1143 of 1171

Actually mine sounds very good right now and I listen to it more than my other amps.  I've just built some amps and preamp's and found the more I lowered the noise floor the more information came through and

I wanted to push this one farther and see what it does.

 

The 317 and 337 are not bad and can be made even better with some circuit tweaks.  I'm not about to cut-up  this board to try adding them.  It will be easier for me just to build the low noise shunt regulators.  Here is an article on regulators and noise if your interested.  http://www.tnt-audio.com/clinica/regulators_noise2_e.html

 

There are some more articles in the EE magazine but most of that goes over my head.:confused_face_2:

post #1144 of 1171
Quote:
Originally Posted by mikaelmark View Post
 

Now I´ve contacted the manufacturer CDIL in India, and they can sell 200 pcs BD139-25 and 200 pcs BD140-25. But the shipping cost and bank transfer cost will be quite high. I think those will even be better (higher hFE) than the old Philips/ NXP!

 

I also gonna buy 50 pcs BC550C and 50 pcs BC560C. And I´ve also bought 8 pcs of Intertechnic Audyn True Copper 1,5uF (at least as good as Clarity Cap MR and almost up to Duelund and V-Cap TFTF/ CuTF)

 

As I just also bought hFE -meter, I´m gonna be able to match all of the above :o2smile:

 

So; do someone want any of the above from me? For Lovely Cube, it will use 2 pcs of each.

 

The Audyn True Copper costs about USD 120/ pair.

 

 

Best regards: Mikael Markstrom


Hi Mikael,

The advantage of Philips BD's is not in their hFE. The hFE of BD's in the LC is not important because they are in a buffer circuit.

 

For those of you guys who has a little humm from the amplifier, consider the nippon's suggestion: http://www.ebay.com/itm/High-end-stereo-Class-A-headphone-amplifier-PCB-1piece-/221131370084

I've built several LC clones and I have good reports from the owners who have their amps based on a newer revision of the PCB.


Edited by DeGato - 4/10/14 at 2:42am
post #1145 of 1171

But why does many people says the BD-1xx-16 and BC5x0C is better than BC-1xx-10 and BC5x0B. And that the -16 is the HiFi section?

 

The only thing I can see differ is the hFE.

 

Do you also think the hFE is not important for the BC5x0?

 

Also, What is the advantage for tis PCB? Is it a newer revision or thincker copper connections? And will it have any difference in connections/ printing diagram? (I have the standard blue China PCB, YS-AUDIO)

 

 

Best regards: Mikael Markstrom

post #1146 of 1171
Quote:
Originally Posted by mikaelmark View Post
 

But why does many people says the BD-1xx-16 and BC5x0C is better than BC-1xx-10 and BC5x0B. And that the -16 is the HiFi section?

 

The only thing I can see differ is the hFE.

 

Do you also think the hFE is not important for the BC5x0?

 

Also, What is the advantage for tis PCB? Is it a newer revision or thincker copper connections? And will it have any difference in connections/ printing diagram? (I have the standard blue China PCB, YS-AUDIO)

 

 

Best regards: Mikael Markstrom


There is no the best or the worst. Every selection grade has its purpose. Generally -10 -16 or B, C selection has nothing in common with audio. It comes from the manufacturers and describes just limits within which one particular transistor from the whole bulk will have its hfe.

 

When it comes to BC5** in the buffer their hfe affect the input impedance of the buffer. It is important if you use OPA which can't handle heavy load with a relatively small impedance. In this case hfe of the BC5** should be quite high. In the other hand, too high hfe has its drawbacks. Another important thing is hfe/current diagram. Depending on how much current flows through a transistor or its temperature the hfe will vary. In the best case the drift of hfe should be as less as possible in a given interval.

It is also worth to consider the thermal drift and the internal capacitance of a bipolar between its pins if you want to achieve a stable and predictable result.

 

The green PCB has slightly different layout in the flip side. But it is still not the best. I am working on my own revision of a PCB with completely separated channels with headphone protection and separate filters, voltage regulators, and rectifiers for each channel optimized for audio components.

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

 

Cheers.

post #1147 of 1171
So; What is the difference between the old Philips/ NXP BD1xx? Why are they better the newer Fairchild, ST Microelectronics, On Semi, CDIL etc?

/ Mikael Markstrom
post #1148 of 1171
Quote:
Originally Posted by mikaelmark View Post

So; What is the difference between the old Philips/ NXP BD1xx? Why are they better the newer Fairchild, ST Microelectronics, On Semi, CDIL etc?

/ Mikael Markstrom

Some explanation is here: http://www.diyaudio.com/forums/parts/97030-bd139-16-bd140-16-anyone-use-these-transistors.html

post #1149 of 1171

Thank´s DeGato!

 

I see this green ebay PCB will have thicker copper inside, 4 times normally, they said. Maybe that´s a big advantage also.

 

What do you mean with "flip side" of the PCB? If it has a different layout, will it require different components or values than the standard BCL/ Lovely Cube?

 

For the BD140, I have some old genuine Philips  - but they are just BD140-10. Do you think those will do better in this circuit then new versions of BD140-16, like ST, On Semi etc?

 

And is there any of the new BD1xx-16 to prefer/ will any of the following be better than the other: ST Microelectronic, Fairchild, On Semi, CDIL, Taiwan...?

 

Also, if the hFE for those will not be important in this circiut, still I guess it will be important to match them, by use all 4 ones with similar hFE and mabye also measure them by capacitance and resistance?

 

http://www.wikihow.com/Test-a-Transistor

 

 

Thank´s in advance: Mikael Markstrom

post #1150 of 1171
Quote:
Originally Posted by mikaelmark View Post
 

Thank´s DeGato!

 

I see this green ebay PCB will have thicker copper inside, 4 times normally, they said. Maybe that´s a big advantage also.

 

What do you mean with "flip side" of the PCB? If it has a different layout, will it require different components or values than the standard BCL/ Lovely Cube?

 

For the BD140, I have some old genuine Philips  - but they are just BD140-10. Do you think those will do better in this circuit then new versions of BD140-16, like ST, On Semi etc?

 

And is there any of the new BD1xx-16 to prefer/ will any of the following be better than the other: ST Microelectronic, Fairchild, On Semi, CDIL, Taiwan...?

 

Also, if the hFE for those will not be important in this circiut, still I guess it will be important to match them, by use all 4 ones with similar hFE and mabye also measure them by capacitance and resistance?

 

http://www.wikihow.com/Test-a-Transistor

 

 

Thank´s in advance: Mikael Markstrom

The green PCB require the same components as the blue one. In the original design of the BCL there are just minor changes in capacitors. "Flip side" - the bottom side.

As for the "modern" BD's, I would choose between ST Microelectronic, Fairchild or On Semi (try some of them, measure and listen).  The matching process for small power transistors described here: http://www.diamondstar.de/transistor_matching_bjt.html For medium power transistors you should increase IC (collector current) during the matching process for proper results (consider the same as in the amplifier). Matching capacitance is not important, just keep it as low as possible.

 

Cheers.


Edited by DeGato - 4/12/14 at 5:09am
post #1151 of 1171

How about these: http://www.ebay.com/itm/50PCS-BD139-TRANSISTOR-NPN-1-5A-80V-TO126-NEW-GOOD-QUALITY-TO2-/121119586369?pt=LH_DefaultDomain_0&hash=item1c334a3841

 

Looks like those comes in the ebay-kits, and are maybe not original NXP. But it would be nice to have so many when matching.

 

 

/ Mikael Markstrom

post #1152 of 1171

These are fakes. I've bought the similar transistors which now I have no idea where to use. Better use Farnell, DigiKey, Mouser for component purchase.

post #1153 of 1171
post #1154 of 1171

http://de.mouser.com/Search/Refine.aspx?Keyword=bc550

Why don't you use official reliable suppliers?

post #1155 of 1171

Now I´ve received all the capacitors, and measured all of them. The Mundof MLytic 10.000uF are +- 20%, and they measured between 9.33x to 10.18x, and that is within 10%. But when I matched them, all was paired within 3,5%. And thre pairs measured exactly the same with two decimals like 9,69. Quite impressive!

 

Also, the Silmic II 470uF 50V and Muse KZ 1.000uF 50V measured well, paired 2pcs and 4pcs.

 

I also bought 2pcs of the Nippon´s recommended PCB´s from Jim´s Audio. Now I´m just waiting for the Audyn True Copper 1,5uF, that I´ve bought from europe-audio.com 6 weeks ago, they´re still backorder.

 

So as I told befor, if someone want to buy anything of my stuff, please tell me. I have a lot more than I need :o2smile:

 

It´s also possible to buy a complete kit, unsoldered or soldered with your choosed compontents - I will give a nice deal, course I´m not doing this to earn money. Just because it´s fun and that I have bought too much to get better prices! I will use unleaded RoHS -solder and have good soldering skills. I have just sold one complete soldered kit with OPA627 in Class A.

 

 

Best regards: Mikael Markstrom

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