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The "Lovely Cube" Headphone Amp (Lehmann Black Cube Linear Clone) - Page 69

post #1021 of 1171

My lovely cube has a buzz when turned on, only heard through headphones. It does not play music. I have no idea how to fix it, so I kept it in storage for 3 years.

 

I need money quickly, here I am selling it.

 

http://head-fi.org/t/653920/lovely-cube


Edited by Comfortable - 3/4/13 at 7:02am
post #1022 of 1171

Modifying a Lovely Cube to take it close to the Lehmann SE version.....

 

Briefly...I have taken a Lovely Cube, replaced some parts, built an outer case and made my own version of a LEHMANN AUDIO BLACK CUBE LINEAR SE headphone amp.

 

On the Lehmann website, the SE version details are as follows:

 

Power Supply Caps: Mundorf MLytic
Signal Capacitors: Mundorf MCap

Internal Cabling:

Feet:

Fuse:

Mogami Neglex

SSC vibration absorbing feet

AHP Fuse

 

Right!

 

I bought a Lovely Cube which had been assembled by someone else, from 'a well known auction site', and when it arrived, it sounded VERY good. I could not believe that on this clone, even the circuit board said LEHMANN, and the front panel, instead of being printed with the words 'LOVELY CUBE', actually said Lehmann Audio Black Cube Linear'. Naughty.... :-)  It sounded excellent with my HD650s and my Beyer T1s...

 

However, I had been reading about the SE changes that Lehmann had used in their latest version, and thought that I'd have a go at modding it.....

The changes I made were:

1. Replace the 2 Power supply caps with Mundorff AG Electrolytics.

2. Replace the 6 capacitors at the front of the main board with larger Panasonic FC types.

3. Replace the input caps with the same ones that Lehmann uses: Mundorff 2.2uF polypropylenes.

4. I also decided to upgrade the Toroidal transformer to a higher VA. I changed it from a 30VA to a 60VA. The original Lehmann and Lovely Cube ones are 15-0-15s. However, my Lovely Cube had arrived with a 18-0-18 transformer, so I decided to stick with that voltage. I JUST managed to cram it in!

5. I also replaced the input cables with Mogami Neglex Quad microphone cable, which is similar to that which Lehmann use on the SE.

6. I tried an OPA2111AM IC and loved it, but I thought I could go one better. I put in a Class A resistor Bias board. That helped! Then I thought why not reduce crosstalk even further by using MONO chips, the OPA111AM on a Stereo to Mono board. The result is in the pics.

7. Out of sight, I put a pure silver audio fuse, hidden away in the fuseholder, just like Lehmann do....

8. Under the circuit board, I bypassed the 2 main capacitors with 2 small polystyrene caps.

9. I used car sound deadening panels to help deaden the main metal panels of the casing.

10. I made an outer case out of perspex (acrylic) sheet 3mm thick. I have access to a laser cutter, so this was easy. Lehmann use an extruded aluminium outer case, veneered, so I veneered my acrylic on the top and sides with genuine Santos Rosewood. I used a cabinet scraper to get it smooth, and then gave it 2 thin coats of finish.

11. I masked the case and spray painted the inside of the case front silver.

12. I bought some SSC feet, the same ones that Lehmann use on their SE, and fitted those.

13. The inner case is fitted to the outer case using the ORIGINAL bolts which had held the original rubber feet.

 

What do you reckon? :-)

 

The first pic is of the beautiful, genuine, Lehmann SE headphone amp range....

And below, its innards....

 

 

 

And here is my home-made, not for profit own version....

 

Santos Rosewood veneered casing...

 

...have to fix those scratches on the silver interior....

 

...you can see the edge of the black acrylic casing...

 

SSC isolation feet...

 

...outer casing (above in pic) and main casing (below) separated for clarity...

the black 'mesh appearance material is self adhesive damping material for car panels...

 

...ditto...

 

2 Mundorff Electrolytics, 2 Mundorff M-cap polypropylenes, larger transformer and Mogami Neglex Quad cable...

On the underside of the circuit board there are several high quality high tolerance polystyrene capacitors in parallel with all the electrolytics.

ALSO....If you look at the edge of the transformer, there appears to be a grey line round it. This is an RFI/EMI shield.

I bought the material which is a tight weave plastic coated material and formed it into a tube which fits neatly over the transformer,

I don't know if it helps but I doubt it does much harm!

 

6 Panasonic FC capacitors, and the dual mono IC board with 2 OPA111AM chips, sitting atop a Class A BIAS adaptor...

 

Clearer view of the dual mono IC and Class A adaptor underneath...

 

Mogami Neglex Quad cable. This is REALLY good cable!

 

The changes have REALLY opened up the sound.....cymbals shimmer and bass notes are clearer but feel deeper... separation between instruments and voices is more naturally pronounced, but most importantly, the Pace and the sense of people playing together is there. It almost sounds as if the players are more professional, because the sound, whilst clearer, is more coherent.

 

Now I need to look at a few other issues....

The next thing I want to look at is the output transistors, the BD139 and BD140. I have a load of genuine Philips BD140-16s, but no BD139s. I have loads of non-Philips stuff, but if anyone has any Philips BD139-16s, I will willingly swap some Philips BD140-16s for them....

Then there's the other elec components....not sure which to change as a priority...any suggestions, guys?


Edited by ictmanager - 4/28/13 at 12:11pm
post #1023 of 1171

waiting for my cube clone circuit board to arrive, cannot figure out how I could put in those mundorfs and still have those square red capacitors also, have checked the board on the lovely cube website.

post #1024 of 1171
Quote:
Originally Posted by ictmanager View Post

Modifying a Lovely Cube to take it close to the Lehmann SE version.....

 

I have taken a Lovely Cube, replaced some parts, built an outer case and made my own version of a LEHMANN AUDIO BLACK CUBE LINEAR SE headphone amp.

 

I bought a Lovely Cube which had been assembled by someone else, from 'a well known auction site', and when it arrived, it sounded VERY good. I could not believe that on this clone, even the circuit board said LEHMANN, and the front panel, instead of being printed with the words 'LOVELY CUBE', actually said Lehmann Audio Black Cube Linear'. Naughty.... :-)  It sounded excellent with my HD650s and my Beyer T1s...

 

However, I had been reading about the SE changes that Lehmann had used in their latest version, and thought that I'd have a go at modding it.....

The changes I made were:

1. Replace the 2 Power supply caps with Mundorff AG Electrolytics.

2. Replace the 6 capacitors at the front of the main board with larger Panasonic FC types.

3. Replace the input caps with the same ones that Lehmann uses: Mundorff 2.2uF polypropylenes.

4. I also decided to upgrade the Toroidal transformer to a higher VA. I changed it from a 30VA to a 60VA. The original Lehmann and Lovely Cube ones are 15-0-15s. However, my Lovely Cube had arrived with a 18-0-18 transformer, so I decided to stick with that voltage. I JUST managed to cram it in!

5. I also replaced the input cables with Mogami Neglex Quad microphone cable, which is similar to that which Lehmann use on the SE.

6. I tried an OPA2111AM IC and loved it, but I thought I could go one better. I put in a Class A resistor Bias board. That helped! Then I thought why not reduce crosstalk even further by using MONO chips, the OPA111AM on a Stereo to Mono board. The result is in the pics.

7. Out of sight, I put a pure silver audio fuse, hidden away in the fuseholder, just like Lehmann do....

8. Under the circuit board, I bypassed the 2 main capacitors with 2 small polystyrene caps.

9. I used car sound deadening panels to help deaden the main metal panels of the casing.

10. I made an outer case out of perspex (acrylic) sheet 3mm thick. I have access to a laser cutter, so this was easy. Lehmann use an extruded aluminium outer case, veneered, so I veneered my acrylic on the top and sides with genuine Santos Rosewood. I used a cabinet scraper to get it smooth, and then gave it 2 thin coats of finish.

11. I masked the case and spray painted the inside front silver.

12. I bought some SSC feet, the same ones that Lehmann use on their SE, and fitted those.

13. The inner case is fitted to the outer case using the ORIGINAL bolts which had held the original rubber feet.

 

What do you reckon? :-)

 

The first pic is of the beautiful, genuine, Lehmann SE headphone amp range....

 

And here is my home-made, not for profit own version....

 

Santos Rosewood veneered casing...

 

...have to fix those scratches on the silver interior....

...you can see the edge of the black acrylic casing...

 

SSC isolation feet...

 

...outer casing (above in pic) and main casing (below) separated for clarity...

 

...ditto...

 

2 Mundorff Electrolytics, 2 Mundorff M-cap polypropylenes, larger transformer and Mogami Neglex Quad cable...

 

6 Panasonic FC capacitors, and the dual mono IC board with 2 OPA111AM chips, sitting atop a Class A BIAS adaptor...

 

Clearer view of the dual mono IC and Class A adaptor underneath...

 

Mogami Neglex Quad cable. This is REALLY good cable!

 

The changes have REALLY opened up the sound.....cymbals shimmer and bass notes are clearer but feel deeper... separation between instruments and voices is more naturally pronounced, but most importantly, the Pace and the sense of people playing together is there. It almost sounds as if the players are more professional, because the sound, whilst clearer, is more coherent.

 

Now I need to look at a few other issues....

The next thing I want to look at is the output transistors, the BD139 and BD140. I have a load of genuine Philips BD140-16s, but no BD139s. I have loads of non-Philips stuff, but if anyone has any Philips BD139-16s, I will willingly swap some Philips BD140-16s for them....

Then there's the other elec components....not sure which to change as a priority...any suggestions, guys?

Love the design. Aesthetically simple and classy! great work there

post #1025 of 1171

Thank you for your appreciative comment!

post #1026 of 1171

I am also starting to build one

post #1027 of 1171

Let me know if you want any advice about parts or building, etc....

post #1028 of 1171

Many thanks for the offer, so glad to see someone who does not replace input capacitors with a piece of wire, already wondering if you can buy  Mogami Neglex cable by the metre. 

post #1029 of 1171

Mogami Neglex QUAD cable IS available on the net. My transformer was from a certain auction site, and HifiCollective are great for caps. Stephen at Lovely Cube is VERY helpful and gives great advice. The dual mono IC board was also a Buy It Now...about £3 I think.

 

Get the cable in the UK here:

 

http://www.hhb.co.uk/product_list.php?section=124

 

I bought 6 used patch cables with stereo 1/4" jacks for very little and sacrificed one of them for the cause!

post #1030 of 1171

Quite pleased I have found the enclosure for sale on Alibaba, as Stephen will not sell it on it's own.

 All the enclosures on Ebay that are large enough are just a little too spacious.

looked at that Mogami Neglex cannot believe it is less than 5mm diameter, your photo is so deceptive, also looked at the cable on Hificollective site, can hardly believe the price of some of them.

Still compiling the list of parts I need at the moment with the help of BlaBlaBla 

post #1031 of 1171
Quote:
Originally Posted by timjar View Post

Quite pleased I have found the enclosure for sale on Alibaba, as Stephen will not sell it on it's own.

 All the enclosures on Ebay that are large enough are just a little too spacious.

looked at that Mogami Neglex cannot believe it is less than 5mm diameter, your photo is so deceptive, also looked at the cable on Hificollective site, can hardly believe the price of some of them.

Still compiling the list of parts I need at the moment with the help of BlaBlaBla 

Timjar, if you are in the UK, I will send you some of the Mogami I used...and you are correct, the cable is around 5-6mm diameter. The cable used in the Lehmann SE version is Mogami, but it's not the Quad cable I used, which has 4 cores, twisted together, so provides some RFI rejection. I have some spare and can send you enough for the job free of charge if you IM your address to me.

post #1032 of 1171

Can you send me a link to the Alibaba page where you found the enclosure, please?

post #1033 of 1171

I have already emailed to check if a black front panel is available, but unfortunately it is not.  http://www.aliexpress.com/item/DIY-Headphone-amplifier-case-amp-chassis-enclosure-JR001/578840933.html

post #1034 of 1171

I was lucky. The clone I bought, which I am still modding, was built in Hong Kong by a guy who had made several....and he had been naughty enough to even copy the official logo onto the front panel. Even the circuit board had 'apparently' proper markings...

But although it was very good, the mods that are outlined in Head-fi, and the mods I have decided to do, have pushed it ito a different league altogether.

I use Grado PS-1s, Beyer T1s, Sennheiser HD650s and....Sony MDR-XB500s...cheap but really quite good! (although I have an ongoing 'beef' with Sony so I generally avoid their products... :-)  )

post #1035 of 1171
Quote:
Originally Posted by timjar View Post

I have already emailed to check if a black front panel is available, but unfortunately it is not.  http://www.aliexpress.com/item/DIY-Headphone-amplifier-case-amp-chassis-enclosure-JR001/578840933.html

Yeah, it's not brill, is it!

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