The "Lovely Cube" Headphone Amp (Lehmann Black Cube Linear Clone)
Jan 6, 2012 at 10:39 AM Post #961 of 1,624
Hi there,
 
After a pair of weeks of listenig, I tell you my impressions about the LC.
The most surprising things about this amp are the differences I can hear between my 3 favourite headphones, which I know very well:

D5000 -
Great matching! This headphone is very warm and bass oriented, but the coupling with LC generate a perfect balance between all range of sound.
Trebles are really precise, voices are great, the low range gets less bloomy, producing a warm and pleasant sound.

K701 -
Not so good as D5000 . The middle-high range, strongest point of this headphone, becomes tinny and unless extended as canned. Low range, weak point of the AKG sound, becomes worse, and the headstage (another great AKG characteristic) gets smaller.

Sony MDR 7509 HD -
Unrecognizable! The high range is analytic but becomes much cold , middle range is backward, and the low range is too much emphasized but totally out of control!
Normally they are really precise, the opposite of what I heard with LC, I don't like it.

This is everything about headphones, let's talk about opamps!
By changing opamps, you can surely hear sound differences, but they are not so incisive and the don't change too much what I
said about headphones.

NE5532 famous opamp, it gives out an equilibrate sound, but it's a pretty normal component, not magic as I heard.

OPA6104 better than NE5532, linear and accurate on the high range.

OPA2604 and LME47920 *
they are pretty similar and very pleasant, they also mix very well the low and the high range giving a warm sound.
*without the box, this opamp has a little problem, I heard some treble distortion, which disappeared by closing the box.

OPA627 accurate, balanced, perhaps tending warm, detailed, it's not always the best choice because sometimes it seems to be "away" without personality

OPA2111AM the most detailed in the middle-high range, maybe a bit cold ant too much bright.
 

CLASS A MOD
I cannot hear any difference, and I think it turns nothing in class A.
It has been a long time since I ended my studies, but I can't figure out how a resistor linked between ground
and output could change the class of the opamp. ( 1, 4 pins are output - 7 pin is GND )
 

Synthetically: I know I wrote a critic review, but it's what I heard, LC is well built, not magic and it's a pay for value. But attention to the coupling with various headphones.
 
I'll modify LC following the suggestions I received in this forum
.
Thank you, BlaBlaBla and francisdemarte, Flukell and other
 
Jan 6, 2012 at 9:24 PM Post #962 of 1,624


Quote:
Hi there,
 
After a pair of weeks of listenig, I tell you my impressions about the LC.
The most surprising things about this amp are the differences I can hear between my 3 favourite headphones, which I know very well:

D5000 -
Great matching! This headphone is very warm and bass oriented, but the coupling with LC generate a perfect balance between all range of sound.
Trebles are really precise, voices are great, the low range gets less bloomy, producing a warm and pleasant sound.

K701 -
Not so good as D5000 . The middle-high range, strongest point of this headphone, becomes tinny and unless extended as canned. Low range, weak point of the AKG sound, becomes worse, and the headstage (another great AKG characteristic) gets smaller.

Sony MDR 7509 HD -
Unrecognizable! The high range is analytic but becomes much cold , middle range is backward, and the low range is too much emphasized but totally out of control!
Normally they are really precise, the opposite of what I heard with LC, I don't like it.

This is everything about headphones, let's talk about opamps!
By changing opamps, you can surely hear sound differences, but they are not so incisive and the don't change too much what I
said about headphones.

NE5532 famous opamp, it gives out an equilibrate sound, but it's a pretty normal component, not magic as I heard.

OPA6104 better than NE5532, linear and accurate on the high range.

OPA2604 and LME47920 *
they are pretty similar and very pleasant, they also mix very well the low and the high range giving a warm sound.
*without the box, this opamp has a little problem, I heard some treble distortion, which disappeared by closing the box.

OPA627 accurate, balanced, perhaps tending warm, detailed, it's not always the best choice because sometimes it seems to be "away" without personality

OPA2111AM the most detailed in the middle-high range, maybe a bit cold ant too much bright.
 

CLASS A MOD
I cannot hear any difference, and I think it turns nothing in class A.
It has been a long time since I ended my studies, but I can't figure out how a resistor linked between ground
and output could change the class of the opamp. ( 1, 4 pins are output - 7 pin is GND )
 

Synthetically: I know I wrote a critic review, but it's what I heard, LC is well built, not magic and it's a pay for value. But attention to the coupling with various headphones.
 
I'll modify LC following the suggestions I received in this forum
.
Thank you, BlaBlaBla and francisdemarte, Flukell and other


Nice review man!
 
It seems that LC loves high current headphones from 32 to 64 Ohms. Grado works good too.
 
95% agree about opamps. I can't say nothing about OPA627 because I think that don't have genuine TI. Agree about OPA2604. It shines with Grado too.
 
It has to be connected between out and (-) or (+). Pin 1 is OUT A, Pin 7 is OUT B, and Pin 4 is (-).
 
Jan 10, 2012 at 8:28 AM Post #964 of 1,624
I think I'm going to order a Lovely Cube PCB kit and build one with a few upgrades.
I was just wondering which and in what order, 1,2,3..., are upgrades worthwhile?
Don't want to go overboard - limited budget
smile.gif

 
Jan 11, 2012 at 12:11 PM Post #965 of 1,624
Hi,
 
I have an AKG K701 and actually hesitate between M-Stage and Lovely Cube.
Do you have an idea of which one will sound the best without making any mods except OpAmp swap ?
 
Thanks a lot for your answer.
 
 
Jan 11, 2012 at 8:43 PM Post #966 of 1,624
Jan 12, 2012 at 10:42 AM Post #967 of 1,624
Thanks Tribbs.
 
Do you mean Sheer Audio H-006+ is better on a purely technical point of view ?
Price is not my first criteria and anyway Sheer Audio H-006+ is not much more expensive than M-Stage and LC.
Sheer Audio H-006+ is available with x1, x3 and x11 gain. Which one would you recommend?
 
 

 
 
Jan 12, 2012 at 1:21 PM Post #968 of 1,624
I can not give you a firm answer comparing the Lovely Cube/Matrix to the Sheer Audio as I do not have my Lovely, yet.
 
In regards to gain for Sheer Audio. It was recommended by others here, as well as the manufacturer, to go with a gain of +3 with my Grados. That is spot on as I find my preferred volume setting on the Sheer Audio to end up between about 11-12 o'clock - perfect.
 
The gain can be changed if neccessary.  The manufacturer will give you instructions.
 
There is an interesting post in this thread
http://www.head-fi.org/t/589983/headamps-gs-x-vs-gilmore-lite-for-high-end-grado
discussing some "high-end" Gilmore DynaLo amps that you may be interested.
 
Pay particular attention to this review comparing two Gilmore DynaLo designs to the original Lehmann Black Cube of which the Lovely Cube & M-Stage are clones: http://www.head-fi.org/t/278691/six-way-review-square-wave-gs-1-canamp-ec-ss-gilmore-lite-black-cube-linear
 
If I had the cash right now I'd dump everything and get a GS-X!  Err, or maybe settle for a GS-1
smily_headphones1.gif

 
Jan 22, 2012 at 11:05 AM Post #970 of 1,624
I received my Lovely Cube kit and am now deciding which components to upgrade.  But I need some help.
 
I happen to have a Hammond 182M15 80VA torroid that just barely fits inside the Lovely Cube's case.  I would like to use it but was concerned about power-up current surge (182M15 is rated 15V @ 5.34A).  With such a large surge of current filling the capacitors upon power-up I was wondering if I need to beef up some components in the power supply to prevent blowing the fuse or worse.
 
FlukeII discusses changing the torroid on this page:
http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/390
 
...and BlaBlaBla mentions a larger torroid for the Lehmann BCL here:
http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures/30#post_7875531
 
Jan 22, 2012 at 5:54 PM Post #972 of 1,624
Quote:
I received my Lovely Cube kit and am now deciding which components to upgrade.  But I need some help.
 
I happen to have a Hammond 182M15 80VA torroid that just barely fits inside the Lovely Cube's case.  I would like to use it but was concerned about power-up current surge (182M15 is rated 15V @ 5.34A).  With such a large surge of current filling the capacitors upon power-up I was wondering if I need to beef up some components in the power supply to prevent blowing the fuse or worse.
 
FlukeII discusses changing the torroid on this page:
http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/390
 
...and BlaBlaBla mentions a larger torroid for the Lehmann BCL here:
http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures/30#post_7875531


BlaBlaBla was kind enough to repond to my question above in the Lehmann BCL thread here:
http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures/30#post_8080368
 
Essentially, the only change that needs to be done to accomodate the larger, 80VA, torroid is to use a slow blow fuse (Slo-Blo 0.3A - 0.5A for 115Vac).
Upon initial power up the larger torroid will draw a higher surge current from the AC mains which would likely blow the stock fast blow 0.9A fuse (115Vac).
 
 
Jan 23, 2012 at 7:41 PM Post #973 of 1,624
After being a read-only visitor at Head-Fi for some years, this is my first post on this forum, so please be kind if cut some corners.
I've currently purchased some Beyer DT880/600 and while looking for an offordable and suitable solution i discovered the Little Cube, amon the Matrix M-Stage (New 2010 revision) and the Little Dot MKIII.

Since all three amps are similarily priced I would like to know of you guys what you think, which of these three would be most suitable for my new cans. I'm also open to new suggestions beyond the three named amps, as long as they hit a similiar price-point.
Eventhough I mostly listen to rock, I also got a hang of some other electronical or even 80's stuff, so maybe you could consider this while giving your opinion.
The source will mostly be my PC playing FLAC files via my Infrasonic Quartet interface.
 
I'm not sure if the LC would really fit my cans best after reading through a lot of posts in this thread, but I'm sure there are some experienced guys in here who can give a reliable statement regarding my issue.
 
In case you recommend me to open a seperate thread for this, not to get this one specially regarded to the LC too messy, I'll do so.
 
Feb 9, 2012 at 10:31 PM Post #974 of 1,624
I have owned a Lehmann Audio BCL for over a year. This may not be the correct place to post regarding this amp but the upgrade mod that I have performed will apply equally to the Lovely Cube clone. I use Sennheiser HD-650s but have also used HD-800s and it is already well known that the Sennheisers match up extremely well with the BCL as they do with the Musical Fidelity X-CAN v3. In both cases, the synergy between the amp and phones is remarkable.
 
First, get rid of the input capacitors as they are polyester type (notoriously bad for good sound) and replace them with polypropylene. They are expensive but well worth changing. The larger ones are 1.5uF in the LC but 2.2uF in the BCL. Next, I would replace the Op-Amp as the OPA2134 is good but the sound is lacking in the very lowest bass registers. After trying many different Op-Amps, my personal favorite is the OPA2604 and it does not matter whether it is the original BB or the TI/BB version. If you have any acoustic music with low bass in it you will notice right away that the very lowest bass is produced well with the OPA2604 but somewhat absent with the original OPA2134. It is my absolute favorite chip and prefer it over all others including a set of OPA627Bs I have on hand. I enjoy everything about it and the amp has more detail, is plenty fast, and much better on the low frequencies while the highs remain clear and unstressed. If you do not want to solder (best way) in your choice of Op-Amp then use a really high quality dip socket. I use the Swiss made Augat brand as they are high retention type with 4-fingered contacts for reliability. It is probably the next best thing to soldering it in place.
 
Next, I would replace the six 470uF/35V electrolytics with Panasonic FC series and I took it one step further and replaced the Op-Amp decoupling caps with .1uF polyesters (they were .022uF originally). The main power supply capacitors were changed to Nichicon KG series Gold Tune Type II. The value was left at 4700uF each as that is more than sufficient capacity given the power level of the amp. From this point on, returns on investment with further parts changing produces diminishing returns. But I did replace resistors R13, R14, R21~R24 with PRP PR9372 metal film. The resistors used in local feedback for the Op-Amp (R21& R22) can be important and they can have a direct effect on the overall sound. Vishay Dale are very good with a neutral sound but I wanted the PRPs as they are non-magnetic and designed for audio purposes. I hope this has helped!
 
 

 
Feb 10, 2012 at 4:26 AM Post #975 of 1,624

Quote:
Originally Posted by Big Sky Audio /img/forum/go_quote.gif
 
I have owned a Lehmann Audio BCL for over a year. This may not be the correct place to post regarding this amp but the upgrade mod that I have performed will apply equally to the Lovely Cube clone. I use Sennheiser HD-650s but have also used HD-800s and it is already well known that the Sennheisers match up extremely well with the BCL as they do with the Musical Fidelity X-CAN v3. In both cases, the synergy between the amp and phones is remarkable.
 
First, get rid of the input capacitors as they are polyester type (notoriously bad for good sound) and replace them with polypropylene. They are expensive but well worth changing. The larger ones are 1.5uF in the LC but 2.2uF in the BCL. Next, I would replace the Op-Amp as the OPA2134 is good but the sound is lacking in the very lowest bass registers. After trying many different Op-Amps, my personal favorite is the OPA2604 and it does not matter whether it is the original BB or the TI/BB version. If you have any acoustic music with low bass in it you will notice right away that the very lowest bass is produced well with the OPA2604 but somewhat absent with the original OPA2134. It is my absolute favorite chip and prefer it over all others including a set of OPA627Bs I have on hand. I enjoy everything about it and the amp has more detail, is plenty fast, and much better on the low frequencies while the highs remain clear and unstressed. If you do not want to solder (best way) in your choice of Op-Amp then use a really high quality dip socket. I use the Swiss made Augat brand as they are high retention type with 4-fingered contacts for reliability. It is probably the next best thing to soldering it in place.
 
Next, I would replace the six 470uF/35V electrolytics with Panasonic FC series and I took it one step further and replaced the Op-Amp decoupling caps with .1uF polyesters (they were .022uF originally). The main power supply capacitors were changed to Nichicon KG series Gold Tune Type II. The value was left at 4700uF each as that is more than sufficient capacity given the power level of the amp. From this point on, returns on investment with further parts changing produces diminishing returns. But I did replace resistors R13, R14, R21~R24 with PRP PR9372 metal film. The resistors used in local feedback for the Op-Amp (R21& R22) can be important and they can have a direct effect on the overall sound. Vishay Dale are very good with a neutral sound but I wanted the PRPs as they are non-magnetic and designed for audio purposes. I hope this has helped!
 
 



I like PRPs too. They are excellent.
 

Users who are viewing this thread

Back
Top