[LarsHP]

Question #1 to be addressed: Is it 50Hz (or for US and other countries 60Hz) hum or 100Hz (respectively 120Hz) hum. If it's 50 or 60Hz, then the main trafo is most likely the reason for the hum. If it's 100 or 120Hz, then the hum is from the PSU and can be fixed with a choke as earlier posted in this thread.

I checked my CS300 recently and heard 100Hz hum. I'll double check it, but if this is the case, then I'll get it fixed. If not, away it goes to a new home.

 

[ardilla]

Question #1 to be addressed: Is it 50Hz (or for US and other countries 60Hz) hum or 100Hz (respectively 120Hz) hum. If it's 50 or 60Hz, then the main trafo is most likely the reason for the hum. If it's 100 or 120Hz, then the hum is from the PSU and can be fixed with a choke as earlier posted in this thread.

I checked my CS300 recently and heard 100Hz hum. I'll double check it, but if this is the case, then I'll get it fixed. If not, away it goes to a new home.

 
I just cecked running a 50Hz and 100Hz test tone whil using my 300 ohm HD650
 
1) I definetly has got a 50 Hz hum in the HD650. It is unaffected by the volume. It is like a smooth almost constant bass tone, but waving back and forth, almost only in the right channel. 
 
2) If I crank the volume very high up - I get a 100 Hz buzz. More disorted sound. This increases when I ncrease the volume. It is not present enough to notice at normal listening levels
 
I have now tried a few cans, and the only one that hums is the only one with high impedance. AKGq701, Shure1940, Audeze2 and 3, Hifiman HE500+6, Ultrasone Pro2900, Sennheiser Momentum - none of them have the hum. The Yuin PK2 earbuds have got a very slight hum, clearly less than the HD650 and not really bothering me (Impedance:16±2.5ohm(at 1KHz)Sensitivity:108±3dB(at 1KHz) 
 
So again - seems that the hum is high impedance related

 

[Clayton SF]

^ I just thought that I'd chime in on my Leben CS600 (even thought this is a CS300 thread). I don't think that there are many CS600 owners on Head-Fi, although I may be mistaken.
 
In the past I've stated that my CS600 was hum-free when using headphones but I just tried out my HD650 and it also has a hum in the right channel but the hum does not increase with the volume change and is barely noticeable when my apartment is completely silent, which is rare because I live next to a busy street in San Francisco.

 

[magiccabbage]

  ^ I just thought that I'd chime in on my Leben CS600 (even thought this is a CS300 thread). I don't think that there are many CS600 owners on Head-Fi, although I may be mistaken.
 
In the past I've stated that my CS600 was hum-free when using headphones but I just tried out my HD650 and it also has a hum in the right channel but the hum does not increase with the volume change and is barely noticeable when my apartment is completely silent, which is rare because I live next to a busy street in San Francisco.

wow the CS600! Beautiful amp! Its a pity its out of my price range. you still have your cs300? How do they compare? 

 

[kazsud]

There is a CS-300F Pre-amp version now which has headphone out as well.
http://lebenhifi.com/products/cs300f.html

What are the lead times for Lebens?

 

[Clayton SF]

  wow the CS600! Beautiful amp! Its a pity its out of my price range. you still have your cs300? How do they compare? 

It is a nice improvement over the 300 but not x2.
 

There is a CS-300F Pre-amp version now which has headphone out as well.
http://lebenhifi.com/products/cs300f.html

What are the lead times for Lebens?

About 6-8 weeks.

 

[Skylab]

There is a CS-300F Pre-amp version now which has headphone out as well.
http://lebenhifi.com/products/cs300f.html

What are the lead times for Lebens?

Leben's product name is confusing but the CS-300F is a full integrated amp, not just a preamp. But it uses different tubes than the CS-300/X/XS

 

[ardilla]

Leben's product name is confusing but the CS-300F is a full integrated amp, not just a preamp. But it uses different tubes than the CS-300/X/XS

So, does the F use different brands of tubes? Or incompatible tubes?

EDIT: Seems the tubes are incompatibla with the other CS300-versions

CS-300F is equipped with GE JAN-6197 which was developped for use in Computors and we used this tube for audio purpose for the first time in the world.

http://lebenhifi.com/products/cs300f.htm

 

[LarsHP]

No, different tube types, not just other brands.

http://lebenhifi.com/products.html

 

[Raaf]

Indeed the 300F is a completely different amp om the inside, you cant swap a EL84 / 6P14P-EB with a JAN-6197

 

[LarsHP]

   
I just cecked running a 50Hz and 100Hz test tone whil using my 300 ohm HD650
 
1) I definetly has got a 50 Hz hum in the HD650. It is unaffected by the volume. It is like a smooth almost constant bass tone, but waving back and forth, almost only in the right channel. 
 
2) If I crank the volume very high up - I get a 100 Hz buzz. More disorted sound. This increases when I ncrease the volume. It is not present enough to notice at normal listening levels
 
I have now tried a few cans, and the only one that hums is the only one with high impedance. AKGq701, Shure1940, Audeze2 and 3, Hifiman HE500+6, Ultrasone Pro2900, Sennheiser Momentum - none of them have the hum. The Yuin PK2 earbuds have got a very slight hum, clearly less than the HD650 and not really bothering me (Impedance:16±2.5ohm(at 1KHz)Sensitivity:108±3dB(at 1KHz) 
 
So again - seems that the hum is high impedance related

Strange!
 
I have checked again, and the humming/buzzing in my CS300 is 100Hz, not 50Hz. It's constant / not affected by volume control.
 
I don't have high impedance 'phones to check with, but both LCD-2 via headphone output and HE-6 via speaker output (with a 10 Ohm resistor in parallel) has a slight humming/buzzing (primarily in right channel). My headphones are semi-low impedance (around 50 Ohm) and far from sensitive.
 
The hum/buzz is audible in a completely quiet room when no music is playing as well as in more quiet music passages or with solo instruments.

 

[ardilla]

Hmmm. I had more buzzing with the old tubes.

It's almost dead silent with all but hd650 for me.

Maybe you have the burnt resistor problem mentioned earlier?

 

[chowyeung]

Dear all,
Any one using Denon D7100 with Leben CS300XS? I just bought a Leben CS300XS. I am now thinking to buy a headphone for it. Not sure if there is any 'hum' problem with D7100. 

Cheers

 

[Larryonfire]

The new F version has a bit changed soundsignature in the headphone out, just read this review, it´s less dark and lighter sounding. Of cause the tubes matters also.  
 
http://www.highfidelity.pl/@main-377&lang=en 
 
 
And Ardilla you told me in the Auralic thread hum was no problem with the Leben, now we get the whole truth

.  

 

[LarsHP]

  Dear all,
Any one using Denon D7100 with Leben CS300XS? I just bought a Leben CS300XS. I am now thinking to buy a headphone for it. Not sure if there is any 'hum' problem with D7100. 

Cheers

I am beginning to think that the answer to some extent depends of two factors that aren't about the headphones you use:
 
1) How silent or noisy is the place you use the headphones? If you live in a big city like you do (Hong Kong), then the background noise will mask the buzzing/humming som much that you might not hear it. If you live in the countryside - like I do - then you will probably be able to hear humming/buzzing that you wouldn't be able to hear in an apartment in a big city.
 
2) The electricity from the wall outlet. If there's a lot of electrical noise in that, this may cause the amp to hum/buzz (more). This of course can be fixed partly or fully by using power conditioners etc.
 
In my case, I can't think of any headphone that will both be so insensitive that you don't hear hum/buzz and at the same time so sensitive that it will reach loud "party" levels or peaks. Well, maybe except HiFiMan HE-5 (or the modded version Code-X) which in sensitivity is between the two headphones that I have: HE-6 and LCD-2. The latter one (91dB/mW) gets loud enough, but I get a low noise. The former (83.5dB/mW) has no noise regardless of volume setting, but doesn't get crazy loud (EDIT: via headphone output) - especially not without distortion in the peaks.
 
When all this is said, I should add that the hum/buzz/noise I hear is very low, but high enough to annoy me when the room is dead silent.