[Knusperfisch]

Did you mean with BLC the Lehmann BCL ?
If yes, you really think that this combo wouldn't work well ?

 

[purrin]

 

Quote:

Did you mean with BLC the Lehmann BCL ?
If yes, you really think that this combo wouldn't work well ?

 
Yeah, that's what I meant. Here is where I'm coming from:
 
A couple of years ago, I actually had the K701 for a month and ran it with a fairly pricey balanced SS amp. I even tried burning the K701 in for 300 hours. I really tried to like it. My problem with the K701 was that it sounded cold, dry, and sterile. One way to compensate is with a tube amp. However, "reasonably" priced tubed amps just don't control bass well or have good treble extension, thereby they limit the potential of the K701, which have the capacity to provide very controlled bass and extended treble.
 
For something that may not break the bank, I would consider maybe a hybrid like the Schitt Lyr for the K701 instead of the BCL/M-Stage/LC. I've yet to hear the Lyr, but I'll get a chance in a week at the NorCal meet.
 
But that's just me. YMMV.

 

[JiggaD369]

Agreed.
 
K701 is a fine piece of gear but just not my cup of tea. And a M^3 is more than enough to power it.
 
And $1000+ for a amp? Are you kidding me? That is just rediculous.
 
Please spend that money on something more meaningful in life.

 

[BlaBlaBla]

Quote:

Agreed.
 
K701 is a fine piece of gear but just not my cup of tea. And a M^3 is more than enough to power it.
 
And $1000+ for a amp? Are you kidding me? That is just rediculous.
 
Please spend that money on something more meaningful in life.
 

 

 

[purrin]

 

[BlaBlaBla]

Quote:

Agreed.
 
K701 is a fine piece of gear but just not my cup of tea. And a M^3 is more than enough to power it.
 
And $1000+ for a amp? Are you kidding me? That is just rediculous.
 
Please spend that money on something more meaningful in life.

 
What will be meaning of our lives when third world war is in front of our doors? I could spare money for ticket to Mars...
 
Live when you still can.
 

 

[JiggaD369]

Not everyone is rich.
 

 

[BlaBlaBla]

Quote:

Not everyone is rich.
 

 
Well it depends what you like to do, in your life.. I like visiting bordels and spend all my money on whores and cheap whiskey.

Sometimes I put some money into amplifier or headphones. But that is only when my wife stays at home, because I forgot to give her money for shopping.

 
For God's sake, I have to neutralize her babbling with something (whiskey does not help in that)...

 

[Knusperfisch]

Just heard my LC the first time. It is my first headphone amp and until now I've also never listened through an amp. The improvement is not thaaat big but what I've experience until now is that the sound gets really more detailed, the harshness is reduced to a fair amount  and a much better location of the instruments. (Just heard for about 30min so thats my very first impression)
So the LC seems to do it's work quite well.
By the way the DC Offset of my stock LC lies at 2.5mV and 0,09mV which is pretty good!

 

[BlaBlaBla]

Quote:

Just heard my LC the first time. It is my first headphone amp and until now I've also never listened through an amp. The improvement is not thaaat big but what I've experience until now is that the sound gets really more detailed, the harshness is reduced to a fair amount  and a much better location of the instruments. (Just heard for about 30min so thats my very first impression)
So the LC seems to do it's work quite well.
By the way the DC Offset of my stock LC lies at 2.5mV and 0,09mV which is pretty good!

 
DC offset is good. Measure DC offset after 30 hours of listening to music... If it is the same, everything is ok. Your headphones will be happy and last  for a long time.
 
You have to wait for 20-30 hours. After that, bass will go deeper and mid frequencies (vocals) will become more "in front". Sound stage will become slightly wider. Today I was listening to music on laptop from my brother. Then I saw what really means "crappy sound".
Now, LC shines again.

 
So if you think that your equipment is not "up to standards", try to listen to music on something that is "usually sold" (mainstream) on the market. Then you will run to your old equipment and suddenly feel heavenly revelation.

 

[Knusperfisch]

I've got a question. Is it normal that I've got a DC offset of max. 5mV at a gain of 20dB while I've got 11mV at a gain of 0 ?
Should the DC offset stay constant within the burn in time ? Is it normal when it rises or is this a bad sign ?

 

[BlaBlaBla]

 
Quote:

I've got a question. Is it normal that I've got a DC offset of max. 5mV at a gain of 20dB while I've got 11mV at a gain of 0 ?
Should the DC offset stay constant within the burn in time ? Is it normal when it rises or is this a bad sign ?

 
Hi, Knusperfisch!
 
I will answer to you, but first I would like to try to explain something.
 
Let say in this way. DC offset depends (mostly) on your transistors.  But let say that you cannot change your transistors (because that demands soldernig another transistors and "guess and error" game play),  you can replace regulator resistors with potentiometer (trim pot).  That is easier. And you can change an opamp. Without any tool.
 
DC offset depends (mainly) on those two things mentioned before. (regulators and opamp). I tried five (5) opamps. OPA2134, 2132, 2107, 2x627, 2xAD797. All this opamps had different DC offset. Some of them had (AD797) very high offset (11mV), and some of them too god to be true (OPA 2107 - 1mV).  Situation becomes more complicated if you try to put opamp into A class. And it changes if you change gain (0, 10, 18, 20 dB).
 
So it depends on lots of things.
 
You can improve DC offset if you do fine tuning of regulator voltages. Because LC have exactly the same voltage on both channels you can raise or lover positive or negative voltage on LM317 or LM337 regulators. That will make small "drift" (push pull) but only what matters is situation on headphone output. So it does not matter if you have for example +15.1V and -14.95V after regulators . DC gain (as I said before) changes with gain, so you will have to choose gain that suits your headphones the best, and then tune DC offset.
 
DC offset of 11 mV only matters if you have low impedance headphones like Denon, Grado, ATH. In that case 5 mV or below, will be better because two things. First is that low impedance headphones need small voltage to be driven, and small DC offset involved in entire signal will make sound bad. Second is rule U2/R=P. U - DC offset, R - impedance, P - power dissipated into your headphones because DC offset.
 
If you have high impedance headphones like Sennhesier (300 Ohm) or Beyerdinamic (600 Ohm) then DC offset can be as high as 20-30 mV.  The reason is the same, like stated before. High impedance headphones need more voltage to be driven, so DC offset is less involved into entire signal. And power dissipated into headphone coil is less, because bigger resistance.
 
Also, you have to look at technical specification of you headphones, especially in stated power (in mW) where you have to divide that stated power with number two (2) (because of some other things...).
But power does not tells you all. Some headphones are easy to drive, and some not. For example ATH W1000X is rated about 500-1000 mW AND EASLY DRIVEN. AKG K701, for example, is rated to 100 mW and NOT EASLY DRIVEN. So, with AKG you have to be very careful and have flawless amplifier - if you want to raise your volume. You will need a good amount of power (closer to headphones rated power, than with ATH, for the same amount of volume) WITHOUT DC offset. AKG K701 coils do not forgive if they are overpowered with wasted power (DC), but in the same time they need a lot of power. ATH forgive much more wasted power (DC), and need less power to be properly driven.
 
That is reason why I always talk about  VERY GOOD amplifier, when someone says:  "AKG K701".  You should try different amplifiers. You would be amazed how power sensitive (quality dependent) AKG K701 are.
 
Sorry for bad english. I tried to explain as much as I could.

 

[taiyoyuden]

A related question, does the maker measure the DC offset during testing as well?

 

[BlaBlaBla]

Quote:

A related question, does the maker measure the DC offset during testing as well?

 
You can not know that. If we talk about mass market amplifiers, so if there is a lot amplifiers to make and sold, probably someone turns amplifier for 5 min on,  and sees if there is going something wrong (overheating, oscillation, bad sound). But I do not think that someone is trying to measure DC offset. Especially if he is making 100 amps per day. And has to sold them out.
 
But if we talk about small market products, (for example LC, CK3, M3, Lehmann, etc) then seller might be the person who is checking DC offset before the amplifier goes away. (If you want LC assembled, seller will try amplifier before sending it to you.) Also, I know that  LC is sold in very small quantities ... Smaller quantity, in most cases means - better quality control. Probably.
 
But, again, what is the meaning of  "to check DC offset"? It depends... Maybe that person considers that value "under" 20 mV is satisfied or maybe that 10 mV is "not good enough"?
 
In first case, as a buyer, you might be disappointed with quality control because 20 mV is quite high for "low impedance headphones" (just my opinion)...
But in second case, maybe you will be stunned with a value of a few mV... 
 
Because too many sentences that start with "it always depends.....", I trust only to myself.

 
You should check DC offset, always when you buy an amplifier, or after you bought an amplifier.  At least, your headphones will be happy and serve you for a long time. I think that is not good to rely on seller's words, when you might kill headphones that cost 200+ USD alone...

 

[JiggaD369]

Hmm, I think I learning what all this DC offset is all about, now. Thanks bla.
 
But what confuses me is one channel is 14.3 mV and the other is 4.2mV. Is something wrong? I tried every gain setting but it's always about ~10mV apart. 
 
P.s. I use 2107.