Thanks MM- That cleared up a thing-or-three!
Now I am wondering . . .
I sometimes read that 'philes felt the need to wind the wick up a bit more to get the fullness of sound they expected. Do you think that may be anything to do with overloaded/badly mis-matched sections of the signal train?
It's just one of many things I'm trying to get clear - is it something to do with mis-matching ELECTRICALLY or perhaps just the wrong driver/cabinet for the amplifier type?
Now I am wondering . . .
I sometimes read that 'philes felt the need to wind the wick up a bit more to get the fullness of sound they expected. Do you think that may be anything to do with overloaded/badly mis-matched sections of the signal train?
It's just one of many things I'm trying to get clear - is it something to do with mis-matching ELECTRICALLY or perhaps just the wrong driver/cabinet for the amplifier type?
Pano,
So do you support power buffers driving speakers? This way we can easily tailor our pre, if it can handle the voltage, to be the only gain stage. Since the pre would likely have only mA output then a stepped attenuator could do the job between the pre and buffer. I think Nelson had a power buffer didnt he? Will have to search around. Could swear I remember seeing one.
Uriah
So do you support power buffers driving speakers? This way we can easily tailor our pre, if it can handle the voltage, to be the only gain stage. Since the pre would likely have only mA output then a stepped attenuator could do the job between the pre and buffer. I think Nelson had a power buffer didnt he? Will have to search around. Could swear I remember seeing one.
Uriah
Strange you should ask that, I was just looking at the symmetrical B1 buffer thread. But that not a power buffer, just a line stage.
I have not really used an amp that was a "power buffer" or has unity voltage gain with more output current. With modern sources and speakers in the 92dB/watt range or higher, it might be all that most people need. With horns in a domestic setting we are usually running them at a lower voltage than the output of the CD player or DAC.
For efficient speakers in a normal size domestic listening room I find that the amp volume control is often turned down far enough that the power amp is, in effect, just a power buffer.
I have not really used an amp that was a "power buffer" or has unity voltage gain with more output current. With modern sources and speakers in the 92dB/watt range or higher, it might be all that most people need. With horns in a domestic setting we are usually running them at a lower voltage than the output of the CD player or DAC.
For efficient speakers in a normal size domestic listening room I find that the amp volume control is often turned down far enough that the power amp is, in effect, just a power buffer.
Wow this is great article! Thank you!
Now I understand what I am doing by using both the output level control of my CDX993, the volume control of the C85 and the attenuators of the MX-1000. Everybody has always told me to seek pure signal path only a single attenuator and etc... But I have found that there is an audible difference and that is why I did it that way.
The same applies for my first encounter with the difference of the sound from only altering signal levels. The system was a Pioneer SACD player, Behringer VMX-100 and a Pioneer receiver. Adjusting the Gain on the Behringer and then the output volume gives audible results in dynamics and clarity.
Thank You again!
Now I understand what I am doing by using both the output level control of my CDX993, the volume control of the C85 and the attenuators of the MX-1000. Everybody has always told me to seek pure signal path only a single attenuator and etc... But I have found that there is an audible difference and that is why I did it that way.
The same applies for my first encounter with the difference of the sound from only altering signal levels. The system was a Pioneer SACD player, Behringer VMX-100 and a Pioneer receiver. Adjusting the Gain on the Behringer and then the output volume gives audible results in dynamics and clarity.
Thank You again!
Initially I did it after I read the equipment manuals and saw that maximum output level of the player was higher than the input sensitivity of the amplifier. That made me thinking. I got the Behringer only to serve as a preamp. The most improvement was achieved when I reduced the gain amount, don't know how much, but significantly below the middle for most music material. Also the reduced main out volume served very well.
The results are both clarity and dynamics, although I never knew what is the science behind this and the purpose of the additional preamp was solely to counter possible clipping in the amplifier input.
The results are both clarity and dynamics, although I never knew what is the science behind this and the purpose of the additional preamp was solely to counter possible clipping in the amplifier input.
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Gain structure can be found in audio mixers.
You can have line inputs to the mixer which dont need much gain.
It starts to get a bit more complicated with low output microphones where the signal can be very small. Simply having loads of gain will also amplifiy noise or ground hum.
So often mixers can have a variable microphone pre amp gain to keep the gain low but the signal at a good level.
You can have line inputs to the mixer which dont need much gain.
It starts to get a bit more complicated with low output microphones where the signal can be very small. Simply having loads of gain will also amplifiy noise or ground hum.
So often mixers can have a variable microphone pre amp gain to keep the gain low but the signal at a good level.
I must study this very carefully... I am actually using a line buffer instead of the "normal" 16x preamp I used for so long and the gains in stage size, dynamics, clarity and control are uge.... but sometimes I would like to have a louder listening session and just can´t. I would like to have some gain in the preamp but not always. Variable gain is the way to go for me now.
Don't confuse variable gain with variable attenuation. Variable attenuation is how almost all volume controls work, even the mic preamps on a mixer strip.
Having a preamp with a bit of voltage gain is not a bad idea, as Mr. Cruz points out. 6-12dB gain can sometimes be useful.
Actual variable gain is not all that common because variable attenuation is so much easier to do.
Having a preamp with a bit of voltage gain is not a bad idea, as Mr. Cruz points out. 6-12dB gain can sometimes be useful.
Actual variable gain is not all that common because variable attenuation is so much easier to do.
What is Gain Sructure?
I advocate the design doctrine of Nelson Pass which is: "keep it simple". A CD player has a volume-controlled headphone amp. It is a high fidelity mini power amp ~15-20mW (rms) into 30 Ohm loads. The CD player's volume control may be manual (e.g. Marantz), or motorized via a remote controller (Sony). The resultant output then goes directly to the input of the power amp. This approach is a high efficiency and least-noise gain structure.
I advocate the design doctrine of Nelson Pass which is: "keep it simple". A CD player has a volume-controlled headphone amp. It is a high fidelity mini power amp ~15-20mW (rms) into 30 Ohm loads. The CD player's volume control may be manual (e.g. Marantz), or motorized via a remote controller (Sony). The resultant output then goes directly to the input of the power amp. This approach is a high efficiency and least-noise gain structure.
"I advocate the design doctrine of Nelson Pass which is: "keep it simple". A CD player has a volume-controlled headphone amp. It is a high fidelity mini power amp ~15-20mW (rms) into 30 Ohm loads. The CD player's volume control may be manual (e.g. Marantz), or motorized via a remote controller (Sony). The resultant output then goes directly to the input of the power amp. This approach is a high efficiency and least-noise gain structure. "
Antoinel,
while it is feasible, to put headphone cd output straight to the amp, it usually does not sound very good. The reason is that the best cd players do not have headphone output at all, those who have have it for some sort of monitoring, not for real listening. Well, I tried it, it just does not compare with dedicated high quality headphone amp fed by line signal. The line level out can be high quality, but headphone amp inside cd player is usually of mediocre quality. Most of the time one OPA. Rarely discrete. Never tube headphone output. If yes, please point me to such cd player.
Antoinel,
while it is feasible, to put headphone cd output straight to the amp, it usually does not sound very good. The reason is that the best cd players do not have headphone output at all, those who have have it for some sort of monitoring, not for real listening. Well, I tried it, it just does not compare with dedicated high quality headphone amp fed by line signal. The line level out can be high quality, but headphone amp inside cd player is usually of mediocre quality. Most of the time one OPA. Rarely discrete. Never tube headphone output. If yes, please point me to such cd player.
Sorry, I do not not know of a CD player to report. The CD players I have are a Marantz (manual vol control) and an older Sony which uses a motorized unit. A very handy feature. Is this feature found on high end CD players? I do not know; but I hope/guess it can be. You are correct. The headphone amp of a typical CD player is an OPA used as a unity gain buffer. It is driven directly by the output signal which appears simultaneously at the RCA outputs. No reason for the signal to be mediocre because it is processed by an OPA. Its distortion is low and will be even lower when it feeds the input of a power amplifier of impedance ~47 K. It is barely doing any work. Its fidelity may beat that of its externally processed RCA signal. One needs to consider the balance between the added cost and the performance of the external preamplifier or attenuator. Your following thought is valuable. It is preferred for a high end CD player to have an internal volume controlled high end headphone amp.