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Old 17th June 2012, 04:05 AM   #1
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Default Clarifications on role of pre VS power

Hi,

I am relativly new to this passion and would like to clarify some of my key questions:

1. Power cord: Should I use my best power cord for my dac (because it is the one creating the sound) or for my power amp (because he needs more power)?

2. In an HTPC setup: PC -> DAC -> Preamp -> Power amp, why do you still need a Preamp? Volume control and the likes can be done on the computer. Is the only role of the preamp is to connect multiple source or does it actually do something on the sound? and if so, what? (This is not for Tube pre: I clearly understand that a tube pre makes huge difference)

3. I have owned an integrated tube amplifier (Yaqin MC-10L) and sold it (because I got a good offer). I clearly understand the difference in using tubes for preamp, but I am not too sure about using tube for Power amp. I am now facing 2 options:
a. Buy a tube preamp (like Yaqin MS-12B) and connect to my power amp (2 * Marantz ma-500, mono block 120W, class A).
b. Buy a new integrated tube amp (probably Yaqin MC-100B)
Could someone highlight the key difference in using tube for the power stage as well?


Thanks,

Serge
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Old 17th June 2012, 09:16 AM   #2
12E1 is offline 12E1  United Kingdom
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Some would disagree with me on these - others may agree. Some would say these points are more a matter or religion or belief than engineering. I would argue that for most people, the answers to your questions often just come down to personal choice.

Quote:
Originally Posted by sergedc View Post
Hi,

I am relativly new to this passion and would like to clarify some of my key questions:

1. Power cord: Should I use my best power cord for my dac (because it is the one creating the sound) or for my power amp (because he needs more power)?
I would say that if each unit has a well designed power supply and adheres to good earthing and screening practices (itself an area for some to debate) then the power cord should make no real difference. If you have a very noisy mains supply then everything might need a bit more filtering since noise can get into a system at any point, whether DAC, pre-amp, power-amp, inputs, or even speaker leads.

Quote:
Originally Posted by sergedc View Post
Hi,
2. In an HTPC setup: PC -> DAC -> Preamp -> Power amp, why do you still need a Preamp? Volume control and the likes can be done on the computer. Is the only role of the preamp is to connect multiple source or does it actually do something on the sound? and if so, what? (This is not for Tube pre: I clearly understand that a tube pre makes huge difference)
You do not have to have a separate pre-amplifier. Some would choose to for source selection, level controls, and maybe for some other reasons. I prefer to take a minimalist approach. I have one input on my amplifier which goes to a volume control. After that, straight to the amplifier circuits. I would always recommend a least a volume control. Yes, you can control volume solely via the source (HTPC), but if something unexpected happens (phone rings, or software crashes), a simple rotary control can be turned down or adjusted very much faster than a volume control that my be obscured by some application that you are running on the PC.

Quote:
Originally Posted by sergedc View Post
Hi,
3. I have owned an integrated tube amplifier (Yaqin MC-10L) and sold it (because I got a good offer). I clearly understand the difference in using tubes for preamp, but I am not too sure about using tube for Power amp. I am now facing 2 options:
a. Buy a tube preamp (like Yaqin MS-12B) and connect to my power amp (2 * Marantz ma-500, mono block 120W, class A).
b. Buy a new integrated tube amp (probably Yaqin MC-100B)
Could someone highlight the key difference in using tube for the power stage as well?
I mean no disrepect, but it sounds like you already have some "religion or belief" here. I would argue that you should use transistors or tubes according to your own choice whether for pre-amp or power-amp, or anywhere else (power supply rectification, etc). Some choose one over the other for the perceived differences in sound, some may do so just because they like the way it looks, and some just because they want to. Depending on the design specifics the audible differences can be as small or as huge as you like. Taking a different view, if using the unit in a very small room with minimal shelf space, tubes obviously add more heat and require a bit more ventilation (for their own cooling and to avoid heating things around them). I would argue that if you are the person using the equipment then it should be your choice, no-one else's.
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Old 17th June 2012, 01:27 PM   #3
DF96 is offline DF96  England
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12E1 has given some good advice. I would add that a "tube pre" should not make a huge difference, unless it is poorly designed or intended to be an FX box.
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Old 17th June 2012, 03:38 PM   #4
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Sorry, what is an FX box?
I am surprised by your comment. I though the preamp stage is where the tube makes the most difference, rather than the power stage.

Can you clarify?
Thanks
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Old 17th June 2012, 07:08 PM   #5
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Quote:
Originally Posted by sergedc View Post
Sorry, what is an FX box?
I am surprised by your comment. I though the preamp stage is where the tube makes the most difference, rather than the power stage.

Can you clarify?
Thanks
FX box = effects box

I believe what DF96 is saying is that a well designed pre-whether tube or SS, should not "sound" like anything; it should be sonically transparent (or close to it). If you are using a tubed pre to add some 2nd harmonic, "tubieness" etc, you are using it as an effects box.
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Old 17th June 2012, 09:06 PM   #6
DF96 is offline DF96  England
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Yes. If a preamp is necessary (often it is not) then it will avoid (or reduce) sound degradation by things like excessive cable capacitance. It should not add anything, merely stop something being taken away.
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