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Confused with term, Pre-Amp

post #1 of 16
10/11/09 at 6:01pm
Thread Starter 
Hello everyone,

I am confused by the term Pre-amp on Headphone amplifiers, have I got the following correct... Please correct me if I am wrong.

I will give the RSA Apache as an example
http://www.raysamuelsaudio.com/asset...1/DSC_0027.jpg

If I take an Active nearfield monitor that has balanced XLRs, does the pre-amp mean that I could connect the Active monitors XLRs to the Balanced Pre-Outs on the headphone amp and then use the Volume controll on the Headphone amplifier to controll the Monitors volume?

If I have indeed got this right, what tube amps support this?
If this is wrong, what sort of extra device would I need to get to controll the volume on an active nearfield monitor.

Thanks.
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post #2 of 16
10/11/09 at 8:03pm
It would depend on the monitors. Some of them have a volume control, some don't. If the active monitors don't, then the preamp should control their volume.
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post #3 of 16
10/11/09 at 8:19pm
The basic purposes of a preamp are volume control and source switching (multiple sources are connected to the preamp through multiple RCA or XLR inputs.) In addition, some but not all preamps provide some initial amplification of a source's signal. (If it amplifies the source's signal, it is referred to as an active preamp. If it does not, it is a passive preamp. Most preamps are active.) Initial amplification is required if the source is a turntable, in which case the preamp is said to have a phono stage. If the preamp does not have a phono stage, it is referred to as a linestage.

As far as finding a tube headphone amp that meets your requirements, your best bet is to contact the manufacturer (i.e. Ray Samuels) and ask them. It sounds to me like you need a balanced preamp, i.e. one that has XLR inputs and outputs. The majority of tube headphone amps, even those that can serve as preamps, have RCA inputs and outputs, not XLR.
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post #4 of 16
10/11/09 at 8:20pm
Yes.
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post #5 of 16
10/11/09 at 8:22pm
....
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post #6 of 16
10/11/09 at 10:12pm
I suppose it's common to use a full-sized integrated receiver/amplifier as a pre-amp for a dedicated headphone amp? I'm wondering if this is recommended; I'm thinking about doing it with my Cambridge 540a stereo receiver.
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post #7 of 16
10/12/09 at 1:44pm
Quote:
Originally Posted by ChiComm4 View Post
I suppose it's common to use a full-sized integrated receiver/amplifier as a pre-amp for a dedicated headphone amp? I'm wondering if this is recommended; I'm thinking about doing it with my Cambridge 540a stereo receiver.
I've been wondering about this too since my first headphone amp will be arriving today.

So now I will be unconnecting my DAC from my Cambridge 640a v2 amp (that I use for my speakers and have been using the headphone out on) and connecting my headphone amp to my DAC everytime I want to switch between speakers and cans. Annoying. But I don't really want to buy a pre-amp just for convenience.
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post #8 of 16
10/12/09 at 11:05pm
Quote:
Originally Posted by Pariah1 View Post
I've been wondering about this too since my first headphone amp will be arriving today.

So now I will be unconnecting my DAC from my Cambridge 640a v2 amp (that I use for my speakers and have been using the headphone out on) and connecting my headphone amp to my DAC everytime I want to switch between speakers and cans. Annoying. But I don't really want to buy a pre-amp just for convenience.
If your integrated amp has fixed level line-outs (like a tape out), you can just connect those into the input of the headphone amp.
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post #9 of 16
10/13/09 at 12:28am
Quote:
Originally Posted by jellojoe View Post
If your integrated amp has fixed level line-outs (like a tape out), you can just connect those into the input of the headphone amp.
So connect my DAC to my main amp like always, then connect my head phone amp into my main amp as long as it has fixed line outs, ok. I'm ignorant of connections and just don't want to blow anything up!

I don't have a tape out, I have a "rec out" (2 of them) and a tape in, but no out. (It's a Cambridge 640a v2 integrated amp).
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post #10 of 16
10/13/09 at 10:26pm
Quote:
Originally Posted by Pariah1 View Post
So connect my DAC to my main amp like always, then connect my head phone amp into my main amp as long as it has fixed line outs, ok. I'm ignorant of connections and just don't want to blow anything up!

I don't have a tape out, I have a "rec out" (2 of them) and a tape in, but no out. (It's a Cambridge 640a v2 integrated amp).
Rec out should work.
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post #11 of 16
10/14/09 at 7:12am
Quote:
Originally Posted by jellojoe View Post
Rec out should work.
Thanks. What is that anyway? Recording out? I would think a record out, as in albums, would be phono out, and I think the 640a requires a separate phono stage.

I also have a pre amp out, but I think I'm going to use that with a sub...that is if you can.

Man I need to read up on this stuff!
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post #12 of 16
10/14/09 at 7:23am
Quote:
Originally Posted by Pariah1 View Post
Thanks. What is that anyway? Recording out? I would think a record out, as in albums, would be phono out, and I think the 640a requires a separate phono stage.
It's a rec as in recording, not rec as in vinyl record.

It's so you can put a tape player in the loop and record what is being played on the phono/tuner/CD/aux. It's a loop with both in and out so the tape player can both record and play back and so you can hear (monitor) what the tape player is doing (is the level OK?).

Some headphone amps have a set of jacks for both in and out specifically so they can be inserted in the tape loop without breaking the loop.
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post #13 of 16
10/14/09 at 5:51pm
Quote:
Originally Posted by Ham Sandwich View Post
It's a rec as in recording, not rec as in vinyl record.

It's so you can put a tape player in the loop and record what is being played on the phono/tuner/CD/aux. It's a loop with both in and out so the tape player can both record and play back and so you can hear (monitor) what the tape player is doing (is the level OK?).

Some headphone amps have a set of jacks for both in and out specifically so they can be inserted in the tape loop without breaking the loop.
Thanks Ham, once again you're helpful!

I figured it was for recording, not records lol.

I'll try it, I just don't want to blow anything up! (Some outs when I have plugged in cables before just emit really loud feedback).

Another stupid question while I'm at it: Should my DAC be plugged into the AUX on the amp? Or is another input "better" SQ wise. I don't think it matters, but again I'm not real informed on this stuff.
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post #14 of 16
10/15/09 at 1:42am
Quote:
Originally Posted by Pariah1 View Post
Another stupid question while I'm at it: Should my DAC be plugged into the AUX on the amp? Or is another input "better" SQ wise. I don't think it matters, but again I'm not real informed on this stuff.
All of the line level inputs on your amp are equal. One is not better than the other. They differ only in the label that is above the button.
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post #15 of 16
10/15/09 at 2:36pm
Quote:
Originally Posted by Ham Sandwich View Post
All of the line level inputs on your amp are equal. One is not better than the other. They differ only in the label that is above the button.
That's what I figured...thanks!
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