As title suggests, are the Preamp outs on the Topping headphone amps, just a alternate type of Socket of their headphone jack? Are they connected in parallel? Or is there are dedicated Preamp stage specially designed inside those amps? When I checked the specs of their headphone outs and Preamp outs all of them are same in terms of crosstalk, distortion etc. So Cant we then just use a 3.5mm to RCA from the heaphone out to get the same functionality ?
-
WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Topping "Preamps" simply an extension of headphone out as RCA sockets?
- Thread starter dogmamann
- Start date
staticV3
Master Contributor
- Joined
- Aug 29, 2019
- Messages
- 7,951
- Likes
- 12,758
You can always use headphone outputs as though they were Line outs.
You cannot in most cases use a Line out as though it were a headphone out.
On Topping Amps, headphone out and Line out are not identical, as you can see by the difference in output impedance.
While headphone out and Line out should perform basically the same when used as Line out, if you try to use the Line out as Headphone out, depending on the headphone impedance, it'll distort quickly as it's not designed to handle much current.
You cannot in most cases use a Line out as though it were a headphone out.
On Topping Amps, headphone out and Line out are not identical, as you can see by the difference in output impedance.
While headphone out and Line out should perform basically the same when used as Line out, if you try to use the Line out as Headphone out, depending on the headphone impedance, it'll distort quickly as it's not designed to handle much current.
Last edited:
The distinction between both exists because its harder to design and build a good headphone out than a good line out.
Headphones have much, much lower load impedance than line-in equipment, so having high current capability and near-zero output impedance on a headphone out is critical.
Line-outs on the other hand doesn't need to be as stringent, as they are only expected to push around 1/100 or lower power of a headphone out.
Headphones have much, much lower load impedance than line-in equipment, so having high current capability and near-zero output impedance on a headphone out is critical.
Line-outs on the other hand doesn't need to be as stringent, as they are only expected to push around 1/100 or lower power of a headphone out.
Last edited:
- Thread Starter
- #4
I understand the general idea of low impedance thing with headphones; my question was if on Topping amps their are just parallel connections.
Just checked once again,(l70, l30ii, a90D) every single spec between the preamp and headphone out are 1 to 1 match except the output impedance suggesting it’s a 20 ohm resistor attached to the same outputs then to the RCA. If that’s the case, adding a 20 ohm high quality resistor to the headphone out would get a preamp out of every topping amp?
Am I wrong here?
Can someone mark the preamplifier part in this circuit ?
Just checked once again,(l70, l30ii, a90D) every single spec between the preamp and headphone out are 1 to 1 match except the output impedance suggesting it’s a 20 ohm resistor attached to the same outputs then to the RCA. If that’s the case, adding a 20 ohm high quality resistor to the headphone out would get a preamp out of every topping amp?
Am I wrong here?
Can someone mark the preamplifier part in this circuit ?
How will the balanced outputs work then?
- Thread Starter
- #7
It’s quoted 40ohms, perhaps 2 40ohms resister per channel ?
You may want to draw a simple circuit diagram to see that what you are suggesting doesn't make sense. If you do not know about circuits at all, may I suggest not to worry?
Last edited:
- Thread Starter
- #9
What I assumed may be completely wrong, but it would be helpful if it’s explained why it’s wrong.
In the past I have repaired integrated amps, following the service manuals. Most amps with a headphone jack in the front had a speaker terminals connected to the headphone outs with a high value to resistor to dissipate the high power so that it’s acceptable for headphones.
Since headphone amps are very clean and devices working similar to a preamp, only thing stopping them being a proper preamp would be just the output impedance. Seeing it’s fixed at 20 ohms, I thought may be they just added a 20ohm resistor in Series to the RCA outs while the signal comes directly from the output stage of the headphone amplifier.
Also in a box so small, how can they possibly have two different circuits one for headphone amp and one for preamp with the exact same specs?
Joachim Herbert
Senior Member
You're kidding, are you?
- Thread Starter
- #11
No. Now, please explain why my assumption is wrong, if you know it.
Joachim Herbert
Senior Member
Size doesn't matter. For a start.
- Thread Starter
- #13
Ha. Ha.
Similar threads
