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Review and Measurements of iFi Ear Buddy (and iEMatch)
- Thread starter amirm
- Start date
Zilfallion
Member
- Joined
- Feb 16, 2018
- Messages
- 82
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- 65
That second voltage damping calculator is a nice addition. I've seen the voltage divider ones before. Thanks.Here is a calculator you can play with: http://www.sengpielaudio.com/calculator-voltagedivider.htm
OP
- Thread Starter
- #23
The ratio determines how much lower the gain will be so it is important. It should be matched to the application (amp output versus headphone efficiency). Good thing about building your own is that you can play with the value and listen until it is right.
If you pick too small of a value though, the amp may shut down because it sees a very low impedance.
Zilfallion
Member
- Joined
- Feb 16, 2018
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- 65
Good to know, though not a huge worry for my use-case. What I plan to plug it into already powers my IEMs without shutting down, which are lower impedance than the resistor values I was thinking about using. 8-15 Ohms for one of my IEMs. Wasn't really planning on less than an 18-ohm or so for my Z1 resistor, though I may play around with things a little.
I recently made a DIY attenuator based on this guide too, was wondering on what's the resistor value used for the Ear Buddy (and consequently, the IEMatch on both settings).
due to some shenanigans on the resistor, my resistance values when measured ended up like this:
tip to tip: 33ohms
tip to ground: 3.7ohms
ring to ring: 33ohms
ring to ground: 3.7ohms
is it important for the resistor value to be 10% of the bigger one?
due to some shenanigans on the resistor, my resistance values when measured ended up like this:
tip to tip: 33ohms
tip to ground: 3.7ohms
ring to ring: 33ohms
ring to ground: 3.7ohms
is it important for the resistor value to be 10% of the bigger one?
Not really, no. A lower value gives you more attenuation and lower output impedance, and vice versa.
Could someone explain to me how the addition of a series (33ohm) and parallel (3.7 ohm and the 'phone) resistance reduces the output impedance?
OP
- Thread Starter
- #28
I explained that earlier:
It is because of the much smaller resistor parallel with the headphone that the other one is not noticed (much).
thanks, I'm actually stupid or just inattentive. I re-read the entire thread and finally get what the values are for.
OP
- Thread Starter
- #32
This is all I tested but I am assuming results would be similar.
solderdude
Grand Contributor
It does the exact same thing except the IEmatch has 2 attenuation settings and also works for 'balanced' connections.
It lowers the max output power and at the same time lowers the noise of the amplifier itself by the exact same attenuation (not the noise in a recording of course)
These are intended to use powerful amps with sensitive In Ears.
This way.. A: you can't blow them up. B: You got better travel on your volpot and can avoid L-R differences at lower volpot settings.
The fun part is that it provides a nice continuous resistive load to the amplifier.
It also has a certain (low) output resistance.
So if your amplifier has an output resistance above 3 Ohm this will lower the output resistance the headphone 'sees'.
If your amplifier has a low output resistance it will increase the output resistance depending on the setting.
in IEMatch this can be either slightly under 1 Ohm or 2.5 Ohm (depends on the attenuation)
It uses an extra resistor when used in balanced mode.
Basically it is a switchable version of the attenuators I described here but with a lower resistance.
It lowers the max output power and at the same time lowers the noise of the amplifier itself by the exact same attenuation (not the noise in a recording of course)
These are intended to use powerful amps with sensitive In Ears.
This way.. A: you can't blow them up. B: You got better travel on your volpot and can avoid L-R differences at lower volpot settings.
The fun part is that it provides a nice continuous resistive load to the amplifier.
It also has a certain (low) output resistance.
So if your amplifier has an output resistance above 3 Ohm this will lower the output resistance the headphone 'sees'.
If your amplifier has a low output resistance it will increase the output resistance depending on the setting.
in IEMatch this can be either slightly under 1 Ohm or 2.5 Ohm (depends on the attenuation)
It uses an extra resistor when used in balanced mode.
Basically it is a switchable version of the attenuators I described here but with a lower resistance.
Last edited:
Can I ask how you calculated that the headphones would see an impedance of 2.7 ohms here? As I'd like to work out what the value would be for my amp, which has an even higher output impedance than 15 ohms.
1/Z = 1/Z1 + 1/Z2 + 1/Z3
Ah of course, reciprocal parallel resistance/impedance addition from school electronics is coming back to me now. I believe the impedance the headphones see in this case is actually given by 1/Z = 1/Z1 + 1/(Z2 + Z3) though, as Z2 (the 15.3 ohm Ear Buddy resistor) and Z3 (the amp impedance) are in series here? That gives 2.73 ohms as Amir concluded.
Correct. My apologies - it is 1 AM here, and I am doing this while on a long and boring conference call...
Thanks for this review!
I saw another product that seems to do the same thing but I'm not sure if I'm right in thinking so.
Does the UE Sound Guard or Line Drive do the same thing but in a better way?
I saw another product that seems to do the same thing but I'm not sure if I'm right in thinking so.
Does the UE Sound Guard or Line Drive do the same thing but in a better way?
