I have ordered a set of Audio Technica ATH -R70x headphones due to arrive later today. I have in addition ordered an Ampapa A1 phono preaamp/ headphone amp which is rated for headphones between 16 - 300 ohms. Will this amp adequately drive the ATH's? Also the cans are arriving the day before the Ampapa. Would it be advised to test these on a normal 32 ohm headphone output on an integrated amp Thanks in advance for your answers!
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Matching a 470 ohm headphone to 300 ohm headphone amp
- Thread starter DRich65
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johny_2000
Addicted to Fun and Learning
A headphone amplifier rated for a 16-300 ohm load will work adequately with 470 ohm headphones. It will just send less power to the headphones, so it might not blow your ears 
. For example, if an amplifier can deliver 500 mW max into a 300 ohm load, then into a 470 ohm load it will output (300/470) * 500 mW = 319 mW max.
. For example, if an amplifier can deliver 500 mW max into a 300 ohm load, then into a 470 ohm load it will output (300/470) * 500 mW = 319 mW max.Of course, you can test it on the 32 ohm headphone output of an integrated amplifier. Again, a load with a higher impedance will receive less power from the amplifier and will sound quieter.
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johny_2000
Addicted to Fun and Learning
Never heard of this amp, but I have experimented with JAN5654 vacuum tubes in another DAC. Please keep us posted on your impressions of it.
johny_2000
Addicted to Fun and Learning
I edited the original post with this answer.
johny_2000
Addicted to Fun and Learning
solderdude
Grand Contributor
Yes, will be fine on that tube thingy and can reach 3mW = 109dB SPL peaks so fairly loud.
You can also try it on a phone if you want. It just won't play very loud on it (between 100 and 103dB peak)
Matching impedances is not a thing in the headphone and speaker world.
johny_2000
Addicted to Fun and Learning
If the implementation of the tubes is the same as I found in the Douk Audio DAC circuit, then they are used as a cathode follower (buffer) stage between the preamp and the headphone amp to slightly color the sound with harmonic distortions typical for tubes. The amp outputs there are implemented on integrated circuits.
- Thread Starter
- #11
Lol! The grammar may be poor but I did actually own one of these before I sold it. I absolutely loved it.View attachment 425222
@amirm might want to test the performance of a device designed by our local experts
solderdude
Grand Contributor
That's the idea of using tubes in these devices (output voltage max. 2V and very low output resistance)
Distortion is not really a thing here as it can be very low in a follower config.
Distortion is not really a thing here as it can be very low in a follower config.
johny_2000
Addicted to Fun and Learning
It still gives about -65...-70 dBFS second-order harmonic, and about -95...-100 dBFS third-order harmonic in the cathode follower circuit. I did a SPICE simulation with this tube model and measurements of the Douk Audio DAC output signal. However, the main drawback was the bass roll-off in the Douk's frequency response. This was noticeable when compared to the high-performance solid-state amplifier in the RME ADI-2 DAC. And that's why it would be interesting to measure this device to see if they all do this.
solderdude
Grand Contributor
Inaudible so inconsequential... the tubes are mainly for placebo effects (people believing they will change the sound because they are told they do) in this particular amp.
What it has going for it is looks (if you like it), the phono input and tone controls.
Output power is a bit limited.
Play music pretty loud and then attenuate 65dB .... there will be silence (or some very faint sounds).
Now, consider masking effects of 2nd harmonics (which is level dependent as well) which is about 20-30dB rendering -65dB 2nd harmonic inaudible.
Suppose we have a 440Hz tone set at 0dB and a 2nd harmonic of that tone (from the instrument) at -20dB then that 2nd harmonic (when in phase) will be 0.05dB 'louder' than without any added distortion.
As you say, frequency modification and for output stages output resistance (for some low imp. headphones) is usually the biggest reason for perceived sound differences.
In some cases IM distortion (which comes with HD).
What it has going for it is looks (if you like it), the phono input and tone controls.
Output power is a bit limited.
Play music pretty loud and then attenuate 65dB .... there will be silence (or some very faint sounds).
Now, consider masking effects of 2nd harmonics (which is level dependent as well) which is about 20-30dB rendering -65dB 2nd harmonic inaudible.
Suppose we have a 440Hz tone set at 0dB and a 2nd harmonic of that tone (from the instrument) at -20dB then that 2nd harmonic (when in phase) will be 0.05dB 'louder' than without any added distortion.
As you say, frequency modification and for output stages output resistance (for some low imp. headphones) is usually the biggest reason for perceived sound differences.
In some cases IM distortion (which comes with HD).
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johny_2000
Addicted to Fun and Learning
This device has already been discussed on this forum.
Third-party measurements for headphone output:
THD+N(A) -55 dB,
IMD -58 dB,
Crosstalk -82dB
Frequency response:
Linear outputs measured worse in every aspect. Example, frequency response:
Notice -3dB @ 45Hz!
Third-party measurements for headphone output:
THD+N(A) -55 dB,
IMD -58 dB,
Crosstalk -82dB
Linear outputs measured worse in every aspect. Example, frequency response:
Notice -3dB @ 45Hz!
solderdude
Grand Contributor
45Hz -3dB would be audible.
Fortunately that amp has tone controls !
The distortion plot would be different at a different level and the output level at which it is measured is not disclosed.
When one does not reach that level (which is pretty loud) harmonics will be substantially lower (and less masking will be there too).
Fortunately that amp has tone controls !
The distortion plot would be different at a different level and the output level at which it is measured is not disclosed.
When one does not reach that level (which is pretty loud) harmonics will be substantially lower (and less masking will be there too).
- Thread Starter
- #17
Hey guys! The Ampapa A1 is an absolutely great addition to my entire setup. I do wish that the phono preamp generated a bit more volume over the headphones but they do still sound awesome to my ears! Listened to The Beatles Abbey Road on the new Audio Technica ATH -R70x cans. Soundstage and imaging is outstanding with remarkable clarity and with the tone controls on the Ampapa I even got some decent bass. Where the Ampapa really shines is in how it took my Juson JTA 35 integrated tube amp from being a really good piece of audio equipment with problems to frankly the absolute best piece of equipment I have owned so far in my audiophile journey. The problems were that despite it being very natural sounding, especially vocals, it had poor separation causing a weakness in soundstage and imaging. Also the Internat Phono stage is nothing to write home about. But the Ampapa transformed it into a thing of beauty. Now it has a wide open soundstage with just about perfect imaging and great clarity. This little guy cost $140 on Amazon and is worth every penny. I recommend it highly! Thanks again guys for all of your responses;
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Holy shit, that's really bad. Easily perceivable, severe lack of subbass. Isn't that one of the main points of using good headphones? Getting super deep bass response for cheap, the kind you'd have to pay thousands for if you wanted that from speakers and subwoofers? Hell, my old 8" bookshelves, 1000€ in 1999 moneys can do better than 45Hz at -3dB in a room.
johny_2000
Addicted to Fun and Learning
These graphs do not relate to headphones in any way. These are the frequency response measurements of the Ampapa A1 phono preamp/headphone amplifier.
However, @DRich65 mentioned that he likes the way it sounds. So measurements and sound preferences vary widely. Also, do not forget that the device has adjustable tone compensation for low and high frequencies (essentially a built-in equalizer), which may be able to change the frequency response in one direction or another.
Then what is the "linear output" graph supposed to mean? I'm curious.
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