[eddyino]

I still have my unit, but trying different amps with it now. I have a thx-789 on order in august and using a loxjie p20 to tide me over.

I have heard 789 is a revolutionary amp. Ud-503 on the other hand has plenty of power. Does it make any difference when using it with amp? Or are you using some very tight cans?

 

[foreverzer0]

I have heard 789 is a revolutionary amp. Ud-503 on the other hand has plenty of power. Does it make any difference when using it with amp? Or are you using some very tight cans?

I don't have the 789 yet as it's delivering in august/september. I do have the loxjie p20, which puts out over 300mw at 300ohm. I have hd800's, which are 300ohm cans.

Not sure how much power the UD-503 is putting out in that ohm range, but if it's 750mw per channel at 32ohm, I would think it's quite a bit less at 300ohm.

 

[eddyino]

I don't have the 789 yet as it's delivering in august/september. I do have the loxjie p20, which puts out over 300mw at 300ohm. I have hd800's, which are 300ohm cans.

Not sure how much power the UD-503 is putting out in that ohm range, but if it's 750mw per channel at 32ohm, I would think it's quite a bit less at 300ohm.

Do you feel like you do not have enough power in teac to drive hd800s? It seems to me it has plenty enough volume for my hd650.

 

[foreverzer0]

Do you feel like you do not have enough power in teac to drive hd800s? It seems to me it has plenty enough volume for my hd650.

It gets loud per se, but not as engaging as on my more efficient he-400S. It even gets "loud" on my sabaj da3 mini dac/amp, but without much bass or dynamics. Also, I'm just curious how it will sound on more powerful or different amps to see if it makes much difference. I hear the hd800 is pretty picky when it comes to amps.

 

[eddyino]

It gets loud per se, but not as engaging as on my more efficient he-400S. It even gets "loud" on my sabaj da3 mini dac/amp, but without much bass or dynamics. Also, I'm just curious how it will sound on more powerful or different amps to see if it makes much difference. I hear the hd800 is pretty picky when it comes to amps.

This is very interesting. How can one understand from the sound if he needs more amplification?

 

[beautiophile]

This is very interesting. How can one understand from the sound if he needs more amplification?

There is a rule of thumb: while listening at your comfortable volume, you hear some less-detailed quiet sounds (like background drums or pianos) then you increase the volume to reveal them (usually over 2/3 of max volume) and you end up with distortion/hiss of the other sounds. This is a sign you need a stronger amplifier.

 

[eddyino]

There is a rule of thumb: while listening at your comfortable volume, you hear some less-detailed quiet sounds (like background drums or pianos) then you increase the volume to reveal them (usually over 2/3 of max volume) and you end up with distortion/hiss of the other sounds. This is a sign you need a stronger amplifier.

Thank you for your explanation. It makes sense. Not sure whether I have had such issues with Ud-503 so far. At least, with my headphones.

 

[Josef Parran]

I don't have the 789 yet as it's delivering in august/september. I do have the loxjie p20, which puts out over 300mw at 300ohm. I have hd800's, which are 300ohm cans.

Not sure how much power the UD-503 is putting out in that ohm range, but if it's 750mw per channel at 32ohm, I would think it's quite a bit less at 300ohm.

The 700mW per channel at 32ohm spec is in Balanced mode. Unbalanced is 500mW. And you're right, at 300ohm it's significantly less, about 100mW.

 

[foreverzer0]

The 700mW per channel at 32ohm spec is in Balanced mode. Unbalanced is 500mW. And you're right, at 300ohm it's significantly less, about 100mW.

Yes, using the balanced out for highest potential performance. I wish they had more specs around this.

 

[eddyino]

The 700mW per channel at 32ohm spec is in Balanced mode. Unbalanced is 500mW. And you're right, at 300ohm it's significantly less, about 100mW.

And what is considered enough at 300 ohm? So that the sound is amplified correctly? 500mW?

Recently I had a chance to compare the output of Teac UD-503 and Teac Ha-501. The latter one is pure amp and considerably more powerful by specs. It turns out, however, that I need to turn the volume to almost max in ha-501 to drive my Beyer dt250. No such issues with ud-503. It seems, the output volume is not only about specified amp power...

 

[Josef Parran]

And what is considered enough at 300 ohm? So that the sound is amplified correctly? 500mW?

That's almost impossible to answer. Depends on the headphone, your amp's output impedance, etc. BTW the output impedance on the UD-503 is about 12 ohms. The 500mW is the maximum power handling on the HD 650. That spec tells you how much power the headphone can handle without sustaining physical damage. It has nothing to do with required power.

Recently I had a chance to compare the output of Teac UD-503 and Teac Ha-501. The latter one is pure amp and considerably more powerful by specs. It turns out, however, that I need to turn the volume to almost max in ha-501 to drive my Beyer dt250. No such issues with ud-503. It seems, the output volume is not only about specified amp power...

Volume IS a function of power, unless the amp is doing some other more complex things. But strictly speaking, output volume will be about amp power. However sound quality is not, there are a lot of other variables in the equation, of which power is only one.

 

[eddyino]

That's almost impossible to answer. Depends on the headphone, your amp's output impedance, etc. BTW the output impedance on the UD-503 is about 12 ohms. The 500mW is the maximum power handling on the HD 650. That spec tells you how much power the headphone can handle without sustaining physical damage. It has nothing to do with required power.
Volume IS a function of power, unless the amp is doing some other more complex things. But strictly speaking, output volume will be about amp power. However sound quality is not, there are a lot of other variables in the equation, of which power is only one.

Yes, as I said the output volume is a function of power, but the power is not the only driver of volume. Otherwise, it is not clear how I managed to get higher volume on ha-501 relative to ud-503.

 

[Josef Parran]

Yes, as I said the output volume is a function of power, but the power is not the only driver of volume. Otherwise, it is not clear how I managed to get higher volume on ha-501 relative to ud-503.

That statement is contradictory. If volume is a function of power, it means power will drive volume. So technically you should get more volume from the HA-501 with most headphones. However the UD-503 amp has current matching which allows it to be more efficient with your DT 250 (i.e. driving them louder). The HA-501 is probably less efficient with lower impedance cans. This is where it gets a bit complicated. Search the thread if you want a better explanation as it was brought up earlier. Also, try the same comparison with your HD 650 and see if you get any different results.

 

[eddyino]

That statement is contradictory. If volume is a function of power, it means power will drive volume. So technically you should get more volume from the HA-501 with most headphones. However the UD-503 amp has current matching which allows it to be more efficient with your DT 250 (i.e. driving them louder). The HA-501 is probably less efficient with lower impedance cans. This is where it gets a bit complicated. Search the thread if you want a better explanation as it was brought up earlier. Also, try the same comparison with your HD 650 and see if you get any different results.

No, it is not. Volume depends on power, but it also seems to depend on some other factors or combination of factors. Due to these “other factors”, whatever they are, I am getting lower output volume on more powerful amplifier. The question is what these other factors are?
I have read the article you sent me. It is really good, clarifies a lot of thing about volume-power issues.

 

[Josef Parran]

Due to these “other factors”, whatever they are, I am getting lower output volume on more powerful amplifier. The question is what these other factors are?

One of these factors is output impedance. The HA-501 has a damping factor knob, which adjusts the amp's OI for use with a specific headphone. It could have been set really high when you tested it. Just guessing here...