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what amp can save my PRaTless DT880? - Page 3

post #31 of 42
Quote:
Originally Posted by Noob Meister Jr View Post
 


Thanks for the detailed response! there is no way in my country I can get the chance to try out different cans or amps so I may just keep the cans I've got as it is probably hard (/expensive to ship overseas) to resell them anyway. So what amp would you recommend for the 250 ohm DT880? I'm hoping something for around max $200 US because after this i start having to pay import fee, customs duty and goods and services tax, which increases the cost dramatically. 

What country do you live in?

 

Solid state amps

Schiit Magni

O2 (Objective 2)

 

Tube amp

Bravo Ocean

 

There are a lot of low cost tube amplifiers sold on eBay, $50- $130.

The Indeed brand seems to be one of the better ones.

post #32 of 42
Quote:
Originally Posted by PurpleAngel View Post
 

What country do you live in?

 

Solid state amps

Schiit Magni

O2 (Objective 2)

 

Tube amp

Bravo Ocean

 

There are a lot of low cost tube amplifiers sold on eBay, $50- $130.

The Indeed brand seems to be one of the better ones.

I doubt that you're going to get a decent tube amp that inexpensively. I wouldn't want to have plate voltage circulating through my cans on my head if the circuit fails in a bad way. I don't think that using a single tube (dual triode. etc) design to drive quality cans is going to pan out.

post #33 of 42
Thread Starter 
Quote:
Originally Posted by StanD View Post
 

I doubt that you're going to get a decent tube amp that inexpensively. I wouldn't want to have plate voltage circulating through my cans on my head if the circuit fails in a bad way. I don't think that using a single tube (dual triode. etc) design to drive quality cans is going to pan out.


What about the little dot mk3? I like the idea of tubes to colour the sound for when i'm listening to vinyl and so can't use EQ. I don't currenlty have a large collection of vinyl or digital or CD due to being burgled so I'm not sure what direction to go in for my hi-fi listening as yet.

post #34 of 42
Quote:
Originally Posted by Noob Meister Jr View Post
 


What about the little dot mk3? I like the idea of tubes to colour the sound for when i'm listening to vinyl and so can't use EQ. I don't currenlty have a large collection of vinyl or digital or CD due to being burgled so I'm not sure what direction to go in for my hi-fi listening as yet.

 

If you decide to buy it, buy directly from the manufacturer so you have a full warranty.

post #35 of 42
Quote:
Originally Posted by Noob Meister Jr View Post


What about the little dot mk3? I like the idea of tubes to colour the sound for when i'm listening to vinyl and so can't use EQ. I don't currenlty have a large collection of vinyl or digital or CD due to being burgled so I'm not sure what direction to go in for my hi-fi listening as yet.


I had the Little Dot MKIII for about a year. I used it with my 250 ohm DT-990, as well as with the Q701. It's a competent amp. Build quality is good, and most extra tubes you might want to try should cost $10-15 a pair on Ebay. I'm not sure if it will give the sense of speed and prat that you're looking for, but it definitely colors the sound in a distinctive way. Smooth with some warmth and wetness in the midbass. 

Have you considered the Schiit Vali? I haven't heard it, but it's half the price and much more powerful. 

post #36 of 42
Thread Starter 
Quote:
Originally Posted by manbear View Post
 


I had the Little Dot MKIII for about a year. I used it with my 250 ohm DT-990, as well as with the Q701. It's a competent amp. Build quality is good, and most extra tubes you might want to try should cost $10-15 a pair on Ebay. I'm not sure if it will give the sense of speed and prat that you're looking for, but it definitely colors the sound in a distinctive way. Smooth with some warmth and wetness in the midbass. 

Thanks for this...

 

Quote:
Have you considered the Schiit Vali? I haven't heard it, but it's half the price and much more powerful. 

 

According to the specs on their respective sites the vali produces 220MW at 300 ohms whereas the mk3 produces 350 MW at 300 ohm, so the mk3 is a lot more powerful. It has a lot less distortion too and I've read bad things about the vali. also, if i'm going tubes i might as well go all out rather than hybrid. Have you used the vali?

post #37 of 42
Thread Starter 
Quote:
Originally Posted by StanD View Post
 

The Schiit Magni desktop amp can deliver 260mW at 300 Ohms and even more at 250 Ohms. That'll put you above 120 db, which is the threshold of pain.

The FiiO E12 portable amp can drive my 300 Ohm HD600's rather loudly and the DT880's are more sensitive. I just did some quick math based upon their minimum output voltage spec and it should crank out at least 100mW which is just under 117 dB and trust me that will be much louder than you will ever listen. If I look at one of their newer specs it should crank out 150mW at 300 Ohms which means more than that at 250 Ohms which would place it above 117 dB. Either of these amps are very reasonably priced and perform well.

 

Model

Impedance

Sensitivity

Power required by

95dB sound pressure

Power required by

105dB sound pressure

Power required by

120dB sound pressure

DT880

250

96

0.79

7.94

251.19


Hey mate I'd appreciate if you'd give me your opinion on teh following: is it all about volume? in other words, if the volume is enough do i need an amp? otehrs have said no, that certain frequencies need higher voltage and therefore although i can't bare my volume on my macbook being more than 50% most of the time, when feeding into my dt880, i may not be driving certain frequencies as well as i could with a better amp. The Fiio x3 I just bougth for my partner to use her DT660s with at work and the 880/660 at home don't drive the 880 to a volume anywhere nearly as high as  what the macbook does. Does this mean the macbooks amplifier is better?


Edited by Noob Meister Jr - 12/25/13 at 2:44am
post #38 of 42
Quote:
Originally Posted by Noob Meister Jr View Post
 

According to the specs on their respective sites the vali produces 220MW at 300 ohms whereas the mk3 produces 350 MW at 300 ohm, so the mk3 is a lot more powerful. It has a lot less distortion too and I've read bad things about the vali. also, if i'm going tubes i might as well go all out rather than hybrid. Have you used the vali?


Good point, I forgot about the impedances. I have not used the Vali. I mentioned it mostly because it is cheap and it seems like a lot of people are happy with it. In any case, the Little Dot was a good introduction to tubes for me. Tube rolling is fun and a lot cheaper for the LD than for some other tube amps. 

post #39 of 42
Quote:
Originally Posted by Noob Meister Jr View Post
 


Hey mate I'd appreciate if you'd give me your opinion on teh following: is it all about volume? in other words, if the volume is enough do i need an amp? otehrs have said no, that certain frequencies need higher voltage and therefore although i can't bare my volume on my macbook being more than 50% most of the time, when feeding into my dt880, i may not be driving certain frequencies as well as i could with a better amp. The Fiio x3 I just bougth for my partner to use her DT660s with at work and the 880/660 at home don't drive the 880 to a volume anywhere nearly as high as  what the macbook does. Does this mean the macbooks amplifier is better?

If an amplifier has a flat frequency response, which is what we want, to work properly it should be able to to drive your cans equally across all audio frequencies. If the impedance of your cans change with frequency your amp will have to be able to drive the same voltages and supply different current levels to satisfy the imedance. This might a problem if impedances get lower and the amp can't supply enought current to drive to the same voltage and sustain volume levels. Generaly this shouldn't be the problem as for example some Sennheisers have impedances that rise somewhere around the mid-bass  and the current deman is less not more. Low impedances require more current. A headphone has a sensitivity rating in dB per mW. to reach a level loud enough the amp has to supply enough power to drive the headphones to the dB level you want to listen to and have enought spare for headroom.

No you do not need higher voltages at certain frequencies. You will need higher voltages to drive cans at higher impedance for the same sensitivity. So if two cans have the same 89 dB/mW sensitivity and one is 50 Ohms and the other is 300 Ohms, the amp driving the 300 Ohm cans will need to have more gain and be able to drive the cans to a higher voltage.

P=E^2 / R

P = power

E = voltage so E^2 neans E squared

R = resistance or impedance of the cans.

 

So

 

E = sqrt(P x R)

So the 250 Ohm DT880's at 96 dB/mW ro reach lets say 117 dB would require 128 mA. That means the amp woud have to be able to reach approx 5.7V or about 16 Vp-p which is around the upper limit of a FiiO E12, not bad at all as do you need to reach the threshold of pain?

 

So basically higher impedance cans require more gain to reach higher voltages and lower impedance cans require more current at a lower voltage. Since amplifiers amplify the signal voltage by a constant set by the volume control, changing the load impedance with frequency does not change the expected voltage output of the amp. It only changes the output current required to meet that voltage. If the impedance gets too low and the amplifier cannot supply enough current to meet the required voltage you will get distortion. Also if the impedance drops to less than 8 or 10 times the Amp's output impedance you will lower the damping ratio a the quality of bass will suffer.

 

So your statement that certain frequencies require more voltage is not correct. If the volume/loudness is sufficient but the output impedance of the amp is not low enough the bass will suffer and you will need an amp with a lower output impedance to improve the damping factor. some say that the output impedance of your amp shoud be 1/8th the impedance of your cans, others say 1/10th. Don't forget that you need headroom to prevent distortion at high dynamics (the loud side of it).

 

So as I said previously, the Schiit Magni should drive you to pain with the 250 Ohm DT880's.


Edited by StanD - 12/25/13 at 6:08pm
post #40 of 42
Thread Starter 
Quote:
Originally Posted by StanD View Post
 

If an amplifier has a flat frequency response, which is what we want, to work properly it should be able to to drive your cans equally across all audio frequencies. If the impedance of your cans change with frequency your amp will have to be able to drive the same voltages and supply different current levels to satisfy the imedance. This might a problem if impedances get lower and the amp can't supply enought current to drive to the same voltage and sustain volume levels. Generaly this shouldn't be the problem as for example some Sennheisers have impedances that rise somewhere around the mid-bass  and the current deman is less not more. Low impedances require more current. A headphone has a sensitivity rating in dB per mW. to reach a level loud enough the amp has to supply enough power to drive the headphones to the dB level you want to listen to and have enought spare for headroom.

No you do not need higher voltages at certain frequencies. You will need higher voltages to drive cans at higher impedance for the same sensitivity. So if two cans have the same 89 dB/mW sensitivity and one is 50 Ohms and the other is 300 Ohms, the amp driving the 300 Ohm cans will need to have more gain and be able to drive the cans to a higher voltage.

P=E^2 / R

P = power

E = voltage so E^2 neans E squared

R = resistance or impedance of the cans.

 

So

 

E = sqrt(P x R)

So the 250 Ohm DT880's at 96 dB/mW ro reach lets say 117 dB would require 128 mA. That means the amp woud have to be able to reach approx 5.7V or about 16 Vp-p which is around the upper limit of a FiiO E12, not bad at all as do you need to reach the threshold of pain?

 

So basically higher impedance cans require more gain to reach higher voltages and lower impedance cans require more current at a lower voltage. Since amplifiers amplify the signal voltage by a constant set by the volume control, changing the load impedance with frequency does not change the expected voltage output of the amp. It only changes the output current required to meet that voltage. If the impedance gets too low and the amplifier cannot supply enough current to meet the required voltage you will get distortion. Also if the impedance drops to less than 8 or 10 times the Amp's output impedance you will lower the damping ratio a the quality of bass will suffer.

 

So your statement that certain frequencies require more voltage is not correct. If the volume/loudness is sufficient but the output impedance of the amp is not low enough the bass will suffer and you will need an amp with a lower output impedance to improve the damping factor. some say that the output impedance of your amp shoud be 1/8th the impedance of your cans, others say 1/10th. Don't forget that you need headroom to prevent distortion at high dynamics (the loud side of it).

 

So as I said previously, the Schiit Magni should drive you to pain with the 250 Ohm DT880's.

 

 

 


Thanks for this response, I really appreciate the effort adn should have thanked you earlier. I'm not sure I'm 100% clear on this though...From what you say I would suspect  that lower impedance cans through the same amp would be more likely to distort. So if my 32 ohm dt660 sound good, i.e. not distorted,  through a certain amplifier then the 250 ohm DT880 should have less distortion, providing it can get loud enough, with headroom. So if the DT880 gets loud enough at say 70% volume, presuming that is enough headroom (????), then there should be no distortion and I should be happy with the amp? Correct?

post #41 of 42
Quote:
Originally Posted by Noob Meister Jr View Post
 

 

 

 


Thanks for this response, I really appreciate the effort adn should have thanked you earlier. I'm not sure I'm 100% clear on this though...From what you say I would suspect  that lower impedance cans through the same amp would be more likely to distort. So if my 32 ohm dt660 sound good, i.e. not distorted,  through a certain amplifier then the 250 ohm DT880 should have less distortion, providing it can get loud enough, with headroom. So if the DT880 gets loud enough at say 70% volume, presuming that is enough headroom (????), then there should be no distortion and I should be happy with the amp? Correct?

You're welcome. :happy_face1:

A lower impedance can will only distort if your amp cannot supply the current necessary to reach the voltage required by the cans to reach the desired loudness . That loudness is determined by the can's sensitivity rating.

Amps amplify voltage and should be able to supply enough current to reach that voltage while under load (impedance). The Voltage is determined by how loud you want to listen based upon the can's sensitivity which can be found in their spec's and is given either as:

Number of dB at 1 Volt RMS

or 

Number of dB at 1 mW

 

So to answer your questions:

A lower impedance can might have a problem with a specific amp based upon it's power rating and the can's impedance as well as sensitivity. Or they might work fine. If you use a lower impedance can, then the amps should also have a impedance that is 1/8th or 1/10th of the can;'s impedance, or lower. This is to provide proper damping to control the inertia of the cone/diaphragm of a dynamic can. An Orthodynamic or Planar Magnetic can usually doesn't need such a damping ratio. An electrostatic can is another proposition, a very expensive one. 

One has either to do the math or plug them in and listen carefully as not to hurt your ears.

If you get no distortion at 70% and things sound good during loud or dynamic passages, you are probably in good shape.

post #42 of 42

My experience with the DT880 (had the older--and I always thought the better-- 2003 version of the 250 ohm version, and later the 600 ohm, version) gave me the impression of a very even-handed, "neutralish" sound character.  I ran mine with the all-tube Darkvoice 336SE and the hybrid Bada PH-12, which bought some added color, contour and fullness to the stock DT880 sound.  But frankly, my thoughts are that the voicing of the DT880 is not inherently endowed with Pace, Rhythm and Timing in the manner you might expect.


Edited by pataburd - 1/17/14 at 8:01pm
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