germanium
Headphoneus Supremus
Anyone make a D.C. coupled battery powered portable amp for headphones??
I would like to buy one if they do.
I would like to buy one if they do.
D.C. coupling
- Thread starter germanium
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germanium
Headphoneus Supremus
I see no reason it can't be done as it would be less expensive & sound better at the same time. The money saved on not needing capacitors could be spent on an even better opamp. The only cost increase being the need for dual power supply rails. Since most outboard portable amps use 2 or more batteries you only need a terminal between the 2 batteries for ground. I don't think that would be very hard to do at all.
BennyBoy
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If they were worth doing? folks would be making them! It's not like any of the amp designs were not thought up 30~50 years ago. There must be some down fall to a D.C. coupled design?
dsavitsk
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Quote:
I can't think of any battery powered amps that aren't DC coupled.
| Originally Posted by germanium Anyone make a D.C. coupled battery powered portable amp for headphones?? |
I can't think of any battery powered amps that aren't DC coupled.
nikongod
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Quote:
many have caps on the inputs.
there are a couple that have output caps, but they largely suck.
aside from the input, the vast majority as stated elsewhere are dc coupled from there on.
| Originally Posted by dsavitsk I can't think of any battery powered amps that aren't DC coupled. |
many have caps on the inputs.
there are a couple that have output caps, but they largely suck.
aside from the input, the vast majority as stated elsewhere are dc coupled from there on.
recephasan
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I thought the SR-71 was DC Coupled
ATAT
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The PPAS is DC coupled. in fact, I didn't put in spaces for caps (to save space)..
germanium
Headphoneus Supremus
Quote:
Looks very interesting but what is the sound signature that you speak of & will they be marketing complete amps any time soon. This is the first time seeing a a buffered ground amplifier. I have done a fair amout of modifying before but have not actually built an amp from the ground up. In some way modifying an existing product is more dificult I believe due to the fact that you can only apply heat so many times to the board before the board starts to delaminate but building from scratch with simd componants is definately a challenge. what is the required voltage for this amp. I would like to be able to use it with litium-ion batteries instead of nickel metal hydride as they are lighter.
Will you be providing a kit or will i have to hunt down the required parts. I work very long hours & really have only 1 day a week to work on such a project.
| Originally Posted by ATAT The PPAS is DC coupled. in fact, I didn't put in spaces for caps (to save space).. |
Looks very interesting but what is the sound signature that you speak of & will they be marketing complete amps any time soon. This is the first time seeing a a buffered ground amplifier. I have done a fair amout of modifying before but have not actually built an amp from the ground up. In some way modifying an existing product is more dificult I believe due to the fact that you can only apply heat so many times to the board before the board starts to delaminate but building from scratch with simd componants is definately a challenge. what is the required voltage for this amp. I would like to be able to use it with litium-ion batteries instead of nickel metal hydride as they are lighter.
Will you be providing a kit or will i have to hunt down the required parts. I work very long hours & really have only 1 day a week to work on such a project.
germanium
Headphoneus Supremus
Quote:
Not D.C. coupled If it were D.C. coupled the frequency response would be from 0Hz to 100KHz instead of 10Hz-100KHz
| Originally Posted by recephasan I thought the SR-71 was DC Coupled |
Not D.C. coupled If it were D.C. coupled the frequency response would be from 0Hz to 100KHz instead of 10Hz-100KHz
germanium
Headphoneus Supremus
Quote:
There is a downfall in terms of not having any protection against D.C. at the output & the amp will continue to amplify even a pure D.C. signal. This could cause the amp to overheat & alse damage the speakers. These conditions are usually only present if there is a failure in an upstream componant. Given the rarity of these failures & the sonic benifits of true D.C. coupling I prefer to listen to music through amps that are D.C. coupled. most of my home equipment is modified for true D.C. coupling & it sounds superb.
As you can see I understand both the benefits & drawbacks to D.C. coupling but still prefer it to the veiled sound that you get from most capacitor coupled amps as the loss through the electrolytic coupling caps comes in at 5% & is very noticable. In places that you can't D.C. couple I replace electrolytics with metallized film if there is room. By the way That 5% loss is due to dielectic absorbtion and that is not the only losses encountered with electrolytics. Using electrolytics as a bleed for the negative feedback to control the gain of a high gain amplifier brings out the very worst in them. They sound absolutely dead with no redeeming sonic quality at all where as using either D.C. coupling or metalized film in this sensitive location of the amp results in a very open revealing sound with incredable bass extension & detail.
| Originally Posted by BennyBoy If they were worth doing? folks would be making them! It's not like any of the amp designs were not thought up 30~50 years ago. There must be some down fall to a D.C. coupled design?
|
There is a downfall in terms of not having any protection against D.C. at the output & the amp will continue to amplify even a pure D.C. signal. This could cause the amp to overheat & alse damage the speakers. These conditions are usually only present if there is a failure in an upstream componant. Given the rarity of these failures & the sonic benifits of true D.C. coupling I prefer to listen to music through amps that are D.C. coupled. most of my home equipment is modified for true D.C. coupling & it sounds superb.
As you can see I understand both the benefits & drawbacks to D.C. coupling but still prefer it to the veiled sound that you get from most capacitor coupled amps as the loss through the electrolytic coupling caps comes in at 5% & is very noticable. In places that you can't D.C. couple I replace electrolytics with metallized film if there is room. By the way That 5% loss is due to dielectic absorbtion and that is not the only losses encountered with electrolytics. Using electrolytics as a bleed for the negative feedback to control the gain of a high gain amplifier brings out the very worst in them. They sound absolutely dead with no redeeming sonic quality at all where as using either D.C. coupling or metalized film in this sensitive location of the amp results in a very open revealing sound with incredable bass extension & detail.
nikongod
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Quote:
i deleted the rest, i really ony care about that last sentance.
who here uses an electrolytic cap in a portable amp for dc blocking purposes?
all of the portables (and home based amps) that i have seen with interstage& "before-amp" caps use film.
| Originally Posted by germanium As you can see I understand both the benefits & drawbacks to D.C. coupling but still prefer it to the veiled sound that you get from most capacitor coupled amps as the loss through the electrolytic coupling caps comes in at 5% & is very noticable. |
i deleted the rest, i really ony care about that last sentance.
who here uses an electrolytic cap in a portable amp for dc blocking purposes?
all of the portables (and home based amps) that i have seen with interstage& "before-amp" caps use film.
ATAT
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Agreed on the electrolyt, but if you have a low DC offset source, why have an input cap at all? and the so called film input resistors are pretty low quality (because of space constraints) compared to the higher-end desktop counterparts.
germanium
Headphoneus Supremus
Quote:
Most mid fi & all portables that I have seen use electrolytics.
| Originally Posted by nikongod i deleted the rest, i really ony care about that last sentance. who here uses an electrolytic cap in a portable amp for dc blocking purposes? all of the portables (and home based amps) that i have seen with interstage& "before-amp" caps use film. |
Most mid fi & all portables that I have seen use electrolytics.
germanium
Headphoneus Supremus
Quote:
That was the way I look at it too actually. I only use mettalized film when dealing with High D.C. offset that can't be corrected without extraordinary redesign. Some places the only option is electrolytics as there is no room for anything physically larger & film capacitors are very large compared to thier capacity. D.C. coupling is to me the best sounding but film is a very very close second, almost indistinguishable from D.C. coupling except in rare circumstances.
| Originally Posted by ATAT Agreed on the electrolyt, but if you have a low DC offset source, why have an input cap at all? and the so called film input resistors are pretty low quality (because of space constraints) compared to the higher-end desktop counterparts. |
That was the way I look at it too actually. I only use mettalized film when dealing with High D.C. offset that can't be corrected without extraordinary redesign. Some places the only option is electrolytics as there is no room for anything physically larger & film capacitors are very large compared to thier capacity. D.C. coupling is to me the best sounding but film is a very very close second, almost indistinguishable from D.C. coupling except in rare circumstances.
ATAT
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Well, I have no issues with high quality film caps in the path, consider that your DAC already has film caps to kill the offset there.. so that's your weakest link (unless you have something like the AD1868 or use a voltage servo..)
too bad there's not enough space in portable gear for that.. I usually just make sure all my sources are OK with the offset.
| Originally Posted by germanium That was the way I look at it too actually. I only use mettalized film when dealing with High D.C. offset that can't be corrected without extraordinary redesign. Some places the only option is electrolytics as there is no room for anything physically larger & film capacitors are very large compared to thier capacity. D.C. coupling is to me the best sounding but film is a very very close second, almost indistinguishable from D.C. coupling except in rare circumstances. |
Well, I have no issues with high quality film caps in the path, consider that your DAC already has film caps to kill the offset there.. so that's your weakest link (unless you have something like the AD1868 or use a voltage servo..)
too bad there's not enough space in portable gear for that.. I usually just make sure all my sources are OK with the offset.
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