O2 AMP + ODAC

[adydula]

I have a magni 3 and an o2. I've compared them back to back. If there is a difference in sound, It's subtle enough that I can't hear the difference.

There ya go...my point exactly!

I have torn apart lots of amps, including $1K + and thoes $100-$500 Chi-FI amps....and let me tell you besides the worry about crappy parts and comonents, which there are many. The overall quality
inside if often very, very apparent. From poor soldering, crappy wiring, safety grounding issues etc...

And when your chi-fi amp goes south its a several week and month back and forth from over there to over here...

When there are so many really great amps and dacs made in the USA its a no bariner for me....

A.

 

[439598]

There ya go...my point exactly!

I have torn apart lots of amps, including $1K + and thoes $100-$500 Chi-FI amps....and let me tell you besides the worry about crappy parts and comonents, which there are many. The overall quality
inside if often very, very apparent. From poor soldering, crappy wiring, safety grounding issues etc...

And when your chi-fi amp goes south its a several week and month back and forth from over there to over here...

When there are so many really great amps and dacs made in the USA its a no bariner for me....

A.

It sounds like you opened a LOT of ''chi-fi'' amps. How about you name 3 of them, so we know what to look out for??

AudioGD use shady capacitors. This british brand called Nover that you cant seem to buy anymore and have basically no info (if it ever existed to begin with), either they are some counterfeits stealing the brand or these are old stock.
Electrolytic capacitors have a limited lifespan, they will still work after many decades but their performance will be severly degraded and the older they get the more likely they are to fail.
If they are counterfeits that doesnt necessarily mean they are bad capacitors, could just be a fancy wrapping on standard cheap cap, anyway AGD is the only main chinese brand I would agree about quality concerns, their customer service system is worryingly primitive and I think their stuff is probably overhyped with how polarised people are about them.


Fiio, Topping, SMSL, Monoprice(?), Gustard - all build top quality products, as good any american or european brands. Which sound the best is a different discussion entirely.

 

[adydula]

Well,

Counterfiets IMO are illegal and just wrong when people go out of there way to steal someones else's work or prodcut. Period.
Thats "my" feeling on that one.

Ususally the electrolytic knock offs, have inferior dielectric material and chemicals, doping that dont last very long compared to the "real" thing...they often short or partially short causing all kinds of issues. Seveal major pc vendors had these cap issues for years....but the chi-fi guys often use these less than stellar, lack of any real QC on the parts blindly....and couple that with poor soldering and crappy point to point wiring makes me cringe...

BUT hey its your money..take a look at your Ch-fi stuff and if it meets your standards, great , enjoy the gear...just beware.

Not all ch-fi stuff is bad, but lots of the el cheopp ebay stuff, low cost stuff is not to be trusted....again thats my experience and opinion.

In the end it your choice, and buy what you want. I just buy stuff from honest vendors that have a good track record. On Ebay you need to be careful what you buy....

Alex

 

[439598]

Well,

Counterfiets IMO are illegal and just wrong when people go out of there way to steal someones else's work or prodcut. Period.
Thats "my" feeling on that one.

Ususally the electrolytic knock offs, have inferior dielectric material and chemicals, doping that dont last very long compared to the "real" thing...they often short or partially short causing all kinds of issues. Seveal major pc vendors had these cap issues for years....but the chi-fi guys often use these less than stellar, lack of any real QC on the parts blindly....and couple that with poor soldering and crappy point to point wiring makes me cringe...

BUT hey its your money..take a look at your Ch-fi stuff and if it meets your standards, great , enjoy the gear...just beware.

Not all ch-fi stuff is bad, but lots of the el cheopp ebay stuff, low cost stuff is not to be trusted....again thats my experience and opinion.

In the end it your choice, and buy what you want. I just buy stuff from honest vendors that have a good track record. On Ebay you need to be careful what you buy....

Alex

If we are just talking about the unbranded chinese ebay stuff then I agree, its 50/50 on the quality of what you get.
They are good for DIY, where you can buy them for next to nothing and improve them with modding where needed without spending much.

Ali express is miles better than ebay for these sort of things, their refund policies and item specific feedback kind of the force the sellers not to sell junk (in fact there is a ton of really cool stuff on there you wont find in other places)

 

[adydula]

Agree its hit or miss, I just dont like buying crap from overseas and having to muck with it when there is so much other good stuff to play with....DIY is fun and understand the aspect of that, I have a dozen DIY projects here and most are done with parts from Digikey and Mouser etc...Some from diyaudio, some homebrew stuff with my own pcbs..but when a company like Schitt comes out with a $99 high quality amp...well...

I have built several O2 derivitives with a fellow called AGDR over at Diyaudio...O2 booster boards, inverting and non inverting types...lots of fun, all sold now.

The attraction to DIY has always been for me to build an amp thats as good as one costing much more...but with the $99 great stuff out there thats a thing of the past for me.

 

[matti621]

Not really, in fact voltage requirement is depended only on headphone's sensitivity which doesn't necessarily correlates with hp's impedance curve. Look here: http://doctorhead.ru/upload/iblock/efd/fr.png
At 500 Hz it has higher sensitivity than on 1 kHz despite being higher impedance on 500 Hz.

In worst case they measured sensitivity of 96 dB/V and at best 109.9 dB/V. Which means that for playing 110 dB you would need 5.01 V in worst case and 1.01 V in best case and in average it's 3.13 V. O2 amp max output is 7.15 V, but exact number depends on used source and gain.
Feel free to ask more if you are interested

P.S: Beyers T1 has a relatively hot treble which when used with O2 can make some not very pleasing sound.

Thanks for the explanation. Finally someone explains it well.

 

[schmalgausen]

Hi all,

I have noticed that drop combo described as Rear RCA input/output:

- USB and RCA only: DAC is active, and RCA is set as output (amp is unpowered)
- Power brick and RCA only: DAC is bypassed and RCA is set as input for amp (DAC is unpowered)
- Power brick, USB, and RCA: DAC is active, RCA is set as additional input for amp

I wonder if I can use ODAC 1/8" output jack as input with disconnected USB in my DIY O2+ODAC combo? Does it affect sound quality?

Sorry for electronics nub question.

 

[BenF]

Hi all,

I have noticed that drop combo described as Rear RCA input/output:

- USB and RCA only: DAC is active, and RCA is set as output (amp is unpowered)
- Power brick and RCA only: DAC is bypassed and RCA is set as input for amp (DAC is unpowered)
- Power brick, USB, and RCA: DAC is active, RCA is set as additional input for amp

I wonder if I can use ODAC 1/8" output jack as input with disconnected USB in my DIY O2+ODAC combo? Does it affect sound quality?

Sorry for electronics nub question.

Sure, you can do this with 3.5mm -> RCA adapter, sound quality will be as great as ODAC + O2 (which I have).

 

[Starbound]

I got an O2/ODAC amp last month and I have been very impressed by it. I use it to drive HD580 and MDR-7506 headphones. The MDR-7506 is very easy to drive, but it seems to also benefit from using it with the Objective2/ODAC, it sounds cleaner and more controlled.

This is am amazing amp, very clear and with no discernible noise!

I just got an old Austria-made K240 Monitor (the 600 ohm model). Will the O2 be enough to drive it? According to the notorious vlogger Zeos it is almost as hard to drive as an HE-6, though I take Zeos's opinions with a grain of salt (he is very entertaining but sometimes I think he is too sensationalistic).

My O2 has the 2.5x / 6.5x gain and I use it on AC power. I have a TRIAD 1000mAh, which is recommended for cans with high power demands.

What is the most power-hungry headphones an Objective 2 amp can drive with this power supply, in your opinion?

 

[gargani]

I got an O2/ODAC amp last month and I have been very impressed by it. I use it to drive HD580 and MDR-7506 headphones. The MDR-7506 is very easy to drive, but it seems to also benefit from using it with the Objective2/ODAC, it sounds cleaner and more controlled.

This is am amazing amp, very clear and with no discernible noise!

I just got an old Austria-made K240 Monitor (the 600 ohm model). Will the O2 be enough to drive it? According to the notorious vlogger Zeos it is almost as hard to drive as an HE-6, though I take Zeos's opinions with a grain of salt (he is very entertaining but sometimes I think he is too sensationalistic).

My O2 has the 2.5x / 6.5x gain and I use it on AC power. I have a TRIAD 1000mAh, which is recommended for cans with high power demands.

What is the most power-hungry headphones an Objective 2 amp can drive with this power supply, in your opinion?

My Objective 2 can power my 600 Ohm Beyer dt990 pemium headphones. With low gain I set it at 3 o'clock. With high gain I set it at 12 o'clock.

I owned the Austrian-made k240m for years before they finally gave up the ghost. I used them with my Yamaha receiver, at the time.

 

[Starbound]

My Objective 2 can power my 600 Ohm Beyer dt990 pemium headphones. With low gain I set it at 3 o'clock. With high gain I set it at 12 o'clock.

I owned the Austrian-made k240m for years before they finally gave up the ghost. I used them with my Yamaha receiver, at the time.

Thank you for the reference point. I believe for some reason the old K240 600 ohm cans tend to be harder to drive than more modern headphones at the same impedance.

I also hear a lot of good stuff about the K240M getting paired with old receivers. What music did you use the K240M to listen? I can't wait to get mine and give them a try. They will be the oldest headphones I have ever listened to, and the classic K240 models have a sort of mystique surrounding them.

 

[Starbound]

There ya go...my point exactly!

I have torn apart lots of amps, including $1K + and thoes $100-$500 Chi-FI amps....and let me tell you besides the worry about crappy parts and comonents, which there are many. The overall quality
inside if often very, very apparent. From poor soldering, crappy wiring, safety grounding issues etc...

And when your chi-fi amp goes south its a several week and month back and forth from over there to over here...

When there are so many really great amps and dacs made in the USA its a no bariner for me....

A.

Interesting you say this, and although it might be a hasty generalization, I think there must be some truth to it in many cases. Did you hear about the Topping L30 issues?

 

[gargani]

Thank you for the reference point. I believe for some reason the old K240 600 ohm cans tend to be harder to drive than more modern headphones at the same impedance.

I also hear a lot of good stuff about the K240M getting paired with old receivers. What music did you use the K240M to listen? I can't wait to get mine and give them a try. They will be the oldest headphones I have ever listened to, and the classic K240 models have a sort of mystique surrounding them.

It was about 20 years ago that they gave up the ghost; so I have no idea how they would stand up to headphones today.
I listened to what is now classic rock and early prog rock. Also I never owned a headphone amp at the time.
It would be interesting to know how you make out with the objective 02 and how you think about them as compared to the other headphones you mentioned.

 

[raoultrifan]

I believe for some reason the old K240 600 ohm cans tend to be harder to drive than more modern headphones at the same impedance.

Everything is related to basic math here: AKG K240 has a sensitivity of 104 dB SPL/V @ 1 kHz and according to Digizoid we have this:

�

Listening Loudness	Voltage Needed	Current Needed	Power Needed
Safe	85 dB SPL	0.11 Vrms	0.18 mA	0.02 mW
Moderate	100 dB SPL	0.63 Vrms	1.05 mA	0.66 mW
Fairly Loud	110 dB SPL	2 Vrms	3.33 mA	6.67 mW
Very Loud	115 dB SPL	3.55 Vrms	5.92 mA	21 mW
Painful	120 dB SPL	6.31 Vrms	10.52 mA	66.36 mW

Given that O2 has a max. output power of about 7.3 V RMS, I see no problems driving K240.

My DT880 has a lower sensitivity and O2 will not drive them to full power, but I can still get acceptable dB levels to my ears.

I also hear a lot of good stuff about the K240M getting paired with old receivers.

Probably folks thinking that a simple resistors added to speakers output will make 600-Ohms headphones sound "better". I would ignore them and use a dedicated headamp with a low output impedance (even if the 1/8-rule will not matter to our 600-Ohms headset, you never know when you'll pair a 16-Ohms headset with that amp).

 

[Starbound]

It was about 20 years ago that they gave up the ghost; so I have no idea how they would stand up to headphones today.
I listened to what is now classic rock and early prog rock. Also I never owned a headphone amp at the time.
It would be interesting to know how you make out with the objective 02 and how you think about them as compared to the other headphones you mentioned.

Yes, I will post about my experience with them. I really look forward to getting them, they will be my first AKG headphone. I remember eons ago when I was a very young child hearing music at some friends of my parents in their stereo on some AKG headphones, I believe an AKG K240 Sextett. Fond memories!