[bpower]

Hi Guys,
 
I recently bought the EHP-02 from Epiphany. When listening to some tracks with a lot of dynamic range Im getting a lot of distortion (clipping?) at the load bits. I get the distortion at high volumes . but not crazy high, I could turn it up another couple of notches and still listen comfortably. A In the track below on Spotify at around 6:30 it gets really bad, like listening to a speaker phone up too loud. I get similar results with my hd 600s and M50. I get much less distortion on iems but the sound gets a bit mushed together and seems to struggle generally.
 
Alexei Sultanov – Rachmaninov : Piano Concerto No.2 in C minor Op.18 : II Adagio sostenuto
 
 
Am I just asking too much of the amp to power the cans comfortably at high volumes? At gain x6 I never goes past 11 oclock, so I thought it would have plenty of power in reserve.

 

[SilverEars]

I have the HD-650 and pressed the gain button, and the music distorted like a mutha.  I have it on unity gain now and it's much tighter.  If you raise the gain, does it drastically raise the output impedance?

 

[skeptic]

Gain doesn't affect output impedance. What you are hearing is likely clipping - a known issue with the o2 if you have a high output source and try to run the o2 at high gain. Just run it in the low gain setting, or by clipping one resistor, you can set it to 1x/2.5x as the two positions.

 

[skeptic]

On an unrelated note, I was all excited to try my agdr booster board for the first time today. Had everything fully populated and looking pretty good, and then, like a total genius I soldered ic1 in backwards and ripped a leg off trying to reverse it. A torrent of invective followed...

The most frustrating part is that I am leaving on a family trip Friday and there is no chance mouser or digikey will ship a replacement in time. Guess I'll have something to anticipate upon returning. Otherwise I think I did okay for a newbie at surface mount.

 

[bpower]

Yes, the low gain improved things. Its not clipping now, but it still fells like its struggling. Instrument separation, soundstage and detail suffer badly. 
 
 Im feeding it with usb, I have dac/amp combo, so thats my source. 

 

[SilverEars]

Anybody know of a portable DAC/Amp that is on the same level or can better the ODAC/O2 combo?  So far, I haven't found anything that can top it.  I listen to iems though.  I have tested with really high end iems such as the 334 and the 846.

 

[James-uk]

For them easy to drive HP the I phone 5s will sound identical .

 

[James-uk]

Yes, the low gain improved things. Its not clipping now, but it still fells like its struggling. Instrument separation, soundstage and detail suffer badly. 

 Im feeding it with usb, I have dac/amp combo, so thats my source. 

The only way the O2 will struggle is with power into inefficient headphones on dynamic / quiet records. This will only show itself as the volume pot not getting any louder after a certain point. For example I had a 'high res' copy of muse and I pumped it really loud one day , after turning it up to ear splitting levels at 12 o clock on the volume pot I turned it even more ( stupid I know!) but it didn't get louder , I continued to turn it and nothing happened. Basically the O2 ran out if steam but the sq was the same. It didn't matter because A , it was already too loud, and B, I just downloaded a different master with 'normal' mastering and it would louder while having the same dynamic range ( but why would I want to go louder !)

 

[JacobLee89]

On an unrelated note, I was all excited to try my agdr booster board for the first time today. Had everything fully populated and looking pretty good, and then, like a total genius I soldered ic1 in backwards and ripped a leg off trying to reverse it. A torrent of invective followed...

The most frustrating part is that I am leaving on a family trip Friday and there is no chance mouser or digikey will ship a replacement in time. Guess I'll have something to anticipate upon returning. Otherwise I think I did okay for a newbie at surface mount.

 
Your surface mount soldering looks cleaner than mine!
 
I also did the same mistake: soldering an IC backwards.. I fixed it by using a heatgun, and ensuring I did not apply more heat than necessary, and stopping once the IC showed signs of moving.

 

[headwhacker]

  Anybody know of a portable DAC/Amp that is on the same level or can better the ODAC/O2 combo?  So far, I haven't found anything that can top it.  I listen to iems though.  I have tested with really high end iems such as the 334 and the 846.

 
Amp-wise, the Leckerton UHA-6SMKII can match, if not exceed, O2 in transparency and clean background. As for the DAC, it's no contest. ODAC is better. But if you consider the size and if you are going to use it mainly as a portable the Leckerton paired with a DAP with a very capable DAC is the way to go.

 

[SilverEars]

   
Amp-wise, the Leckerton UHA-6SMKII can match, if not exceed, O2 in transparency and clean background. As for the DAC, it's no contest. ODAC is better. But if you consider the size and if you are going to use it mainly as a portable the Leckerton paired with a DAP with a very capable DAC is the way to go.

Thanks for the response I may try it out.  What about the UHA760?  Is it better SQ wise?  Why is it twice the value?

 

[headwhacker]

  Thanks for the response I may try it out.  What about the UHA760?  Is it better SQ wise?  Why is it twice the value?

 
 
The 760 adds minor improvements on the amp section, digital volume control, 3-step gain switch and crossfeed. But it's the same amp otherwise. However, I think the 760 is a step back with the DACs implementation as you will lose the TOSlink, Coax SPDIF input.
 
Also the 6SMKII has socketed opamp so you have an option to use different opamps anytime you like. For 760, you have to choose one upon purchase because you can't change it later down the road.
 
Personally if you will not use the crossfeed function, get the 6S-MKII and ask Nick to modify the gain steps from the default 0dB/18dB (low/high) to -12dB/12dB.
 
If you have a sensitive iems, the default low gain (0dB) is too much and does not allow wider range on the volume pot.

 

[SilverEars]

ask Nick to modify the gain steps from the default 0dB/18dB (low/high) to -12dB/12dB.
 
If you have a sensitive iems, the default low gain (0dB) is too much and does not allow wider range on the volume pot.

 
You have Roxanne and I know it's very sensitive and IEMs I will be using will be sensitive like Roxanne.  Is yours set from -12dB/12dB?  Is it like the Alps Pot?  If you get lucky with a good pot you're golden? 

​
 
I'm guessing you have tried the ODAC/O2 combo and compared with the Leckerton.

 

[headwhacker]

   
You have Roxanne and I know it's very sensitive and IEMs I will be using will be sensitive like Roxanne.  Is yours set from -12dB/12dB?  Is it like the Alps Pot?  If you get lucky with a good pot you're golden? 

​
 
I'm guessing you have tried the ODAC/O2 combo and compared with the Leckerton.

 
I only have the O2 not the ODAC and I use the amp section of the leckerton since I don't like it's CL DAC compared to the Wolfson on DX50. I used bring the O2/DX50 on the go. While the SQ is top notch, the size and awkward placement of jacks and switches on the O2 is a hassle sometimes. The leckerton is much compact and a better fit with my DX50. 
 
I compared a number of portable amps against O2 (C5D, UHA-4, PHA-1), none of them can match it's transparency and clear background except for UHA-6SMKII with the ADA4627-1 opamp.
 
I use my O2 now as a desktop amp.

 

[SilverEars]

I have the C5D right not and I personally feel that it's not up to snuff.  It sound artificial.  
 
The thing is I've tried feeding other DACs to the O2, and I could notice the suttle differences, and favor the ODAC.   The thing is I need a good DAC/Amp combo, and from what it sounds, you think it's the amp that makes the sound transparent.  I put lots of weight on the ODAC also.  Without both, it's not transparent to me.  I guess I will try the Leckerton and find out if it can match the ODAC/O2 combo.