Originally Posted by lucifix /img/forum/go_quote.gif Thanks. How do I tell which are dual and single opamps, supposing I am not using the iBasso provided opamps?
Thanks!
The best way to make certain is to check the datasheet supplied by the opamp manufacturer. Often the marking will indicate if it is dual, but not aways. For example, the OPA2134 is dual whereas the OPA134 is single. Likewise, the OPA2227 is dual, the OPA227 is single. Mostly, you will have no idea, unless you check the datasheet. These can be found, usually as a .pdf file as one of the first Google hits if you type in the name of the opamp.
I have tried to duplicate this with my Heron and UM2s but I get normal sound, albeit at extremely low volume position due to the extremely sensitive UM2s. Your recording sounds like it has some 60hz hum in it. Running on batteries, there should be none. I would first try unplugging the DC adapter, if you are using it. Then try a different source using different interconnect cables.
If the problem persists, try changing the LR opamp and putting in the bypass buffers.
If problem persists, back to Dr iBasso for them to fix.
That sound is usually due to an opamp artifact, but can be mimiced by cables, etc.
FWIW, my Heron is running the LTC6241HV, iBasso-supplied transistor buffers, and an OPA2134 opamp in the ground channel.
Good luck, and post your results of the above trials.
HiFlight
Quote:
Originally Posted by lucifix /img/forum/go_quote.gif Ok I was running the Heron in its stock opamp configuration with the Transister Buffer being used, and encountered a serious problem and was wondering if any other P3 owners experience the same problem.
I have the P3 in low gain setting, and had my UM2's on with no music playing.
Adjusting the volume pot within the range of the first two dots as shown in the diagram where the red arrow indicates the range of volume pot adjustment, I heard lots of unwanted noise.
I will try to describe it to the best of my ability but have included a direct-download link to the .WMA file which I have tried to record the sound with success by attaching my voice recoreder input to the output of the Heron.
What I heard was a shrill whistling sound that was never before heard in my Viper. This sound was very persistent and there was lots of white noise also, and only untill I move the volume pot past the second dot, where it would be pitch black and then noisy again, with lots of white noise.
Whilst recording I first turned on the unit with music playing and turned it to the second dot, where I then stopped playing music and turned the knob back down again.
Please let me know if anyone else has been experiencing this and if I should return this to iBasso.
Btw, I have given the P3 a good 24 hour burn in period with the buffers as I thought the problem will go away after that.
Originally Posted by HiFlight /img/forum/go_quote.gif The best way to make certain is to check the datasheet supplied by the opamp manufacturer. Often the marking will indicate if it is dual, but not aways. For example, the OPA2134 is dual whereas the OPA134 is single. Likewise, the OPA2227 is dual, the OPA227 is single. Mostly, you will have no idea, unless you check the datasheet. These can be found, usually as a .pdf file as one of the first Google hits if you type in the name of the opamp.
I tried downloading for example the specification sheet of the LMH6655MA but do not know where on the spec sheet can I find info on whether it is a single or dual opamp.
Originally Posted by lucifix /img/forum/go_quote.gif I tried downloading for example the specification sheet of the LMH6655MA but do not know where on the spec sheet can I find info on whether it is a single or dual opamp.
Please help, thanks!
Here is a link to the .pdf file. At the very top, it states that the specs are for the LMH6654/55 single/dual ....That makes it pretty clear: 6654=single, 6655=dual.
Lucifix, was your problem been fixed?
That happened with my P2 just last week. It has something to do with the line in. If anything was plugged into the line in jack I would get noise like yours. If I touch the line in plug the noise would increase to what sounded like RF interference. At times it sounded like bad reception on a AM radio.
It started after I ran the battery down and recharged and listened at the same time. Since it sounded like RF, I put a ferrite tube on the charger and recharged the P2. The noise was significantly smaller. After two more charge cycles it was dead silent.
Originally Posted by sunneebear /img/forum/go_quote.gif Lucifix, was your problem been fixed?
That happened with my P2 just last week. It has something to do with the line in. If anything was plugged into the line in jack I would get noise like yours. If I touch the line in plug the noise would increase to what sounded like RF interference. At times it sounded like bad reception on a AM radio.
It started after I ran the battery down and recharged and listened at the same time. Since it sounded like RF, I put a ferrite tube on the charger and recharged the P2. The noise was significantly smaller. After two more charge cycles it was dead silent.
It has been fixed and I managed to find that the problem was caused by the AD797 opamps, which after swapping them with 6655MA opamps, it disappeared.
I think the 60hz hum will be there so as long as the charger is in use.
I'm considering either getting the D3 or the P3 and I have a couple of questions for whoever can help me out.
Firstly, is it worth it to get a DAC (the D3) if I have an X-FI music or should I just do the op-amp mod on the X-FI instead? I really wouldn't need the DAC for anything else besides use with the machine with the X-FI installed.
Secondly, as I understand it the P3 is rollable and the D3 is not. Does that make the P3 better/more versatile as a pure amp or is the D3 more powerful/better in that respect as well?
Originally Posted by googan /img/forum/go_quote.gif I'm considering either getting the D3 or the P3 and I have a couple of questions for whoever can help me out.
Firstly, is it worth it to get a DAC (the D3) if I have an X-FI music or should I just do the op-amp mod on the X-FI instead? I really wouldn't need the DAC for anything else besides use with the machine with the X-FI installed.
Secondly, as I understand it the P3 is rollable and the D3 is not. Does that make the P3 better/more versatile as a pure amp or is the D3 more powerful/better in that respect as well?
If you like to experiment with different opamps, and have no need for a DAC, the P3 would likely be your best choice, however the D3 has really top-of-the-line sound that I have not yet been able to better by rolling opamps in the P3. I am close to matching it, but the soundstage and realism of the D3 is just superb.
I doubt that I can find an opamp combination that will provide a significantly better SQ or soundstage and imaging than that of the D3.
Originally Posted by HiFlight /img/forum/go_quote.gif If you like to experiment with different opamps, and have no need for a DAC, the P3 would likely be your best choice, however the D3 has really top-of-the-line sound that I have not yet been able to better by rolling opamps in the P3. I am close to matching it, but the soundstage and realism of the D3 is just superb.
I doubt that I can find an opamp combination that will provide a significantly better SQ or soundstage and imaging than that of the D3.
So what think you then? Nothing to shove it over the top. . . .
Originally Posted by googan /img/forum/go_quote.gif I'm considering either getting the D3 or the P3 and I have a couple of questions for whoever can help me out.
Firstly, is it worth it to get a DAC (the D3) if I have an X-FI music or should I just do the op-amp mod on the X-FI instead? I really wouldn't need the DAC for anything else besides use with the machine with the X-FI installed.
Secondly, as I understand it the P3 is rollable and the D3 is not. Does that make the P3 better/more versatile as a pure amp or is the D3 more powerful/better in that respect as well?
I have a modded X-fi that I have piped into the P3 and have done some opamp rolling on the P3 the D3 is superior in sonic sound stage I still have not found a combo of opamps that beats the D3 for the P3. Hiflight has mentioned this. I say get the D3, I currently use the P3 for portable use and the X-fi piped into the p3 for games to some HD595's and the D3 for music into HD650's
Just got my D3 today (ordered on Friday)! Very fast shipping! (love DHL) I am very pleased with it so far. Major improvement in sound from my SE420s (using with my Ipod).
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