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Your advice needed

post #1 of 13
Thread Starter 

Hi, my first post in computer audio. I really need your input and experience here people so I appreciate your time in a big way. I have just recently purchased an SPL Auditor amp, which I love, but I need to upgrade my source as my current CD player while nice, does not have balanced output so I am not giving the Auditor enough voltage to work with. I have found a CD player with a really nice DAC in it, Audiolab 8200CD with the 32 bit Saber ESS DAC if I remember. When discussing this with my brother he thinks I'm nuts. He has converted to computer music serving and swears that I can essentially equal or best the sonic performance of a $1000 CD player with around a $200 sound card. I am simplifying his logic, but he is a highly experienced computer user and certainly with audio.

 

That said, I need to know if I was to spend say $400 on a sound card that would run under Windows 7 can I actually get one with true balanced output which I require. My brother was describing some software (I forget which) that allows the soundcard or it's DAC anyway,to be locked away from Windows so that you don't get the Windows sound management processing happening. Is this all true, can I really just skid the use of a CD transport for such a low dollar value and not suffer any SQ degradation? If so I think I am ready to make the jump to computer audio, but I am afraid of all the possible issues, i.e sound processing from the OS, USB problems, this problem, that problem. I guess I am just having a hrad time accepting how far computer audio has come.

 

So, do you experienced head-fiers concur, I can get just as good sound as the Audiolab 8200CD player for less money? It just sounds too good to be true and in my experience when that is the case, it usually means it is too good to be true. Anyway, please give me the benefit of your collective experience. Thanks in advance.


Edited by Sonic Defender - 7/9/12 at 9:23am
post #2 of 13

Straight from Headphone.com

 

"As mentioned above, the source is generally (keep reading!) the most important aspect of an audio system. We build a variety of digital to analog converters (DACs) to further improve your audio source. HeadRoom amps with internal DACs, and our stand-alone DACs, both contain high quality DAC chips in our designs; and, these contemporary high-end digital recievers and DACs are extremely good at reducing or virtually eliminating jitter from the digital bit-stream. Now, here's the exception to our rule about sources being so critical: when constructing a front-end for your stereo system, it is much less important where the digital signal is coming from when a very high-quality DAC is used. We've even found, in fact, that sometimes very expensive CD transports sound only slightly better than the digital output of inexpensive CD players or USB audio outputs from computers when using a good DAC. So, keep that in mind when putting together your rig!"

 

http://www.headphone.com/selection-guide/top-picks/top-headroom-amps-and-dacs.php

 

This has been my experience as well.  If you rip your music to lossless or say 256 kbps compression and use a high quality USB DAC you are not going to hear a significant difference in sound quality compared to the same music play via CD player.  I have tested this time and time again and honestly cannot hear big differences if any at all between my m903 and the same music from CD.

 

Of course your problem stems from the inputs for the SPL Auditor are only XLR.  There is no other input on the device.  So if you end up using a soundcard or an external DAC like Headroom's Micro DAC or even the CENtrance DACport both below $400 you are going to need a stereo to XLR adapter.

 

Stereo to XLR Adapter

http://www.amazon.com/Hosa-Right-Stereo-Female-CYX-402F/dp/B00394LYIQ/ref=sr_1_12?s=electronics&ie=UTF8&qid=1341871105&sr=1-12&keywords=stereo+to+xlr

 

Using an external DAC like the Micro or DACport goes like this:

PC--->USB--->DAC--->Stereo to XLR (x2 ) adapter--->SPL Auditor--->Headphone out--->Headphones

 

The audio train seems pretty long, but in the end will take up less space than the 8200CD and cost less.  For the DAC and the adapter you are looking at $450 tops.  Plus you will have a more portable rig than lugging the 8200CD around.  Now if your heart is set on the 8200CD by all means go for it.  It is an excellent piece of equipment with a great DAC chip inside.  You will of course need x2 XLR to XLR connectors to hook it up to your SPR Auditor.

 

I think if you end up with the 8200CD you will have a harder time finding issues with the audio train than with the USB DAC setup.  What I like about the USB DAC setup is that I can have all my CD collection loaded onto my PC.  There is no need to change CD so there is little or no risk at scratching my loved CD collection.

 

If you can afford it and do not mind changing the CD frequently then the 8200CD is a great option.  If you would rather have all of your music loaded in lossless format on the PC and use an external USB DAC to deliver the signal to your SPL then that is going to be the way to go.  In my opinion you are going to get roughly the same quality out of both so it is more about your intended use rather than quality.

post #3 of 13
Thread Starter 

Thanks NA BLUR for the very thorough and thoughtful response. That is why I love this community, there is always somebody who is willing to share the benefit of their experience. I guess I am still on the fence as I have used CD players for so long that it is hard to change. I think I am mostly good with the notion of computer based audio being as good or at least so very close to set-top players. It just seems so strange to use a computer for audio. My brother has the nice JRiver server happening and I can see why he loves it. So I will be able to get the appropriate output voltage to drive the Auditor in this way? The 8200 provides a 4.1V balanced output. I am off to do some DAC research it seems, thank you very much again.

post #4 of 13

I do not think it is a matter of voltage.  I think it is more about having the correct outputs to go to the necessary XLR connectors on the SPL.  After all the SPL is the amp so you are expecting to put somewhat low voltage into it and have it due the gain process.

 

You may/should be able to go from a stereo jack to a split XLR on your current CD player.  You would simply plug in the stereo jack into the stereo out on the CD player and run the separate XLR cables into the back of the SPL.  Have you tried this already?  What makes you think that it is a voltage issue?  From what I understand the SPL has pretty high gain so having low voltage going into it is somewhat expected.

post #5 of 13
Thread Starter 

Adapters don't help I have tried it, and it is the voltage of the output that determines the output volume capability, at least in this situation. Another user here has his Auditor fed by proper balanced outputs and at 4.1V his volume levels achieved with the same headphone are well above what I am able to achieve. I have spoken with several people who say that unless the output supplies the required voltage the amp wants, in the Auditor's case 5V, the amp is not driven loud enough by the source which in turn limits it's output. Truthfully I do not know the deeper relationship between the  output voltage of the source and how it does what it does to the amplifiers output, but that is the case. I was speaking with an electrical engineer I know the other day and he confirmed this principle so that is all I can say on the matter.

post #6 of 13
Quote:
Originally Posted by Sonic Defender View Post

Adapters don't help I have tried it, and it is the voltage of the output that determines the output volume capability, at least in this situation. Another user here has his Auditor fed by proper balanced outputs and at 4.1V his volume levels achieved with the same headphone are well above what I am able to achieve. I have spoken with several people who say that unless the output supplies the required voltage the amp wants, in the Auditor's case 5V, the amp is not driven loud enough by the source which in turn limits it's output. Truthfully I do not know the deeper relationship between the  output voltage of the source and how it does what it does to the amplifiers output, but that is the case. I was speaking with an electrical engineer I know the other day and he confirmed this principle so that is all I can say on the matter.
Unless you have some very hard to drive headphones, you probably won't need that last volt or so. Sure, running balanced inputs means you'll get 6dB more volume, but this shouldn't matter since you should be able to drive your headphones to ear shattering volumes without that last 6dB.
post #7 of 13
Thread Starter 

I wish that were true Tilpo, but no, my 600ohm 880s are only at normal listening level with the volume turned to 90% with older dynamic recordings I have to turn the volume to 100%. My 300ohm 650s are of course driven to better volume levels. Zombie_X has the Auditor and with his balanced output from his Violectric DAC he says he couldn't put the volume control past 50% with his 600 ohm T1s without extreme volume levels being achieved. Here are a few of his comments from our discussions:

 

"No, using a cable from XLR to RCA would still give you this issue. What happens is that XLR carries two signals while a RCA only has one signal. Two signal means double the volume. So there is no way around that."

 

"The SQ is not affected at all, just a loss in total volume. The Auditor is designed to be used with a 5V or more input signal (per channel) and RCA signals are 2V-2.5V. This gives you much less volume."

 

"The DT880 should be incredibly loud at right before the volume is set to half. If I set the volume to half then it's unbearable. That's the way it is with mine. May I ask how your Auditor is hooked up? If you are using RCA>XLR adapters then they cut the voltage to half and the volume would have to be double of what a normal balanced signal would be."

 

My experience confirms this and others have also confirmed this principle for me. That is all I know and I have to defer to those with more knowledge and experience.

post #8 of 13
Quote:
Originally Posted by Sonic Defender View Post

I wish that were true Tilpo, but no, my 600ohm 880s are only at normal listening level with the volume turned to 90% with older dynamic recordings I have to turn the volume to 100%. My 300ohm 650s are of course driven to better volume levels. Zombie_X has the Auditor and with his balanced output from his Violectric DAC he says he couldn't put the volume control past 50% with his 600 ohm T1s without extreme volume levels being achieved. Here are a few of his comments from our discussions:

"No, using a cable from XLR to RCA would still give you this issue. What happens is that XLR carries two signals while a RCA only has one signal. Two signal means double the volume. So there is no way around that."

"The SQ is not affected at all, just a loss in total volume. The Auditor is designed to be used with a 5V or more input signal (per channel) and RCA signals are 2V-2.5V. This gives you much less volume."

"The DT880 should be incredibly loud at right before the volume is set to half. If I set the volume to half then it's unbearable. That's the way it is with mine. May I ask how your Auditor is hooked up? If you are using RCA>XLR adapters then they cut the voltage to half and the volume would have to be double of what a normal balanced signal would be."

My experience confirms this and others have also confirmed this principle for me. That is all I know and I have to defer to those with more knowledge and experience.
I see. Well in that case running balanced won't solve the issue either, since, like I said, it will only add 6dB. This is a significant amount, but from what I'm hearing you need much more than that.

I think there is something more serious going on here, so I'm going to ask: are you sure you even reach that 2V? It sounds like your output is much lower.
Do you have a multimeter? If you do, play back a 60Hz tone, and measure the AC voltage between one of the channels and ground.
post #9 of 13
Thread Starter 

No, there is nothing going on here as best I can tell. My current CD player fed my Valhalla to very strong listening levels as it did with a Graham Slee Novo, but they were designed for RCA input voltage. Plus, the CD player through my integrated provided insane amounts of volume so that would seem to indicate that the CD output was to spec. 6db is indeed a significant amount and I suspect able to account for my experience. Don't forget, the real lack of volume is when I am playing older recordings with dynamics, but as a result much lower levels of volume so the short-fall in these cases is quite dramatic. Hot modern recordings that are loud provide much more volume through the current setup. My post needs to be considered in that context, almost every recording I have listened to is by nature more quiet than the norm of today, sometimes much quieter.

post #10 of 13

How are you connection to the SPL now?  You say your current CD player is not giving it enough voltage so how are you connecting it?  You said the CD player you are currently using does not have balanced outs so you must be using an adapter?

 

Please accurately describe your audio train including volume levels.

 

Example:

CD via Foobar2000--->90% volume ---> m903 ( USB DAC ) --->m903 ( headamp ) ---> Denon AH-D2000 running between 50 and 60 dB on the volume scale.

post #11 of 13
Thread Starter 

Hi NA BLUR, I don't have any equipment to measure the actual decible level of output, but you can be assured I am being accurate when I say it is indeed significantly lower than it should be. Yes I am using adapters into the Auditor, the chain is just as I have stated in words CD > adapter/XLR > Auditor. I am surprised that you do not feel the explanation of the lack of balanced output from my source explains what is happening. I say I am surprised only because several experienced individuals, like yourself, feel that explanation is itself complete. Here is some of the the answer the rep at the company who sold me the Auditor had to say about my problem, keep in mind he has been with this company for over 15 years and has a great deal of experience. It is also important to realise that this company supplies clients who are mostly in the recording industry so you would have to consider their knowledge likely to be adequate to assess such a situation. This individual feels that it is nothing but a lack of compatability between RCA out from the source and the needs of the balanced input on the Auditor. Here is his thoughts:

 

"If you want to go purely from your cd player to the headphone amp, you will need either a dac ... this way you will need to go digital out of your cd player into the dac and then analogue out of your dac into you headphone amp ( which can be expensive and again depending on the brand and model [Benchmark/Lavry/Mytek] will alter the sound or have its own signature  ... )
or you could use some very transparent transformers to convert the -10db unbalanced analogue signal of your cd player's rca outputs into a +4db balanced signal ... and then into the Auditor ... that will normalize your gain and should suffice in rendering the needed power without changing or coloring the sound too much, especially if you go with good quality transparent transformers used in brands like Radial Engineering .... 
 
it is a $200.00 solution verses a $1000.00 and over solution ... the $200.00 solution can not be looked at as just a cheap solution ... again both choices will affect the sound of the source ...
transparent output transformers will mainly transform the signal from -10db to +4db and keep as much as possible the sound of your cd player, Radial products are often thought as odorless and colorless because they are often used in conjuncture with sonically type cast sources, so you should not notice that they are being used in between ... where dac converters vary in sound ... in the area's of richness/stereo image/wider bass response/sweeter highs or reminiscing of analogue tape .... some prerefed for studio recording, others for mastering others for hi-fi application ... over $1000.00 you are getting something decent under that, I would try the Radial option ..."
 
Not saying his view of the $1000 benchmark for DAC costs is perfectly valid, that is subjective, but the technical explanation is consistent with what I am being told by others, including an electrical engineer I spoke with. I appreciate your taking an interest in my problem so I hope you don't think I am being defensive, I am not as technically savy as some of those advising me and in this situation I am trying to find the consensus opinion in order to best solve my problem.
post #12 of 13

He hits the point right on the head.  It is a matter of getting the imbalanced RCA out from your CD player to a balanced signal that your SPL can use.  Hence the "voltage" gain from -10dB to the +4dB of the balanced output.

 

This should work just fine:

http://www.bhphotovideo.com/c/product/289839-REG/RDL_FP_UBC2_2_Channel_Unbal_to_Balanc.html

 

Thank you for clarifying.

post #13 of 13
Thread Starter 

Thanks NA Blur, that looks like an excellent product. I am just wrestling with the notion of getting a used Audiolab 8200CD which would solve my problem and upgrade my DAC. I have been thinking about a new CD player for sometime now, I just need to scare up the funds. Thanks again for your help.

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