Thanks for everyone's suggestions. I've done just aobut everything I can with the current equipment I have on hand to try to hear the subtle differences between the dithers and wordlengths. Even thought the differences were obvious in another system I have listened to in the past, I just have to accept the fact that I won't hear the differences on mine.
I believe my DAC might be the culprit since Meridian recommends one using a DAC with at least 18 bits, and my sigma has only 1bit (with 18bit resolution).
I have hooked my preamp back up, and used the 518 in type 1 mode with no attenuation, this means no loss of bits, yet I still cannot hear any sonic difference/improvements by playing around with the dsps.
However, the 518 allows me to hook the dac straight into the amp and dejitters the jitters. This, by itself, has made me a happy happy camper.
I will try to listen for the dithers after I upgrade my digital fronts, which won't be in the near future unless I see a Sonic Frontiers SFD1 DAC for about.. 400? |
I agree with Glaucon but although Meridian prefer you use a DAC with analog de-empahasis (of course they would really much prefer you use one of their own DAC's....) you will still benefit even if the DAC has digital stages. The effects of using the 518 can be very subtle and it takes time to appreciate these effects. There are many users who have expressed disappointment upon first using the 518 in their system, but once they have spent some time with the unit the benefits become more apparent. It may sound cruel but using the 518 can very often show-up deficiencies in your DAC Regards, Richard |
(1) You are losing exactly 4 bits of resolution (out of a theoretically possible 16) - that's almost the sonic equivalent of listening to an AM radio built into the stomach of a plastic teddy bear.
(2) The resistors (10db in my case) are Vishay. It sounds like you're going to need 20db ones. BTW, this mod will void the warranty on your amp.
(3) The reason you don't hear a difference between PREEMPHASIS and none is that your CAL Sigma has a digital demphasis circuit (I use this very DAC for my Home Theater system). Preemphasis only works with with analogue circuits (which means it won't work with ALL of the newer DACs out there). When it does work, it makes a HUGE difference.
Hope this helps... |
Hello Ed! The main difference with the "1.22" version appears to be a few additional functions on the display, the audio performance seems unaffected If you are getting clipping when using EMPHASIS try reducing the gain by a couple of dB as you will still get better resolution with your DAC The other suggestion I would make is to try the 518 in TYPE 1 mode as well. Also in TYPE 1 there is a BYPASS mode in addition to the other DSP modes so that should help in your comparisons, although of course you will have to place your pre-amp back in circuit Regards, Richard. |
Hey Richard,
Thanks for being very informative!!
I checked the version of software on the 518, and I've got the older version, 1.14. I doubt the older version would penalize the audio performance?
I've already have designated the 518 as a Type 0.
It seems I am at a disadvantage for using the 518 as a preamp. Lowering the volume on the 518 cuts into the resolution of my digital source. However, using the 518 as a preamp with curtailed resolution and forgoing the DSP still sounds better than having my Nakamichi Ca-7a in the audio loop.
Ed |
Hello Ed! As far as I am aware there are no differences in 518 models regarding DSP function, they should all be the same Check your software version by pressing and holding DSP whilst switching ON the 518 from the power switch on the rear. The display should read "518" and the version number (either "1.14" or "1.22"). You can also read the version when the 518 is in standby, just press the DISPLAY button Also double-check you have selected TYPE 0 by pressing and holding SOURCE whilst switching ON the 518 from the power switch on the rear. With TYPE 0 selected, wait at least one second then switch OFF at the rear for one-half second then switch back ON again. The 518 will now be in normal mode You could try the following settings as a start: From standby, press SOURCE - select. Then press DITHER - select FLAT. Then press DSP - select Emphasis As Glaucon states above, try and get as close to 87 as you can. Also ensure you have selected the IN and OUT to match your transport and DAC. Pressing DISPLAY will scroll thru your selections so you can check the In and OUT settings along with the DSP and DITHER settings Once you start listening you can then work your way thru the DITHER settings. Take your time here. Happy listening! Regards, Richard |
Hey Richard,
Believe it or not, I don't hear anything different when switching between preemph and no preemph. And, yes, my dac, the sigma, is deemphed...
Hey Sarah,
You bet I read my manual inside and out after my beloved 518 is not harnessing its full potential. And I got the type setting to 0, which is for preamp. I do believe the dsp functions, dither, wordlength and emph, are used in every mode. Only certain functions are customed differently between the various types like type 0 negates bypass to keep your speakers from going full steam ahead.
Hey Glaucon,
Did you have the same problem I've had before you installed the resistors on you amp? And what are these resistors? They sound "heavenly", where can I get my hands on them? They do not hinder with the sound quality at all? So far, I've only have my 518 up to 60, goodness how much resolution am I losing......
I made a "virtual system" and i found there is two models of 518 available amongst the choices. One with dsp and one is without. Could the problem be that I purchased a model without dsp eventhough the buttons and displays for them are still there?
Ed |
One more thing...
Make sure you're operating the 518 as close to unity gain as possible, i.e., 87. When I first used my unit, I could only go up to 72. The sound was great, but I didn't realize how compromised it was until I had resistors installed into the inputs of my amp, and was able to get up to the 80s. Heaven!
Remember, you lose 1-bit of resolution for every 6 db decrease. |
Another thought: when you use the 518 as a preamp, you have to set the unit up that way. There is a code you punch in right after turning it on, either 0 or 1 or 2, I can't remember which code is for the preamp and which for the resolution enhancer function. Anyway, could it be that you don't have the unit in preamp mode yet? Then I guess your choices of shapes etc. wouldn't be affecting your sound. I sold mine with the manual, of course, so I can't remember off the top of my head what the proper code is. However, I can give you the phone no. of my dealer, Mike of JS Audio in Bethesda, MD, who is an expert on all things and units Meridian and WILL be able to tell you off the top of his head.
Sarah |
Assuming the input to the 518 is not already pre-emphasised (the red EMPH light will show this), using EMPH will ensure the 518 output is ALWAYS pre-emphasised and will give you audible gains in your system (be careful of material that has too much high-frequency signal though) Try a well recorded track and relax and listen several times first with the shaper FLAT, then HP, then each SHAPE A, B,etc.... Although Shape A and E have very similar curves they have different degrees of noise reduction so try switching between those two after your initial test above. It takes time to learn and get used to the 518 but it is worth the wait..! Regards, Richard. |
Thanks for your inputs!!
However, I am still not getting any difference in sound quality when fumbling between the different bits and shapes.
Does it matter whether I am using the 518 as a preamp, thus I am using the gain stage with emph? Or do I have to bypass the dsp?
So far, I am using Emph, with sound shape E, and 16bit in, 18 bit out. |
Hi, when I had my 518 (with Meridian 500 transport and 563 DAC), I matched the output bits to my DAC (24) and found Shapes A and E to sound the best for my tastes. I found each shape had a different sound, and sometimes the recording I was playing sounded better with a different shape. You can really drive yourself crazy with this piece, but I absolutely loved it and settled on Shape A for most of my listening.
Sarah |
Reading the manual for the 518 can be a bit confusing at first and you need to go through it several times to start to get a handle on all the functions We have some basic set up info posted at http://vantageaudio.com/info/518.htm We use a 518 every day and can give you more info (especially regarding the noise shape settings, etc) if you email directly (it would take too long to post here). Hope this helps..??? Regards, Richard |
