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Buffalo DAC (ESS Sabre 9008)

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#1,181
Yes, I used the regulator.

I've tried using either VD (7.2V after teddyreg supply) and also a higher supply from the LCDPS (about 11V). Neither makes any difference.

I am using one of the earlier buffaloes - v1.1 - so I only have the 3 headers together at the I2C output: G, SCL and SDA and I was using a fourth wire from the VD input terminal of the buffalo.

Heres a pic, and note that I have the wire supplying VCC removed here!:

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.



******************************************

I don't know if there is any difference increasing C1 of AVCC board to 1500uF. Certainly doesn't sound worse anyway!


Heading to bed now....


Fran
 
#1,182
woodturner-fran said:
Yes, I used the regulator.

I've tried using either VD (7.2V after teddyreg supply) and also a higher supply from the LCDPS (about 11V). Neither makes any difference.

I am using one of the earlier buffaloes - v1.1 - so I only have the 3 headers together at the I2C output: G, SCL and SDA and I was using a fourth wire from the VD input terminal of the buffalo.

Heres a pic, and note that I have the wire supplying VCC removed here!:

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.



******************************************

I don't know if there is any difference increasing C1 of AVCC board to 1500uF. Certainly doesn't sound worse anyway!


Heading to bed now....


Fran
Click to expand...


Hi Fran, no the AVV VREF won't make any difference here at all.

Then only thing I can think of is that you may not have a good power on sequence.

The Buffalo VD needs to come up prior to the Volumite coming active.

The Buffalo VD also need to come up quickly. It could be that the slow startup of the teddy reg is causing your issues.

Try powering VD and the Volumite directly from the LCDPS.

Its very difficult to say from here.

Cheers!
Russ
 
#1,183
OK, I have this sorted out. Its a timing issue on power up cos if I power up the volumite after everything else has come up then it all works fine.


So what I've done is add 2K in series from buffalo VD to VCC and 220uF nonpolar between VCC and G. Kinda like the amb e12 muting device (which I've been thinking about cos of the counterpoint!).

Seems to work AOK now!


Fran
 
#1,184
Ok turns out 2K is too much, so I've brought that down to 500R. Playing now ok and seems to be stable on startup as well. We'll see can we get rid of the cap next, although it isn't actually doing much only acting as a reservoir I think.

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Did I add the extra capacitance for the AVCC at the wrong place? Should it have been at C2 or actually added direct to C6 on the buffalo board?

Fran
 
#1,185
woodturner-fran said:
Did I add the extra capacitance for the AVCC at the wrong place? Should it have been at C2 or actually added direct to C6 on the buffalo board?

Fran
Click to expand...

You can add it in parallel with C6 (C1 on the REF board) which is the output of the AVCC VREF.

The problem is not that the volumite is coming up too fast, but that the VD is reg is coming up too slow. 🙂

The Volumite has a 50ms window for the digital side of the Buffalo to come up completely.

Your little RC cct probably baught you a few more ms. 🙂

Glad its working for you now.
 
#1,187
Re: And the sound ?

muizel said:
Hej guy's,

Just asking, before I have to take everything apart over here :cannotbe: is the sound after the upgrade really that much better, I mean is it so much better that it is worth taking my whole cd player apart ?


Ren�.
Click to expand...

That's a hard question to answer... Its not really that hard a mod to perform.

I cannot actually say I noticed very much difference, but others seem to think it is better. It's not really my opinion that counts. 🙂 What I have noticed is that some 80mhz and 160mhz junk that was on the outputs is no longer there. 🙂

I only offered the mod to show that it is possible and to test the effect of completely isolating AVCC from VD.. 🙂

So I guess I would say if you are happy with it as it is, then leave it alone. If you feel like doing some tweaking then go for it. 🙂

Cheers!
Russ
 
#1,188
Re: Re: And the sound ?

Russ White said:


That's a hard question to answer... Its not really that hard a mod to perform.

I cannot actually say I noticed very much difference, but others seem to think it is better. It's not really my opinion that counts. 🙂 What I have noticed is that some 80mhz and 160mhz junk that was on the outputs is no longer there. 🙂

I only offered the mod to show that it is possible and to test the effect of completely isolating AVCC from VD.. 🙂

So I guess I would say if you are happy with it as it is, then leave it alone. If you feel like doing some tweaking then go for it. 🙂

Cheers!
Russ
Click to expand...


Thanks Russ,

I am happy as it is, and maybe in the future i will do the modification.


Thanks and a happy New 2009 to you and yours !

🙂

René.
 
#1,189
Muizel: What you should do is take your time, make one of the little circuit boards and populate it. Then test it out on the bench, tweak it and so on. Finally when you have about 3.4-3.5V output, its only a quick job to swap it in.

I do think it makes an improvement, so its worth doing imho.


Fran
 
#1,191
Hi Fran, I fitted my volumite just before Christmas ( thanks Brian ) and had similiar problems with power and the older Buffalo board. I took power straight from the VD VG power into the Buffalo. Worked fine after that... apart from the fact that my volume knob seems to have no stop and goes round and round, although of course the volume actually stops changing at a certain point.

Although I cannot get it to absolute silence, it is fine for me and sounds, well sounded, pretty good before one of the PS's on my Welborne 300b monoblocks blew again...

I'd also like to hear what you thought of the above mod, although I'm going to have to put it on the back burner for now.

Happy New Year to those who celebrate such things at this time.

Russ
 
#1,193
muizel said:
Hi Fran,

Can you tell me in your own words what is the difference for you ? do you here more details, depht ? bass ?

Would be off much help for me


🙂


Thanks in advance,

Ren�.
Click to expand...

OK,

I'll take a stab at it. What I hear is better soundstage, separation and it would seem like better dynamics. So when you are listening to say a fairly busy recording, you can make out all the instuments more clearly and where there are multiple vocals, each singer has his/her own space, much more clearly defined. And when its quiet its really inky black quiet. Now to be honest, thats kind of what I heard when I added in the teddy regs as well, but this seems to bring it on again. The other thing is that it does sound very musical... it kind of treads a fine line between having superb resolution but doesn't veer over into sounding too clinical or harsh.

Now all that was with pretty good recordings - I haven't listened that extensively yet, but I would imagine that poor recordings etc will be shown up pretty ruthlessly. Other shortcomings in your setup will also become apparent.

The other thing I have been having a listen to is using the volumite directly to my power amp. My pre is a 24V aikido and it sounds pretty good. However the volumite setup is at least as good, maybe even better. There are differences whether I run it through the pre or direct, but its kind of different flavours. Direct is a cleaner sound, but through the pre it is a little warmer, and probably would be a little more forgiving long term. Let me put it this way though - if you only had one source (or at least only digital sources feeding the buffalo) then its a no brainer to go direct to the power amp.


I don't feel as if I've given a good description of what I've heard with the AVCC circuit done. I mean, its not a huge jump, but it is certainly audible. Its probably a case of adding super regulators adds 5%, adding AVCC adds 5%, flat layout adds 2%, and so on, which in cumulative terms adds up to a fairly big difference.

A few things that would be interesting to try out:

1. Don't use teddy regs on VA/VD, just use AVCC only.
2. Don't use LCDPS/LCBPS - just a simple CRC filter into super regs.
3. Use other regulators with LCBPS/DPS., jung/cetoole/alwsr.


and more I can't think of right now. The scope to personalise this DAC is pretty unique I think - and for small outlay (eg the AVCC) you can reap good benefits.

Fran
 
#1,196
OK,


just here from a marathon listening session!! 4 hours later and waaaayy past my bedtime. Just couldn't turn the shaggin' thing off! Yes it does sound great. I know it might be a PITA to go and open back up the case, but I have to share my enthusiasm - its well worth adding the teddy regs and the AVCC circuit! A soundstage in 3 dimensions - and to be honest the one area I would have said my quads weren't the best in was soundstage depth. Seems now to have been what I was feeding them.

However, I do have a problem.... and I'll bet that it relates to power supply, volumite and timing - in other words - Russ - HELP!


What happens is that I am getting what sounds like the start of a digital lock... you know that crackling sound that happens just as a DAC locks on to the signal? Well I am getting that... but its not regular. I get it at the start of some tracks, but not others. I've heard it a couple of times in the middle of songs, and not in quiet sections. I will get it at the start of some tracks on a CD and not at the start of others on the same CD. Anyway, you get the picture. The lock LED stays lit all the time, automute never comes on.

Its kind of like the DAC has to remind itself that its receiving a signal to keep going. Or maybe like the volumite forgets that it has to keep the volume up and every now and then tells the DAC to go back up.

All of this is with the volumite fully turned up - which may also be something to do with it as when I ran the DAC direct to the power amp earlier and didn't have it turned up full I never heard the noise.

Could it be something to do with that comparator chip (mine is the older one)? I never changed mine or ordered one as I couldn't find it in Mouser.

Ideas welcome as I would like to keep the volumite - very handy for matching levels between the CDP and the turntable. I know I should have done more experiments tonight with the volumite turned down a bit but I couldn;t stop!


Fran
 
#1,197
Fran, as I said earlier, when using volumite, VD has to come up quickly otherwise you are going to run into startup synchronization issues. Your teddyregs have far too slow a start up time. I would not recommend them at all on VD. They really are not doing much there anyway since there are local VREGs after them and because of their high impedance. If you simulate load regulation on a teddyreg (which I have) you will see exactly what I mean. 🙂

I don't mean to dampen your enthusiasm, just redirect it to more fruitful prospects. 🙂

You also should not have the resistor in series with your volumite supply terminal.

Tweaking is fine, but remember you are totally on your own. If it does not work as described, well then *you* need to know enough about how the whole system (DAC and all its attending ccts) works to determine if the mod is even desirable. 🙂

Some other regulators with feedback would be much more suitable.

I do agree that the AVCC VREF is a sensible mod, and easy to accomplish with little risk.

I am not sure the rest of it will make any tangible difference given the local VREGs etc. 🙂

Just my 2C.

Its your DAC, do what you like, and of course have fun. 😎

Cheers!
Russ
 
#1,198
All points taken in the spirit in which they were given.... all fair too. In fact I knew about both the slow startup time of the teddy reg and also its high output impedance but said what the heck and gave it a go anyway. There is a mod to the teddyreg which gives it a faster startup time, but then you still have the high impedance issue.

Also understand about tweaking and being on my own.... not fair to expect back up for that kind of thing. :nod: blame it on the enthusiasm :clown:

**************
Disclaimer:
I should also have probably stated way back up there that these are all mods, and are experimental, and some will work and others won't. Also (as is the case right here) I might think (yes, think) that something sounds better, but cause other problems. And yes, these are my problems, not a TP problem!
**************


A very valid point too Russ, is that the teddyreg on VD might not be contributing much at all. I will change it back, and the volumite too and see what comes of it.

I guess what I'm saying is... I hear ya.

Is it ok to continue posting here or am I thread crapping?!

Fran
 
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