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Valab NOS DAC - subjective listening and modifications - Page 115

post #1711 of 1987
2/5/10 at 9:03am
Quote:
Originally Posted by marcelnl View Post
yeah the remote controlled volume control, I looked at it a while ago but ca not find how it attenuates (series/parallel). I am playing with the thought to build a lightspeed, or a similar device.
You must like the TXses as 24*16 USD adds up ;-)
It only uses resistors in series, That's the reason I chose this controller. I don't want resistors in parallel. :-)
It even more expensive as some higher values are more expensive.

Even with the stock resistors it is more transparent than any stepped attenuator I used/heard before. And you are right: I really love those resistors.
They are the most "unhearable" resistors I've ever 'heard' (Uhm, this sounds a bit strange, I know. LOL)
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post #1712 of 1987
2/5/10 at 9:36am
Thread Starter 

lacquer?

Quote:
Originally Posted by skibum View Post
Thank you Pat, but I intended to do exactly what I think you are saying. From what I can see I believe I have. Would you mind looking at my photos?
Are you supposed to be lacquering those resistors?
They are supposed to be nude.
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post #1713 of 1987
2/5/10 at 9:45am
Quote:
Originally Posted by PatOMalley View Post
Are you supposed to be lacquering those resistors?
They are supposed to be nude.
I haven't seen/read anything about having to leave them nude...

Bill mentioned doing this ages ago - decided to give it a try.

Can't imagine that is my problem? Could it be???
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post #1714 of 1987
2/5/10 at 10:16am

Source in Europe for TDA 1543 chips.....

Goes from bad to worse...

As I was sliding the board back into the case the DAC chip that I messed up before got caught on something. It's ruined. 2 legs torn off.

Any suggestions on where I can order some new Chips? I am in France so looking for European source.

thanks -

scott
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post #1715 of 1987
2/5/10 at 10:19am
Thread Starter 

ebay

Thos NOS chips can be found easily on ebay in lots of 4, 6, 8, etc.
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post #1716 of 1987
2/5/10 at 10:20am
Quote:
Originally Posted by skibum View Post
Goes from bad to worse...

As I was sliding the board back into the case the DAC chip that I messed up before got caught on something. It's ruined. 2 legs torn off.

Any suggestions on where I can order some new Chips? I am in France so looking for European source.
Best thing is to buy them on eBay directly from Taiwan. That will be the most cheap solution. Here for example.
Be sure to take the I2S input version. :-)
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post #1717 of 1987
2/5/10 at 10:40am
Quote:
Originally Posted by rhodes54 View Post
Best thing is to buy them on eBay directly from Taiwan. That will be the most cheap solution. Here for example.
Be sure to take the I2S input version. :-)
Thanks Rhodes. Just ordered those. Won't see them for at least a week but were cheap enough.
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post #1718 of 1987
2/5/10 at 1:59pm
Skibum; difficult to tell what went wrong as I can not see the connection to the board where the resistors used to be....
As a side note; when you invest in Duelunds and TXs you might want to exchange the RCAs as the stock ones stink.

@Rhodes; sounds like a great option if the optical resistor I am thinking about does not work (needs a low output impendance)/sounds bad
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post #1719 of 1987
2/5/10 at 2:12pm
Quote:
Originally Posted by marcelnl View Post
Skibum; difficult to tell what went wrong as I can not see the connection to the board where the resistors used to be....
As a side note; when you invest in Duelunds and TXs you might want to exchange the RCAs as the stock ones stink.

@Rhodes; sounds like a great option if the optical resistor I am thinking about does not work (needs a low output impendance)/sounds bad
I have attached 2 photos that show the Left & Right Channel connection points clearly
LL
LL
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post #1720 of 1987
2/6/10 at 10:39am
skibum,
is that a shadow on the left side of your fuse holder? or is it char, like from an electric spark,
it is tough for me to see what is going on with your wiring, what i can see seems ok
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post #1721 of 1987
2/6/10 at 11:14am
what is the point of spending extra money on TX2575 and then covering them with laquer? we pay good money for them to leave the epoxy coat off, you may as well buy the regular Zfoils Z201. those long unshielded and even untwisted wires to and from the duelunds will be big long RF antenna, since you have created a star ground, wouldnt you need to sever the old ground?
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post #1722 of 1987
2/6/10 at 1:39pm
Quote:
Originally Posted by errnst View Post
skibum,
is that a shadow on the left side of your fuse holder? or is it char, like from an electric spark,
it is tough for me to see what is going on with your wiring, what i can see seems ok
I blew the fuse by mistake. This happened after my problems with distortion. I had the board out of the case and the power cable plugged it. I piece of wire was laying on my table and caused a short on the power supply....
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post #1723 of 1987
2/6/10 at 1:44pm
Quote:
Originally Posted by qusp View Post
what is the point of spending extra money on TX2575 and then covering them with laquer? we pay good money for them to leave the epoxy coat off, you may as well buy the regular Zfoils Z201. those long unshielded and even untwisted wires to and from the duelunds will be big long RF antenna, since you have created a star ground, wouldnt you need to sever the old ground?
Hi Qusp, I am obviously new at this so I am looking for help here. What cable should I be using to connect to my Duelands? I have seen other pictures of star grounds without the old grounds removed. Should this be done? (easy enough) I laquered my TX2575's to wood because ths is what Bill recommended to try out in one of his posts.
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post #1724 of 1987
2/6/10 at 3:39pm
give that 1 Megaohm green Inductor between the dac board and main PCB a close look. I broke mine, I did not realize it even. It is fragile and will break with slight pressure on the dac PCB. I suspected it as a problem one day and grabbed it with some tweezers and it snapped right in half, it was already broken but I could not see it because the coating had not broke. That inductor is required and cannot be bypassed with wire. You can use the ones you took out of the low pass filter network to replace it.
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post #1725 of 1987
2/6/10 at 4:03pm
Thread Starter 

not true

Quote:
Originally Posted by MikeW View Post
g[snip]That inductor is required [snip]

No it ain't. I came off the board using Bill's SSOM mod, reused the stock resistors while chucking the inductor. No longer on the board. Not going thru it. Don't need it.

My TX nudies are being cooked up now and will replace the stock ones.

And after all the damned fooling around with channel balance and every other god damned thing I finally noticed that my Kimber Hero's are broken and that was the fault. All this plug and unplug killed them ...

I iwll also test my CineMags and see if they are not dose with DC somehow as well and if they are healthy I will hardwire them to the output.
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