SHEK DAC lampy mods ?
- pre65
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#1 SHEK DAC lampy mods ?
My first DAC was a Shek non o/s TDA1543 model. Since DAC number two (in a WD series 3 case) is in the main system I thought the Shek might be ripe for Lampy mods, inspired by Richards latest project.
The Shek has a CS8412-cs digital audio interface reciever and a Phillips 74HC4040n 12 stage binary ripple counter.
From what I have read, the Lampy stage is taken from the resistors after the DAC chip. On the Shek there seems to be a 2K7 resistor for each channel after the chip, so is the feed taken before, or after the resistor ?
The Shek has a CS8412-cs digital audio interface reciever and a Phillips 74HC4040n 12 stage binary ripple counter.
From what I have read, the Lampy stage is taken from the resistors after the DAC chip. On the Shek there seems to be a 2K7 resistor for each channel after the chip, so is the feed taken before, or after the resistor ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#2
Depends where the resistor is, I would expect its the I/V resistor after the dac, so the other side of the resistor will be ground.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- pre65
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#3
This is a close up of what I think is the DAC output.
Shows two resistors and two caps + a variable resistor.
Shows two resistors and two caps + a variable resistor.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#5
I was hoping to find where to take the DAC output from for the Lampy output stage.Nick wrote:Ok, and?
Looking at the first picture there does not seem to be an op-amp on the output ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#6
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- pre65
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#7
Aha, thanks for that Nick, I should have thought of that myself.
Seems in my ignorance I was right, those 2K7R resistors are on pins AOR and AOL which is the output.
Another thing, I did not know that TDA1543 was an "economy" DAC chip.
So now I know where to take the signal out. Magic.
Seems in my ignorance I was right, those 2K7R resistors are on pins AOR and AOL which is the output.
Another thing, I did not know that TDA1543 was an "economy" DAC chip.
So now I know where to take the signal out. Magic.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#8
After reading about Richards noble efforts I have decided to have a go on a valve output stage on my Shek DAC which has the TDA1543 chip.
I too, was looking at the Thorsten circuit, and for stage one will give that a go.
One thing I'm not sure about, is where to take the DAC output from, is it straight from the DAC, before the (in this case) 2K7 resistor ?
Another thing, these 6n2p valves, are the cheapie Russian ones OK or are there better ?
I too, was looking at the Thorsten circuit, and for stage one will give that a go.
One thing I'm not sure about, is where to take the DAC output from, is it straight from the DAC, before the (in this case) 2K7 resistor ?
Another thing, these 6n2p valves, are the cheapie Russian ones OK or are there better ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#9
Sort of progress.
I've ordered 4 6n2p valves.
I found this article about a DIY DAC using the TD1543 chip, and was interested to see how they have coped with the falling output above 20K hz by a parallel resonant circuit.
So, one of them into Richards version of the 6n2p output stage and whizzo, we have a plan.
http://www.diyparadise.com/rm20dac.html
If this works I can be a bit more bold and try modding the Honkers DAC in the main system.
I've ordered 4 6n2p valves.
I found this article about a DIY DAC using the TD1543 chip, and was interested to see how they have coped with the falling output above 20K hz by a parallel resonant circuit.
So, one of them into Richards version of the 6n2p output stage and whizzo, we have a plan.
http://www.diyparadise.com/rm20dac.html
If this works I can be a bit more bold and try modding the Honkers DAC in the main system.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#10
They should be ok, unless there are any with the EV suffix available.pre65 wrote:
Another thing, these 6n2p valves, are the cheapie Russian ones OK or are there better ?
6n6p-EV and 6n1p-EV are supposedly more desirable than the standard tubes, but i can't hear any audible difference.
Much to learn there is.
- pre65
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#11
The 4 I ordered are 6n2p EV.al newall wrote:They should be ok, unless there are any with the EV suffix available.pre65 wrote:
Another thing, these 6n2p valves, are the cheapie Russian ones OK or are there better ?
6n6p-EV and 6n1p-EV are supposedly more desirable than the standard tubes, but i can't hear any audible difference.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#12
Jolly good.The 4 I ordered are 6n2p EV.
May as well start off with the best.
Might have a look at 6n2p myself, while the prices are low.
They might get popular like 6n6p did.
Much to learn there is.