One more thing,
Connecting the board directly to the SAA7210 leaves out the muting: you hear 'garbage' between tracks and when it is searching. Also at 'pause' I need to find the line in the player and connect it to the dac board: there is a mute input on the GAL with pull-up. Then there will be silence.
Now looking at the cd player connection, i have some fast ttl-ttl optocouplers ordered.
GuidoB
Connecting the board directly to the SAA7210 leaves out the muting: you hear 'garbage' between tracks and when it is searching. Also at 'pause' I need to find the line in the player and connect it to the dac board: there is a mute input on the GAL with pull-up. Then there will be silence.
Now looking at the cd player connection, i have some fast ttl-ttl optocouplers ordered.
GuidoB
If anybody wondered whatever happend to this, i've put the thing inside my CD650 and connected it to try the DAC out.
I've used the players powersupply and just hooked the DAC up with the SAA7210.
As for the output, i did the following:
50 ohm resistor from DAC output to gnd on all four outputs.
DAC in differential mode
TM3 amplimo 1:15 transformer connected over the DAC output
pins. Therefore double signal
I've used the players powersupply and just hooked the DAC up with the SAA7210.
As for the output, i did the following:
50 ohm resistor from DAC output to gnd on all four outputs.
DAC in differential mode
TM3 amplimo 1:15 transformer connected over the DAC output
pins. Therefore double signal
Oops, wrong button
Therefore double voltage over the transformer and NO DC over the transformer. They don't like DC, can be ruined by even measuring them with ohm meter.
The signal after the TM3 is 2.1 volt RMS if i calculated correctly.
So only needed is a buffer, i'm using AD811 opamps at the moment. Just had them at hand. Looking at other options (plenty on the forum, i know).
So i need as output: 4 resistors for i/v, two TM3 transformers for 'amplification' and they also perform (most of) the filtering.
Last thing is a buffer, since the transformers cannot drive a cable.
No caps in the signalpath, all DC coupled.
The TM3 is the same used in the Adagio btw. Co-insidence, saw
that later. However, in the adagio there is a small DC component over the transformer. Don't know how 'bad' this actually is.
i have no additional filtering then the transformer. From hearing i cannot say it is needed. Since i have a tube preamp, i don't think i'll bother. If there is any HF signals left they should pass the AD811 and the tube should be ok with it.
What i do notice is more hiss ('ruis') than my standard (CD60) player. I also notice my DAC is better (thank god :-> ), just i cannot really compare since my good installation is not setup now.
I'm using an old PM64 Marantz amp at the moment.
Greetings,
GuidoB
Therefore double voltage over the transformer and NO DC over the transformer. They don't like DC, can be ruined by even measuring them with ohm meter.
The signal after the TM3 is 2.1 volt RMS if i calculated correctly.
So only needed is a buffer, i'm using AD811 opamps at the moment. Just had them at hand. Looking at other options (plenty on the forum, i know).
So i need as output: 4 resistors for i/v, two TM3 transformers for 'amplification' and they also perform (most of) the filtering.
Last thing is a buffer, since the transformers cannot drive a cable.
No caps in the signalpath, all DC coupled.
The TM3 is the same used in the Adagio btw. Co-insidence, saw
that later. However, in the adagio there is a small DC component over the transformer. Don't know how 'bad' this actually is.
i have no additional filtering then the transformer. From hearing i cannot say it is needed. Since i have a tube preamp, i don't think i'll bother. If there is any HF signals left they should pass the AD811 and the tube should be ok with it.
What i do notice is more hiss ('ruis') than my standard (CD60) player. I also notice my DAC is better (thank god :-> ), just i cannot really compare since my good installation is not setup now.
I'm using an old PM64 Marantz amp at the moment.
Greetings,
GuidoB
Reread the post, might not be 100% clear:
One 1541 per channel, differential mode. So inverted output signal on one output of a 1541, the other non-inverted. One DAC a channel. Both DAC outputs have resistor to gnd for i/v conversion.
The transformer is connected to the left output of one DAC and to the right output of the DAC. Therefore it is NOT connected to gnd.
Since both outputs are at the same DC voltage if there is no signal (0.5*-4mA*50), there is no DC over the transformer.
(actually inverted output is one LSB off, so there is a DC component of the above divided by 2^16 ;-> )
One transformer is connected to one DAC for left channel, ditto for the right channel.
GuidoB
One 1541 per channel, differential mode. So inverted output signal on one output of a 1541, the other non-inverted. One DAC a channel. Both DAC outputs have resistor to gnd for i/v conversion.
The transformer is connected to the left output of one DAC and to the right output of the DAC. Therefore it is NOT connected to gnd.
Since both outputs are at the same DC voltage if there is no signal (0.5*-4mA*50), there is no DC over the transformer.
(actually inverted output is one LSB off, so there is a DC component of the above divided by 2^16 ;-> )
One transformer is connected to one DAC for left channel, ditto for the right channel.
GuidoB
"just i cannot really compare since my good installation is not setup now. I'm using an old PM64 Marantz amp at the moment."
That is the status. I'm going to listen to it next week at a friends place who has his stuff up and running. Since we compared more stuff to his kenwood cdp, we should be able to judge the DAC.
My setup in the future will be
- P11 preamp audio&techniek (hit www below)
- AudioAnalyse B90mk2 amp
- Driade speakers.
Old and exotic stuff so to say.
I also need to do something to the output buffer (fet,transistor) and power supply. And i would like to 'port' the DAC to a CD60 player, since it looks much nicer than my old CD650 (and i have plenty of CDM4 spares 🙂
GuidoB
That is the status. I'm going to listen to it next week at a friends place who has his stuff up and running. Since we compared more stuff to his kenwood cdp, we should be able to judge the DAC.
My setup in the future will be
- P11 preamp audio&techniek (hit www below)
- AudioAnalyse B90mk2 amp
- Driade speakers.
Old and exotic stuff so to say.
I also need to do something to the output buffer (fet,transistor) and power supply. And i would like to 'port' the DAC to a CD60 player, since it looks much nicer than my old CD650 (and i have plenty of CDM4 spares 🙂
GuidoB
Field transistors cannot be used in analog path of CD player. There is a plenty of high-frequency noise and the field transistor even more it will emphasize. They strongly detect a signal.
Sorry, I'm not an EE...
Please explain. ( why / whynot )?
And howcome Marantz can use discrete fet-buffers in their HDAM (buffer)?
Arne K
Please explain. ( why / whynot )?
And howcome Marantz can use discrete fet-buffers in their HDAM (buffer)?
Arne K
And and here MARANTZ? They can and not think of it (to know).
These are complex(difficult) enough thermodynamic effects. So the field structure behaves.
Such structure very strongly reacts to high-frequency noise together with the basic signal. The bipolar transistor is much better in this respect.
These are complex(difficult) enough thermodynamic effects. So the field structure behaves.
Such structure very strongly reacts to high-frequency noise together with the basic signal. The bipolar transistor is much better in this respect.
- my name is GUMP....
...and I still do not get the problem...(look at it as a challenge!).
But then again, I have made dumb ideas sound good before...
Or, I do as you suggest, and try something similar; buffer out of bi-polar units. (when everything else fails...
)
Arne K
...and I still do not get the problem...(look at it as a challenge!).
But then again, I have made dumb ideas sound good before...
Or, I do as you suggest, and try something similar; buffer out of bi-polar units. (when everything else fails...
)Arne K
I would offer to make the buffer on the operational amplifier in inverting inclusion. In this place perfectly will approach AD711.
Sorry for the tread-jack...
- but I did not get anywhere...
-what I really wondered about, was:
(as we all know?): a discrete circuit can sound better than any fancy op-amp. (IMHO).
And I just wanted to explore other SIMPLE ways of doing this, than with tubes
Arne K 🙂
- but I did not get anywhere...
-what I really wondered about, was:
(as we all know?): a discrete circuit can sound better than any fancy op-amp. (IMHO).
And I just wanted to explore other SIMPLE ways of doing this, than with tubes
Arne K 🙂
Very interestingly, but all the well-known true is not as such.
The discrete circuit never will be and can not sound more correctly integrated.
It sounds more brightly, probably it is more beautiful. But it is a deceit, lie. It strongly adorns and brings the sounding in a signal. In result the lie turns out.
The intensifying active space intensifying active and passive elements ideally can not strengthen imp signals which sound signals are.
Only the aspiration of an intensifying part in the sizes to zero can give approximation ideal amplification.
Certainly the majority of operational amplifiers is constructed incorrectly. It is difficult to choose the ideal operational amplifier. But it is a problem in circuitry of operational amplifiers and a problem in developers of them.
The discrete circuit never will be and can not sound more correctly integrated.
It sounds more brightly, probably it is more beautiful. But it is a deceit, lie. It strongly adorns and brings the sounding in a signal. In result the lie turns out.
The intensifying active space intensifying active and passive elements ideally can not strengthen imp signals which sound signals are.
Only the aspiration of an intensifying part in the sizes to zero can give approximation ideal amplification.
Certainly the majority of operational amplifiers is constructed incorrectly. It is difficult to choose the ideal operational amplifier. But it is a problem in circuitry of operational amplifiers and a problem in developers of them.
Cobra2 said:
Good comment. I listened to the DAC before, when it had no opamp buffer. Volume level was way too low, since the TM3 could not 'drive' the cable. Now with the buffer it has nearly the level of a normal cd player, easier to compare (think i need to go to 2.2 v rms and not the calculated 2).
Anyway, we remembered the DAC before (allthough low volume level and loss of highs) as to be promissing.
Now with the AD811 CFB opamp as buffer, the sound was flat and not 'sparkling', compared to the kenwood.
So the next move is a buffer instead of the 'normal' opamp. Thinking of the BUF634 or the 5002. And a separate PS to go with that in one go.
GuidoB
Greetings to all !
I bring to your attention ideally working circuit on TDA1541A/S2 :
http://images4.fotki.com/v48/free/491d4/6/67485/270142/DAC_TDA1541A_-or.jpg
I bring to your attention ideally working circuit on TDA1541A/S2 :
http://images4.fotki.com/v48/free/491d4/6/67485/270142/DAC_TDA1541A_-or.jpg
Unfortunately the link gives as answer "HTTP 403 Access denied"
Can you verify the link?
Cheers
Andrea
Can you verify the link?
Cheers
Andrea
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