Output stage for the Soekris R2R

[robertrowett]

Is there a power off "pop" also on the un-buffered output?

//

Yes. It is louder or quieter depending on which filter is loaded.

 

[bambadoo]

Actually sometimes it pops/cracks just by changing song with the same samplingrate

 

[vgeorge]

Hi Vgeorge,
thank you for the Info. If there's no output resistor, will the circuit oscillate very easily? Im thinking of using a cap paralleled to the load to avoid oscillation......

Well, you can lower the output resistor value, but you need a scope to see at which value it will start oscillating. Keep in mind that 2SK170 internal resistance is about 47 Ohms, so to calculate the output impedance you add this to the output resistor value.
A cap parallel to the load will limit the speed and bandwidth of the buffer and I do not know will do regarding the oscillation.
Better ask at the appropriate thread.

 

[DEQ+TheEnd]

And lets face it, the power down pop will not be fixed in firmware - it's going to require additional circuit to do so.

I understand how to mute the balanced outputs. But as this thread is about alternative output stage where would be the best place to implement mute? At J7, or at the end of whatever buffer we decide to use?

If we mute at J7 can it be done by just shorting the output pins to ground with a relay? Do we need a resistor or a time progressive resistance?

 

[acko]

I understand how to mute the balanced outputs. But as this thread is about alternative output stage where would be the best place to implement mute? At J7, or at the end of whatever buffer we decide to use?

If we mute at J7 can it be done by just shorting the output pins to ground with a relay? Do we need a resistor or a time progressive resistance?

At the output of the final stage.
I have done something similar for my ESS IV module and works very well. Active action for both power up/down

 

[DEQ+TheEnd]

Thanks acko! So your experience with SE is that we can simply short the signal to ground without introducing new pops? I find internet being too big to give me consistent answers.

 

[new2hifi]

At the output of the final stage.
I have done something similar for my ESS IV module and works very well. Active action for both power up/down

Let's say I don't want to use additional stage then what is the best way to time delay/mute J7?

 

[acko]

Thanks acko! So your experience with SE is that we can simply short the signal to ground without introducing new pops? I find internet being too big to give me consistent answers.

Yes, this is the way. Assuming of course music is not playing ...

 

[acko]

At the output of the final stage.
I have done something similar for my ESS IV module and works very well. Active action for both power up/down

Let's say I don't want to use additional stage then what is the best way to time delay/mute J7?

Re: my design, initially was integrated to IV module but now I have separated the functions into a new module as I will be using 3rd party IV modules also. So quite general purpose for just about any system requiring pop suppression.
Concept: time delay mute upon power up (adjustable delays to suit). Then power fail monitoring and fast action mute when power goes down.

For use with DAM 1021, connect this Pop-Buster module across the outputs of J7. Physically disconnects from signal path after action so does not interfere with normal operation.

Will preview some pics soon...

 

[new2hifi]

shunt relay

.........................So quite general purpose for just about any system requiring pop suppression.
Concept: time delay mute upon power up (adjustable delays to suit). Then power fail monitoring and fast action mute when power goes down.

For use with DAM 1021, connect this Pop-Buster module across the outputs of J7. Physically disconnects from signal path after action so does not interfere with normal operation...........................

I concerned that any relay (which one is most transparent?) in series with signal might degrade the quality. While I have heard about shunt relay (that shunts the signal to ground) I am not sure how to implement that here.

 

[acko]

I concerned that any relay (which one is most transparent?) in series with signal might degrade the quality. While I have heard about shunt relay (that shunts the signal to ground) I am not sure how to implement that here.

It is a shunt relay arrangement here

 

[alecm]

What about the Super V/I converted For DAC (http://www.diyaudio.com/forums/quanghao-audio-design/246579-super-v-i-converted-ll1684.html)?

Is it suitable for Soekris R2R?

 

[Dimdim]

Not without some major modifications, as it assumes that your DAC has balanced ouputs.

 

[new2hifi]

Lundahl Transformer?

Which Lundahl Transformer will be perfect match?

To,

1. Block the output DC?

2. Give somewhat passive filtering of image noise

 

[alecm]

Which Lundahl Transformer will be perfect match?

The simple approach to take the LUNDALH LL1684 and connect it according the schema #1. But i would recommend to check DC presence in a good time.

 

[new2hifi]

2V DC?

The simple approach to take the LUNDALH LL1684 and connect it according the schema #1. But i would recommend to check DC presence in a good time.

stijn001 measured 2V DC. Here is the post, http://www.diyaudio.com/forums/vend...magnitude-24-bit-384-khz-229.html#post4267912

 

[normundss]

On my unit there is no DC voltage on raw outputs. On balanced outputs there is about 0.5 mV DC, which is nothing for any practical purpose.

The power on/off pops do produce about 2 Vpp pulses on raw output. Have not measured them on balanced outputs, but it should be about the same.

 

[acko]

Re: my design, initially was integrated to IV module but now I have separated the functions into a new module as I will be using 3rd party IV modules also. So quite general purpose for just about any system requiring pop suppression.
Concept: time delay mute upon power up (adjustable delays to suit). Then power fail monitoring and fast action mute when power goes down.

For use with DAM 1021, connect this Pop-Buster module across the outputs of J7. Physically disconnects from signal path after action so does not interfere with normal operation.

Will preview some pics soon...

As promised ... the Pop Eliminator!

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

 

[new2hifi]

As promised ... the Pop Eliminator!

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

Thanks acko!

Do you plan to sell assembled board?
Can you share the specifics of white replay unit used? Just asking as there are a whole threads on golden relays.
http://www.diyaudio.com/forums/solid-state/153935-best-audio-relays.html
http://www.diyaudio.com/forums/analog-line-level/257868-best-sounding-signal-level-relay.html



spikestabber has come up with something that can even, stops "pops/crackles during sample rate changes"
http://www.diyaudio.com/forums/digi...ris-s-dac-implementations-64.html#post4274036

 

[acko]

You can already order from my webpage below. Look under DAC section at the end. There is a bit of lead time at this stage.
Relay is standard type, shunts and not in signal paths at all!