I just meant the power amplifier that is being fed the signal by the dap. No residual currents or voltages on the input line of the power amp.
Contacts will degrade sound appreciably. Its constraining the signal from free flowing in a large conductive piece of metal, to a single point on a piece of silver, That contact point will change every time the switch is engaged. The problem though I have is the relay is not functioning normally, So why not take it out?
Idk how the relay is implemented, because I dont know why its being used.
Some have said it blocks the dc thump, prevents damaging speakers or the amp, But i have had an ibasso dx50 and dx90 with those same nec mini smd relays, and they still had the thump every time its powered on, maybe they were sticking then, but no clue...
I can hear the difference in rotating the 3.5mm output jack from the dac/preamp/dap source, when its plugged into my amplifier. The contacts make all the difference. Even l/r signal gain. Dirty vs polished too make the difference.
Sidementioning
Really I think coax and all other stray input methods should be ditched and it should ALL be shielded 6.5mm jack, if not 3.5mm if not 2.5mm for the ultra slim and bendy smartphones.
Contacts will degrade sound appreciably. Its constraining the signal from free flowing in a large conductive piece of metal, to a single point on a piece of silver, That contact point will change every time the switch is engaged. The problem though I have is the relay is not functioning normally, So why not take it out?
Idk how the relay is implemented, because I dont know why its being used.
Some have said it blocks the dc thump, prevents damaging speakers or the amp, But i have had an ibasso dx50 and dx90 with those same nec mini smd relays, and they still had the thump every time its powered on, maybe they were sticking then, but no clue...
I can hear the difference in rotating the 3.5mm output jack from the dac/preamp/dap source, when its plugged into my amplifier. The contacts make all the difference. Even l/r signal gain. Dirty vs polished too make the difference.
Sidementioning
Really I think coax and all other stray input methods should be ditched and it should ALL be shielded 6.5mm jack, if not 3.5mm if not 2.5mm for the ultra slim and bendy smartphones.
Infineon's PVG612 offers claim of linear AC/ DC operation https://www.infineon.com/cms/en/product/power/solid-state-relay/photovoltaic-relays/pvg612/
I use the EC2 as the protection relay in my HP-2 headphone amp. The output of the amp flows through the relay. I don't have a measurement with 600 Ω, but here's 50 mW into 300 Ω. Note that this measurement was performed using the APx525 and a notch filter to knock down the fundamental at the input of the analyzer. That's why it shows at attenuated. If I recall correctly the filter had 9.2 dB loss at H2.
Tom
Resistance totally dominates though, for signal coupling ie 1 ohm in parallel with maximum of 130pf , so OK
Attachments
Yeah. The notch filter was on a piece of perf board dangling from the input connector to the analyzer. That's also why you see the switching hash above 1 kHz.
It's a challenge to make a setup that works well and doesn't require a bunch of compensation to extract the THD number, so in the end I ended up punting and bought an APx555B.
Tom
It's a challenge to make a setup that works well and doesn't require a bunch of compensation to extract the THD number, so in the end I ended up punting and bought an APx555B.
Tom
Hi Jack,
Love mercury wetted relays!
I have some for switching audio power amps in my dummy loads. Very reliable for signal applications too. The ones you are a very high quality.
Hi rschmitt100,
You have been reading too much stuff written by those who have no real experience. That's all I'm going to say.
-Chris
Love mercury wetted relays!
I have some for switching audio power amps in my dummy loads. Very reliable for signal applications too. The ones you are a very high quality.
Hi rschmitt100,
You have been reading too much stuff written by those who have no real experience. That's all I'm going to say.
-Chris
You are wrong anatch.... Here is why..
The Questyle qp2r is a high end audio player manufactured by foxconn, the ibasso dx50 is another high quality good quality dap BOTH of which I have had problems with them long term use, because of the ouptut relay. The relays stick and degrade over time. It is a mechanical device, and the contacts make contact differently every time they make and break connection. Some of them outright fail, like on my qp2r, it needs that little tap to get them to engage. So, if my headphones are not the problem they are just 32 ohm resistors who gives a crap, and my diy f5 amplifier has nothing on the input meaning no pops or hums, nothing other than 47kohm impedance which is also no problem, then why do you imply my lack of experience, go ahead, tell me more...
Tell me, what is the ouptput relay doing other than complicating the circuitry and degrading the audio signal do a degree...
The Questyle qp2r is a high end audio player manufactured by foxconn, the ibasso dx50 is another high quality good quality dap BOTH of which I have had problems with them long term use, because of the ouptut relay. The relays stick and degrade over time. It is a mechanical device, and the contacts make contact differently every time they make and break connection. Some of them outright fail, like on my qp2r, it needs that little tap to get them to engage. So, if my headphones are not the problem they are just 32 ohm resistors who gives a crap, and my diy f5 amplifier has nothing on the input meaning no pops or hums, nothing other than 47kohm impedance which is also no problem, then why do you imply my lack of experience, go ahead, tell me more...
Tell me, what is the ouptput relay doing other than complicating the circuitry and degrading the audio signal do a degree...
Okay, fine. Here we go.
Output relays for audio power are used in series for two very good reasons. The first is to protect the load in the event of a fault. It is irresponsible to not provide load protection when you are delivering power. Secondly, it eliminates "pops" or thumps when the unit powers up or down. the only other choice to mute the output is to short the output to ground - not very intelligent when you are talking about power. It is perfectly fine for a signal normally, and that is how a lot of audio equipment does operate for signal levels.
How about fuses for protection? Well, they are thermal things which means two things. There is a significant time delay before they operate, and being thermal means that the element resistance changes which causes a lot more distortion than a relay contact. Breakers are relay contacts actuated by bimetallic strips and have their own issues.
You mentioned the relays stick. Okay, you just proved they are cheap relays. Better quality types do not stick, and their contacts are much better (no big shock here!).
Finally, relays are maintenance items. Yup, you are supposed to replace them as required. Good quality relays used properly will last many, many years. In test instrumentation where signal quality is rather more important than audio is (the stuff is more sensitive), relays routinely last three decades or more while allowing the instrument to pass calibration. Sound like a problem component? Not to me, power supplies need work about the same interval, consumer equipment fails more often than that.
So we can point out specific makes and models to support either viewpoint. If we look at good equipment (I mean really good quality, not what the opinion is without technical basis), relays are extremely reliable. If you treat them properly in audio amplifiers they can last decades. You can also destroy the contacts in months by treating the equipment improperly.
Now how do I know this? First hand knowledge my friend. I work in audio service in high end and recording studios, that and I certify and calibrate test equipment (good stuff like HP and others). I've been doing this in excess of 45 years. My colleagues agree by the way (we talk shop). You can also look at MTBF failure curves from relay manufacturers. Look up other components while you're at it.
Just like relays have variable quality levels, so do switches and connectors used between PCBs. Now if you really want to absorb some reality, check out how many connections, switches and relays are in the signal path in a recording studio. Never mind cable runs, then they compress the signal before the final product. If relays contacts were audible to you, you would not be able to listen to any produced music from anywhere, you could only listen to live msic (yes I know it sounds different). And if it was amplified music of any kind, you are back to contacts, switches and relays.
Anyway, when talking about good quality relays used properly, you are completely incorrect. Sorry, but that is the truth of it. It is reality, and we do need relays. They happen to be the best way to accomplish the task of providing a safety disconnect between your headphones or speakers and the power amplifier.
-Chris
Output relays for audio power are used in series for two very good reasons. The first is to protect the load in the event of a fault. It is irresponsible to not provide load protection when you are delivering power. Secondly, it eliminates "pops" or thumps when the unit powers up or down. the only other choice to mute the output is to short the output to ground - not very intelligent when you are talking about power. It is perfectly fine for a signal normally, and that is how a lot of audio equipment does operate for signal levels.
How about fuses for protection? Well, they are thermal things which means two things. There is a significant time delay before they operate, and being thermal means that the element resistance changes which causes a lot more distortion than a relay contact. Breakers are relay contacts actuated by bimetallic strips and have their own issues.
You mentioned the relays stick. Okay, you just proved they are cheap relays. Better quality types do not stick, and their contacts are much better (no big shock here!).
Finally, relays are maintenance items. Yup, you are supposed to replace them as required. Good quality relays used properly will last many, many years. In test instrumentation where signal quality is rather more important than audio is (the stuff is more sensitive), relays routinely last three decades or more while allowing the instrument to pass calibration. Sound like a problem component? Not to me, power supplies need work about the same interval, consumer equipment fails more often than that.
So we can point out specific makes and models to support either viewpoint. If we look at good equipment (I mean really good quality, not what the opinion is without technical basis), relays are extremely reliable. If you treat them properly in audio amplifiers they can last decades. You can also destroy the contacts in months by treating the equipment improperly.
Now how do I know this? First hand knowledge my friend. I work in audio service in high end and recording studios, that and I certify and calibrate test equipment (good stuff like HP and others). I've been doing this in excess of 45 years. My colleagues agree by the way (we talk shop). You can also look at MTBF failure curves from relay manufacturers. Look up other components while you're at it.
Just like relays have variable quality levels, so do switches and connectors used between PCBs. Now if you really want to absorb some reality, check out how many connections, switches and relays are in the signal path in a recording studio. Never mind cable runs, then they compress the signal before the final product. If relays contacts were audible to you, you would not be able to listen to any produced music from anywhere, you could only listen to live msic (yes I know it sounds different). And if it was amplified music of any kind, you are back to contacts, switches and relays.
Anyway, when talking about good quality relays used properly, you are completely incorrect. Sorry, but that is the truth of it. It is reality, and we do need relays. They happen to be the best way to accomplish the task of providing a safety disconnect between your headphones or speakers and the power amplifier.
-Chris
I have seen many issues with the questyle daps (great sq, but bad acting relays), Every "broken" dap has been problems with the realy not connecting or sticking on one channel. Foxconn engineers are probably doing something wrong, however, I still also cannot understand why a preamp needs a relay at all. It does not protect anything. Overcurrent and overvoltage will certainly pass through any relay. If you want ouptut fuses that are plain as day and easily replaceble I am all for that mode of protection. Of couse, some odd user would leave thier equipment plugged in, and i guess the manufacturers are trying to eliminate that from causing problems while booting up other connected equipment and surges but still its unlikely.
This is like an issue that never needed to be, arguing with someone that doesnt want to agrue, or arguing with your debate coach and expecting to win.
Relays connect the device. But the purpose is having the device connected.
What I see is another middle man complicating the equation. If i want best sound quality I do not want 10 relays in the signal path, I dont even want 1. I will tolerate 1 connection to the mains, and 1 connection from the amp to source. Everything else is going to have soldered connections. And that would sound better, It DOES sound better.
They use NEC relays sooo the relays are definitely not cheap, nec is supposed to be top quality, so is questyle(foxconn) and ibasso(chinese engineered)
What is the thump all about too? Thank you for the explanation, but I think now the only reason is the thump for daps/preamps.
Yes yes yes, All of the equipments
This is like an issue that never needed to be, arguing with someone that doesnt want to agrue, or arguing with your debate coach and expecting to win.
Relays connect the device. But the purpose is having the device connected.
What I see is another middle man complicating the equation. If i want best sound quality I do not want 10 relays in the signal path, I dont even want 1. I will tolerate 1 connection to the mains, and 1 connection from the amp to source. Everything else is going to have soldered connections. And that would sound better, It DOES sound better.
They use NEC relays sooo the relays are definitely not cheap, nec is supposed to be top quality, so is questyle(foxconn) and ibasso(chinese engineered)
What is the thump all about too? Thank you for the explanation, but I think now the only reason is the thump for daps/preamps.
Yes yes yes, All of the equipments
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Relays in preamps make handy input selectors, gain selectors, tone control bypass switches, etc. Muting relays on the outputs of preamps prevent thumps if the end user happens to turn the power amp on before the preamp. They can also be handy in tube amps to prevent turn-on thumps when the tubes warm up. It's all part of being a good audio citizen and playing well with others.
Tom
Tom
You want to know why a preamp would use a relay, let see, I open up a Pass Aleph P and I see them used for input selection and volume control, and this is a great sounding preamp and has never malfunctioned in 10 years. I also use them for muting and standby circuits. Use of a relay or a switch contacts of the proper quality is not a issue in high end audiophile equipment so I am happy to design and use them in some very good sounding circuit designs of my own.
Sounds like you need to replace the relays in your equipment with some high quality ones, especially if they are sticky, your ears will thank you.
Sounds like you need to replace the relays in your equipment with some high quality ones, especially if they are sticky, your ears will thank you.
My tip is to avoid any Chinese made relay and certainly those by Chinese brands and try to find NOS relays produced by quality brands. Like Chinese toroids Chinese relays are quite often miserable. Apparently the knowledge to make good alloys for contacts has been lost somewhere. While I have repaired audio for decades relays were not the least reliable part in amplifiers at all except for wrongly applied relay types by Japanese brands. Anyone that repaired Sony, Pioneer, Yamaha etc. knows defective protection relays. It is today that I find defective signal relays with often unknown brand names in relatively young equipment!
Don't get fooled by a known brand name as many brands are taken over etc. Of course there exist good Chinese ones but those are the ones you haven't bought
So the circle is round again: at the end of the transformer era SMPS will be better than cheap toroids, semis will be more reliable than cheap relays etc. but it is just a question of what part is lowest in cost. Relays have various precious metals, a copper wire coil and mechanical parts and they're complicated to produce. In some circles relays and relay muting still are novelties (ha ha) left out by the brand which is a pity as muting to GND will give the joys and not the pains of relays.
Don't get fooled by a known brand name as many brands are taken over etc. Of course there exist good Chinese ones but those are the ones you haven't bought
So the circle is round again: at the end of the transformer era SMPS will be better than cheap toroids, semis will be more reliable than cheap relays etc. but it is just a question of what part is lowest in cost. Relays have various precious metals, a copper wire coil and mechanical parts and they're complicated to produce. In some circles relays and relay muting still are novelties (ha ha) left out by the brand which is a pity as muting to GND will give the joys and not the pains of relays.
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+1, the Questyle daps use NEC UD2-3NU relay.
According to spec, Axicom IM01GR can last 10 to 50 times longer.
I have seen the ud2 NEC relays used in EXPENSIVE lab equipment and oscilloscopes, so it ts probably bad implementation.
Trying a new relay wouldn't solve my problem; chrisng, but axicom I think Ive seen in servers and modems so they are probably more reliable too.
Why isnt it all solid state switching taken care with somewhere up the signal path chain, I would think a silicon scr would be more complimentary to sound quality over a relay. Its not like we're dealing with more than a few volts and a few amps to get acceptable amounts of sound, so why all of the mechanisms and physical contacts for isolation???
Trying a new relay wouldn't solve my problem; chrisng, but axicom I think Ive seen in servers and modems so they are probably more reliable too.
Why isnt it all solid state switching taken care with somewhere up the signal path chain, I would think a silicon scr would be more complimentary to sound quality over a relay. Its not like we're dealing with more than a few volts and a few amps to get acceptable amounts of sound, so why all of the mechanisms and physical contacts for isolation???