Loudspeaker protection
Look here, it is completely electronic and it works. http://www.diyaudio.com/forums/solid-state/182554-thermaltrak-tmc-amp-6.html#post2910364
dado
Look here, it is completely electronic and it works. http://www.diyaudio.com/forums/solid-state/182554-thermaltrak-tmc-amp-6.html#post2910364
dado
There are probably millions of amps that use relay with no problems, I have 30 year old vintage amps using relays that still function correctly.
probably because they have never been abused and thus the relay contacts have never asked to break a high DC fault current.
Some units get abused every weekend for over 7 years in nightclubs, 1500 watt amps. Relay also protects against dc,hard clipping and that happens some times when the drunk DJs drop a mike. Sometimes the amp blows but the relay remains intact.
You guys are right relay can't be more reliable than electronic solution but this amp will not be used at his limits or abused by drunk people at parties so it does not need such a complicated solution. If one day I make an pro amp will go ahead with something better but now I prefer something simple mostly for turn on delay and some protection just in case if something go wrong.
Will go ahead with RSK schematic but will make different PCB to put an available to me relay.
Regards!
Will go ahead with RSK schematic but will make different PCB to put an available to me relay.
Regards!
If you read all the thread I linked to you will see I experienced the "relay issue" first hand. The more "abuse" an amp gets, the less likely it is to suffer the problem.
It was something I would not have believed... but it happened to me 🙂
It was something I would not have believed... but it happened to me 🙂
This sounds like if you drive a car less the possibility to crash it will become higher. Makes no sense but you experienced it so I believe you but still will go for relay because as I said before main function of it will be the turn on delay.
It does make sense when you think about it 🙂
Normal listening involves very low powers and voltage. Those voltages and currents can not break down any contamination on the contacts. If the amp is used at high power then the current "cleans" the contacts. Also I don't power the amp on or off with a loud signal present so that again means the contacts don't get cleaned. By being kind to the amp the contacts suffered over the years.
I'm sure you have seen this on just how little power is needed.
http://www.diyaudio.com/forums/mult...much-voltage-power-do-your-speakers-need.html
Normal listening involves very low powers and voltage. Those voltages and currents can not break down any contamination on the contacts. If the amp is used at high power then the current "cleans" the contacts. Also I don't power the amp on or off with a loud signal present so that again means the contacts don't get cleaned. By being kind to the amp the contacts suffered over the years.
I'm sure you have seen this on just how little power is needed.
http://www.diyaudio.com/forums/mult...much-voltage-power-do-your-speakers-need.html
Your post inspired me for an a bit stupid idea:
Yes contact contamination will be a problem but if I make a button to say on the rear panel where is not visible and when is pressed it will force the relay to break. So now we can make a "cleaning" procedure time to time. Crank up the volume and force the relay to break several times the high current that flows trough it. This way also you can notice any problem with the relay if it stop breaking.
Stupid isn't it....🙂
Yes contact contamination will be a problem but if I make a button to say on the rear panel where is not visible and when is pressed it will force the relay to break. So now we can make a "cleaning" procedure time to time. Crank up the volume and force the relay to break several times the high current that flows trough it. This way also you can notice any problem with the relay if it stop breaking.
Stupid isn't it....🙂
If so it didn't work for me assuming the relays I used had that feature. Even small switches that pass line level audio always seem to become noisy too and I think they are often described as self wiping.
some switches/relays use a rocker to open and close the contacts.
I might surmise that if the rocker contact and the fixed contact are quite rigid, then there may be very little of the wiping action.
If you can get hold of a BIG transparent relay and look at the contact mechanism you will usually see that one contact is mounted on a flexible strip. That strip bends as the contact is brought across to touch and then over stroked. That over stroking and recovery is part of the wiping action.
I am not a relay designer. I see what I look at.
I might surmise that if the rocker contact and the fixed contact are quite rigid, then there may be very little of the wiping action.
If you can get hold of a BIG transparent relay and look at the contact mechanism you will usually see that one contact is mounted on a flexible strip. That strip bends as the contact is brought across to touch and then over stroked. That over stroking and recovery is part of the wiping action.
I am not a relay designer. I see what I look at.
I'm Alive!!!
Well guys GOD was kind enough to preserve my life.
Last week my town Pernik was epicenter of an 5.8 grade earthquake.
My old TV felt down and it is useless now , there are some cracks on the walls in my apartment building which has 8 floors but thank god no collapsed buildings or death people. This happens in 3.00 o'clock in the morning when all people was asleep - I was too. The earthquake waked me up and scared the crap out of me.
All people get out of the building start their cars and run out - it was unseen panic.
Let now leave this and say something about this project.
Last month I started a new job. I have less free time now and abandoned a bit all my projects. I hope soon to order the trafo and heatsinks and finish it if everything is OK. Will inform you if there is something new on this.
Wish you health and luck because there is nothing more important than this in the world.
Best Regards!
Well guys GOD was kind enough to preserve my life.
Last week my town Pernik was epicenter of an 5.8 grade earthquake.
My old TV felt down and it is useless now , there are some cracks on the walls in my apartment building which has 8 floors but thank god no collapsed buildings or death people. This happens in 3.00 o'clock in the morning when all people was asleep - I was too. The earthquake waked me up and scared the crap out of me.
All people get out of the building start their cars and run out - it was unseen panic.
Let now leave this and say something about this project.
Last month I started a new job. I have less free time now and abandoned a bit all my projects. I hope soon to order the trafo and heatsinks and finish it if everything is OK. Will inform you if there is something new on this.
Wish you health and luck because there is nothing more important than this in the world.
Best Regards!
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