Hi,
Does implementing a delay turn on circuit in addition to the on/off switch in a power amp degrade the quality ? I want to avoid the thump on turn on. Is there any good quality rely circuit available which implement good contact using special metals or any such ? What is the recommended part for this used for very high quality amps ?
Links to people who sell these and high quality on/off switchs will be much appreciated.
Does implementing a delay turn on circuit in addition to the on/off switch in a power amp degrade the quality ? I want to avoid the thump on turn on. Is there any good quality rely circuit available which implement good contact using special metals or any such ? What is the recommended part for this used for very high quality amps ?
Links to people who sell these and high quality on/off switchs will be much appreciated.
I think I’ll explain further. I am a newbie in DIY but an audiophile for some 15 years or so.
I have seen that most branded amplifiers have some soft start function to the on/off switch. This prevents that thump from the speakers that happens with sudden power up. I think it works when powering down too. I have seen this implemented in quite expensive (good sounding amps) too. I want to know how this is done. Most DIY folk do not implement this fearing degradation to the sound. But I am assuming there must be a good way to achieve this with the right kind of high quality “soft start “ circuit or other solution. Any thoughts ? Any recommended ready-made circuits or other solution / work-around available? I may get into a semi-diy power amp project soon.
I am a minimalist at heart, so would like to keep as less parts / bottle necks in the signal path as possible.
I have seen that most branded amplifiers have some soft start function to the on/off switch. This prevents that thump from the speakers that happens with sudden power up. I think it works when powering down too. I have seen this implemented in quite expensive (good sounding amps) too. I want to know how this is done. Most DIY folk do not implement this fearing degradation to the sound. But I am assuming there must be a good way to achieve this with the right kind of high quality “soft start “ circuit or other solution. Any thoughts ? Any recommended ready-made circuits or other solution / work-around available? I may get into a semi-diy power amp project soon.
I am a minimalist at heart, so would like to keep as less parts / bottle necks in the signal path as possible.
I misunderstood a bit. Sure, the wrong type of relay can surely degrade performance.Delay turn on circuit
Square Wave
I don't know of any ready made modules, but they are sure to be available.
I do however,have a magazine project's details of how they operate and a circuit to go with it.
If you email me , I will forward the details.
SandyK
alexkethel@optusnet.com.au
Square Wave
I don't know of any ready made modules, but they are sure to be available.
I do however,have a magazine project's details of how they operate and a circuit to go with it.
If you email me , I will forward the details.
SandyK
alexkethel@optusnet.com.au
Regarding relays for speaker output, don't forget the special design for this purpose that Jan Didden has recommended. It seems not possible to link directly to it, but look under "Amplifier Modules" in this link and you find the relay
http://www.amplimo.nl/
http://www.amplimo.nl/
The answer was 2 posts down in that thread... use free trial version of Eagle....
Once you have the board open hit the ratsnest button, to fill groundplane...
All it does, is wait a few seconds then flips the relay from one position to the next.... you can connect anything to be switched to the relay...
Part number for the relay used is on the board and is from RS components... It is made by Finder, and you should be able to get same model from your prefered supplier...
If you use the circuit as is, you can connect it between even + and - 15V, useing the first resistor to drop voltage to the chip as I did... simple ohms law calculation...
Once you have the board open hit the ratsnest button, to fill groundplane...
All it does, is wait a few seconds then flips the relay from one position to the next.... you can connect anything to be switched to the relay...
Part number for the relay used is on the board and is from RS components... It is made by Finder, and you should be able to get same model from your prefered supplier...
If you use the circuit as is, you can connect it between even + and - 15V, useing the first resistor to drop voltage to the chip as I did... simple ohms law calculation...
Borbely audio (http://www.borbelyaudio.com/eb292132.asp) does a delay/dc speaker protector which covers what you want. Uses 2 Schrack V23057 relays with Silver/Nickel contacts
Here is a design that i have been using for quite a while and provides DC detection a turn on delay and Loss of AC detection. Simple and easy.
An externally hosted image should be here but it was not working when we last tested it.
Loudspeaker protection
Hello, I use a circuit which was originally published in Electronics Australia in the early 1990's (1992 I think).
It has 4 way protection:-
1. Delay on switch-on (power-on de-thump)
2. Fast disconnect on switch-off (power-off de-thump)
3. Disconnect on DC detection.
4. Disconnect on Oscillation detect.
I have been building amps for centuries. On one occassion destroyed one of my speakers when the output transistors blew in one channel... it was a rather unpleasant sound... and hurt the back pocket badly as well.
Have built heaps of these into a range of amps, both DIY and commercial, and they always work well..... although I am not aware of any occassions where one has gone off in anger (DC or Osc fault)... but the de-thump functions very well.
It terms of the relay... the PCB for this made allowance for a couple of types of relay (although I usually mount the relay away from the PCB and close to the output terminals)..... One would buy a high quality 12v relay. I have usually used salvaged relays from industrial control boards, not the elcheapos from hobbiest outlets.
The protector I am referring to is available from Altronics in Australia (K5052)... interestingly, it is still on sale and I consider it superior to later version protectors I have looked at in other electronics magazines (mainly because it's the only one with de-thump on power-off).
I have also looked at various other kits or units on various sites in the US and UK... these look OK but do not appear to have the power-off de-thump function.
I am in the process of doing two of the SKA 150w amps as monoblocks and am in the process of laying out the Protector PCB on a longer board (165 x 55) with integral small toriod (I also make my own PCBs).
My first post here..... thanks guys.
Hello, I use a circuit which was originally published in Electronics Australia in the early 1990's (1992 I think).
It has 4 way protection:-
1. Delay on switch-on (power-on de-thump)
2. Fast disconnect on switch-off (power-off de-thump)
3. Disconnect on DC detection.
4. Disconnect on Oscillation detect.
I have been building amps for centuries. On one occassion destroyed one of my speakers when the output transistors blew in one channel... it was a rather unpleasant sound... and hurt the back pocket badly as well.
Have built heaps of these into a range of amps, both DIY and commercial, and they always work well..... although I am not aware of any occassions where one has gone off in anger (DC or Osc fault)... but the de-thump functions very well.
It terms of the relay... the PCB for this made allowance for a couple of types of relay (although I usually mount the relay away from the PCB and close to the output terminals)..... One would buy a high quality 12v relay. I have usually used salvaged relays from industrial control boards, not the elcheapos from hobbiest outlets.
The protector I am referring to is available from Altronics in Australia (K5052)... interestingly, it is still on sale and I consider it superior to later version protectors I have looked at in other electronics magazines (mainly because it's the only one with de-thump on power-off).
I have also looked at various other kits or units on various sites in the US and UK... these look OK but do not appear to have the power-off de-thump function.
I am in the process of doing two of the SKA 150w amps as monoblocks and am in the process of laying out the Protector PCB on a longer board (165 x 55) with integral small toriod (I also make my own PCBs).
My first post here..... thanks guys.
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