Delay turn on circuit for amps

square_wave · 15th June 2007, 07:55 AM

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.

peranders · 15th June 2007, 09:03 AM

Degrade? Hardly.

If you search for "inrush current limiter" or "soft start" you will get a couple of hits.

richie00boy · 15th June 2007, 09:11 AM

I think you have the wrong idea Per-Anders, he wants something to disconnect the speaker at turn-on to avoid passing the pop to his speaker.

There can be quality issues with some relays. It's not easy to find out which ones are good though.

square_wave · 15th June 2007, 09:50 AM

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.

peranders · 15th June 2007, 11:19 AM

Quote:

Originally posted by richie00boy
I think you have the wrong idea Per-Anders, he wants something to disconnect the speaker at turn-on to avoid passing the pop to his speaker.

There can be quality issues with some relays. It's not easy to find out which ones are good though.

I misunderstood a bit. Sure, the wrong type of relay can surely degrade performance.

Hardsilver contacts are pretty good and quite common since AgCdS is forbidden.

sandyK · 15th June 2007, 01:01 PM

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

Hi Speed · 15th June 2007, 01:13 PM

Quote:

Originally posted by square_wave
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.

The circuit you mentioned on branded amplifiers, is the protection circuit, after you turn on it verifies that no have DC component in the loudspeaker utilizing a relay, some amps have more delay turn on than others.

richie00boy · 15th June 2007, 01:13 PM

Rod Elliot / ESP project P33 is one way to do it.

square_wave · 15th June 2007, 02:04 PM

Thanks guys......
I am off for the weekend. Won't be checking this till monday. Will get back to you all then.,
Cheers to all of you. Have a rockin weekend.

Christer · 15th June 2007, 02:05 PM

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/

15th June 2007, 07:55 AM	#1
square_wave diyAudio Member Join Date: May 2007	Delay turn on circuit for amps 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.

15th June 2007, 09:03 AM	#2
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Degrade? Hardly. If you search for "inrush current limiter" or "soft start" you will get a couple of hits. __________________ /Per-Anders (my first name) or P-A as my friends call me

15th June 2007, 09:11 AM	#3
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	I think you have the wrong idea Per-Anders, he wants something to disconnect the speaker at turn-on to avoid passing the pop to his speaker. There can be quality issues with some relays. It's not easy to find out which ones are good though. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

15th June 2007, 01:01 PM	#6
sandyK diyAudio Member Join Date: Apr 2007 Location: Sydney	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

15th June 2007, 01:13 PM	#8
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Rod Elliot / ESP project P33 is one way to do it. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more


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15th June 2007, 09:50 AM	#4
square_wave diyAudio Member Join Date: May 2007	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.

15th June 2007, 02:04 PM	#9
square_wave diyAudio Member Join Date: May 2007	Thanks guys...... I am off for the weekend. Won't be checking this till monday. Will get back to you all then., Cheers to all of you. Have a rockin weekend.

15th June 2007, 02:05 PM	#10
Christer diyAudio Member Join Date: Sep 2002 Location: Sweden	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/

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