Hello, would it be possible to add an anti-thump circuit to my integrated amplifier? It is from the early 70's- a Sony Ta-1055, which is 35W X 2. Unfortunately, it creates a thump every time it is shut down, which rocks the 8" advent woofers in my speakers. The surrounds on these were recently replaced (maybe 2 or 3 months ago), and one of them is starting to tear- there is a small hole in it. So far the only way i have found to stop the thump when it is shut down it to turn off the main speaker switch, but it seems like if the switch is constantly pushed on and off, it might break. Would it be simple to add in an anti-thump circuit to save the surrounds on these speakers?? I don't have any experience working on stereo equipment, just basic soldering skills (from working on speakers). Is this doable? tia
Dave
Dave
It's hard to believe that a thump at turn off is going to put a hole in the woofer surround. Perhaps the new surround was damaged before or after installation.
Turn off thump is normal for some equipment and normally won't damage the speakers. Is it the same on both channels? Look at the woofers and see how far they move.
You could always leave it on all the time or maybe install an outboard toggle switch for the speakers if you don't think the built in switch can handle it.
Turn off thump is normal for some equipment and normally won't damage the speakers. Is it the same on both channels? Look at the woofers and see how far they move.
You could always leave it on all the time or maybe install an outboard toggle switch for the speakers if you don't think the built in switch can handle it.
If your only problem is turnoff thump, a simple normaly open relay that powered by your on/off switch and conected your speaker outputs could be a easy solution, That way when you switch off the power the speakers will disconect from the amp
How do you eliminate turn-on/off transients in a bi- or triamped speaker system where this could kill the tweeter?
Hi sobazz
The amp itself should provide a way for the tweeter from seeing any DC, but if in doubt, protect the tweeter with a capacitor(better yet, fix the amp or the equipment that is leaking the standing DC voltage).
You might also want to take a look at: http://www.mitedu.freeserve.co.uk/Design/dcthump.htm
Regards,
Tiago
DC on the output was not the issue sobazz was talking about. He was meaning on the initial powerup of the amplifier when you get a powerup thump put thru the speakers, how do you eliminate this.
The answer is the same and the circuit posted by paulb, this accomplish that.
The relays are off when the amp is off and are off when DC is detected at the output. When the amp turns on this is DC at the output, so the circuit will keep the relays open. After the amp has been on a few seconds and the output has steadied DC will drop to the standard few millivolts and then the relays will close connecting speaker to amp, therefore eliminating the thump at turn on. Woofers and mid/woofers wills survive this anyway tweeters are less likely to, I just put a cap in the way.
Im kinda paranoid about destroying expensive tweeters, so even if I had the DC protection thingy I would probably still use a cap. Even though the chance of the DC circuit failing is quite slim, id rather not take the chance in frying my tweets.
The answer is the same and the circuit posted by paulb, this accomplish that.
The relays are off when the amp is off and are off when DC is detected at the output. When the amp turns on this is DC at the output, so the circuit will keep the relays open. After the amp has been on a few seconds and the output has steadied DC will drop to the standard few millivolts and then the relays will close connecting speaker to amp, therefore eliminating the thump at turn on. Woofers and mid/woofers wills survive this anyway tweeters are less likely to, I just put a cap in the way.
Im kinda paranoid about destroying expensive tweeters, so even if I had the DC protection thingy I would probably still use a cap. Even though the chance of the DC circuit failing is quite slim, id rather not take the chance in frying my tweets.
When you get the "thump" at the powerup, it is still DC coming to the speakers. Probably due to any standing DC voltage in the equipment passing through while a DC blocking cap is charging.
Sure.. I couldn't agree more. But anyone who goes throught the trouble of bi/tri-amping a speaker is probably trying to avoid any passive component which may cause other kind of side effects anyway(as phase deviations caused by caps).
I agree too on this front, one of the reasons is to remove all passive components. This is one reason why I have a triamped system 😀, but id rather not take the chance in frying my ss97's
relay
B.VDBOS, what type of relay would be required to do this? (# of amps, volts, etc. ) Also, would you need a schematic of the sony to be able to do this? Oh, and if you could provide some sort of schematic to show how this sort of thing would be wired, that would be great too. Would this be a difficult job, and what precautions are necessary to ensure that the amp will be ok? Thanks
Dave
B.VDBOS, what type of relay would be required to do this? (# of amps, volts, etc. ) Also, would you need a schematic of the sony to be able to do this? Oh, and if you could provide some sort of schematic to show how this sort of thing would be wired, that would be great too. Would this be a difficult job, and what precautions are necessary to ensure that the amp will be ok? Thanks
Dave
I think (just think mind you) that turn-on-thump and turn-off-thump have different origins. I have seen a .01uF ceramic disk cap (rated 300+ Vac) placed parralel to the power switch to eliminate power-off noises. To the 50/60 hz mains power it looks like an open circuit and is presumably safe. There may be caps designed for this specific purpose such that the only fail open and never fail short. I would like more concrete data on failure modes for such a cap before using it since failing short would be inconvenient at best, a hazard at worst.
sam9 said:
FYI, (a little something I was working on...) 😉
X and Y Mains rated capacitors
Two types of safety mains rated capacitor are available: Class X and Class Y. Both types are designed for connection across the 230v mains supply, and are are self-healing, and flame resistant. However Class X must NOT be used where failure could pose a shock hazard, such as across live and earth. Class Y should be used for these applications, and in general, are a better solution for the DIYer.
These are the only type of capacitor rated for connection across mains AC voltages, for instance in mains supply EMF filtration. Any other type will fail when subjected to the stresses of constant mains AC.
Pinkmouse,
Are these the ones (Panasonic ECK-xxxxx and ECC-xxxxx series) that appear on page 800 of the current Digikey catalog?
Are these the ones (Panasonic ECK-xxxxx and ECC-xxxxx series) that appear on page 800 of the current Digikey catalog?
Sam,
Sorry, I have no idea, we don't get Digikey over this side of the pond. 🙁 However they should note the X1 or Y1 Mains rating in the specs. on the page, (and on the cap itself), as it is important.
Most rated types these days are film, as I believe ceramics don't always fail safe.
Sorry, I have no idea, we don't get Digikey over this side of the pond. 🙁 However they should note the X1 or Y1 Mains rating in the specs. on the page, (and on the cap itself), as it is important.
Most rated types these days are film, as I believe ceramics don't always fail safe.
Pinkmouse,
Here is the Panasonic data sheet:
http://www.panasonic.com/industrial/components/pdf/ABB0000CE11.pdf
Unless I misunderstand, some versions serve meet both "X" and "Y" standards. (IEC384-14 sub-class Y1/X1)
This link: http://www.panasonic.com/industrial/components/pdf/ABD0000PE61.pdf has info on the construction of the Panasonic cap, both Y and X. They seem to be internally fused which suggests to me that both types fail open.
I also found some other google reference that seem to indicate X is for Live-Neutral while Y is Live-Ground or Neutral-Ground. One was this FAQ: http://www.okaya.com/FAQ1.html
I'm interested for obviously selfish, personal reasons that I understand this subject without ambiguity.
Here is the Panasonic data sheet:
http://www.panasonic.com/industrial/components/pdf/ABB0000CE11.pdf
Unless I misunderstand, some versions serve meet both "X" and "Y" standards. (IEC384-14 sub-class Y1/X1)
This link: http://www.panasonic.com/industrial/components/pdf/ABD0000PE61.pdf has info on the construction of the Panasonic cap, both Y and X. They seem to be internally fused which suggests to me that both types fail open.
I also found some other google reference that seem to indicate X is for Live-Neutral while Y is Live-Ground or Neutral-Ground. One was this FAQ: http://www.okaya.com/FAQ1.html
I'm interested for obviously selfish, personal reasons that I understand this subject without ambiguity.
Right, I'll try to be succinct about this.
Yes, Y class should be used whenever a cap is connected to possible mains potential, (either L or N) and to earth. This is to prevent a possible current flow to a case or chassis that could cause harm.
The main difference between X and Y is that for a certain voltage, ( the number part of the code), the caps will definately fail safe. If you look at spec sheets, you will usually see that voltage ratings for Y types are lower than the equvalent X type. This is to ensure the failsafe, as higher voltages can still cross even a blown cap.
Does that make sense?
Personally I always just buy Y1 types, to save having to worry...😉
Yes, Y class should be used whenever a cap is connected to possible mains potential, (either L or N) and to earth. This is to prevent a possible current flow to a case or chassis that could cause harm.
The main difference between X and Y is that for a certain voltage, ( the number part of the code), the caps will definately fail safe. If you look at spec sheets, you will usually see that voltage ratings for Y types are lower than the equvalent X type. This is to ensure the failsafe, as higher voltages can still cross even a blown cap.
Does that make sense?
Personally I always just buy Y1 types, to save having to worry...😉
This thread has turn into discussions about mains filtering and a cap across the power switch.
I do not believe this talk is addressing the problem as originally posted.
I do not believe this talk is addressing the problem as originally posted.
Sorry. Although, if the cure for turn-off thump that the original poster chooses is a cap parrallel to the power switch, then the choice of cap is a safety issue involving mains wiring. Since most of the available info seems to focus on connections across mains it's difficult to avoid it entirely and discussion re "X" vs. "Y" caps is pertinent.
However, I think Pinkmouse has covered this branch adequately.
However, I think Pinkmouse has covered this branch adequately.
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