Amplifier and speaker protection circuits

Status
Not open for further replies.
Jump to Latest
#121
fcel,

You could try to put the relay contacts in series.
These anti plops are designed with this in mind.
The action of the relay is delayed on (turn off) and
immediate off (turn off).

If this still does not solve the problem, I will try to
find a suitable circuit for you.

regards
 
#123
Correction on previous message

After 30 minutes the author of a message can no longer
edit it?

fcel,

You could try to put the relay contacts in series.
These anti plops are designed with this in mind.
The action of the relay is delayed on (turn on ) and
immediate off (turn off).

If this still does not solve the problem, I will try to
find a suitable circuit for you.

regards
 
#124
Roberto,
I have meant to ask you this before. Am I correct to assume that when you said you don't get any thump, you are using the balanced output of the BOSOZ? For balanced operation, I don't get any turn on/off thump either. I got turn on/off thump on unbalanced output only.
 
#125
fcel said:
Roberto,
I have meant to ask you this before. Am I correct to assume that when you said you don't get any thump, you are using the balanced output of the BOSOZ? For balanced operation, I don't get any turn on/off thump either. I got turn on/off thump on unbalanced output only.
Click to expand...

No, I don't get any thump either ways. All is silent, balanced or not.

ciao,
Roberto Amato
 
#126
rtirion,

I have mentioned in my earlier post that if I installed the relay contact in series, it will cause buzzing noise before the relay kicks in. Once the relay kicks in, everything works nicely. I'm using Pass A40 as my power amp.

Currently, I have installed the relay so that the pre-amp output is short to ground before the pre-amp is turn on. And yes, it's doing delay on (turn on) and immediate off (turn off). I have measured both the transient turn on (~10mv) and transient turn off voltage (0v). I'm assuming that the pop sound when I turn off the pre-amp is the actual sound of the relay clicking because I can't measured any voltage. At this moment, the pop sound at turn off still bothers me.

Just curious ... I understand that capacitors would block DC ... would installing a capacitors (& what value?) to ground from the relay output do anything to stop the pop sound?

Roberto,
As I'm writing this, I saw your response. Did you built your BOSOZ exactly as written up on the article? You must have done something different. I build mine exactly as described in the original article.
 
#127
fcel said:
rtirion,
Roberto,
As I'm writing this, I saw your response. Did you built your BOSOZ exactly as written up on the article? You must have done something different. I build mine exactly as described in the original article.
Click to expand...

The only difference is in the power supply. There are two power supplyes (one for each channel) with two transformers each... and a lot of capacitance, about 20.000uf. I have an inrush protection circuit (the one we wrote about many times) and that's all. Without that circuit the BOSOZ surely DOES thump on turn on... but still does not on turn off.

As seems strange to you my BOSOZ does not thump, as to me seem strange your does!:bigeyes:

If yours does thump on turn off, even with volume down to zero, must be something in the wiring of the relay circuit, or in the relay itself, or in the sequence contacts are shorted out... hard to say from here.

ciao,
Roberto Amato
 
#129
Try to connect the output of the preamp to the ground with a piece of wire. Then you will Know what makes pop. If it's preamp it means that is something wrong with your ground wiring. Yuou can also try different relay. I wouldn't bother with connecting contacts in series (this can actually cause more noise in speakers). Also if your pot is at the input, it doesn't matter what position it is in.
 
#132
Zen4 Soft Start

Hi,
I just finish and test my Soft Start Circuit, it works fine😀

I want to drive the PS of my futur Zen4 and in this case I want to know what kind of fuse I may use in the SSC!

I have some T4 fuse, it's that a good value or not?
 
#133
Re: Zen4 Soft Start

PsykoK said:
Hi,
I just finish and test my Soft Start Circuit, it works fine😀

I want to drive the PS of my futur Zen4 and in this case I want to know what kind of fuse I may use in the SSC!

I have some T4 fuse, it's that a good value or not?
Click to expand...
..ahem, what does "SSC" means? Also I'm not quite sure about "T4" meaning. 4A?
In my monoblock SoZ I use a slow-blow 750ma fuse. The inrush current is so much tamed by the soft-start, that the fuse rating needed is just slightly above the current sucked from the AC line.

ciao,
Roberto Amato
 
#135
My F5 has two 10A fuses in the AC supplies from the transformers to the bridge rectifiers. Immediately after the fuses I have two 30A relays which, in the event of a fault being detected short the AC rails causing the fuses to rupture. OK the PSU capacitors are still charged and will discharge through the speakers but this takes seconds. No relay contacts are in the path of the DC supplies, nor are there any contacts in the speaker paths. It's BRUTE FORCE I know but it has absolutely NO effect on the sonic performance of the amp and does give a degree of protection to the speakers.

You might argue that the mains fuse would probably blow in the case of major amp failure. I've never had a problem.
 
#136
Recently I have lost two Focal woofers due to a failing DC protection circuit. Plus, it wasn't the first time that this happend to me. Thus I always considered speaker protection as an important issue and have wondered why so many amps are buildt without it. In my mind a poor protection circuit is worse than no protection ciurcuit!
Now I am in the process of building F5's without any protection circuits at all. As I need new speakers too, I really hope (and expect) that the F5's will work better and safe..!
 
Last edited:
#137
Tiroler said:
Recently I have lost two Focal woofers due to a failing DC protection circuit. Plus, it wasn't the first time that this happend to me. Thus I always considered speaker protection as an important issue and have wondered why so many amps are buildt without it. In my mind a poor protection circuit is worse than no protection ciurcuit!
Now I am in the process of building F5's without any protection circuits at all. As I need new speakers too, I really hope (and expect) that the F5's will work better and safe..!
Click to expand...
I am in the same boat about speaker protection. What did you end up implementing.

Thanks
Pandu
 
#138
My experience says that the F5 is very reliable. Now I think that is a pity that I made my F5's without DC-protection. And there is no room left to put such a circuit into the cramped F5's now. A good protection circuit probably needs more board surface than the amp itself... When I used the BoSoZ I felt pretty safe. Now I have the fantastic UGS preamp and my whole system is DC-coupled. That is not exactly without risk.
Therefore my next power amps must have an adequate protection. I think it should sit at the output and must disconnect the speaker or short the supply rails really fast. The electrolytics should not be allowed to discharge through the speaker.
 
Status
Not open for further replies.
Top Bottom