@Richie00boy,
Would a relay in the speaker path be audible? I want to use Velleman DC protection but am afraid i'll loose a lot of quality.
Maybe the relay isn't audible, but there's a lot of circuitry (handful of diodes, 2 caps, a resistor) parallel on the path to trigger the relay when needed.
Would the switching of the diodes (kind of bridge to detect dc) be audible to the speakers?
Would a relay in the speaker path be audible? I want to use Velleman DC protection but am afraid i'll loose a lot of quality.
Maybe the relay isn't audible, but there's a lot of circuitry (handful of diodes, 2 caps, a resistor) parallel on the path to trigger the relay when needed.
Would the switching of the diodes (kind of bridge to detect dc) be audible to the speakers?
As far as speaker muting/protection relays that is a different matter. For a start the potential for high and inductive currents is much higher, so you need a capable, high quality relay. Some cheap relays use a part inside them that is a little non-linear to provide the conduction path. I believe that these types of relay are included in the Velleman kits. The good news is that the relays used are of a standard footprint (FR-1) so a better quality replacement is just a drop in fit and easy enough to find.
As for the trigger circuitry affecting the audio, IMO it has no impact as it's all relatively very high impedance.
As for the trigger circuitry affecting the audio, IMO it has no impact as it's all relatively very high impedance.
Thanks richieboy, I'm looking for other relays for audio use based on that footprint.
I'm afraid to run the UcD's without DC protection. In theory, if one of the rails shorts to the output, DC should be so high, that the currect protection comes into play, but with expensive speakers that's quite a gamble.
Yves
I'm afraid to run the UcD's without DC protection. In theory, if one of the rails shorts to the output, DC should be so high, that the currect protection comes into play, but with expensive speakers that's quite a gamble.
Yves
I think if one of the output devices goes faulty and shorts, the current limit will not work. I share your concerns and have designed a board based on a Velleman kit that seems to be no longer available. The unit disconnects the speakers in the event of DC, but is totally passive so can be put inside amps with no additional power required or even inside speaker boxes. Again as with the soft start board, you are welcome to the layout.
Thanks Richieboy, I already have 2 of the velleman K4701 kits, those are the passive DC protections.
I'll just have to replace the relay with something decent. If you know a part number or something, that would be nice 🙂
I'll just have to replace the relay with something decent. If you know a part number or something, that would be nice 🙂
I wondered from your description a few posts up if you actually had the 4701 kit. The relays I use are higher rated (16A) than the ones in the kit and are made by Schrack. I get mine from RS Components in the UK, part number 198-6977.
SOFT START
May I suggest a simple soft start device which I`ve been using for many years: Take one power resistor and one non latching push switch and connect them in parallel with the on/off switch. With both switches side by side operate the non latching switch by depressing for about 3 seconds, operate the on/off switch then release the soft start switch. Simple,cheap and no dodgy relay contacts to worry about!
Also consider a circuit breaker on/off switch and do away with fuse holders. I use some of RS Components devices. Take a look at their website CBE pages;thermal/thermal magnetic circuit breaker switches.
Bob Lewis
May I suggest a simple soft start device which I`ve been using for many years: Take one power resistor and one non latching push switch and connect them in parallel with the on/off switch. With both switches side by side operate the non latching switch by depressing for about 3 seconds, operate the on/off switch then release the soft start switch. Simple,cheap and no dodgy relay contacts to worry about!
Also consider a circuit breaker on/off switch and do away with fuse holders. I use some of RS Components devices. Take a look at their website CBE pages;thermal/thermal magnetic circuit breaker switches.
Bob Lewis
@bob lewis,
That would work of course, but it has quite a bad WAF factor 😀
@Luismax,
That design seems to have (more or less) the same basic components than the velleman design. The relay is better though!
That would work of course, but it has quite a bad WAF factor 😀
@Luismax,
That design seems to have (more or less) the same basic components than the velleman design. The relay is better though!
Luismax said:
Hi Luismax,
That is a very interesting site. These guys have a lot of interesting stuff for sale. I'm especially interested in their Active PSU. Thinking of using it as a supply for UcD modules.
This power supply also has a shutdown input. This sounds good, could possibly be used in combination with a DC detection circuit to shutdown the power. Then you may not need a relay between amp and speaker.
Best regards and thanks again for the link
Gertjan
Just be aware that the Active PSU is basically a capacitance multiplier which doesn't offer much benefit for highly variable loads such as class-d or class-b amps. In fact you need so much headroom that you may almost as well use a regulator. IMO you would be best with a meaty unregulated PSU -- simple, cheaper, more compact and runs cooler.
The shutdown feature is nice though, but you would have to be sure that it shut down *after* the cap bank to use it for protection. (I can't check right now as I can't access their site here at work because it's written in some stupid scripts which our security systems block.)
EDIT: followed link in power supply thread. I also add now that the unit appears to have a 10A current limit. This is OK for UcD180, but not so good for UcD400.
The shutdown feature is nice though, but you would have to be sure that it shut down *after* the cap bank to use it for protection. (I can't check right now as I can't access their site here at work because it's written in some stupid scripts which our security systems block.)
EDIT: followed link in power supply thread. I also add now that the unit appears to have a 10A current limit. This is OK for UcD180, but not so good for UcD400.
Wnaudio has very interestings kits, but a little expensive I think.
I supose that nobody here speak spanish, 🙂 but the prices from this spanish dealer have a comprensible €.
http://www.audiohum.com/articulos.php?categoria=30
http://www.audiohum.com
Luismax
I supose that nobody here speak spanish, 🙂 but the prices from this spanish dealer have a comprensible €.
http://www.audiohum.com/articulos.php?categoria=30
http://www.audiohum.com
Luismax
You can also see prices in Euro and more complete descriptions in English by downloading their catalog.
I wrote to David at White Noise today, alerting him to this thread and inviting him to join the discussion. Here's his reply:
Hi Brad,
Thanks for giving me the heads up to the posts. I don't get invloved in discussions of my products on the forums - its all too easy to get involved in very public polemic. Anyway who's going to believe what I say? - I'm trying to sell you stuff!But if people want to email me directly then I am only too happy to help and always reply. As regards the active power supply it is indeed a capacitance multiplier unit. The short term current capability is over 50A but the rectifier diodes normally supplied with the kits are limited to 14A continuous and the pass transistors in the
capacitance multipliers to 25A. The current limit is set to 15A as standard ( you can alter the time that the max current has to persist before shutdown ) and reset is by pushbutton. The current capability can obviously be increased by using higher current rectifier diodes and paralleling (offboard ) the pass transistors. The trip current is set by a pair of sensing resistors. The shutdown input kills both power rails simultaneously and operates after the reservoir capacitors - it removes base drive from the pass transistors. Incidentally it works pretty well with high current class b amplifiers - no problems with the MOS250 250W power amp. I haven't tried the active psu with a class D amplifier but don't forsee any problems provided there is no significant switching spillback from the amp onto its supply lines. You can post this reply if you wish.
Regards, David
Hi Brad,
Thanks for giving me the heads up to the posts. I don't get invloved in discussions of my products on the forums - its all too easy to get involved in very public polemic. Anyway who's going to believe what I say? - I'm trying to sell you stuff!But if people want to email me directly then I am only too happy to help and always reply. As regards the active power supply it is indeed a capacitance multiplier unit. The short term current capability is over 50A but the rectifier diodes normally supplied with the kits are limited to 14A continuous and the pass transistors in the
capacitance multipliers to 25A. The current limit is set to 15A as standard ( you can alter the time that the max current has to persist before shutdown ) and reset is by pushbutton. The current capability can obviously be increased by using higher current rectifier diodes and paralleling (offboard ) the pass transistors. The trip current is set by a pair of sensing resistors. The shutdown input kills both power rails simultaneously and operates after the reservoir capacitors - it removes base drive from the pass transistors. Incidentally it works pretty well with high current class b amplifiers - no problems with the MOS250 250W power amp. I haven't tried the active psu with a class D amplifier but don't forsee any problems provided there is no significant switching spillback from the amp onto its supply lines. You can post this reply if you wish.
Regards, David
dc said:
Thanks, good reply, I was thinking of mailing White Noise as well. This answers most of my questions and in principle, there is no 10A limit but can go to 25A with the current setup bu just changing the rectifiers. Very good, I was thinking of using one unit with 3 amps for an actibe 3-way with UcD modules. Should be fine with this supply.
Best regards
Gertjan
input coupling caps
Sorry if this has been covered in the prior 116 pages...
Are there just two coupling caps on the UcD180 board? I don't want to remove them. Rather, I want to upgrade them with something like BG's.
TIA. mac.
Sorry if this has been covered in the prior 116 pages...
Are there just two coupling caps on the UcD180 board? I don't want to remove them. Rather, I want to upgrade them with something like BG's.
An externally hosted image should be here but it was not working when we last tested it.
TIA. mac.
Re: input coupling caps
Yes, only two and I also upgraded them to BGs. I assume you have the UcD180 with the NE5532 opamp? If you have another version, the coupling caps may not be there or maybe placed in front of the opamps (as seems to be the case with UcD400).
Maybe Jan-Peter will reply on that.
Gertjan
mac said:
Yes, only two and I also upgraded them to BGs. I assume you have the UcD180 with the NE5532 opamp? If you have another version, the coupling caps may not be there or maybe placed in front of the opamps (as seems to be the case with UcD400).
Maybe Jan-Peter will reply on that.
Gertjan