ninjanki said:
Exactly, I use Schrack RT424048, they've never failed('ve used about 200).
http://relays.tycoelectronics.com/datasheets/RT2.pdf
ewildgoose said:
The thing is they will break a long time before the amp output will reach 50V.
The offset trigger level is about 200mv which combined with the switch off time of the relay and electronics is sufficient to never reach the dangerous amp. levels.
Tried this with my Crecendo amps. by using a switch to induce a + or - 2V on the input, amp is completely dc coupled , with speakers connected. It switched of the speakers even before making a noise. Once in a while I had a Mosfet shortcut(they started oscilating and blew up).......no problem.
BTW they are in series with the output. For me the best protection, least damage way. Fuses are cheap(they are in my + and - lines).
pfff..
......)
Jan-Peter,
Won't having the protection relay on the power supply rails have a similar sonic effect to a relay in the output? After all the MOSFETS are switching the supply rails or does the UCD use a feedback mechanism that compensates for the relay resistance in the power supply (PSRR)?
What about a technique that shorts the output to ground (or with a 1 ohm resistor) when DC is detected and blows the supply fuse? This way there is never a relay contact in either the output or the power supply.
Regards,
Dean
Won't having the protection relay on the power supply rails have a similar sonic effect to a relay in the output? After all the MOSFETS are switching the supply rails or does the UCD use a feedback mechanism that compensates for the relay resistance in the power supply (PSRR)?
What about a technique that shorts the output to ground (or with a 1 ohm resistor) when DC is detected and blows the supply fuse? This way there is never a relay contact in either the output or the power supply.
Regards,
Dean
Deandob,
It has NO sonic effect, there are sufficient local coupling capacitors on the UcD modules, so it will also not degreed the PSRR.
To put a relay in series with the output of the amplifier, this will have for sure sonic effect, that's the same as with fuses. A good relay is rated for a high current or for a very low current never both.
I would kindly close the discussion about DC protection, this is our way, and everybody is of course free to do it in an other way...
Regards,
Jan-Peter
It has NO sonic effect, there are sufficient local coupling capacitors on the UcD modules, so it will also not degreed the PSRR.
To put a relay in series with the output of the amplifier, this will have for sure sonic effect, that's the same as with fuses. A good relay is rated for a high current or for a very low current never both.
I would kindly close the discussion about DC protection, this is our way, and everybody is of course free to do it in an other way...
Regards,
Jan-Peter
Pasi P said:
Hello Pasi P,
Just to clarify for you. In the schematic that Jan-Peter posted, you should not connect the dc-prot wire to the speaker terminal. There is some additional circuit being used that does the additional DC detection. That additional (not shown) circuit is connected to the speaker output terminals and generates a signal that is connected to DC-prot. Hope this explains it.
Best regards
Gertjan
Is there real benefit for using a balanced vs single-end setup with the UcD400 module? Is it a true balanced circuit design ? I will install a volume pot and I was wondering if there is a real advantage of using two stereo pots to control both negative and positive signal for each channel or just connect the negative to the ground and use mono pots. I feed the amp directly from the source.
Thanks!
Thanks!
As long as you draw more than 10 mA or so there is no problem with "low" currents. 1mA or lower down to uA can cause real problems with power contacts (have sold relays for 20 years now)Jan-Peter said:
This is one way of solving the problem and I think it's OK. Since the relays never will switch any high current they will also last long. If you switch on these relays into capacitive load you might test wolfram contacts made for lamps and high inrush currents. the relay has two contacts which work in parallel. The first inrush is taken by the tingsten/wolfram contact and the continuous current is taken care of hardsilver. I can tell you more about if you are interested.Jan-Peter said:
Need I say that this special relay has an extremely high sonic impact ?
