Beast said:
The application that I used (Sprint Layout) can export to:
- Gerber
- Excellon (drill data)
- Isolation Milling (HPGL, *.plt)
- PCB Outline Milling (HPGL, *.plt)
If this helps let me know and I'll export and post the files.
Cheers
Q
Hi quasi!
Congratulations for your great amp!!
However it's extremely hard to find the latest schematics for it - could you point me to the latest? Or maybe you could put the links into your signature for easy access?
Thanks a lot!
Cheers, Hannes
PS: of course one could also do a wiki 😀 any volunteers?
Congratulations for your great amp!!
However it's extremely hard to find the latest schematics for it - could you point me to the latest? Or maybe you could put the links into your signature for easy access?
Thanks a lot!
Cheers, Hannes
PS: of course one could also do a wiki 😀 any volunteers?
Hi H_a,
If you send me an email, I'll send you the latest documentation containing all the amps in this series.
Cheers
Q
If you send me an email, I'll send you the latest documentation containing all the amps in this series.
Cheers
Q
h_a said:
Hannes,
I am the "ghost" of the in thread links collection until I have time to take it a step further and create the quasi "super guide" document. If you look at Post #1568 it will give you the current links NMOS200 aside.
Guys,
Yes I am still alive, but there have been several crisis here over the last number of weeks. I have not been able to continue the specifications links collection. I was hoping I would have completed the specifications links collection long before now. The updates to Post #1568 to include the NMOS200 stuff has not been done as it will not take as much time to do and it seemed the priority was the specifications links collection. I have the specification links collection saved on my system so I can continue the effort once life here lowers down a few notches.
I am not sure when these series of crisis will end. Soon I hope. At one point I had no time to look at the thread for over 5 weeks even if I was not replying or able to continue the links collections effort a bit at a time towards completion. Talk about withdrawal!!!! I am sure you guys are not suffering any "keypunch" withdrawals! lol lol lol lol
Quick question while I am posting this reply. The question concerns the module DC protection relay. I like to know what DC and AC V and A part ratings and the Vrail being used for the amplifier module associated with that relay rating. I may have lucked out a few weeks ago and found a relay that fits the quasi PCB based form factor and pinout locations of the relay on the PCB image. Now I need to see if this is yet again too under dimensioned, barely or with some luck will do the job. I am thinking I may need to do yet another famous "keypunch" GIMP edit to allow for a different relay.
I have to run. It is after 02:30 and I need to be up and out the door about 08:00. No rest for the wicked!
Regards,
John L. Males
Willowdale, Ontario
15 May 2007 02:37
Unofficial Quasi Thread Researcher
15 May 2007 02:41 Typo and wording corrections. jlm
15 May 2007 02:43 Typo correction. jlm
15 May 2007 02:55 Typo corection. jlm
Hi,
small relays will have a difficult time protecting the speakers.
Closing the relays and coping with the current pulses needed to charge up the capacitances is bad enough.
The real problem is opening them, either during normal operation or during a high current fault condition.
The conatcts will erode during repeated opening of normal currents and unforunately may weld together if the relay tries to protect during a high current fault.
I think you could/should look at using input mute and/or voltage amplifier mute and maybe going as far as Triac/FET switching. Otherwise, we may all end up using relays that appear to work until they are asked to do the difficult job and then they act like typical teenagers (stubborn refusal!) .
small relays will have a difficult time protecting the speakers.
Closing the relays and coping with the current pulses needed to charge up the capacitances is bad enough.
The real problem is opening them, either during normal operation or during a high current fault condition.
The conatcts will erode during repeated opening of normal currents and unforunately may weld together if the relay tries to protect during a high current fault.
I think you could/should look at using input mute and/or voltage amplifier mute and maybe going as far as Triac/FET switching. Otherwise, we may all end up using relays that appear to work until they are asked to do the difficult job and then they act like typical teenagers (stubborn refusal!) .
Hi Andrew,
-Chris
A point I agree strongly with, and that you point out well ....
I've seen that more than once. False security.
Agree, with a triac short on the output (watch for dv/dt triggering) or a real relay.
-Chris
Hi Anatech,
I was still thinking along the poster's idea of switching the supply rails rather than the speaker output line.
But, in either location, switching the high fault current off is the problem.
During a shorted output condition, removing drive signal from the input to the output removes the fault current, then the relay can switch off safely (or your suggestion of crow barring the output to force the rail fuse to blow). To avoid chattering the relay or the mute should latch.
A failed output device allowing direct rail to speaker current is a different ball game, but again anything that can reduce the magnitude of the fault current before the relay tries to open will help ensure that the relay does not arc, possibly continuously. A fuse to back up the relay in the supply rail may work if you want to avoid the Solid State switch and control system.
I was still thinking along the poster's idea of switching the supply rails rather than the speaker output line.
But, in either location, switching the high fault current off is the problem.
During a shorted output condition, removing drive signal from the input to the output removes the fault current, then the relay can switch off safely (or your suggestion of crow barring the output to force the rail fuse to blow). To avoid chattering the relay or the mute should latch.
A failed output device allowing direct rail to speaker current is a different ball game, but again anything that can reduce the magnitude of the fault current before the relay tries to open will help ensure that the relay does not arc, possibly continuously. A fuse to back up the relay in the supply rail may work if you want to avoid the Solid State switch and control system.
Hi Andrew,
Running the relay off a "housekeeping supply" would allow latching whatever device(s) you choose. I'm more concerned with the load than the amp. Input muting would operate a few ms before a larger relay could disconnect and save the contacts. Device failure would cause more damage in the circuit before any relay could operate, so it only makes sense to protect your load (speaker) - then try to reduce damage in the amplifier itself. At this point you would be worried more about copper traces and capacitor ripple current. The transistors have already modified their own construction. 😉
-Chris
Running the relay off a "housekeeping supply" would allow latching whatever device(s) you choose. I'm more concerned with the load than the amp. Input muting would operate a few ms before a larger relay could disconnect and save the contacts. Device failure would cause more damage in the circuit before any relay could operate, so it only makes sense to protect your load (speaker) - then try to reduce damage in the amplifier itself. At this point you would be worried more about copper traces and capacitor ripple current. The transistors have already modified their own construction. 😉
-Chris
Hi,
In an N-channel project, wouldn't switching the rails with N-channel devices come in handy? 😀
R. G. Keen discusses some approaches without resorting to a specific recommendation. But high-voltage, low-resistance MOSFETS are available, an auxillary supply should be no problem, and a high-side driver and control circuit can be built either discrete or monolithic. All of which would be required for a relais control anyway.
I guess it would take a square inch of board space and two power devices.
Did anyone dig into this further, or does anyone have the intention? I cannot afford it at the moment, as I'm finishing university at the moment. But I would be very interrested in the results.
Cheers,
Sebastian.
In an N-channel project, wouldn't switching the rails with N-channel devices come in handy? 😀
R. G. Keen discusses some approaches without resorting to a specific recommendation. But high-voltage, low-resistance MOSFETS are available, an auxillary supply should be no problem, and a high-side driver and control circuit can be built either discrete or monolithic. All of which would be required for a relais control anyway.
I guess it would take a square inch of board space and two power devices.
Did anyone dig into this further, or does anyone have the intention? I cannot afford it at the moment, as I'm finishing university at the moment. But I would be very interrested in the results.
Cheers,
Sebastian.
Hi Sek,
there was a discussion a year or so back on FET shutdown of the rail supplies. I don't recall us getting as far as posting circuits or control logic.
I'll look at Keen's page. Thanks.
there was a discussion a year or so back on FET shutdown of the rail supplies. I don't recall us getting as far as posting circuits or control logic.
I'll look at Keen's page. Thanks.
agreed,anatech said:
if the amp is broke there is little left of the output stage to save.
But the speakers should still be saveable if the shutdown is fast enough. I expect supply rail or output shutdown to be equally effective.
Hi Guys,
I did not realize my relay question would stir todays thunderstorms, hail and extreme downpours in Toronto and much of Southern Ontario.
Would it be safe to assume there is no advantage to modifying the existing relay DC protection circuit to disconnect the module input signal instead of the speaker load? I would keep the DC sensing where it curently is and instead have the relay disconnect input signal to the module rather than the speaker load.
Regards,
John L. Males
Willowdale, Ontario
15 May 2007 22:14
Unofficial quasi amp Thread Researcher
I did not realize my relay question would stir todays thunderstorms, hail and extreme downpours in Toronto and much of Southern Ontario.
Would it be safe to assume there is no advantage to modifying the existing relay DC protection circuit to disconnect the module input signal instead of the speaker load? I would keep the DC sensing where it curently is and instead have the relay disconnect input signal to the module rather than the speaker load.
Regards,
John L. Males
Willowdale, Ontario
15 May 2007 22:14
Unofficial quasi amp Thread Researcher
Hi John,
I feel there is value in muting both the input and output. In DIY you can do it right.
Hi Andrew,
I like disconnecting the load in case there is a voltage amp fault causing DC offset, but not excesive current draw (until the load is connected that is).
The shut down used in Carver power amps is very effective. That would work just fine. Carver shuts off the primary and allows enough energy for partial power up. This tends to cycle the amp on and off. It is very effective in saving outputs. Note that the stored energy in most common amlifier designs would be enough to finish the output stage and possibly the load.
-Chris
I feel there is value in muting both the input and output. In DIY you can do it right.
Hi Andrew,
I like disconnecting the load in case there is a voltage amp fault causing DC offset, but not excesive current draw (until the load is connected that is).
The shut down used in Carver power amps is very effective. That would work just fine. Carver shuts off the primary and allows enough energy for partial power up. This tends to cycle the amp on and off. It is very effective in saving outputs. Note that the stored energy in most common amlifier designs would be enough to finish the output stage and possibly the load.
-Chris
quasi said:
Hi,
Gerber should be ok, but i'm not sure. It will be very nice if you could send it in all those formats, then i can see which looks the best to use in machine. You can also send them in my email piisti@mbnet.fi if it's easier..
Just for clarification;
.
The only protection provided for on the Nmos350 and Nmos500 boards is DC detection. For rails of 75 volts the maximum current drawn by a typical 8 ohm load (Re = 6 ohms) could be as high 12 amps depending on the power supply capability. This equates to a dissipation in the woofer voice coil of 870 watts or so and must removed immediately. This is really beyond the long term switching capabilty of most relays that will fit, but in my experience the relay will still release. So the currents involved are not that large (even with a 4 ohm load) as we still have a legitimate load and not a short circuit (yet). Having said that if there any concerns, then a much bigger (off board) relay can be used or some other technique deployed.
The relay will probably be useless under a combined short circuit and rail swing fault. The current flow, albeit brief will be maybe a hundred amps or so and the fuses should do the job very quickly.
Now one thing is for sure if this circuit activates. The amp is already dead and we are just trying to save the speakers. For most DIY'ers losing the amp is cheaper than losing the speakers
.
The only protection provided for on the Nmos350 and Nmos500 boards is DC detection. For rails of 75 volts the maximum current drawn by a typical 8 ohm load (Re = 6 ohms) could be as high 12 amps depending on the power supply capability. This equates to a dissipation in the woofer voice coil of 870 watts or so and must removed immediately. This is really beyond the long term switching capabilty of most relays that will fit, but in my experience the relay will still release. So the currents involved are not that large (even with a 4 ohm load) as we still have a legitimate load and not a short circuit (yet). Having said that if there any concerns, then a much bigger (off board) relay can be used or some other technique deployed.
The relay will probably be useless under a combined short circuit and rail swing fault. The current flow, albeit brief will be maybe a hundred amps or so and the fuses should do the job very quickly.
Now one thing is for sure if this circuit activates. The amp is already dead and we are just trying to save the speakers. For most DIY'ers losing the amp is cheaper than losing the speakers
It seems that some other guys too are interested to use milling machine, so it would be great if you could put them here 😎
Btw. How much power is practicable to get, if i build two-channel amp which consist of two nmos350 board with six irfp450's and abt. 1000va toroidal with 2x53v secondaries. 😕
Btw. How much power is practicable to get, if i build two-channel amp which consist of two nmos350 board with six irfp450's and abt. 1000va toroidal with 2x53v secondaries. 😕
Beast said:
Beast,
The short answer is 210W RMS @ 8 Ohms resistive, 420W RMS @ 4 Ohms resistive.
Based on quasi's own tests with a 53V 500VA toroid using a 15 second RMS test you should be fine with 210W/8 Ohms and 420W/4 Ohms. These ratings are for home music, not DJ use. You will need to ensure you have much more heatsinking or fan assisted cooling to ensure your six IRFP450's do not exceed their SOA due to the temperature rise. I would also make sure you have thermal protection sensing for the output devices. I would think disconnection of the PSU at 60C heatsink temperature would give you enough thermal protection.
Of course if I am wrong someone will speak up. Andrew is one who has excellent knowledge in regards to SOA vs power vs load.
Regards,
John L. Males
Willowdale, Ontario
Canada
17 May 2007 21:47
I have made 4 quasis dc protections. Two of them had to do the job 🙂 Two channels, from four, gone bad and put some dc on speaker out. Both speaker were saved!! 🙂 The transformer is 2x39v which gives some 2x55dc. One channel had +35 volts on speaker output and other had full 55 volts! The relays were nothing special, not some high-end sort of. The thing is that protection worked and i'm very pleased.
Doing some test with it i can see that when dc i smaller then it takes much more time for relay to disconect. For 12 volts i takes second or so, for smaller then 12 it takes more seconds. Will that 12 volts within one second burn speaker?
Doing some test with it i can see that when dc i smaller then it takes much more time for relay to disconect. For 12 volts i takes second or so, for smaller then 12 it takes more seconds. Will that 12 volts within one second burn speaker?
Hi,
are the 6devices a 3pair output stage?
Then 420Winto 4ohm @ 60degree phase angle is way outside the dc SOAR and getting close to the 10mS SOAR. Peak dissipation is 820W.
The 6ohm 46degree load looks much more like a sensible limit for 3pair of irfp450. 320W into 6r0.
That suggests 4 to 8 ohm speakers as the worst domestic load. But partying will need a switch on the heatsink.
8ohm speakers, easy, all day at 60degree phase angle and keep the sink below 40degC. 260W into 8r0 using 53Vac 500VA, +-30mF.
are the 6devices a 3pair output stage?
Then 420Winto 4ohm @ 60degree phase angle is way outside the dc SOAR and getting close to the 10mS SOAR. Peak dissipation is 820W.
The 6ohm 46degree load looks much more like a sensible limit for 3pair of irfp450. 320W into 6r0.
That suggests 4 to 8 ohm speakers as the worst domestic load. But partying will need a switch on the heatsink.
8ohm speakers, easy, all day at 60degree phase angle and keep the sink below 40degC. 260W into 8r0 using 53Vac 500VA, +-30mF.