Hey.
I just assembly my NCD modules today, it have been collecting dust in the closet for a while.
Netfilter
NewclassD Softstart DC filter
Homemade PSU supply. 2x24v 300VA
2 Rectifiers
4pcs 10.000uF Nichicon KG caps 63V
->Correct Connected. Triple checked the connections.
Starup and nothing happens. No blinking blue leds.
Measure 13.8 Volt DC offset at both channel spk terminals with no speaker attached.
No inputs.
(0.8mV with spk attached. )
I attach a simple MSpaintpicture of my layout. 😉
I just assembly my NCD modules today, it have been collecting dust in the closet for a while.
Netfilter
NewclassD Softstart DC filter
Homemade PSU supply. 2x24v 300VA
2 Rectifiers
4pcs 10.000uF Nichicon KG caps 63V
->Correct Connected. Triple checked the connections.
Starup and nothing happens. No blinking blue leds.
Measure 13.8 Volt DC offset at both channel spk terminals with no speaker attached.
No inputs.
(0.8mV with spk attached. )
I attach a simple MSpaintpicture of my layout. 😉
Yo.
I got contact with Lars at Newclassd, (quick answered) he said I forgot the Gate Drive transformator 15Vac / 20Vdc.
Well I didnt find any information in the ncd cookbook that I need a gate drive supply to make NCD modules work.
Only that it lower the power idle, and could wrk without them.
Must get a 15Vac transformator then, or will a 12 Vac do the job?
I got contact with Lars at Newclassd, (quick answered) he said I forgot the Gate Drive transformator 15Vac / 20Vdc.
Well I didnt find any information in the ncd cookbook that I need a gate drive supply to make NCD modules work.
Only that it lower the power idle, and could wrk without them.
Must get a 15Vac transformator then, or will a 12 Vac do the job?
Lars C. recommend between 15-21 Volt for the Gate Drive.
I fixed a Gatedrive PSU.
[12 VAC trafo 35VA: 1x12VAC]
[4pcs 1N5401 diods]
[2 pcs Rubycon YXF 1000uF 50V]
-> Unload 16.5 volt with load 14.5-15.5 Volt.
The NCD1 modules works now with some minor/major issues.
- With turn on clicks in the spks.
- Shutdown procedure create a shutdown noise, sounds like
#caps venting#. Measured 12 vdc on the spks output so I
guess the sound come from the treble.
#Lars C. recommend two power off switches.
1. Turn off the gate Drive supply
2. The rest of the system.
That worked and resulted in a silent shutdown.
But turn on clicks still exist.
I will need to do a new layout for the new objects thats have been added, now the just float around in the chassi 😉
*Without any source connected its "silent"
The ear have to be extremly close to the spks to hear a weak noise. No hum at all.
But I got a huge signal ground loop when I use computer soundcard as sourse. I even hear when I move the mouse around on the screen in the spks + high level of noise and humm.
Found something in other NewclassD topic about adding 10k resistor in serie with the "hot" input.
I did that and it lower the noise.
Lower the gain?!
But its still useless with the soundcard.
The sound I got from the NCD1 except the high noise is a flat and no dynamics and hard sound.
mismatched inimpendance?
I had some test with inimpendance of my gainclones and with higher inimpendance (20k +) more dynamics, softer and more detailed sound I got, with lower inimpedance (10k and lower) the opposite. flat, hard, no bass etc.
My gainclones LM3886, deadsilent with same setup and play with high details and dynamics + wonderful bass.
more to come.
I fixed a Gatedrive PSU.
[12 VAC trafo 35VA: 1x12VAC]
[4pcs 1N5401 diods]
[2 pcs Rubycon YXF 1000uF 50V]
-> Unload 16.5 volt with load 14.5-15.5 Volt.
The NCD1 modules works now with some minor/major issues.
- With turn on clicks in the spks.
- Shutdown procedure create a shutdown noise, sounds like
#caps venting#. Measured 12 vdc on the spks output so I
guess the sound come from the treble.
#Lars C. recommend two power off switches.
1. Turn off the gate Drive supply
2. The rest of the system.
That worked and resulted in a silent shutdown.
But turn on clicks still exist.
I will need to do a new layout for the new objects thats have been added, now the just float around in the chassi 😉
*Without any source connected its "silent"
The ear have to be extremly close to the spks to hear a weak noise. No hum at all.
But I got a huge signal ground loop when I use computer soundcard as sourse. I even hear when I move the mouse around on the screen in the spks + high level of noise and humm.
Found something in other NewclassD topic about adding 10k resistor in serie with the "hot" input.
I did that and it lower the noise.
Lower the gain?!
But its still useless with the soundcard.
The sound I got from the NCD1 except the high noise is a flat and no dynamics and hard sound.
mismatched inimpendance?
I had some test with inimpendance of my gainclones and with higher inimpendance (20k +) more dynamics, softer and more detailed sound I got, with lower inimpedance (10k and lower) the opposite. flat, hard, no bass etc.
My gainclones LM3886, deadsilent with same setup and play with high details and dynamics + wonderful bass.
more to come.
Attachments
Nice work, your amp has more stuff (but less mess) inside than my NCD does ;-) I have the turn-on clicks too - have had the amp for a year or two now, they are always there and seem to be harmless.
I also have small shutdown noises, but as long as there is no signal on the amp, they really are nothing much. The shutdown noise could be caused by a small amount of DC on the input?
Computers are difficult sound-wise because they are connected to ADSLs and other stuff, so hum from connecting computers to hifi is pretty common in my experience. Especially if you have the computer connected to the telephone net (one ground potential) and the hifi to a tuner or TV with an antenne (where ground can be very different from telephone ground!). Also, lots of computers can put out some DC on their line out connectors - if there's any DC you will have to get rid of it for the NCD to work.
I have never used my NCD directly connected to the computer, but I regularly listen to the computer via my DIY preamp (with DC servo), and it works fine. My guess on your hum problem is that the ground potentials of computer and amp are different... have you checked that? I use three-prong mains cords for computer and hifi so that everything is "in phase" and with a common ground (I know this is less important w. some devices that have double insulated power supplies). Also try connecting computer and amp to the same outlet.
If you already have them on common ground (or if grounding them together doesn't help), double check internal grounding of the amp - there should be about 12 ohm resistance from amplifier ground to chassis. If it's OK, you can try to connect a ground lead between computer case and amplifer case (measure the voltage first to make sure it's not too crazy...). If that helps you know where the problem is. You may need to build in a ground loop breaker... but really, it shouldn't be necessary.
The sound of the amp does change a bit after playing for a while. But it should sound pretty good from the beginning, mine did.
When reading your experience with impedance on your gainclones, I get the impression that your soundcard may be a bit picky about impedance. I believe NCD has an impedance of 20k which should be OK. But maybe in combination with the high gain (=> you have to turn the sound card volume way down) it might be a problem. Can you test running through a preamp? Maybe just a potmeter (passive preamp) so you can crank the soundcard up to full, and reduce volume with the pot. You may want to try playing with impedance and gain. Also, grounding issues / DC could be causing the bad sound quality, so make sure that's sorted out first.
Hope this helps and you manage to solve the problems!!! and that you become as happy with your amp as I am.
/cdl
I also have small shutdown noises, but as long as there is no signal on the amp, they really are nothing much. The shutdown noise could be caused by a small amount of DC on the input?
Computers are difficult sound-wise because they are connected to ADSLs and other stuff, so hum from connecting computers to hifi is pretty common in my experience. Especially if you have the computer connected to the telephone net (one ground potential) and the hifi to a tuner or TV with an antenne (where ground can be very different from telephone ground!). Also, lots of computers can put out some DC on their line out connectors - if there's any DC you will have to get rid of it for the NCD to work.
I have never used my NCD directly connected to the computer, but I regularly listen to the computer via my DIY preamp (with DC servo), and it works fine. My guess on your hum problem is that the ground potentials of computer and amp are different... have you checked that? I use three-prong mains cords for computer and hifi so that everything is "in phase" and with a common ground (I know this is less important w. some devices that have double insulated power supplies). Also try connecting computer and amp to the same outlet.
If you already have them on common ground (or if grounding them together doesn't help), double check internal grounding of the amp - there should be about 12 ohm resistance from amplifier ground to chassis. If it's OK, you can try to connect a ground lead between computer case and amplifer case (measure the voltage first to make sure it's not too crazy...). If that helps you know where the problem is. You may need to build in a ground loop breaker... but really, it shouldn't be necessary.
The sound of the amp does change a bit after playing for a while. But it should sound pretty good from the beginning, mine did.
When reading your experience with impedance on your gainclones, I get the impression that your soundcard may be a bit picky about impedance. I believe NCD has an impedance of 20k which should be OK. But maybe in combination with the high gain (=> you have to turn the sound card volume way down) it might be a problem. Can you test running through a preamp? Maybe just a potmeter (passive preamp) so you can crank the soundcard up to full, and reduce volume with the pot. You may want to try playing with impedance and gain. Also, grounding issues / DC could be causing the bad sound quality, so make sure that's sorted out first.
Hope this helps and you manage to solve the problems!!! and that you become as happy with your amp as I am.
/cdl
Hey.
Thanks.
Some NCD1 updates:
I changed to a 15Vac trafo.
With the change I got some shutdown noise again. A quick answer from Lars C. told me to have the V.gate PSU power off switch after the caps on the V.gate PSU "module" and that wotks. Now silent.
No groundbreaker. I dont think the NCD have any contact with the chassi, floating ground!?
No grounded wall outlets.
No DC output from soundcard, it go dcblocking caps (10uF rubycon yxf)
NCD it´s completly useless together with the sources I got´for now. I even tried it with a CD player and played a piece of intro fron a CD. Strange digital noise, hear it searching and alot more. But with my gainclone its "deadsilent"
I think it´s all about the gain issue, too much gain its not good.
The input impedance of NCD is 5k
Gain 45db ?
I have started building a preamp, the NCD micro preamp described in the cookbook, if it´s not going to bee any improvments. I think I get rid of it.
So long...
Thanks.
Some NCD1 updates:
I changed to a 15Vac trafo.
With the change I got some shutdown noise again. A quick answer from Lars C. told me to have the V.gate PSU power off switch after the caps on the V.gate PSU "module" and that wotks. Now silent.
No groundbreaker. I dont think the NCD have any contact with the chassi, floating ground!?
No grounded wall outlets.
No DC output from soundcard, it go dcblocking caps (10uF rubycon yxf)
NCD it´s completly useless together with the sources I got´for now. I even tried it with a CD player and played a piece of intro fron a CD. Strange digital noise, hear it searching and alot more. But with my gainclone its "deadsilent"
I think it´s all about the gain issue, too much gain its not good.
The input impedance of NCD is 5k
Gain 45db ?
I have started building a preamp, the NCD micro preamp described in the cookbook, if it´s not going to bee any improvments. I think I get rid of it.
So long...
Thzar said:
Really? Completely silent? Maybe I should think of a way to shut off V.gate before the rest...
Mine does have contact with chassis - there should be 12 ohm from signal ground to the aluminum plate. If not there's something wrong... whoops! I have the NCD psu - the ground resistor might be on there... if yoy have no measurable contact between chassis and GND, then connect power GND to chassis with a 10 ohm resistor (½W or larger). Make sure the aluminum plate under the modules has electrical contact with your chassis ;-)
OK, not to worry. But I'm pretty sure grounding is part of your problem... so try this: 1) Get a big power strip (multistik / fordelserstik på dansk), make sure it is one of the kind that has a ground rail in it (some of them here have holes for the ground pin, but no conductor inside!). Then get three prong connectors for computer, NCD etc. Plug everything into the power strip.
Now there should be direct contact between computer chassis and NCD chassis, and some 10 or 12 ohm between computer chassis and signal ground (NCD). I am pretty sure that will help!
Try a 22k resistor in series as suggested by Lars in the cookbook (under use of tube amp). Careful with large (>1µF) blocking caps, in my experience they can need some "loading" - you may want to try 10k or 20k in parallel with the input (that is between + and GND).
Just to exclude more grounding issues, can you try it out using something battery-powered - MP3 player or the like - without connection elsewhere? Works fine with my NCD.
Hearing the CD search (in the speakers) is common in case of problems with grounding.
To me it sounds like either something is really wrong with the amps, or something is really wrong with the wiring. You sound like a bright guy but I don't know your level of electronics skill - so please forgive me for asking this: are you sure you have connected the inputs correct: Signal live to input+, ground to inputGND and short input- to inputGND? (page 13 /21). Just making sure that you didn't put signal GND into the - terminal ... sorry for asking if you're all in control, no PUN intended
Does the amp react to your touching signal ground (when on, no input connected)?
Hmm, you're right about the input impedance... 5k is pretty low. Your soundcard may not like that. Should still play OK though.
Yes the gain is high - makes it possible to do without preamp. You can easily limit the gain using simple 2 resistors - better too much than too little.
Before you finish the preamp, I would do a quick test with a pot (wired up as suggested just above the preamp). If the gain is really a problem for your setup (possible), then once you find the optimal setting of the pot, you can just measure and buy 2 resistors to replace the pot.
Before you get rid of it, do ask Lars for help too - you might have to ship it to him, but he will get it running I'm sure.
/cdl
Hmmm. Does not sound familiar. I've build mine using the PSU's from Lars.
First prototype on plywood (to prevent any groundloops), second one 100% by the cookbook.
Only thing is thad I did not use is a separate ground drain wire to the inputs (and both are floating vs case)
But because I'm using a dual-mono configuration I had to use a GND-Left GND-Right wire to prevent some residual hiss (interference)
No problems whatsoever besides some very, very, very small shutdown noise. No humm, no ground loops, just music...!!!
Currently attached to audiolab pré
Sound is great and realy addictive...
I would check, check and re-check all wires....
First prototype on plywood (to prevent any groundloops), second one 100% by the cookbook.
Only thing is thad I did not use is a separate ground drain wire to the inputs (and both are floating vs case)
But because I'm using a dual-mono configuration I had to use a GND-Left GND-Right wire to prevent some residual hiss (interference)
No problems whatsoever besides some very, very, very small shutdown noise. No humm, no ground loops, just music...!!!
Currently attached to audiolab pré
Sound is great and realy addictive...
I would check, check and re-check all wires....
Attachments
cdl:
Hey,
I tried the gnd drain wire as well, no change.
I borrowed a creative zen mp3 player and pushed play-
some serious sound issues. groundloops among others..
You said "short input- to inputGND?"
What?
What version of the ncdcookbook do you have? I got the 1.06 version. nothing about short inpu- to input gnd, or Im blind.
hmm.. I have tried every kind of combos connection with the inputs thats I can remember, same problem...
Hey,
I tried the gnd drain wire as well, no change.
I borrowed a creative zen mp3 player and pushed play-
some serious sound issues. groundloops among others..
You said "short input- to inputGND?"
What?
What version of the ncdcookbook do you have? I got the 1.06 version. nothing about short inpu- to input gnd, or Im blind.
hmm.. I have tried every kind of combos connection with the inputs thats I can remember, same problem...
Thzar said:
Thzar, I'm sorry to hear that you can't get it working, even with the Creative Zen player 🙁 Either something is very wrong with the wiring, or with the modules themselves - however, I doubt that both modules should be defective. Maybe they are disturbing oneanother - can you try out each module on its own (with the other one unpowered and disconnected)?
You are right, the instruction to short the unused -input to GND has been removed from the cookbook 1.06 - it was there in the earlier ones. You can still se a "trace" of it on page 14 where Lars didn't put in a new figure 😉 But anyway - the important thing is to either leave the unused -input unconnected, or connect it only to the GND terminal of the NCD module, as bro pointed out too (page 10) - don't do as on page 2.
So you say that grounding the chassis didn't help at all... so something more serious seems to be the problem. Is the grounding between the modules connected as on P10 / P19 in the cookbook?
Good luck and keep us posted - cdl
Breaking News!!!!!!
I got my wall outlet changed to earthed.
Everything changed!
Now, my Newclassd amps is dead quiet even with a realtek AC97 70 db s/n soundcard.
With no change in wiring.
I guess that the computer MUST be earthed or all hell is breaking lose. But I cant explan the prob with the mp3player.
But I repeat - its dead silent. almost 😉 there is a slighty bit of noise but its so quiet.
But things must work without earthed wall outlets.?
I got my wall outlet changed to earthed.
Everything changed!
Now, my Newclassd amps is dead quiet even with a realtek AC97 70 db s/n soundcard.
With no change in wiring.
I guess that the computer MUST be earthed or all hell is breaking lose. But I cant explan the prob with the mp3player.
But I repeat - its dead silent. almost 😉 there is a slighty bit of noise but its so quiet.
But things must work without earthed wall outlets.?
I'm happy to hear that!!!!
I'm sure you will enjoy the modules a lot - I wouldn't part with them for any price. Good to hear you don't have noise from the PC coming in ;-)
/cdl
I'm sure you will enjoy the modules a lot - I wouldn't part with them for any price. Good to hear you don't have noise from the PC coming in ;-)
/cdl
Congratulations Thzar!
I thought I had problems too with hum and hiss. That is until I swapped to another source and realized that the NCDs are dead silent. No need for the EMC kit and screening for the transformer at all.
Now I have to deal with my naughty DAC and, maybe, the hot ferrite.
I thought I had problems too with hum and hiss. That is until I swapped to another source and realized that the NCDs are dead silent. No need for the EMC kit and screening for the transformer at all.
Now I have to deal with my naughty DAC and, maybe, the hot ferrite.
Congratulations to You all guys!
On the contrary I do have two burned NCD1 modules and three burned base/mid speaker elements as the result of a problem that I have had since I got my NCD to work.
The setup is very simple: A Thermaltake HTPC, E-MU1616M soundcard, NCD1 dual mono and a pair of Thiel speakers (before they were burned out by the amp).
The dual mono setup is done completely 100% from the cookbook, and are checked and double, and triple checked again, and more than that.
From the beginning the NCD shuts down as soon as i play on high-mid volumes. A tiny little bit faster in one of the channels, but both in higher but still not High listening volumes.
A few weeks ago they shut down AND burned to death, and before doing so the voic coils of my Thiel C220-T6 element went to charcoal.
I have measure everything I think I can. No problems with ground as far as I can se. Everything is connected as it should and as far as I can measure I use an electronic normal measure intrument) there is no DC from the soundcard when playing music with any musicplayer (Foobar, Mediaplayer etc).
Does anyone have any idea of what this could be???
So far I got burned speaker element for € 1200 worth and I dont like "trying" any more 🙁
So You guys with a lot more electronical experience - any ideas?
On the contrary I do have two burned NCD1 modules and three burned base/mid speaker elements as the result of a problem that I have had since I got my NCD to work.
The setup is very simple: A Thermaltake HTPC, E-MU1616M soundcard, NCD1 dual mono and a pair of Thiel speakers (before they were burned out by the amp).
The dual mono setup is done completely 100% from the cookbook, and are checked and double, and triple checked again, and more than that.
From the beginning the NCD shuts down as soon as i play on high-mid volumes. A tiny little bit faster in one of the channels, but both in higher but still not High listening volumes.
A few weeks ago they shut down AND burned to death, and before doing so the voic coils of my Thiel C220-T6 element went to charcoal.
I have measure everything I think I can. No problems with ground as far as I can se. Everything is connected as it should and as far as I can measure I use an electronic normal measure intrument) there is no DC from the soundcard when playing music with any musicplayer (Foobar, Mediaplayer etc).
Does anyone have any idea of what this could be???
So far I got burned speaker element for € 1200 worth and I dont like "trying" any more 🙁
So You guys with a lot more electronical experience - any ideas?
BTW:
I´m been using an old 70s Sentec poweramp instead of the dead NCD1 amp and it does the job absolutely fine on all listening levels. . .
I´m been using an old 70s Sentec poweramp instead of the dead NCD1 amp and it does the job absolutely fine on all listening levels. . .
Really sorry to hear of your (very expensive!) troubles :-(
Sounds like you have to do some serious troubleshooting using only old "disposable" speakers until you are 100% sure everything is OK. I would also advise strongly against connecting a high-gain power amp like the NCD directly to a soundcard in a computer without "something" in-between (sorry guys, just bad experience with that sort of setup). Until you have this sorted out 100%, do at least use a simple volume control pot (connection of it is described in the cookbook).
My suggestions for your problem would be (I know you checked some of this, but check again!!):
1) DC somehow arising between your PC and the NCD, possibly your soundcard not liking the low impedance of the NCD
2) are you ABSOLUTELY sure you corrected the input correctly? ground from the source goes to ground on the amp NOT to the (-) input, when you are running single-ended.
3) I would use a different, (non-powered, unbalanced) source THAT YOU KNOW IS GOOD for initial troubleshooting to eliminate any ground etc. problems. I used my MP3 player (before you turn the amp on, turn the volume ALL the way down and don't fiddle with connections of course!)
4) High frequence (possible inaudible) signal from the soundcard loading amp and speaker very heavily? You might need some sort of oscilloscope to make sure. The burning of your bass speakers would rather indicate DC though.
5) Grounding. Make sure that you have both the PC and everything connected to it in earthed wall outlets (and use 3 prong plugs of course!). The NCD of course also needs an earthed outlet / 3-prong plug etc. If you don't have earthed outlets, buy a power strip WITH an earth rail and plug both amp and PC into that. Measure that amp GND and PC chassis are well connected.
6) Check your power supply - are the rail voltages fully symmetric? Reaching the NCD modules correctly (measure it on the module?).
7) Make some measurements on the speaker terminals, with test resistors and/or disposable speakers connected. Measure DC; there should be none, but if any is present on input (or if something else is wrong) you will see it on the output (measure with and without anything playing). Measure AC on the output with nothing playing as well - there should be practically nothing. Signal should increase as you turn up the volume.
8) check again! for DC - any imbalance in the rails or DC on the input might cause such problems.
Just because your old amp works fine does not exclude the above - your old amp certainly has some DC blocking circuitry (probably capacitors), almost certainly has a high frequency filter or bandwith limitation of a sort, and most likely has lower gain. I am almost certain you must have a mistake somewhere in the wiring / power supply and/or some of the above (otherwise perhaps something is wrong with your EMU) - the modules shutting down when increasing volume is a sure sign that something is WRONG. I never experienced mine shutting down even when putting out a lot of watts.
That was my input. Hope we can help you find the mistake - I have been very happy with my NCD-1 for ages now, and there is no doubt you deserve that too!
By the ways, I also listen to soundcard output (Creative Audigy2 ZS) - and my DIY DAC which has a little DC on the output - but I run them through my preamp which has a DC servo... But even with quite some DC on the input my NCD's kept on playing without doing anything nasty (except a loud bang on power-up because of the DC).
When you get around to it, try post back your rail voltages, voltages on the speaker posts (AC+DC), resistance in ohm between chassis etc. You might want to try using a disposable cheap USB soundcard (~100 kr.) as an oscilloscope with some suitable software (winscope or similar).
Good luck - cdl
Sounds like you have to do some serious troubleshooting using only old "disposable" speakers until you are 100% sure everything is OK. I would also advise strongly against connecting a high-gain power amp like the NCD directly to a soundcard in a computer without "something" in-between (sorry guys, just bad experience with that sort of setup). Until you have this sorted out 100%, do at least use a simple volume control pot (connection of it is described in the cookbook).
My suggestions for your problem would be (I know you checked some of this, but check again!!):
1) DC somehow arising between your PC and the NCD, possibly your soundcard not liking the low impedance of the NCD
2) are you ABSOLUTELY sure you corrected the input correctly? ground from the source goes to ground on the amp NOT to the (-) input, when you are running single-ended.
3) I would use a different, (non-powered, unbalanced) source THAT YOU KNOW IS GOOD for initial troubleshooting to eliminate any ground etc. problems. I used my MP3 player (before you turn the amp on, turn the volume ALL the way down and don't fiddle with connections of course!)
4) High frequence (possible inaudible) signal from the soundcard loading amp and speaker very heavily? You might need some sort of oscilloscope to make sure. The burning of your bass speakers would rather indicate DC though.
5) Grounding. Make sure that you have both the PC and everything connected to it in earthed wall outlets (and use 3 prong plugs of course!). The NCD of course also needs an earthed outlet / 3-prong plug etc. If you don't have earthed outlets, buy a power strip WITH an earth rail and plug both amp and PC into that. Measure that amp GND and PC chassis are well connected.
6) Check your power supply - are the rail voltages fully symmetric? Reaching the NCD modules correctly (measure it on the module?).
7) Make some measurements on the speaker terminals, with test resistors and/or disposable speakers connected. Measure DC; there should be none, but if any is present on input (or if something else is wrong) you will see it on the output (measure with and without anything playing). Measure AC on the output with nothing playing as well - there should be practically nothing. Signal should increase as you turn up the volume.
8) check again! for DC - any imbalance in the rails or DC on the input might cause such problems.
Just because your old amp works fine does not exclude the above - your old amp certainly has some DC blocking circuitry (probably capacitors), almost certainly has a high frequency filter or bandwith limitation of a sort, and most likely has lower gain. I am almost certain you must have a mistake somewhere in the wiring / power supply and/or some of the above (otherwise perhaps something is wrong with your EMU) - the modules shutting down when increasing volume is a sure sign that something is WRONG. I never experienced mine shutting down even when putting out a lot of watts.
That was my input. Hope we can help you find the mistake - I have been very happy with my NCD-1 for ages now, and there is no doubt you deserve that too!
By the ways, I also listen to soundcard output (Creative Audigy2 ZS) - and my DIY DAC which has a little DC on the output - but I run them through my preamp which has a DC servo... But even with quite some DC on the input my NCD's kept on playing without doing anything nasty (except a loud bang on power-up because of the DC).
When you get around to it, try post back your rail voltages, voltages on the speaker posts (AC+DC), resistance in ohm between chassis etc. You might want to try using a disposable cheap USB soundcard (~100 kr.) as an oscilloscope with some suitable software (winscope or similar).
Good luck - cdl
That sucks.
Only explanation I got is if you had the NCD running and turned on or off your computer still connected to the NCD modules. Nasty things can happen.
Always use DC blocking cap on input.
But your NCD modules burn to death so there´s someting else.
Defect modules, NCD had some trouble with early modules.
Contact Lars at NewclassD.
Only explanation I got is if you had the NCD running and turned on or off your computer still connected to the NCD modules. Nasty things can happen.
Always use DC blocking cap on input.
But your NCD modules burn to death so there´s someting else.
Defect modules, NCD had some trouble with early modules.
Contact Lars at NewclassD.
Last edited:
Thank You guys,
I try to answer the suggestions as work them through. I also contacted Lars that (as always) answered quickly - and he wants me to send the amp down. I try to measure some more before I do that.
Comments to Your numbered suggestions CDL:
1) I did measure DC between hot and ground on the outgoing cables (no amp connected - as it already had burned) from the Soundcard - No DC there at all. Should I measure in some other way?
2) Absolutely shure. Checked and checked again - I read the cookbook very thoroughly . Started with unbalanced and moved over to blanced after reading on Josef Svalanders homepage about fourtwinned cables etc. At that point I had never used balanced XLR contacts before and was suprised by the placement of the G H C pins in the contact (Intuitive the G would be be pin 3 (C) and not no 1) - but did it all right from the beginning. Checked, checked again and again.
3) I agree it seems like DC (and in that case from the SC) - Should the safety circuit in the NCD take care of that? It now could be a good idea to try with a MP3 player (I didn´t think that was necessary before - but I guess I have to changemy mind :-/ )
4) Could be, but seems like a farfetched cause - I think I stay with DC for a while.
5) Both the equipments has a grund cable and I have a new electrical system in the house with grund in every socket outlet - and no grund problems in the house. The PC and the amp are not connected wtih any Separate ground cable - as they both are grounded through their power cables.
6) I have 56-57V DC from V- and V+ to GND and 117V between them. Cant find any measurable DC on V-gate. . . Hmmm ???? Have 42V AC into the 4 pole power supply.
7) I´ll do that more thoroughly than before
8) Don´t know were more to measure . . . There is just a little little tick when switching the PC on and off with the NCD on - so there is not any DC there when there is no musik on I think.
I will also draw a drawing of ALL cables drawn in the case with measurement everywhere I could measure something - without looking in the cookbook. Just to be sure that I don´t just oversee something that my brain correct on the way from my eyes reading of the cookbook to the reading of the cabling in the amp.
Anything else fellows?
I try to answer the suggestions as work them through. I also contacted Lars that (as always) answered quickly - and he wants me to send the amp down. I try to measure some more before I do that.
Comments to Your numbered suggestions CDL:
1) I did measure DC between hot and ground on the outgoing cables (no amp connected - as it already had burned) from the Soundcard - No DC there at all. Should I measure in some other way?
2) Absolutely shure. Checked and checked again - I read the cookbook very thoroughly . Started with unbalanced and moved over to blanced after reading on Josef Svalanders homepage about fourtwinned cables etc. At that point I had never used balanced XLR contacts before and was suprised by the placement of the G H C pins in the contact (Intuitive the G would be be pin 3 (C) and not no 1) - but did it all right from the beginning. Checked, checked again and again.
3) I agree it seems like DC (and in that case from the SC) - Should the safety circuit in the NCD take care of that? It now could be a good idea to try with a MP3 player (I didn´t think that was necessary before - but I guess I have to changemy mind :-/ )
4) Could be, but seems like a farfetched cause - I think I stay with DC for a while.
5) Both the equipments has a grund cable and I have a new electrical system in the house with grund in every socket outlet - and no grund problems in the house. The PC and the amp are not connected wtih any Separate ground cable - as they both are grounded through their power cables.
6) I have 56-57V DC from V- and V+ to GND and 117V between them. Cant find any measurable DC on V-gate. . . Hmmm ???? Have 42V AC into the 4 pole power supply.
7) I´ll do that more thoroughly than before
8) Don´t know were more to measure . . . There is just a little little tick when switching the PC on and off with the NCD on - so there is not any DC there when there is no musik on I think.
I will also draw a drawing of ALL cables drawn in the case with measurement everywhere I could measure something - without looking in the cookbook. Just to be sure that I don´t just oversee something that my brain correct on the way from my eyes reading of the cookbook to the reading of the cabling in the amp.
Anything else fellows?
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