Finally!
I got my order set to Lars. It took me a number of months due to lack of trust for web shops in generall from a business partner in the "safe card business" that was to order the things, and lack of B2B-functionality (VAT-problems) on the NCD web shop. All sorted out by now and I finally can start my project.
Thank You for Your advice when it comes to transformers The golden mean. Just ordered 2 pcs of 500 VA 42V from Elektrokit.
But where to find good connetors for both input and speakers in Sweden. Have tried to find any web shop for that during the last 6 months while I have been modding two Sonic Impact T-amps for my kids. Haven't found any. They either have good input connectors or speaker connectors.
Also I did se something about a preamp board with motorized remote volume and a relay based input selector here somewhere on DIYAUDIO, but I lost it and can't find it again. Anyone have any ideas what it was or where I could have been seing it?
I got my order set to Lars. It took me a number of months due to lack of trust for web shops in generall from a business partner in the "safe card business" that was to order the things, and lack of B2B-functionality (VAT-problems) on the NCD web shop. All sorted out by now and I finally can start my project.
Thank You for Your advice when it comes to transformers The golden mean. Just ordered 2 pcs of 500 VA 42V from Elektrokit.
But where to find good connetors for both input and speakers in Sweden. Have tried to find any web shop for that during the last 6 months while I have been modding two Sonic Impact T-amps for my kids. Haven't found any. They either have good input connectors or speaker connectors.
Also I did se something about a preamp board with motorized remote volume and a relay based input selector here somewhere on DIYAUDIO, but I lost it and can't find it again. Anyone have any ideas what it was or where I could have been seing it?
help!!!
After several hundred hours of enjoying music, my first problem with ncd is arrived
My config is full independant monos amps. The problem is the same with the 2 amps. When i switch on these, the bass speakers make a big boom and a big move
. After the blue led is fixed light on but no music.
I think to the préamp and i deconnect this. Without it, it's the same thing. After, i've tried another préamp. Allways the same thing....
I have a doubt with my préamp: It's a SRPP type with ECC82. I've some caps at the output. Is it possible that DC current could pass and could destroy the NCD?
I've tried to change the buffer opamp and always the same thing....
HELP
After several hundred hours of enjoying music, my first problem with ncd is arrived
My config is full independant monos amps. The problem is the same with the 2 amps. When i switch on these, the bass speakers make a big boom and a big move
. After the blue led is fixed light on but no music. I think to the préamp and i deconnect this. Without it, it's the same thing. After, i've tried another préamp. Allways the same thing....
I have a doubt with my préamp: It's a SRPP type with ECC82. I've some caps at the output. Is it possible that DC current could pass and could destroy the NCD?
I've tried to change the buffer opamp and always the same thing....
HELP
I recently tested a +/- SMPS with the NCD, but when the volume reaches a certain level, the short circuit protection kicks in and out. Is this an indication that the SMPS impedance is properly matched with the NCD? Power too slow? Too fast? Power ringing? I did not have time to look at the power through a scope, but if someone might have an educated guess, it's much appreciated.
Hi Lars,
After talking with the original manufacturer, they indicated that they were excited about the improvement in the sound that they would like to do some modifications specifically for class-D application, so probably it's good to wait a while. I will be loaning my NCD to them for a month or so to see if they can come up with something. This is very heartbreaking because I have become to accustomed to the NCD sound.
After talking with the original manufacturer, they indicated that they were excited about the improvement in the sound that they would like to do some modifications specifically for class-D application, so probably it's good to wait a while. I will be loaning my NCD to them for a month or so to see if they can come up with something. This is very heartbreaking because I have become to accustomed to the NCD sound.
We just consider that a hiccup in the process of improving the sound. We were pushing the limits trying to figure out the necessity of transient high power capabilities. I won't report sound improvements unless all aspects are improved. Besides, this is a questions thread, and I want to focus on improvements. I do have confidence in people that have worked in the RF frequency region. We were comparing against a Tact Millenium MkII. Recently having listened to Dynaudio Arbiter, and some other high priced stuff from Jeff Roland, Krell, Goldmund, etc. I think the NCDs have a good stand.Anzgar said:
You didn't say there was an improvement,rather that there is a deterioration, as you cant play at a high volume.I wouldn't lend my NCD out even for a day and never to company with no experience of class D....
I would really like to hear your listening experience in much more detail.
Hi Lars,
The power supply that is being tested is an SMPS that has some sort of energy storage technology such that it can deliver instantaniouse power much larger than the rms value. I think the one we ran the other day has a capability of 1000+ watts, others are even larger. I was wondering what kind of instantanious voltage/current capabilities the circuit will take for maybe 10ms~170ms or so without risk of damaging anything?
Another question is, does the output start clipping before the input does in the signal path?
The power supply that is being tested is an SMPS that has some sort of energy storage technology such that it can deliver instantaniouse power much larger than the rms value. I think the one we ran the other day has a capability of 1000+ watts, others are even larger. I was wondering what kind of instantanious voltage/current capabilities the circuit will take for maybe 10ms~170ms or so without risk of damaging anything?
Another question is, does the output start clipping before the input does in the signal path?
Noise from my amp
Maybe there already are answers out there, but why am I hearing noise from the speakers when the amp is powered on. (Whistling.)The noise is not permanent, but has been more rappid and increasing in volume lately. I am specially hearing the high frequent noise and it's getting to annoying.
Can it be from nearby components, wires or maybe that the ncd modules are influenced by each other.
Anyone up for a suggestion??
Maybe there already are answers out there, but why am I hearing noise from the speakers when the amp is powered on. (Whistling.)The noise is not permanent, but has been more rappid and increasing in volume lately. I am specially hearing the high frequent noise and it's getting to annoying.
Can it be from nearby components, wires or maybe that the ncd modules are influenced by each other.
Anyone up for a suggestion??
Re: Noise from my amp
Hi all,
Here are my findings so far for the hissing noise coming out from the modules.
When I use the RCA outputs from my Audia preamp (output imp at 50 ohms which should have no apparent problem driving low impedance power amps) the hissing sound from my 95 db sensitive loudspeakers is bearable. However if i use the XLR outputs the hissing sound is excessive and masks the sound of music...
When i use my passive preamp with a 47k pot, the hissing sound is half of what is coming out from the active one. I belive the input impedance of the NCD modules causes interphase problems with most pre-amps and care should be taken when you choose a partnering one.
Maybe Lars should start working for a matching pre-amp after all...
Nikos
Pboden said:
soongsc said:
Hi all,
Here are my findings so far for the hissing noise coming out from the modules.
When I use the RCA outputs from my Audia preamp (output imp at 50 ohms which should have no apparent problem driving low impedance power amps) the hissing sound from my 95 db sensitive loudspeakers is bearable. However if i use the XLR outputs the hissing sound is excessive and masks the sound of music...
When i use my passive preamp with a 47k pot, the hissing sound is half of what is coming out from the active one. I belive the input impedance of the NCD modules causes interphase problems with most pre-amps and care should be taken when you choose a partnering one.
Maybe Lars should start working for a matching pre-amp after all...
Nikos
I have recently sold my Audio Aero Capitole and bought the Slimdevice Transporter and ripped my entire cd-collection to a hard-drive. By doing this, I removed the cap/resistor on the input on the amp, due to the high sensitivety on the preamp. Since I did not hear this noise before, I may put them back.
The SD Transporter is now my source, and it does not matter if it's switch on or not. The hiss is still there. My speakers is diy, a clone of the AA Isis, so I do not know the exact measure of sencitivity. They do need power thow.
I may take your advise Lars to switch to the LM6172, but since it's generally stated that it's a reducer (of sound quality), I'll wait until last.
The SD Transporter is now my source, and it does not matter if it's switch on or not. The hiss is still there. My speakers is diy, a clone of the AA Isis, so I do not know the exact measure of sencitivity. They do need power thow.
I may take your advise Lars to switch to the LM6172, but since it's generally stated that it's a reducer (of sound quality), I'll wait until last.
I'm not sure it's the same, but I've got a whistling noise in mine, that varies both in frequency and volume. It's somewhat louder when I connect a ZAPfilter output stage through a 10k DACT attenuator, but still there on other sources or totally disconnected. I thought it might be the heterodyning mentioned in the NCD cookbook, but minor changes to the crossover frequency hasn't made any difference. I'm using the LM4562, and I'd rather not change.
I'd like to add that my amp is just temporarily thrown together, with no walls or lid, and rather messy internal wiring.
I'm using dynaBel C22 speakers; dual 5" + tweeter, 90dB sensitivity, 4 ohms.
I'd like to add that my amp is just temporarily thrown together, with no walls or lid, and rather messy internal wiring.
I'm using dynaBel C22 speakers; dual 5" + tweeter, 90dB sensitivity, 4 ohms.
novec said:
Dear Novec,
If you read my comment above you will also agree that the whistling noise comes from the interaction of the output stage/dact attenuator and the NCD modules. Since the attenuator changes the impedance on the various settings of the pot, the whistling noise also changes in density and frequency.
I believe if both the NCD and Zappulse modules had high input impedances, these noises would not be noticable.
Also in your case, since the dact pot follows the zapfilter used as a preamplifier (please correct me if i assume wrong), the NCD modules "see" an impedance at their inputs that change every time you move the pot.
Bye for now,
Nikos
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