wtfaidh said:
Yeah, I agree, "pestering" is not really appropriate, especially since I am actually very happy with the amp
/cdl
P.S.: As for the DIY, well... I do have my hands full with my preamp project (why-oh-why did I want 6 channels??) so I'd like to keep tinkering with the working (and enjoyable sounding) NCD at a minimum
Hi cdl!
I am experiencing exactly the same problem as you describe there. Have recently finished my mono's and since then reception of FM radio is difficult when the blocks are on - even in other rooms! I dont know if my neighbors are also having problems - havent asked yet
I'd be interested in hearing if the kit offered really helps. Please post if/when you try it out, or if you find a different solution.
PS: Have any of you tried the optional cap on the power supply? And is it worth trying?
Best,
Bitnissen
In July 2007 I got a mail as an answer to my question for him about the NCD amps, from a member of this board who has a life threatening disease. He starts with an apology about the delay which given the sad fact wasn´t necessary. I feel sorry for him.
Here´s a translation of a part of the mail;
"I helped two friends of mine, they did the mechanical work under my supervision and I did the little soldering work needed. The result was bettered our expectations except for one important aspect. The amps are emit a considerable amount of EMC that interfere with TV and radio reception. Satellite and ground digital (?) is not affected. The measures that Lars suggests doesn´t help much. You have to use screened loudspeaker cable as the cables are emitting HF."
He had built an amp for himself and was happy with the the quality of sound through it. But appealingly he was not happy about the EMC.
Here´s a translation of a part of the mail;
"I helped two friends of mine, they did the mechanical work under my supervision and I did the little soldering work needed. The result was bettered our expectations except for one important aspect. The amps are emit a considerable amount of EMC that interfere with TV and radio reception. Satellite and ground digital (?) is not affected. The measures that Lars suggests doesn´t help much. You have to use screened loudspeaker cable as the cables are emitting HF."
He had built an amp for himself and was happy with the the quality of sound through it. But appealingly he was not happy about the EMC.
The free low EMI kit wasn't offered to solve the problem so much as it was to pretend that there wasn't one.
Screened speaker cables won't solve it either. It's a a deeply ingrained flaw and your choice is to endure or get something less flawed. Notice that a good portion of this thread talks about hiss, which must be the gain or it must be the op amp or it must be anything other than what it is. It's EMI. Don't say nobody told you.
Screened speaker cables won't solve it either. It's a a deeply ingrained flaw and your choice is to endure or get something less flawed. Notice that a good portion of this thread talks about hiss, which must be the gain or it must be the op amp or it must be anything other than what it is. It's EMI.
Don't say nobody told you.
classdphile said:The free low EMI kit wasn't offered to solve the problem so much as it was to pretend that there wasn't one.
Screened speaker cables won't solve it either. It's a a deeply ingrained flaw and your choice is to endure or get something less flawed. Notice that a good portion of this thread talks about hiss, which must be the gain or it must be the op amp or it must be anything other than what it is. It's EMI.
F.Y.I.: the hiss people are experiencing comes from whatever is connected before the NCD and becomes audible because of the high gain (which basically is a GOOD feature - and can easily be reduced with a couple of resistors). With shorted inputs or nothing connected, the NCD does not produce more - probably more like less - hiss than other amplifiers I've had (Aura PA-200, Aura Va-100II, Marantz PM32, Audiosource Amp-100, NAD-2400).
I believe that audible frequencies in the cable should not disturb radio reception.
wtfaidh said:
Sure, although a bit OT here. I started building a preamp some 6 years ago (because I got a nice power amp but I couldn't really afford a nice pre at that time, I was a student).
Originally, It was very simple, opamp buffer (built on an adapted mic preamp PCB) + analog pot + switch for input selector. Since then the level of ambition increased gradually and it was really always a prototype under construction; I built a 6-channel PGA2310-based volume control of Till's design to replace the pot for 5.1; keeping the old buffer for the stereo channels.
Later, I built new buffers (on nice PCBs with nice components) so as to buffer both before and after the PGA2310, also adding a DC servo. Shortly afterwards I modified the PGA2310 board to be controlled from a Dantimax kit containing relay-based input selector, remote control reciever and a display (to show volume & source).
A year ago I finally had a nice front and rear panel for the case tooled, so now it no longer looks (too much) like a prototype.
At this time the stereo channels are completely finished; headphone amp and buffers for surround are built, but not yet built in. Also need to build a tape buffer and make some minor modifications here and there...
But I just don't often have time + dismantling the preamp means no music until it's put together again!
So I have lots of electronics DIY to play with for the time being
bitnissen said:
The golden mean said:
Thanks for your replies!
OK, seems a lot of people have this problem => nothing wrong with my implementation
I haven't tried any tweaking / mods on the power supply, the NCD is completely stock (except for the adaption to the centre tap transformer which I was forced to).
As for a different solution, I am getting by as follows:
I extended the indoor antenna with a 5m piece of shielded 50ohm coax, so it is some 3m away from the amp and placed carefully, and then I have a ferrite where the antenna goes together witht the coax cable (f-type connector) and one more where the coax cable goes into the reciever. The coax cable must be kept at a small distance from the speaker cables. The DAB signal goes through the ferrites fine, (I haven't really tested that solution with the FM but I'm thinking it should work). In that way I have reception most of the time.
No other devices I have seem to be disturbed, it appears to be only close to the amp / speaker cables, so i'd not worry too much about the neighbors. Even my DIY DAC sitting VERY close to the NCD modules is behaving entirely normal.
Shielding the speaker cables doesn' t really sound like fun...
Since the ferrites are able to keep (most of) the disturbance OUT of the DAB reciever, I guess that there should be some chance they could keep some of it IN the enclosure if applied right, especially together with the 1nF's... guess I will give it a try once I get hold of the parts.
Maybe Lars has other ideas / suggestions... Lars?
/cdl
Hello Everybody
Somehow i only got an e-mail notification of activity on this thread recently, so that's why i havent replied before now. Sorry about that!
The problem about the EMC seems very strange to me, i have myself a standard NCD sitting right next to my tuner, and it receives crystal clear any station. I would like to swap a module from one of you guys who are experiencing problems, to give a good test in our EMC rig.
We have a special room in our concrete basement (for lowest possible background recepition) where we have installed antennae and a spectrum analyzer.
About the EMC kits, the problem is perhaps that people send me e-mail about getting a kit, and i must admit i am not always quick to forward the e-mail to my shipping crew, to get the goods in the pipeline.
We do have EMC kits in stock ready to send to anyone who might experience an EMC problem, but the trick is just to get the message through to the shipping people.
As you might notice from our website i don't work in shipping, but in development, and that is development of also other projects than you see at NewClassD. So sometimes when i receive a request for shipping an EMC kit, i am sitting on an assignment away from home.
I do however recognize the full resonsability, and so will do something about it.
To correct this i will go ahead and setup the EMC kit as a free product on our website. This way you can 'order' an EMC kit, and this way the word will get right up on the screen of Brenda who takes care of our shipping, and not my crowded mail box.
If you don't want to wait for this, you can also click on the E-mail address listed under 'Shipping' and this is Brenda's direct e-mail.
This way you will see some swift action.
CDL i have just forwarded your request to Brenda, so no need for you to do anything, and sorry about the delays.
Somehow i only got an e-mail notification of activity on this thread recently, so that's why i havent replied before now. Sorry about that!
The problem about the EMC seems very strange to me, i have myself a standard NCD sitting right next to my tuner, and it receives crystal clear any station. I would like to swap a module from one of you guys who are experiencing problems, to give a good test in our EMC rig.
We have a special room in our concrete basement (for lowest possible background recepition) where we have installed antennae and a spectrum analyzer.
About the EMC kits, the problem is perhaps that people send me e-mail about getting a kit, and i must admit i am not always quick to forward the e-mail to my shipping crew, to get the goods in the pipeline.
We do have EMC kits in stock ready to send to anyone who might experience an EMC problem, but the trick is just to get the message through to the shipping people.
As you might notice from our website i don't work in shipping, but in development, and that is development of also other projects than you see at NewClassD. So sometimes when i receive a request for shipping an EMC kit, i am sitting on an assignment away from home.
I do however recognize the full resonsability, and so will do something about it.
To correct this i will go ahead and setup the EMC kit as a free product on our website. This way you can 'order' an EMC kit, and this way the word will get right up on the screen of Brenda who takes care of our shipping, and not my crowded mail box.
If you don't want to wait for this, you can also click on the E-mail address listed under 'Shipping' and this is Brenda's direct e-mail.
This way you will see some swift action.
CDL i have just forwarded your request to Brenda, so no need for you to do anything, and sorry about the delays.
Lars Clausen said:
...I would like to swap a module from one of you guys who are experiencing problems, to give a good test in our EMC rig.
CDL i have just forwarded your request to Brenda, so no need for you to do anything, and sorry about the delays.
Thank you Lars, good to hear from you. Looking forward to seeing whether the kit helps.
You might want to have a look at a 'whole' amplifier with EMC trouble in order to get a better indication of what's going on (or going wrong or whatever)? Just in case something in the implementation might also be contibuting... Let us know how we can be of assistance.
Best, cdl
cdl said:The kit was in the mail today - Thanks Lars (and Brenda)
Hope to get it put in during next week, will post results.
Regardless of the outcome, you - and your spectrum analyzer - are welcome, Lars
best, cdl
Hi CDL,
Any news on your progress? Have you received and/or tested Lars' kit?
I'm very curious if it solves your (our) problem
Best,
Bitnissen
Haven't gotten around to it yet - and I might need to get some larger ferrites, the ones from Lars are fine but I'm not sure they are quite big enough for my very thick internal speaker cables (Audioquest Indigo...). Will do it soon and post update when I can Actually there was some interference in the radio this morning so the incitament is certainly there!
OT: I guess the real reason I didn't take apart the amp yet is that I'm also renewing the kitchen in my apt., and that my GF just moved in
/cdl
Actually there was some interference in the radio this morning so the incitament is certainly there!OT: I guess the real reason I didn't take apart the amp yet is that I'm also renewing the kitchen in my apt., and that my GF just moved in
/cdl
Hi CDL and others,
Just a small update on my noise problems, and an attempt to revive the discussion I got the NCD kit mounted today - with the unfortunate result that not much changed
Mounting the kit as described, with the capacitors between copperstrip and LS terminals and a ferrite on the LS-cables inside the enclosure yielded no noticeable change on of the reception of my kitchen radio. Mounting additionally a set of ferrites on the speaker cables outside the enclosure did, however, make a difference. There is still noise on the FM reception but whereas before the music from the NCD amps would play through the radio (albeit distorted and noisy ) it is now the actual FM signal dominating and with significantly reduced noise.
I am a total noob on this subject - could anyone interpret this for me?? Should I try larger ferrites, or are there any other suggestions? There is still quite noticeable noise in the FM reception so an improvement of the 'filter' would be greatly appreciated!
Best,
Bitnissen
Just a small update on my noise problems, and an attempt to revive the discussion
I got the NCD kit mounted today - with the unfortunate result that not much changed Mounting the kit as described, with the capacitors between copperstrip and LS terminals and a ferrite on the LS-cables inside the enclosure yielded no noticeable change on of the reception of my kitchen radio. Mounting additionally a set of ferrites on the speaker cables outside the enclosure did, however, make a difference. There is still noise on the FM reception but whereas before the music from the NCD amps would play through the radio (albeit distorted and noisy
) it is now the actual FM signal dominating and with significantly reduced noise.I am a total noob on this subject - could anyone interpret this for me?? Should I try larger ferrites, or are there any other suggestions? There is still quite noticeable noise in the FM reception so an improvement of the 'filter' would be greatly appreciated!
Best,
Bitnissen
thanks for the update, Bitnissen... sorry to hear that you still have trouble :-(
Have you tried a ferrite around the antenna connection? I let my DAB antenna pass through 2 of them, it doesn't seem to attenuate the DAB signal.
I haven't made it further with my ECM kit than putting the ferrites on the speaker cables outside the enclosure, which does have some effect.
What i HAVE done is to separate the antenna and speaker cables as far as possible, which gives trouble-free DAB reception at least, notably better DAB signal. (This was part of an apartment re-arranging ordered by the girlfriend...)
On the bright side, I was fired from work recently (!!!) so now I have a couple of months (with full salary, fortunately) and hope to mount the ECM kit properly. Will update as soon as I can.
/cdl
Have you tried a ferrite around the antenna connection? I let my DAB antenna pass through 2 of them, it doesn't seem to attenuate the DAB signal.
I haven't made it further with my ECM kit than putting the ferrites on the speaker cables outside the enclosure, which does have some effect.
What i HAVE done is to separate the antenna and speaker cables as far as possible, which gives trouble-free DAB reception at least, notably better DAB signal. (This was part of an apartment re-arranging ordered by the girlfriend...)
On the bright side, I was fired from work recently (!!!) so now I have a couple of months (with full salary, fortunately) and hope to mount the ECM kit properly. Will update as soon as I can.
/cdl
I did not check the connection to the case as I missed the music too much I will look into it soon.
The (for me at least) surprising thing is that the NCD's are located in the livingroom and the radio in the kitchen... Inbetween is a carrying concrete wall!
Anyway, I'm curious to see if the kit has any effect in your case. I just realized that the external ferrite only works for very low volumes on the NCD's - when the music is turned up the radio plays along happily
Best,
Bitnissen
I will look into it soon.The (for me at least) surprising thing is that the NCD's are located in the livingroom and the radio in the kitchen... Inbetween is a carrying concrete wall!
Anyway, I'm curious to see if the kit has any effect in your case. I just realized that the external ferrite only works for very low volumes on the NCD's - when the music is turned up the radio plays along happily
Best,
Bitnissen
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