Troubleshoot advice, noise Lyngdorf and icepower.

[marcus_ec]

Hi Marcus from Sweden and my first thread. I have just connected a icepower 2000as2 to my Lyngdorf DPA-1. But think the noise level is to high. My old 2170 was dead silent. When I shutdown the preamp the speakers are silent. Any suggestions?

Just to clarify everything is new for me. I have never used the preamp before and the poweramp just recieved today. Its a DIY with Ghent case.

EDIT, just installed my computer dac Matrix Mini I and use this as a preamp. Less noise but not totaly silent. Can you do anything with the amp and lower the noise floor?

 

[staticV3]

Hi Marcus! Welcome to ASR.

That the Amp is silent when nothing is plugged into the input means it's not the Amp's own noise that you're hearing, but the noise of whatever is plugged into the input, being amplified along with the signal.

Does the icepower Amp have a volume control built in, or is it a pure power amp?

 

[MASKINEN]

Hi Marcus from Sweden and my first thread. I have just connected a icepower 2000as2 to my Lyngdorf DPA-1. But think the noise level is to high. My old 2170 was dead silent. When I shutdown the preamp the speakers are silent. Any suggestions?

Just to clarify everything is new for me. I have never used the preamp before and the power just recieved today. Its a DIY with Ghent case.

EDIT, just installed my computer dac Matrix Mini I and use this as a preamp. Less noise but not totaly silent. Can you do anything with the amp and lower the noise floor?

Noise level in form of hiss in the tweeters?
The IcePower module does have almost 30dB of gain which’s is pretty high but not unusual.

 

[marcus_ec]

Noise level in form of hiss the the tweeters?
The IcePower module does have almost 30dB of gain which’s is pretty high but not unusual.

Yes hiss of the tweeters and some hiss on the midrange. I can hear i little hiss from my sweetspot 3.5 meters = 11.5 feet. I can lower input and output DB with my lyngdorf. Tried both but not at the same time. But the hiss/noise is constant.

Can something on the inside be miswired or improved?

Can adapters XLR to RCA help?

 

[MASKINEN]

Yes hiss of the tweeters and some hiss on the midrange. I can hear i little hiss from my sweetspot 3.5 meters = 11.5 feet. I can lower input and output DB with my lyngdorf. Tried both but not at the same time. But the hiss/noise is constant.

Can something on the inside be miswired or improved?

Can adapters XLR to RCA help?

Hiss in the midrange? Like white noise? That’s not normal, is it hiss or like a hum noise in the midrange?

XLR adapters should not change the gain.
Maybe you have a ground loop.

What’s the sensitivity of the speakers?

 

[marcus_ec]

Can somebody give me some feedback in this build and i how i can improve it? Bought it like this secondhand. The first thing I did I twisted the cables.

I thinking of buying better XLR connections and solder them. Do anybody know if you can buy any custom internal wires?

 

[MASKINEN]

Can somebody give me some feedback in this build and i how i can improve it? Bought it like this secondhand. The first thing I did I twisted the cables.

I thinking of buying better XLR connections and solder them. Do anybody know if you can buy any custom internal wires?

Ser inga direkta fel på slutsteget men om du svarar på det jag frågade innan kan det förmodligen ge dig svar på äfelet”. Kan lika gärna vara så att du har känsliga högtalare och använder slutsteg med hög gain, det ger dig hiss i högtalarna som inte är onormalt.

 

[marcus_ec]

No 92db - 8 ohm and the old owner have the same power amp but mono 2000as1. Total silent.

 

[BenjaminB]

I have the same power amp but with another enclosure (not Ghent). No problems whatsoever with any of my speaker sets - one set with a sensitivity < 80 dB and the other set with a sensitivity around 98 dB. Agree with MASKINEN that the high gain opens up for issues, care must be taken with all wiring, internal and external.

There are custom wires, take a look at the IcePower homepage (possible to buy directly from them). These sets are pricey and most likely not better. Also Soundimports.eu may have cable sets as they retail IcePower PA:s. (I have the set from IcePower, does not look better than the one I got with the enclosure). Also here I agree with MASKINEN, looks good in the picture you provided. Doubt swapping these cables will improve anything.

Doubt that swapping XLR contacts in the chassis will improve things, any signs that those in place are bad?

Unclear to me what you mean with XLR adapters to RCA - the inputs to your PA are XLR, which your pre-amp also have (?), then no reason to introduce RCA. Introducing RCA/XLR adapters may have consequences!

Grounding is certainly an issue with the IcePower! If I should guess anything then grounding is worth spending some time on. The IcePower have two separate grounds (at least), separated by a small resistor. If you do not have the manual then download from IcePower homepage and read carefully. There are multiple possibilities to get grounding issues, eg your power cords (are they grounded? if so there could be a power cord ground loop - test to break that one. Or the interconnect between pre-amp and PA, some XLR cables are unfortunately connecting the minus (-) to the chassis (test with a multimeter).

Most interested in this, please keep us posted!

//BB

 

[BenjaminB]

Errata: in the text above I wrote

some XLR cables are unfortunately connecting the minus (-) to the chassis

a typo! Should be: in some XLR cables unfortunately the shield is connected to the chassis, ie pin 1 is connected to the chassis which it should not be.
BTW
1) you can measure the resistance between pin 1 and the chassis in your power amp. Should be a small resistance, not zero. power cord should be removed when doing this.
2) if you want to isolate if the sound originates from your power amp you can put pin 2 and 3 to signal ground (pin 1). Then the input to the amp is set to zero - if there still is a sound then it is generated within the power amp. Easiest and most safe way to do this is to get a XLR male connector and make the short in that one (without connecting to chassis ground).

// BB

 

[marcus_ec]

I have bought an rca to xlr to triple check the preamplifier. Will try with my receiver with pre out.

My XLR cable is Supra EFF-IXLR.

 

[marcus_ec]

I got my RCA to XLR today. Pre out from my receiver to my power amp total silence!!! So it seems like my Lyngdorf it's the problem

Tried rca to xlr from my Lyngdorf same noise. So damn frustrated!

 

[MASKINEN]

I got my RCA to XLR today. Pre out from my receiver to my power amp total silence!!! So it seems like my Lyngdorf it's the problem

Tried rca to xlr from my Lyngdorf same noise. So damn frustrated!

Interesting. You could try another XLR cable and see if that would solve the issue. I don’t remember if the Supra XLR is connected to chassis ground but you can open it up and check.

You could also try something like the iFi Audio GND Defender on the pre amp to see if that removes or lowers the noise.

​

 

[marcus_ec]

Sound clip

 

[marcus_ec]

@MASKINEN

 

[MASKINEN]

View attachment 267583@MASKINEN

It’s difficult to see if it’s connected to chassis since the solder tab is underneath the other ones.

 

[marcus_ec]

Look like it's attached to the chassi.

 

[MASKINEN]

It’s usually not an issue but you can try XLR cables that are not using chassis ground to see if that solves the issue.

 

[BenjaminB]

It’s usually not an issue but you can try XLR cables that are not using chassis ground to if if that solves the issue.

Don't agree. The IcePower 2000 has a signal ground and a chassis ground, separated by a small resistance. Thus these should not be galvanic connected; IcePower is very clear that these two should be isolated from eachother..
Somewhere, not really sure where (the spec/manual is rather extensive), it was stated that shorting these may result in increased noise.

There might of course be other issues in the signal chain. It is not even certain that there is connection between signal ground and chassis ground in these connectors. An easy test, still just a test, would be to apply some insulator on the connector to avoid direct contact (this may not be a lasting fix, however,),

//BB

 

[MASKINEN]

Don't agree. The IcePower 2000 has a signal ground and a chassis ground, separated by a small resistance. Thus these should not be galvanic connected; IcePower is very clear that these two should be isolated from eachother..
Somewhere, not really sure where (the spec/manual is rather extensive), it was stated that shorting these may result in increased noise.

There might of course be other issues in the signal chain. It is not even certain that there is connection between signal ground and chassis ground in these connectors. An easy test, still just a test, would be to apply some insulator on the connector to avoid direct contact (this may not be a lasting fix, however,),

//BB

I’m not talking about IcePower in specific but I’ve seen products using XLR cables between with the XLR “chassis ground” connected on the contact which have indeed caused louder hiss/ noise.