Today I built my Hypex Nilai 500 Monoblock kits and everything went together well. One thing that concerns me is the Dc Offset on both, one measures .047Vdc and the other measures .076Vdc. This seems a little on the high side for new amps and specially these types. I am running on the High Gain setting.
Has anyone built these kits and what was the DC Offset on your?
Regards
Steve
Has anyone built these kits and what was the DC Offset on your?
Regards
Steve
Ok, I have been busy enjoying my newly built Hypex Nilai mono block amps.
UPDATE: On the DC Offset issue I ran into and my first post above. When I powered on the Nilai power amps with nothing connected, I was getting higher than normal DC Offset measurements. One amp was measuring DC Offset around 70mVdc and the other was around 47mVdc after the were on around for about 20 min. So I shorted the RCA side of the RCA to XLR adapter cable, and the DC Offset went down to 6mVdc and 8mVdc.
I contacted Hypex about what I experienced and they said the Nilai's should measure Less than 10mVdc DC Offset and more closer to 1.0mVdc. So they told me how to adjust the DC Offset and which pot to adjust for different issues to bring down the DC Offset. There was another builder that experienced the same exact issue, so it wasn't only me that had issue.
Another thing I notice in the beginning before I made the DC Offset adjustments were that while waiting for the Hypex reply, I let the amps break in and for about 5 hours I later checked them again with nothing connected to the amps and the DC Offset measurements came down around 20mVdc on both amps. So when Hypex contacted me I let them know about this as while but the guy just said these modules are Automate adjust and should have caught this. This was told to the other person that was having the same issue. Hmmmm.
So everything seems fine now and I'm enjoying the Hypex Nilai's in my system. They really show what on the source material and different recordings. Sound wonderful with strings, vocals, and horns. Good with all types of music as well!
The big test will come this weekend as I compare them with my EDGE M8 SS power amp.
UPDATE: On the DC Offset issue I ran into and my first post above. When I powered on the Nilai power amps with nothing connected, I was getting higher than normal DC Offset measurements. One amp was measuring DC Offset around 70mVdc and the other was around 47mVdc after the were on around for about 20 min. So I shorted the RCA side of the RCA to XLR adapter cable, and the DC Offset went down to 6mVdc and 8mVdc.
I contacted Hypex about what I experienced and they said the Nilai's should measure Less than 10mVdc DC Offset and more closer to 1.0mVdc. So they told me how to adjust the DC Offset and which pot to adjust for different issues to bring down the DC Offset. There was another builder that experienced the same exact issue, so it wasn't only me that had issue.
Another thing I notice in the beginning before I made the DC Offset adjustments were that while waiting for the Hypex reply, I let the amps break in and for about 5 hours I later checked them again with nothing connected to the amps and the DC Offset measurements came down around 20mVdc on both amps. So when Hypex contacted me I let them know about this as while but the guy just said these modules are Automate adjust and should have caught this. This was told to the other person that was having the same issue. Hmmmm.
So everything seems fine now and I'm enjoying the Hypex Nilai's in my system. They really show what on the source material and different recordings. Sound wonderful with strings, vocals, and horns. Good with all types of music as well!
The big test will come this weekend as I compare them with my EDGE M8 SS power amp.
At first I was a bit worried after the first amp build about all the RED LED's in the amp, I thought something was wrong because there was no mention of it in the instructions as being normal. Then after I finished the second amp and it did the same thing I knew then this was normal and had to be some sort voltage reference. If I read correctly these are used for setting the voltage reference in the amps.
DC offset is usually trimmed with both inputs (-IN and +IN) shorted to ground right at the amplifier PCB.... anything below plus or minus 70mV is pretty much a non-issue. However, the speakers' sensitivity will come into play here as well, as one would expect.
Anyway... which trim-pot(s) did you adjust? DM or CM..? Or both? Did you try to measure DC offset while changing the sensitivity only (low-mid-high)...?? I'd expect the gain setting would also change the DC offset somewhat, i.e. any DC offset trim should be done at the desired gain setting.
Anyway... which trim-pot(s) did you adjust? DM or CM..? Or both? Did you try to measure DC offset while changing the sensitivity only (low-mid-high)...?? I'd expect the gain setting would also change the DC offset somewhat, i.e. any DC offset trim should be done at the desired gain setting.
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I did short the input to ground and the DC Offset drop to 6mVdc on one amp and 7mVdc on the other before I did any adjustments, this seemed ok Hypex is the one that is saying NOTHING connected to the amp and to adjust DM pot to close to 0.0mVdc offset. So I did what they told me which seemed strange but I did it per their instructions. The "Gain" was set to Mid. The guy from Hypex did say higher gain settings would change the DC Offset, I did the adjustment at mid gain.
The topic does seem quite interesting.
However, in my view it would be even more so for current and/or future owners of the amplifier in subject if the OP were a little more detailed.
Ultimately, the purpose of a Forum is to share one's experiences/knowledge in a bi-directional way.
Not only to reach the solution to one's issue, which makes sense only for oneself. IMHO
It would be nice to see at least a pic with related trimmers highlighted...
By the way, it seems that the best performances are obtained with a low gain.
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I'm using the Clearfield Continentals from Counterpoint. These were designed by Albert Von Schweikert. They are 4Ω @ 87db.
The guy from Hypex replied but he didn't know I was doing the DC Offset measurements without anything connected to the amp per his instructions. He mentioned that if I had the RCA>XLR adapter connected while taking the DC Offset measurements that I would need to Adjust the CM pot instead. I never touched that pot as I never had the adapter connected while taking those measurements.
Just so I don't appear to be trolling, please let me explain better what I mean (and meant) and please note that my previous comment comes from my poor ability to follow a discussion like the one between the OP and @Extreme_Boky that I was very interested in, but that I was unable to realize in the specific matter.
And like me I also think of possibly other ones who could find what they read more useful (especially if with the same issue) with a little effort of photographic descriptiveness from your part: in other words, what and where are those DM and CM trimmers? How do DM trimmers differ from CM ones?
Just from my point of view.
And like me I also think of possibly other ones who could find what they read more useful (especially if with the same issue) with a little effort of photographic descriptiveness from your part: in other words, what and where are those DM and CM trimmers? How do DM trimmers differ from CM ones?
Just from my point of view.
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Sorry if I cannot recognize any picture.
I did a bit of research... have a look here:
https://audioasylum.com/forums/amp/messages/25/252500.html
The DC offset trimpot is the DM trimpot:
This what Hypex replied to me a while back. He thought I was using the RCA>XLR adapter when taking measurements but I wasn't.
"If this adapter causes offset, the cause is common mode offset rather than differential mode. In that case the other pot (CM) should be adjusted. Measure between XLR pin 2 or 3 and 1. Adjust CM pot to about zero mV. But note that this is very fiddly and impossible to get exactly right. Once adjusted you’ll probably find that with the adapter in place the DM offset is at an acceptable level.
If necessary also adjust the DM pot as explained before (floating input!)."
"If this adapter causes offset, the cause is common mode offset rather than differential mode. In that case the other pot (CM) should be adjusted. Measure between XLR pin 2 or 3 and 1. Adjust CM pot to about zero mV. But note that this is very fiddly and impossible to get exactly right. Once adjusted you’ll probably find that with the adapter in place the DM offset is at an acceptable level.
If necessary also adjust the DM pot as explained before (floating input!)."
Marking the wiper with a red marker and taking note of how many turns (if any) you are making in one direction or the other.