NPC Analog input clipping


#1

Hi there

Ive read a few posts and solutions for customers getting AD clipping when they are using the phono stage side of an NPC but none when theyre using the analogue inputs. Sadly, I am.

I prefer the sound of recordings made using my Roksan Caspian phono stage and so run my turntable into this and from there into the analogue inputs of my NPC.

My turntable is a heavily modded Technics SL1210 mk2 and I am using an Audio Technica ART9 MC cartridge which outputs a medium 0.5v into the Roksan. All components in the chain are in mint condition (the cartridge has only just been serviced)

I am ripping 90s 12 inch singles (mostly electronic music of various genres) and on certain tracks something is pushing the AD clipping light to come on, sporadically. It doesnt happen at all on most tracks and only occasionally on certain “offenders” but it is nonetheless worrying me as I am attempting to make the best 96/24 Flac rips possible. As this is an analogue device I have no control over the output from the turntable or the phono stage.

Does the fact that the light is coming on mean the NPC is distorting ? Or does it actually have quite a lot of reserve headroom even when the indicator flickers?

Thanks very much. I am otherwise pretty happy with my NPC, although I find my rips are rather soulless, which is partly the fault of the cartridge’s very stark portrayal of music.


#2

Welcome to the forum! The fact the light is coming on suggests you are getting some clipping. Clipping does cause distortion but if it only happens occasionally you may not even notice. Only way to tell is to listen to a recorded track that had a relatively high number of clips. Unfortunately, the analog-in gain on the NPC is not adjustable. If the clipping is bad you might reconsider and use the NPC’s phono input as its gain is adjustable.


#3

What software are you using? With Vinyl Studio you can see if it is clipping, and how bad. I run a HRT Linestreamer+ and had to install a volume pot inline between my phono stage and ADC. I get some really good transfers at 24/96.

So, some options, install a pot, or use the NPC for needle drops.


#4

Welcome Pat! Looking at the specs of the Roksan’s MC input gain of 65.5 dB, I can see why it’s clipping with a 0.5 mV cart. I also utilize a 65 dB gain phono stage in my Gold Note PH-10 (which is wonderful BTW) and I can run into clipping on the analog input on the NPC with on a really hot pressing even with my 0.4 mV Soundsmith Zephyr MIMC Star. Luckily for me I can modulate the gain in 3 dB increments on the Gold Note from 62-71 dB, so I have a good degree of flexibility. I really wish that the NPC had the ability to modulate the analog gain like the phono input. That and the ability to monitor while listening to the analog. You can’t have it all, I guess. If you’re running into clipping, I agree with Steve; just use the NPC. It’s not a reference phono stage, but it’s pretty solid, I think.


#5

Thanks so much for the welcome and such fast replies. I`ll do as you say and use the Roksan for the majority and the NPC for those that clip.

Happy listening.


#6

All y’all (and not to forget Houston, despite all the other disasters goin’ on) “How’s Yer Mom’n Them?”

  • Help me out here. As a NPC (New Power Control - it’s a Prince Product) owner, it seems to me that if one is getting overs on the phono input, you can just turn the gain down.

With the Line in, I’m guessing (and I’m not kidding) that it should be Line Level, and so if the output of a device plugged into it is Line Level, it seems like it shouldn’t create overs. If there is a way to contol the level of the Line out on the device, it oughta be lower.


#7

The problem is that the input to the NPC is clipped from the phono stage due to too much gain for the given voltage of the cart. The signal is already compromised when the NPC sees it. Not a whole the NPC can do there. You can only lower the gain to the NPC by decreasing the gain on the phono stage or switching carts.


#8

The line level of the NPC can handle pretty much what you put into it without clipping - as long as that’s below a couple of volts which it probably should be if it’s not going to clip your amp. Some early models of production had some DC on the A/D converter that caused it to clip. That was a flaw and units sent out in the last year or so should be free of it.


#9
badbeef said

With the Line in, I’m guessing (and I’m not kidding) that it should be Line Level, and so if the output of a device plugged into it is Line Level, it seems like it shouldn’t create overs. If there is a way to contol the level of the Line out on the device, it oughta be lower.


The problem with line level in home audio, and maybe commercial audio gear adheres to a standard. Is that although there is a 2v standard, most gear does not worry about their output being exact. That is one of the reasons that some preamps allow you to set the levels of each input, so they all output at the same volume.

If the OP had a phono stage that he liked, he would have been better off buying standalone ADC, like a Benchmark, Ayre, or one of the many that have their roots in pro gear.

I have probably transferred around a 100 LPs, and they don’t have any standardization of output levels. For example, I record one LP and I almost have my pot wide open, next record the levels are buried in the red. Probably one of the most annoying things is setting levels on the first couple tracks, only to find a later track has started clipping. I have walked away, and come back to find it has clipped over 20 times. Reset levels, delete file and start the record again. With Vinyl Studio you can look at the graphs to see how bad it is, but if is more than 2-3, it needs to be rerecorded.


#10

Thanks, Paul. I assumed the analog line in was clipped from the phono stage since the NPC was indicating clipping. Interesting.

@jeffstarr, I can’t tell you how many times I have experienced that exact problem in ripping my LP’s. Especially problematic is the MoFi Santana Abraxax ultradisc. The end of Black Magic Woman is so hot I have to bury the level on the rest of the LP and it sounds a little soft to me ears as a result. I ended up recording that song as it’s own album side and normalized each album side separately and the problem went away.


#11

Thanks, Paul. Thanks everyone.

Is there a way of telling if my unit is one of the early ones that is likely to have this particular issue and is there any way to do anything about it ?

Jeffstar - I did originally look for an offboard ADC but Im guessing the UK was a little behind the US for vinyl ripping when I started this seemingly endless task about two years ago. Nowhere sold the Benchmark (though their gear is now pretty popular and gets great reviews) and Ayre was an incredibly hard to find brand and stratospherically expensive. The only widely available product was the cheap and cheerful GT40. Fortunately my local retailer stocked PS Audio and the idea of a decent phono stage combined with an ADC was irresistible. Its just that the Roksan sounds a little more subtle and articulate, imho so I ended up never using the phono stage side of the NPC.


#12
patmarcus said

Thanks, Paul. Thanks everyone.

Is there a way of telling if my unit is one of the early ones that is likely to have this particular issue and is there any way to do anything about it ?

Jeffstar - I did originally look for an offboard ADC but Im guessing the UK was a little behind the US for vinyl ripping when I started this seemingly endless task about two years ago. Nowhere sold the Benchmark (though their gear is now pretty popular and gets great reviews) and Ayre was an incredibly hard to find brand and stratospherically expensive. The only widely available product was the cheap and cheerful GT40. Fortunately my local retailer stocked PS Audio and the idea of a decent phono stage combined with an ADC was irresistible. Its just that the Roksan sounds a little more subtle and articulate, imho so I ended up never using the phono stage side of the NPC.


Hi patmarcus,

There was an engineering update that dealt with this issue.

Those NPC’s with serial numbers beginning with ANW-A1-5C or older (3A-5B) will not have this upgrade.

FYI the DC issue only affected the phono input.

The Line in input was unaffected.

One suggestion I can make would be to overwrite the NPC’s firmware and then reset the unit with the Reset button on the rear panel.

Please find the zip file below for the firmware.

If you still have the same problem then consider that there could be a wider issue, perhaps in your system as a whole.

If you absolutely cannot solve the issue please reach out to us at service@psaudio.com

We’ll work to find a resolution for you.

Thanks,

  • Jeremy

#13

NPC Firmware update link:

http://www.psaudio.com/wp-content/uploads/2015/05/11-066-11-X-FMC-15.zip


#14

Jeremy, what timeframe was this problem identified? I ask since I sent my early NPC in a year ago for updating, wondering if this issue was corrected at that time.


#15
pmotz said

Jeremy, what timeframe was this problem identified? I ask since I sent my early NPC in a year ago for updating, wondering if this issue was corrected at that time.


Hi pmotz,

The NPC’s DC hardware update was implemented in March of 2015.

If you sent your NPC here last year then you are definitely up to date.

  • Jeremy

#16

Thanks Jeremy! That’s I was thinking/hoping.