Pacific dac: Lampizator's new top of the line dac

[Anil Kalagatla]

Okay I ran the tests as best as I could (the room is very large, and I had to use the tablet to control the music) and I unfortunately still hear the hum as before. Also, to call out the weird symptom here again: the hum only manifests when I'm actually playing some music and stops a few seconds after I pause or stop. This happens for both LAN and USB inputs.

A couple of other data points: I noticed a persistent hum when the volume control is all the way at -63dB (which is the lowest), independent of whether I'm playing music or not. I also tried the preamp inputs by connecting another DAC (an Ayre Codex) to the XLR inputs and this time I heard a persistent hum (whether the music is playign or not). This last observation was surprising as I was thinking I would avoid the hum if I bypass the digital circuits (if the noise is in the digital portion).

Again thank you so much for your and others generosity of time and a spirit of helping out! And of course, continue to enjoy the DAC immensely. I was listening to the a great performance of Dvorak's 9th Symphony (CSO/Reiner) yesterday night and going through Beethoven's Piano concertos today - pretty amazing! Again, except for the soft passages

Anil

 

[Zero000]

Are you sure this isn't just post ring?

Tap the valves with your finger and the volume at normal listening levels. Does it sound the same as when the music comes to a sudden stop?

If so, you could try mass damping the chassis by putting a large, thick, book on it to stop it ringing. Plus some tube dampers as per an earlier post.

And keep the DAC as far away as possible from the speakers. And anything that might be generating electrical noise.

For instance some tubes act as a receiver in my DAC. Tesla RD27AS picks up a lot of noise from my 4K projector if it is on. It also hates an HDMI switch I have.

There are considerable disadvantages to using triodes in the output stage of a DAC. You have to work your way around them. But when the stars align there is magic to be had

 

[Steve williams]

I have nothing to substantiate my next thought however everything I read before I bought mine was that the LAN input can be a source of extraneous noise. I had no intent to ever connect with anything but USB so I ordered my Pacific with only USB. I have zero hum however as I and User211 states, this could be ringing from the tubes which every user has. I mitigated that with the use of Herbie's tube dampers

 

[Anil Kalagatla]

Steve what exact model of the tube rings do you use for the 242s? I will order a set as well.

Anil

 

[Zero000]

Anil you will find some triodes have far lower microphony than others as you explore alternatives.

By all means get the tube dampers, though.

 

[highstream]

Who's paying if they don't solve the hum?

 

[dminches]

Microphonics and hum are 2 different things. I wouldn't bother with tube dampers if you truly have a hum.

 

[Golum]

Don’t think either hum has to do anything with this issue. Would not stop and start with the play/stop/pause button i would say...

 

[Anil Kalagatla]

Don’t think either hum has to do anything with this issue. Would not stop and start with the play/stop/pause button i would say...

Yeah, that's what I was thinking as well. Though I will be getting the tube dampers using a "doesn't hurt to try" philosophy. FWIW, I also moved the DAC as far away from the amps and speakers as I could (limited by my cables) and the behavior was still there. Again, I don't see this as an urgent issue as I'm still enjoying the sound very much, and am sure I will get to the bottom of it in time (I sent a note to Lampi to see if they have any ideas and may ping Fred as well).

Anil

 

[Alrainbow]

Sorry if I’m just asking not reading this all
after you tried the items I asked what were the results ?
did it stop or get better or worse

 

[Steve williams]

Steve what exact model of the tube rings do you use for the 242s? I will order a set as well.

Anil

I use KR242. You are using RK-KR242. Different sized tubes

 

[Alrainbow]

Can we agree hum is 60 cycle AC period. Anything but this is not hum but noise or buzz. So is the hum 60 cycles .?

 

[Anil Kalagatla]

Hi Alrainbow: yes, I tried them as best as I could and did not see any changes. Here's what I posted yesterday:

Okay I ran the tests as best as I could (the room is very large, and I had to use the tablet to control the music) and I unfortunately still hear the hum as before. Also, to call out the weird symptom here again: the hum only manifests when I'm actually playing some music and stops a few seconds after I pause or stop. This happens for both LAN and USB inputs.

A couple of other data points: I noticed a persistent hum when the volume control is all the way at -63dB (which is the lowest), independent of whether I'm playing music or not. I also tried the preamp inputs by connecting another DAC (an Ayre Codex) to the XLR inputs and this time I heard a persistent hum (whether the music is playign or not). This last observation was surprising as I was thinking I would avoid the hum if I bypass the digital circuits (if the noise is in the digital portion).

And regarding your point about 60Hz: actually, this is not at the frequency, I can hear it in my mid size horn, I didn't check the frequency, but definitely much higher than 60hz. Sorry if I used the wrong term, I didn't realize hum specifically refers to 60hz. May be I should say slight "buzzing" sound? Sorry, don't know the technical term I will try to do a recording when I next get a chance.

Anil

 

[highstream]

Perhaps you mentioned this, but how loud is the sound? Is it loud? I don’t know if absolute silence is a necessary goal. In his book, set-up guru Jim Smith (U.S.) wrote that he never heard a good sounding system that was dead quiet. The last times a loud one happened, it was an spdif cable or IC that wasn’t connected firmly enough, the latter not tightened properly during a repair. Before that, it was the faux balanced ports my TRP came with. Before getting a preamp, they were hooked directly to ATC actives and the buzz could be heard along with the music. Apparently an impedance mismatch that required rewiring the ports.

 

[Anil Kalagatla]

Steve: Got it, I will check with Herbies to find the right dampers.

highstream: Yeah, this is actually not very loud at all, that's why this hasn't been an urgent thing for me. Hopefully I've made that clear in my posts - the DAC really sounds amazing, and this noise is really low volume. Not sure if I'm being a little too anal or what, though it's obvious with some passages, especially when it's nice and quiet (and definitely when compared to the Dave). To be honest, my HVAC vents, when they kick in, are much louder (which is a much more annoying problem).

Anil

 

[highstream]

If you can hear it from the seated position (7-8'?) while the music is playing at any reasonably intelligible volume, then it would seem too loud. If you have to go up near the speaker, then I wouldn't consider it a problem, although not everyone would agree.

 

[Zero000]

Who's paying if they don't solve the hum?

Solve the primary problem first. If the RK242 genuinely seem to be overly microphonic then send them back to their maker.

I wouldn't like to make that call without about 4 or more alternatives to switch between in that specific DAC. The RKs are super expensive compared to some truly excellent much cheaper NOS alternatives. They should be amoung the best in a wide variety of parameters. No tube is the best at all of them.

Hum issues can be a bitch. If moving stuff around and all generally good advice in that region fails that doesn't involve taking the DAC apart, it's internal and needs sorting out by a competent engineer.

In my opinion there are better engineers around in this region than those employed by Lampizator.

 

[Tuckia]

Hum

Hi Alrainbow: yes, I tried them as best as I could and did not see any changes. Here's what I posted yesterday:

Okay I ran the tests as best as I could (the room is very large, and I had to use the tablet to control the music) and I unfortunately still hear the hum as before. Also, to call out the weird symptom here again: the hum only manifests when I'm actually playing some music and stops a few seconds after I pause or stop. This happens for both LAN and USB inputs.

A couple of other data points: I noticed a persistent hum when the volume control is all the way at -63dB (which is the lowest), independent of whether I'm playing music or not. I also tried the preamp inputs by connecting another DAC (an Ayre Codex) to the XLR inputs and this time I heard a persistent hum (whether the music is playign or not). This last observation was surprising as I was thinking I would avoid the hum if I bypass the digital circuits (if the noise is in the digital portion).

And regarding your point about 60Hz: actually, this is not at the frequency, I can hear it in my mid size horn, I didn't check the frequency, but definitely much higher than 60hz. Sorry if I used the wrong term, I didn't realize hum specifically refers to 60hz. May be I should say slight "buzzing" sound? Sorry, don't know the technical term I will try to do a recording when I next get a chance.

Anil

Hum always means AC line frequency in this context. 60 hz if in WA state.

If you don’t have a spectrum analyzer handy, download the Spectrum app to your phone. Hold the phone up to the midrange with the app active. Take a screenshot and post here. If in the right mode it will indicate the frequency peaks and any harmonics to the right of the fundamental.

Make sure the house is quiet during the reading.

 

[Anil Kalagatla]

So using userstream's subjective criteria (which I kind of like, as it helps provide some baseline context): I can only barely hear it from my listening position (~12' away) when the ambient noise is very low and I'm doing critical listening. Even then it's noticeable only when it stops. Interestingly, the noise level also seems to be lower today once I unwound all my different configurations from the weekend. The net difference is that I've put the DAC on a rolling dolly with damping pads used for machines (as I wasn't too crazy about lifting and carrying it all over the place) and a little more distance from the amps and the wifi router. I'm planning on getting a nice stand any way (probably another Symposium ultra ampstand to match my monoblocks). My power cables are pretty generic at this point, so I will be upgrading those as well.

I think at this point, I will stop over-analyzing this and just enjoy the DAC I will still follow up with the Lampi folks if they have any thoughts around what would manifest during playback and stop a few seconds after pausing (just for my intellectual curiosity). Thanks all for your help so far, pretty cool to see this community in action!

Anil

PS: Tuckia, thanks for the pointer to the spectrum app, pretty cool. I downloaded it and will try out when I get sufficient quietude in my listening area

 

[ctydwn]

While I posted over on the Extreme thread, I wanted to be sure to share my experience with the Pacific here on its maiden thread. At the end of 2020 I took the leap of faith to upgrade to the Lampizator Pacific based on a number of owners here that have enjoyed its pairing with the Taiko Audio Extreme and more generally from those that have exclaimed its virtues. More than reviews, I truly took confidence from this forum and especially this thread. I am thrilled to report that I am in sonic bliss with the pairing and my listening experience has gone through the roof.

I ordered the RK242s and EML 274B, balanced w VC and without an ethernet port. These parameters and tube suggestions (at least to start ) I had gathered from folks on the forum. The fit and finish were tailored for my system and are just gorgeous to look at imho. And the newer I2s board was installed.

As I mentioned in my other post, for me, the sound turned a major corner on day 6 of break-in of the Pacific. I'd say about a quarter of my test tracks sounded clearly better out of the box, and that turned to virtually all by the second week - increased substance in both time and space, greater enjoyment and saturation at lower volumes, timing fell into place, classical presentation separation took a wonderful turn whereas prior 6/7 instrument pieces smeared into each other, the cello has become intoxicating, seemingly a more truthful to the recording depth of performers, drinkable liquidity without loss in resolution, and large sound field. The bass grew deeper and more layered than I have ever experienced in my system and imaging improved as well over time.

Overall a more natural sound without any prior digititis (?) or etchiness that I had previously heard. At one point playing Ana Moura, my wife exclaimed "wow, the music just washes over you". The dynamics are explosive and while I was concerned I may lose some compared to my prior SS DAC, I should not have worried as others had assured me.

Thank you to all here and thanks to Rob and Lukasz at Lampizator for your patience, impeccable support and wonderful product.
Take good care everyone.