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Cornwall IV hum with tube amp


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Update....

 

Tech looked at the Lab 12 and said it is functioning perfectly. 

 

Crap.  Now I'm spooked a bit about going tubes.  I have had Octave and Primaluna with no issues but not on 102db speakers and not in this room.

 

They asked about dimmers or maybe switching power supplies. The Lab 12 hummed with even small klipsch bookshelves in another room!

 

Thanks everyone for the help.  I had a ridiculous deal on the amp and it sounded wonderful but not quiet at all.

 

The journey continues....

 

 

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49 minutes ago, roninklipsch said:

Update....

 

Tech looked at the Lab 12 and said it is functioning perfectly. 

 

Crap.  Now I'm spooked a bit about going tubes.  I have had Octave and Primaluna with no issues but not on 102db speakers and not in this room.

 

They asked about dimmers or maybe switching power supplies. The Lab 12 hummed with even small klipsch bookshelves in another room!

 

Thanks everyone for the help.  I had a ridiculous deal on the amp and it sounded wonderful but not quiet at all.

 

The journey continues....

 

 

Did you get to “not hear” the hum at the tech’s shop?

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No but someone I trust took it in.  I'm not super surprised that it is NDF.

 

Different location, load etc.

 

But no harm no foul. Did not cost me anything to audition it.

 

I'll shop a bit but I'm staying away from "boutique".  AR, Quicksilver, Primaluna,Unison, etc.  Folks with a history. Sounded darn good though.

 

Hopefully my room is not possessed...

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On 3/8/2023 at 5:24 PM, roninklipsch said:

No but someone I trust took it in.  I'm not super surprised that it is NDF.

 

Different location, load etc.

 

But no harm no foul. Did not cost me anything to audition it.

 

I'll shop a bit but I'm staying away from "boutique".  AR, Quicksilver, Primaluna,Unison, etc.  Folks with a history. Sounded darn good though.

 

Hopefully my room is not possessed...

The tech probably did not use high efficiency speakers to test for hum. On 85db speakers the amp is probably quite enough. The tech would have to use an harmonic distortion analyzer to see the noise level. I've found 60db to 70db below signal to be quite enough on our speakers when searching for hum which is shown with all amps on a distortion analyzer. Makes no sense all the other amps you use are quite. It tells me that the amp truly is not quite enough for your speakers. No Ghost in your room. 

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Thank you.  I'm not sure what they used but I did a test on the amp in another room with Klipsh bookshelves. Probably 90db?  Anyway I still heard it enough to be spooked. I thought it was a tube for sure. They said all was fine and I'm sure it is....sort of.  Anyway, it ain't fine here so back it went.

 

If this hums and or does not sound Class A really darn good freaking great (lol) I can audition a i50.  If that does not pan out I'll know I have more work to do.  I'm not giving up on the Cornwalls. Even if it solid state all the way....

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11 hours ago, roninklipsch said:

Even if it solid state all the way....

Do not let one bad apple determine your choice. The secret is "Tubes still rule when it comes to sound." Last count I have 24 amps, I believe or possible more both SS and tubes and all are quite on my LaScala's. Tube amps are just as quite as SS amps if designed and working correctly

 

My choice of reproduction is SET's tube amps. A loud hard rocker will be better off with SS but for purist that can appreciate fine music SET tube is the way to go. Mostly only horn speakers can be used with a SET which makes our speakers so desirable. I can shake walls with just 5 watts of SET amplification and it makes music fill your whole room at any level. Holographic is the word often used. Not everyone's taste reason for so many different types of amplification but single ended triode amplification is the purist form. No manipulation of the audio signal in a SET as other forms do. This being said there are some SS amps that come really close to the tube sound but the word is really close. Slight edge still goes to a quality SET amplifier. Detail, singer in the room with you, room filling. Spooky is the word some use to described the sound. Not everyone can appreciate the advantages in sound though. One of my builds is below. Pentode being run single ended.

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I do rock pretty hard at times and it is a lot of fun. The other 60% of the time it's jazz, Govi, acoustic etc.  What's cool about the Corns is it does them all.  I'm sure my past audiophile buddies have throw me out of the club having Klipsch and tubes (lol) but fact is, the Corns rock AND do a great job on most everything. Especially when paired with REL subs.

 

If I could try a SET I would.  If I could find a Decware I would.... I'm new to this tube stuff and folks have some strong opinions on SET, push-pull, Class A, and some a distaste for ultra-linear. It all comes down to what you like in your living room.  I have a hard time with the idea of a 2 watt amp but that is almost 100% because I have no experience.

 

That other amp may be a bad apple or just a poor mix with what ever else I got going on here.  I got a darn 20a dedicated run and a freaking Hurricane power cable. Stuff should work (lol)....   Also I'm still fiddling with room placement with the Corns. I just moved them further apart and placed the subs inside the speakers vs outside.

 

I'm trying another amp today. It's a Class A , works in triode or pentode mode. KT 150s.  That should answer the question as to if the Lab 12 was funky or I have a really noisy room.

 

Thank you for your input.

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It's possible a balanced ac line to the amp would resolve the hum problem, however it can mess with some equipment. You would need a transformer to handle the change in wiring. It's been a part of the electic code since sometime in the '90s.

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UPDATE-

On another forum a gent wrote me and said he had the same Lab 12 amp. His hummed too but not that loud.  I suspect he did not have as efficient speakers.

 

TA DA!  Hooked up the Ayon- not a peep even at 3/4 volume.  Dead quiet.  Volume is touchy though as it gets loud quick.  I did a bias and ran in Pentode.  I hooked up the RELs and did not get a peep but I learned it helps if you watch polarity!  (Rookie mistake).  

 

Tonight I'll switch the subs and try Triode mode.  At least I'm cooking with gas now.....  I can evaluate....

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I thought they two symptoms might be related.  They are not.  Noise is gone but I guess quite frankly, I got more power than I need.  I switched to Triode mode and that is nice and gives me a little more flexibility but a little awkward with remote as 1 "click" can still be too much high or low.

 

I have a workable set up now at least.  I guess in theory I could remove the KT 150s and swap for EL34?

 

I'm going to just listen for a while.  Maybe call Paul at USA.  I have lots of options.  My guess is even (way low power) SET would work fine. But I do like soft acoustic to rock.  Right now I'm probably over shooting on power.  That is better than under shooting with my habits.

 

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In our PM I saw on the website the amp only takes 350mv to clip. For example the amp I sent you picture of clips at 1.6V. Most sources will send more than 2 V's so I knew the amp is designed for low efficiency 85db speakers or around that number. As far as swapping out the KT-150 for EL34, do not waste your money. I have never played with the KT-150 but in my experience the bigger the tube the better the sound. The KT-88, which I am very familiar with, sounds better than any EL34. Nothing wrong with EL34 sound it is just better sound with KT-88 and I am sure the same will hold true for the much bigger KT150.

 

When you talk Paul I bet one will only have to remove a couple of capacitors to lower the gain on the input tube, tubes. I use what is called an active buffer to control volume which enables me to use a sub as well. An inexpensive passive pre for volume control along with adjusting the volume control of the amp, maybe half way, will give you the range you are looking for with our efficient speakers as well. If the passive pre has two outputs you can then use a sub as well much as I do. 

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Holy smokes Henry....  That is great info.  Do you charge for phone consultations?  (lol)

 

Great insight.  The tube rolling hobby I understand has gotten a lot more expensive these days I hear!. 

 

Yeah you are right on at 350mv which at the time did not register with me.  BIG diff between that and 1.6.

 

I'm not quite sure how/what an active buffer / passive pre would look like (on an integrated) ......  BTW- I run subs too. REL T9x (2) but connected at speaker terminals.

 

Another avenue is I'm just using the DAC on board the Ayon.  I can't find any data on it but it's probably not the best.  If I'm lucky a good AKM chip.  I will try a couple inexpensive DACs today I have lying around. I know DACs well but I don't want to go down that rabbit hole just yet.

 

Difference in Lab 12 and Ayon- Lab 12 was really lush. A little more meaty.  Ayon sounds like nothing I have heard really.  Great sense of space with wonderful detail.  However listening experience is determined by volume or in other words- there is a bite to some presentations like piano at volume.  I have experienced this with solid state devices and traditional speakers. Like a Pass into Dynaudio.  My current set up is not near that degree of ear bleed... Ayon seems to have artifacts of tube and SS if that is possible to define in that manner. The Corns like tubes...

 

The capacitor mod is intriguing. 

 

Thank you for your time and insight.

 

 

 

 

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I have had some tube amps that weren’t very quiet.  But right now I have two in house that are. The Music Reference RM-10 and my newly acquired Audio Mirror monoblocks are so quiet that with your ear next to the speaker you’d think the system wasn’t even powered up. And Lascalas are going to let you know if there’s ANY noise.

 

I wouldn’t give up on tubes, that’s where horns shine in my book.

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7 minutes ago, Shakeydeal said:

I have had some tube amps that weren’t very quiet.  But right now I have two in house that are. The Music Reference RM-10 and my newly acquired Audio Mirror monoblocks are so quiet that with your ear next to the speaker you’d think the system wasn’t even powered up. And Lascalas are going to let you know if there’s ANY noise.

 

I wouldn’t give up on tubes, that’s where horns shine in my book.

Hang on to that RM-10. I am a big follower of Roger Modjeski. 

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Thanks guys.

 

I'm not giving up on tubes.  I'm just getting started!  Lots of options though. Now I see Audio Mirror (I love mono blocks) and RM 10.  Looks like great stuff.

 

I'm 100% digital btw.  I run a Laptop as a server with Amazon HD and Spotify.   I have also tried Qobuz. I have also tried Aurender etc bit I like the PC type interface.  The tablet control is pretty good these days though. 

 

Passive pre may be a thought.  Ill research.   It's all fun at this point...

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