babadono Posted February 23 Share Posted February 23 1 hour ago, Edgar said: Neither question is dumb; both are standard procedures in a case like this. Also check to see if the "hot" and "neutral" connections in the wall plug are reversed. One of these will do the job for you. I have a (solid state) amplifier that only hums when the ground is lifted. I have another (solid state) amplifier that always hums unless I use one of these. Op had an electrician check out his house, I certainly HOPE he would have checked for hot and neutral reversal. My understanding so far is that this is a single integrated amplifier system. Where would any kind of isolator go? Quote Link to comment Share on other sites More sharing options...
Edgar Posted February 23 Share Posted February 23 8 hours ago, babadono said: Op had an electrician check out his house, I certainly HOPE he would have checked for hot and neutral reversal. Still worth a double-check, though. For just a few dollars, that gadget is a nice thing to keep around anyway. 8 hours ago, babadono said: My understanding so far is that this is a single integrated amplifier system. Where would any kind of isolator go? Ah, well, that eliminates one possibility. Still useful as general knowledge. Another thing to check: I once encountered a situation where everything on one particular circuit acted strangely. The wiring checked-out OK. When I looked at the breaker, I found that it had tripped, but only partway -- literally the lever was partway between "ON" and "OFF". There was just enough continuity to satisfy the receptacle-testing gadget, but under load things got weird. I reset the breaker and all was well again. 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted February 23 Share Posted February 23 48 minutes ago, Edgar said: Still worth a double-check, though. For just a few dollars, that gadget is a nice thing to keep around anyway. Ah, well, that eliminates one possibility. Still useful as general knowledge. Another thing to check: I once encountered a situation where everything on one particular circuit acted strangely. The wiring checked-out OK. When I looked at the breaker, I found that it had tripped, but only partway -- literally the lever was partway between "ON" and "OFF". There was just enough continuity to satisfy the receptacle-testing gadget, but under load things got weird. I reset the breaker and all was well again. There's that "it measures good but is bad" thing again Yep half tripped breakers, seen it several times in my life as well and not just in audio situations of course. And yes everybody should have one of those outlet checkers. 1 Quote Link to comment Share on other sites More sharing options...
the real Duke Spinner Posted February 23 Share Posted February 23 Don't know if I posted on this I have both The KH certainly have a lot more bottom But The LS whacks you in the chest pretty good 1 Quote Link to comment Share on other sites More sharing options...
Wolfman71 Posted February 23 Share Posted February 23 It boils down to if you can handle the hum from these tube amps, that’s how they were made…you can’t fix the problem…other then getting something different…I went through this for a couple years…taking these amps to friends systems…and even repair shops..they hum … Quote Link to comment Share on other sites More sharing options...
jjptkd Posted February 24 Share Posted February 24 On 2/22/2024 at 1:24 PM, Silverfoxvtx1800 said: I don’t what’s going on with my system but this PassXA25 amp and the XP-12 Pass preamp is dead quiet..it’s the best sound I have had. Bought my first Forte in 1985 and the Forte IV a year ago…haven’t had any other speakers..never will go the tube route again..the sound now gives me shivers …can’t turn it off Steve Guttenberg compared the Carver 285 tube amp to the Pass at 11:36 in his review. I have had several Carver tube amps now and none have had hum or noise. Quote Link to comment Share on other sites More sharing options...
Wolfman71 Posted February 24 Share Posted February 24 Ya I saw that review, one thing about them the reviewer has to say it’s better otherwise no one would send them anything to review, when is the last time any of them said the product they were reviewing was bad?…I see the guy from Carver sent a message thanking him for the review… ‘That out of the way I think the Carver amps are really good probably better then most other tube amps in that 5k price range..Nelson Pass and Bob Carver are great developers of amps and are iconic in their field. I remember in the 70s my father-in-law an I went to somewhere in the Seattle area to the Carver factory and picked the Phase Linear amp and preamp off the factory line, and gave it to me, I about died. I have huge regrets trading it for some concrete work years ago. I have a friend with that Carver amp and we did some A/B listening last weekend, the Carver amp does sound really nice, no complaints here,it did give my Klipsch Fortes tweeter hiss that you could hear when you were about 4 ft or closer to the speakers. If I would have bought a Carver amp instead of the Primaluna most likely i wouldn’t have such a sour taste in my mouth when it comes to tubes. When you get up in the morning and turn your tube amp on and you hear an awful noise in your speakers and a red light next to a tube or blow a fuse you get really pissed. ‘My Pass Labs XA25 amp is really close to the Carver amp but when I put the Pass XP12 preamp on that’s what made the difference in the sound stage and everything else a lot better, if I ever went back to tubes which I won’t it would be the Carver amps for sure.. ‘thanks for reminding me of the Carver amps it brings back some great 1970s memories.. 1 Quote Link to comment Share on other sites More sharing options...
jjptkd Posted February 24 Share Posted February 24 2 hours ago, Silverfoxvtx1800 said: Nelson Pass and Bob Carver are great developers of amps and are iconic in their field. I have a friend with that Carver amp and we did some A/B listening last weekend, the Carver amp does sound really nice, no complaints here it did give my Klipsch Fortes tweeter hiss that you could hear when you were about 4 ft or closer to the speakers. ‘My Pass Labs XA25 amp is really close to the Carver amp As soon as I read that about the hiss I paused my media player and walked up to each of my forte IV's-- 6 inches or so away and no sound at all. Hiss at 4ft is unacceptable I'd send mine back if that were the case, maybe something else in your friends system causing it? I'm sure the XA-25 is a wonderful amplifier, "better" sounding is subjective once you get past a certain point, beyond the hums and hisses amongst other things. Quote Link to comment Share on other sites More sharing options...
Wolfman71 Posted February 24 Share Posted February 24 Could of been a funky tube making it hiss…I know my Primaluna I had made lots of weird noises all the time, speaker thump when shutting it off and a click when turning it on..after about 4 hours I had a noise like bending metal that would come randomly and scare the hell out of me..then after I shut it off and it cooled down it did it again…crazy.. ‘Hiss or not the Carver sounded really good…when I took the Primaluna preamp out and put in the Pass Preamp I can’t believe the difference…when I turn the Pass off and on there is no sounds…actually I have only turned it off a couple times in the last 4 weeks…the preamp,stays on 24/7…I turn the display off …the remote is so nice …. All that is water under the bridge, all the Primaluna stuff is gone and all the tubes.. ‘bottom line what I have learned recently is if you can keep amp and preamp from the same manufacturer…it makes a huge difference… ‘With the Primaluna I couldn’t listen to bad recordings, now I can for example the Audioslave recording of the song Like A Stone is awesome…. Quote Link to comment Share on other sites More sharing options...
Fido Posted February 25 Share Posted February 25 5 hours ago, Silverfoxvtx1800 said: Could of been a funky tube making it hiss…I know my Primaluna I had made lots of weird noises all the time, speaker thump when shutting it off and a click when turning it on..after about 4 hours I had a noise like bending metal that would come randomly and scare the hell out of me..then after I shut it off and it cooled down it did it again…crazy.. ‘Hiss or not the Carver sounded really good…when I took the Primaluna preamp out and put in the Pass Preamp I can’t believe the difference…when I turn the Pass off and on there is no sounds…actually I have only turned it off a couple times in the last 4 weeks…the preamp,stays on 24/7…I turn the display off …the remote is so nice …. All that is water under the bridge, all the Primaluna stuff is gone and all the tubes.. ‘bottom line what I have learned recently is if you can keep amp and preamp and all the same manufacturer…it makes a huge difference… ‘With the Primaluna I couldn’t listen to bad recordings, now I can for example the Audioslave recording of the song Like A Stone is awesome…. I am so glad my Primaluna doesn’t have the problems you experienced and still surprised Upscale didn’t make it right. My Evo400 has not made turn on or off thumps or any hiss or noise.your experience with your Evo 400 sounds terrible. Just clean powerful sound. Warm and rich sounding day in day out. 1 Quote Link to comment Share on other sites More sharing options...
Wolfman71 Posted February 25 Share Posted February 25 I must of got a bad one, nothing is perfect humans made it…even though it was a rough road with the Primaluna where I am now is 100% better. The Pass gear is so much better…no regrets…I have had a lot of tube amps in the past year..I found a Decware in a garage sale on my daily walk for 200$, a Dennis Had from the used market, they were ok …I am definitely done with tubes…sold them… Quote Link to comment Share on other sites More sharing options...
Fido Posted February 25 Share Posted February 25 14 minutes ago, Silverfoxvtx1800 said: I must of got a bad one, nothing is perfect humans made it…even though it was a rough road with the Primaluna where I am now is 100% better. The Pass gear is so much better…no regrets…I have had a lot of tube amps in the past year..I found a Decware in a garage sale on my daily walk for 200$, a Dennis Had from the used market, they were ok …I am definitely done with tubes…sold them… Glad you got your pass labs setup and love it. Congrats Quote Link to comment Share on other sites More sharing options...
Wolfman71 Posted February 25 Share Posted February 25 I have had this Pass gear for a few weeks and at first I thought a month later I would just think it’s ok, getting new gear at first you are excited and that usually wears off..with the Forte lVs….its still really awesome…each note of the music is so engaging, no comparison to the Primaluna and the other tube amps I had..just so much more… 1 Quote Link to comment Share on other sites More sharing options...
ThomBoh Posted March 3 Author Share Posted March 3 Hi everyone! Sorry to take so long to update, some urgent work stuff came up and I spent some time out camping. Unfortunately, the issue persists! On 2/21/2024 at 11:46 AM, Shakeydeal said: That's a good suggestion. Also, you could take it to a friend's system. Even if they don't have high sens. speakers, if the amp has a hum, it'll still be present, just much lower in volume. I actually have a pair of Zu Dirty Weekend 6s (~95dB) that I hauled over to my living room and hooked up to the 300B. There is a very low amount of hum, totally bearable. Makes it seem plausible that we're dealing with an intrinsic hum that is just going to be louder for higher efficiency speakers. That said I would really like to bring the amp somewhere that has La Scalas or Klipschorns set up just to see if we get the same hum -- hoping to do so in the next week or two if I can find a local hifi shop willing to oblige. I think this would give conclusive evidence of whether or not it's just the amp's inherent hum. On 2/21/2024 at 12:07 PM, babadono said: @ThomBoh sorry if I missed it...are you shorting the inputs when trying this hum test with just the amp and speakers? There is a SCIENTIFIC way to troubleshoot these types of problems. If with only the speakers connected to the amp and the inputs to the amp shorted and there is hum there is something wrong(or inherent) in the amp. Given another amp running off the same power outlet is fine. Yes, I tried shorting the inputs, and the level hum I'm getting is actually independent of whether or not the inputs are shorted. Thanks for the suggestion, and would be happy to hear if there are any other things I'm missing here On 2/22/2024 at 8:17 AM, sanblomo said: Hi, I'm not a Klipsch owner, but I have open baffle speakers which are 100db efficient. Also, I have a pair of high sensitivity Audio Note AN-E. I waited for over two years to get my Decware amp. I switched my order to the 300B amp about eight months ago from the SE84UFO25. End of January I finally received the amp and plugged it in. To my disappointment, I heard the hum too. It pressurizes my room at 120Hz with about 50db at my listening position. We are talking amp system specific hum, not ground hum or transformer hum. I listen to classical music often, and in quiet passages the hum is intolerable. I also exchanged mails with Steve Deckert, but he couldn't offer me a remedy. I was able to sell the 300B in no time. I told the new owner all about the hum issue and said he should check the development forum on the issue. The reviewers never mentioned hum. I think that is strange, they certainly should have heard it. One of my goals for my rig has always been to reduce the noise level and increase dynamic range. Unfortunately, the Decware just didn't fit into my system. Oh well, that, I suppose, is just part of the hobby. This sounds very consistent with my experience, and the ~50 dB of hum with your 100 dB speakers seems plausible given my ~58 dB of hum with 105 dB speakers? On 2/22/2024 at 1:55 PM, Silverfoxvtx1800 said: Never tried Aric amps but there is definitely great things said about his amps.i was really close to trying his gear but after burying a shorted out Primaluna tube in the backyard I decided to go SS with the Pass Labs and very happy I did..the Primaluna EVO 400 I had was a constant problem after about 6 months of use and I use my gear more then the average bear being retired…the Decware I could hear the hum from my sitting position and being 70 that’s saying something…I took it to many friends systems and the same results…the Had amp had just a little hum that was bearable but my son could hear it so sold them and went to Primaluna…it had a slight hum but there was other noises too..after 4 hours of use it would make a noise like metal bending…weird..and you could hear weird little noises and tubes were shorting out. I am definitely happy with my Pass gear…I am sure we all have different experiences…for sure there are great tube amps out there… FWIW, I used to have a primaluna evo integrated and got absolutely zero hum out of my La Scala AL5s! On 2/22/2024 at 5:10 PM, mark1101 said: Dumb question: Have you tried a "cheater" plug (temporarily) just to see if lifting ground does anything? Obviously, this is not safe and hopefully you are plugged into a GFI anyhow. Another dumb question: Have you tried shorting the inputs when you power up and have nothing connected on those inputs? April 10, 2024 will be two years I have been waiting on a pair of SE84UFO. I was around number 1250 when I purchased, and now I am around number 400. How stupid.......I will never do anything like that again. I hope I still have the same email and phone number when they finally build those things. I hope I have the same address. I hope I am still alive. 🙂 Yep, tried the cheater plug, and tried shorting the inputs. Neither changed the hum at all. On 2/22/2024 at 7:56 PM, Edgar said: Neither question is dumb; both are standard procedures in a case like this. Also check to see if the "hot" and "neutral" connections in the wall plug are reversed. One of these will do the job for you. I have a (solid state) amplifier that only hums when the ground is lifted. I have another (solid state) amplifier that always hums unless I use one of these. I got one of those outlet testers, and all my outlets are testing perfect As for the second thing you linked, I think I have eliminated the possibility of any ground loop based on the fact that I get the same hum with nothing else plugged in except the amp, and nothing plugged into the inputs (other than a short). Steve asked me to send him a video recording of a dB meter measuring the hum at listening position with the amp off (measuring ~41-43 dB of background noise in the room) and with the amp on (~57-58 dB of hum). Steve replied that he believes that there is no problem with anything, and that this is just the unfortunate consequence of pairing this amp with speakers of efficiency this high, possibly reinforced by placement and room effects. So far, this seems to be consistent with what I've heard with the few other experiences people have shared about me re: pairing this particular amp with super high efficiency speakers. Nonetheless, if I'm missing anything and there is anything else I can try to bring the hum level down I am happy to hear it and try! I think that it's important to know whether or not we have conclusive knowledge that pairing this amp with 105 dB speakers doesn't work, as that is actionable information for other people on the Decware waiting list that may have already made such plans. Thanks again for everyone's suggestions and input! Quote Link to comment Share on other sites More sharing options...
Shakeydeal Posted March 3 Share Posted March 3 That’s a shame because there are very few speakers that will be optimal with such amps. Notice I didn’t say “work with”. Because there are many that will sound good, but those aren’t an ideal pairing and won’t give you the best performance of amp or speaker. So what Steve thinks is acceptable levels of hum limits the use of his amps with speakers that would make them sound the best. 1 Quote Link to comment Share on other sites More sharing options...
ThomBoh Posted March 3 Author Share Posted March 3 27 minutes ago, Shakeydeal said: That’s a shame because there are very few speakers that will be optimal with such amps. Notice I didn’t say “work with”. Because there are many that will sound good, but those aren’t an ideal pairing and won’t give you the best performance of amp or speaker. So what Steve thinks is acceptable levels of hum limits the use of his amps with speakers that would make them sound the best. Yeah, I think it's interesting that the conventional thought is that the lower powered an amp is, the higher efficiency the ideal matching speaker would be, but in the case of the SE84UFO25 (2.3 watts) and the SEWE300B (7 watts), that does not seem to be the case -- there is a limit on how efficient the speaker can be before hum becomes an issue. Nonetheless, I believe that Steve has given a lot of thought about how he wants his amps to sound, and what kind of speakers are ideal pairings with them (and he has written a huge amount about this on the decware forums). Quote Link to comment Share on other sites More sharing options...
babadono Posted March 3 Share Posted March 3 On 2/22/2024 at 6:09 PM, babadono said: Maybe not so dumb...just looking through Decaware documentation they suggest it and say nothing about it being temporary(?). Also specs state 120HZ down only 68dBu (?) So @ThomBoh barring anything magical going on I think you have checked everything. The fact that manufacturer specs 120 HZ only down 68dBu and the 60 HZ only a little more this is why you are objecting to it. Now only you can decide if you can live with it. I could not..but hey that's just me..I relocated all my power amps to a remote utility room because I could not stand the transformer hum. Quote Link to comment Share on other sites More sharing options...
ThomBoh Posted March 4 Author Share Posted March 4 11 minutes ago, babadono said: So @ThomBoh barring anything magical going on I think you have checked everything. The fact that manufacturer specs 120 HZ only down 68dBu and the 60 HZ only a little more this is why you are objecting to it. Now only you can decide if you can live with it. I could not..but hey that's just me..I relocated all my power amps to a remote utility room because I could not stand the transformer hum. Thanks for your thoughts. Oh I know for sure that I can not live with it. Personally, I do not think that anybody could. It is not subtle, it is loud. Notes fade into the hum, not silence, and that has a huge effect on how the music sounds and amount of detail and texture heard. It also rules out low volume background listening. If I had the amp on with no music playing, and other people were in the room talking/socializing etc, I would expect that they would all be pretty annoyed by it. Quote Link to comment Share on other sites More sharing options...
Wolfman71 Posted March 4 Share Posted March 4 I can personally tell you that the solid state Class A,Pass Labs XA25 and the Pass Preamp or the int-25 integrated Pass don’t hum and are dead silent in the Klipsch speakers…last time I looked there was a couple Pass Labs int-25 amps on USA audiomart…at a decent price….and no tube worries… Quote Link to comment Share on other sites More sharing options...
opnly bafld Posted March 4 Share Posted March 4 Anyone that worries about tubes probably shouldn't have a tube amplifier, hum or no hum. 😉 I find it odd that the UFO25 and 300B amplifiers need to hum to sound good? Having owned or heard several not 25 versions of the SE84, an original Taboo, the SE34i, and even owned the original blue Torii (a different sort of p/p) without hum issues, not to mention other brands of single ended tube amplifiers that were quiet. Even my diy ~7 watt SET amplifier is silent. 1 Quote Link to comment Share on other sites More sharing options...
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