[KPzypher]

I have had good experience with the Genelex Gold Lion tubes in general. I used them in my preamp where they replaced JJs in the 12ax7 positions. It was a nice improvement. Also tried one in the pendant. The sound was good but it didn’t get rid of the hum. The 12au7 does significantly reduce the hum. The sound with a 12au7 verses a 12ax7 is a little more laid back but with no loss of detail. It’s certainly a personal preference thing.
Did the EL84 gold pins make much of a difference (verses the JJs) in the Penant?

So far so good. Actually, I was content with the Sovtek el84m, until I started getting some sporadic high pitched ringing.

I think the JJs sound the cleanest but not all that musical. Gold Lions IMO add bit of weight to the music and smooth things out a bit for added enjoyment. But since it takes a while to swap between tubes, it could all just be in my head.

 

[Karnicopia]

I don't have experience with the ZMF Pendant but I think dealing with noise is similar for all tube amps and it's mainly just a difference in how clean our power and environment so I figured I'd share some of the things I've tried with my amp and to me it's been really worth it to sort these out because of the sound you get out of a tube amp is wonderful. I'd suggest trying out different outlets (For constant ground hum you may want to put the amp and dac on the same circuit at least that's what I was reading but I would mainly suggest experimenting) and I noticed a big difference replacing the amp power cable with a beefier one from ace hardware so not like an expensive audiophile cable just one with better shielding. Jinxy suggested I should try out a hospital power cable because the hospital has really high precision equipment that has to reject noise while being in close proximity to other high precision (and sometimes high power) equipment. I have not received this yet but again it was only $10 so in the grand scheme of things worth checking out. I also started out with pretty well shielded cables between my dac and amp (again not really expensive they are just monoprice but they do also seem to have good beefy shielding) and I also changed from USB to optical from my computer into the dac and that didn't reduce a buzzing or hum but overall improved the sound. I think optical more cleaned up high frequency noise from my computer which sounded different than the low frequency noise from my power and I think was a lot more subtle. The optical wasn't like removing a buzzing or hum it was more removing an overall consistent harshness to the sound that was hard to notice until it was gone but sounded a lot better to me (this has actually been one of my favorite changes probably outside the power cord).

I am also going to get a Pi2AES to get a clean signal into my dac and I can use it as a streaming or local source and I'm not expecting much improvement over optical but you can hard wire that to your network and stream or connect a local drive so it's also going to be a lot more convenient for me. There are definitely a lot of streamers that do this stuff too and probably look better but I can just put this out of the way because I don't have to interact with it and at $250 or so the it seems to have really great value and perform at a high level (you have to start looking at pretty expensive streamers to get AES connection which rejects a lot of this noise we are trying to remove). I still don't have this there is like a 3/4 week wait on the AES board but I'm pretty excited to see how it sounds. Also someone had posted a thread where they put in an Automatic Voltage Regulator ($50 https://www.amazon.com/gp/product/B00009RA60/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1) and it made the amp silent and they had a hum issue so this could be another good option but I have no experience with this. I think my problems were more intermittent and due to noise on my power lines but I may still check this out as it seems pretty reasonable and I can always return if it it doesn't do anything.

Tubes do make a big difference in noise rejection too but if you can clean up the power and signal going into the amp it will open up the different types of tubes that work well so it's worth it because some of the bad noise rejecting tubes may sound the best when the noise is sorted. I think I have noticed a case of this on the GOTL there are gec 6j5 that are really highly regarded and sound wonderful but really do not do any help if there is noise in the signal where the GE 6j5 metal tubes reject noise like nobody's business (and still sound pretty great too so I do really like these).

 

[KPzypher]

I don't have experience with the ZMF Pendant but I think dealing with noise is similar for all tube amps and it's mainly just a difference in how clean our power and environment so I figured I'd share some of the things I've tried with my amp and to me it's been really worth it to sort these out because of the sound you get out of a tube amp is wonderful. I'd suggest trying out different outlets (For constant ground hum you may want to put the amp and dac on the same circuit at least that's what I was reading but I would mainly suggest experimenting) and I noticed a big difference replacing the amp power cable with a beefier one from ace hardware so not like an expensive audiophile cable just one with better shielding. Jinxy suggested I should try out a hospital power cable because the hospital has really high precision equipment that has to reject noise while being in close proximity to other high precision (and sometimes high power) equipment. I have not received this yet but again it was only $10 so in the grand scheme of things worth checking out. I also started out with pretty well shielded cables between my dac and amp (again not really expensive they are just monoprice but they do also seem to have good beefy shielding) and I also changed from USB to optical from my computer into the dac and that didn't reduce a buzzing or hum but overall improved the sound. I think optical more cleaned up high frequency noise from my computer which sounded different than the low frequency noise from my power and I think was a lot more subtle. The optical wasn't like removing a buzzing or hum it was more removing an overall consistent harshness to the sound that was hard to notice until it was gone but sounded a lot better to me (this has actually been one of my favorite changes probably outside the power cord).

I am also going to get a Pi2AES to get a clean signal into my dac and I can use it as a streaming or local source and I'm not expecting much improvement over optical but you can hard wire that to your network and stream or connect a local drive so it's also going to be a lot more convenient for me. There are definitely a lot of streamers that do this stuff too and probably look better but I can just put this out of the way because I don't have to interact with it and at $250 or so the it seems to have really great value and perform at a high level (you have to start looking at pretty expensive streamers to get AES connection which rejects a lot of this noise we are trying to remove). I still don't have this there is like a 3/4 week wait on the AES board but I'm pretty excited to see how it sounds. Also someone had posted a thread where they put in an Automatic Voltage Regulator ($50 https://www.amazon.com/gp/product/B00009RA60/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1) and it made the amp silent and they had a hum issue so this could be another good option but I have no experience with this. I think my problems were more intermittent and due to noise on my power lines but I may still check this out as it seems pretty reasonable and I can always return if it it doesn't do anything.

Tubes do make a big difference in noise rejection too but if you can clean up the power and signal going into the amp it will open up the different types of tubes that work well so it's worth it because some of the bad noise rejecting tubes may sound the best when the noise is sorted. I think I have noticed a case of this on the GOTL there are gec 6j5 that are really highly regarded and sound wonderful but really do not do any help if there is noise in the signal where the GE 6j5 metal tubes reject noise like nobody's business (and still sound pretty great too so I do really like these).

Thanks for the tips. Unfortunately, I've tried everything you've mentioned and many others except for using a streamer. But that shouldn't matter as the hum is still there with all input disconnected. I even purchased a power conditioner (Furman Elite 15i) just to make sure I'm getting clean power.

Wanted to avoid this but I'm sending the unit back to Justin to get it tested. Hopefully its a hardware issue and a quick fix. I've sunk a lot of money trying to make it work, so hopefully it comes back with a good news. Like you said, it sounds wonderful and I want to make it work. So more to follow.

 

[zach915m]

One thing about tube amps is that they are just never going to be as quiet as solid state amps regardless of price. As many of you know, I absolutely love tube amps! I own amps from DNA, Eddie Current, Glenn, Feliks and ofcourse ampsandsound, they are pretty quiet, but all of them vary based on what tubes and what is around them as well as their power and output impedance.

What I would categorize as "acceptable" noise from a tube amp would be anything that doesn't interact with the music. If you're plugging a tube amp in (a full tube amp not a hybrid) and expecting it to be as quiet as your solid state gear that's just never going to happen, but that being said, usually the noise is quite low and especially on the low Z outs of my tube amps you have to be looking for it to find it instead of listening to music.

The other downside is that there are many factors and finicky bits about tube amps that make them pick up noise, this is part of the enjoyment for me, but I also realize a lot of people just want to plug and play which is understandable! @ampsandsound and I tried to make the Pendant as plug and play as a tube amp could possibly be, but none-the-less some trouble shooting is needed sometimes, here's what I typically recommend.

1. Isolate the power plug away from other plugs, consider using a monster HTS strip, you can get them on ebay for like 30 bucks usually. By the way I really recommend the monster HTS strips, for whatever reason they have worked better than many audiophile units I have tried at just getting rid of noise. It's also cheaper than most audiophile options!

2. Isolate the USB out so that you are using something that is non usb - this doesn't always cause an issue - but can.

3. Get wifi signal away from the amp, routers and or laptops using wifi can be problematic.

4. Use a 12au7 tube instead of 12ax7.

5. Try unplugging the RCA's to make sure the dac/system isn't bringing noise into the system.

As @KPzypher mentioned though - if you can't get the amp as quiet as you want, we are always happy to check the amp out and make sure nothing is going on, worst case scenario it costs a few bucks for shipping but you'll know that your amp is in good shape! There are a ton of variables in each environment that can make a piece of gear make noise, so sometimes it's impossible for us to diagnose without checking out the amp to make sure that's not the issue.

Regardless of all this I am a big proponent of tube amps, those of us who like to mess around with different tubes, output impedance and sonic characteristics will have exponentially more fun and sonic joy than when using similar solid state gear. That's not to say I don't love solid state amps, but if I'm relaxing instead of measuring and testing I'm almost always using a tube amp!

 

[KPzypher]

One thing about tube amps is that they are just never going to be as quiet as solid state amps regardless of price. As many of you know, I absolutely love tube amps! I own amps from DNA, Eddie Current, Glenn, Feliks and ofcourse ampsandsound, they are pretty quiet, but all of them vary based on what tubes and what is around them as well as their power and output impedance.

What I would categorize as "acceptable" noise from a tube amp would be anything that doesn't interact with the music. If you're plugging a tube amp in ( a full tube amp not a hybrid) and expecting it to be as quiet as your solid state gear that's just never going to happen, but that being said, usually the noise is quite low and especially on the low Z outs of my tube amps you have to be looking for it to find it instead of listening to music.

The other downside is that there are many factors and finicky bits about tube amps that make them pick up noise, this is part of the enjoyment for me, but I also realize a lot of people just want to plug and play which is understandable! @ampsandsound and I tried to make the Pendant as plug and play as a tube amp could possibly be, but non-the-less some trouble shooting is needed sometimes, here's what I typically recommend.

1. Isolate the power plug away from other plugs, consider using a monster HTS strip, you can get them on ebay for like 30 bucks usually. By the way I really recommend the monster HTS strips, for whatever reason they have worked better than many audiophile units I have tried at just getting rid of noise. It's also cheaper than most audiophile options!

2. Isolate the USB out so that you are using something that is non usb - this doesn't always cause an issue - but can.

3. Get wifi signal away from the amp, routers and or laptops using wifi can be problematic.

4. Use a 12au7 tube instead of 12ax7.

5. Try unplugging the RCA's to make sure the dac/system isn't bringing noise into the system.

As @KPzypher mentioned though - if you can't get the amp as quiet as you want, we are always happy to check the amp out and make sure nothing is going on, worst case scenario it costs a few bucks for shipping but you'll know that your amp is in good shape! There are a ton of variables in each environment that can make a piece of gear make noise, so sometimes it's impossible for us to diagnose without checking out the amp to make sure that's not the issue.

Regardless of all this I am a big proponent of tube amps, those of us who like to mess around with different tubes, output impedance and sonic characteristics will have exponentially more fun and sonic joy than when using similar solid state gear. That's not to say I don't love solid state amps, but if I'm relaxing instead of measuring and testing I'm almost always using a tube amp!

Thanks @zach915m! As always, appreciate your input, advise, and assistance. I understand the acceptable 'noise' regarding tube amps. If High-z wasn't completely unusable, I would've just stayed on the low gain tap, as the Verite sounds quite nice on Low-Z. But I'm getting some hum on Low-z as well on HPs like HD650. During the day with ambient noise, it's somewhat manageable (definitely noticeable), but at night when things quiet down, it gets quite distracting.

I can say with confidence that I've taken all measures recommended by Zach, Justin, and other members on this forum without any luck.

I hope it's an isolated issue as the Pendant otherwise sound 'magical.' And you're absolutely right about the 'fun part' of having a tube amp. I love the fact that the Pendant doesn't cost you a fortune to tube-roll unlike some amps in this price range. And did I mention how powerful it is?? This will be my go-to for all high impedance cans in the future.

 

[Bhk1004]

says tube rolling is cheap... in for about 1k into tubes on the pendant... goes to corner and cries...

 

[KPzypher]

says tube rolling is cheap... in for about 1k into tubes on the pendant... goes to corner and cries...

Well if you stay away from expensive NOS/vintage tubes that is

 

[Polygonhell]

Low-Z is currently my workaround the 60hz hum, which I'm still experiencing but not as distracting as on High-Z. Power conditioner is the last thing i'm awaiting to test out before taking further actions.

Mine has exactly the same issue, went back to Justin, he tested it and sent it back, didn’t fix it.
I think the issue is environmental, I tried everything short of a power regenerator, lifted ground, isolation transformer, humX, Furman power conditioner.
I’m not even certain the issue is the power at this point, it might be, looking at my mains on a scope it’s not ideal, and none of the devices listed address the fundamental issues, but the amp is also Very susceptible to RF interference.
I just got a DNA Stratus, it like every other tube amp I own except the Pendant it’s dead silent.
It’s frustrating, I kept the amp on the basis on the Low Impedance output.

 

[Bhk1004]

Try to see if using a slab of wood/metal and rotate it around the 12xx7 tube. Thats the tube I have noticed gets all of my interference. If that helps the "hum" at all, then you can get a cover or maybe a small cut of a pipe to slide over your tube. I did not notice a hum, but did get a really high pitch ringing that could be blocked if something was in the direction that the interference was coming from (hand/salire xD). Mine specifically seems to be picking up the wifi hub in the other room.

It seems to be a generally known issue with that tube family, and apparently guitar amps and such have been known to have tube covers for these tubes preinstalled to minimize interference.

 

[Polygonhell]

Try to see if using a slab of wood/metal and rotate it around the 12xx7 tube. Thats the tube I have noticed gets all of my interference. If that helps the "hum" at all, then you can get a cover or maybe a small cut of a pipe to slide over your tube. I did not notice a hum, but did get a really high pitch ringing that could be blocked if something was in the direction that the interference was coming from (hand/salire xD). Mine specifically seems to be picking up the wifi hub in the other room.

It seems to be a generally known issue with that tube family, and apparently guitar amps and such have been known to have tube covers for these tubes preinstalled to minimize interference.

Tried valve covers, no dice.
mine also picked up my WiFi, but that’s more of a crackle than the hum, I resolved that by moving the amp.

 

[KPzypher]

Tried valve covers, no dice.
mine also picked up my WiFi, but that’s more of a crackle than the hum, I resolved that by moving the amp.

Yeah the crackle and high pitched ringing are all easily fixed. The low hum is what kills me.

Out of the ones you haven't tried, I tried the ground lift and the Furman conditioner, and no luck.

If the Pendant didn't sound so darn good, I would've sold it already, but man does it sound good. So far, I'm determined to make it work.

 

[Bhk1004]

Sucks guys. Hope you guys figure it out. I got nothing...

 

[steve468]

Sorry to change the subject from the noise issue, I'm sure it's frustrating, but I was wondering if anyone has had some experience with trying out tube types that are not specifically mentioned in the specs. In this thread we talked already about the 5755, which I wouldn't know or trust without knowing the recommendation came from the amp designer himself (and it's one of my faves!). I've since been reading about other tubes that could be compatible, but not having much experience with tube amps, I'm unsure of what could happen. Specifically, has anyone tried a pair of 6094 (apparently EL84-ish, but needs an adapter) or a 12BH7? Is there a way to tell if they are compatible, and how much damage can I do if I plug in a tube that the amp doesn't like?

 

[attmci]

Yeah the crackle and high pitched ringing are all easily fixed. The low hum is what kills me.

Out of the ones you haven't tried, I tried the ground lift and the Furman conditioner, and no luck.

If the Pendant didn't sound so darn good, I would've sold it already, but man does it sound good. So far, I'm determined to make it work.

The low hum is from both sides or single side?

Have you tried other tubes?

 

[Polygonhell]

The low hum is from both sides or single side?

Have you tried other tubes?

The hum on mine is uniform and completely volume independent.
yes tried probably 1/2 a dozen sets of el84’s, 3 or 4 12AU7’s and 2 or 3 rectifiers.