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Limberpine

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4 hours ago, MechEngVic said:

Try bypassing the 3rd prong (ground) of the amp's cord with a cheater plug, see if that makes the hum go away. The ground loop may be between the amp and your A/C power.

So I did ground the RCA to itself and hum in both speakers. I also took the RCAs off altogether, just speaker wire to amp and there is still a hum. 

 

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Mech is talking about the power cord. The one you plug into the wall. They sell an adapter for those with old 2 prong wiring in their home for this at most any hardware store. Ground loops are notorious in professional bands when not done properly. One question, is your amplifier and the other equipment plugged into the same AC outlet? If not could be the problem.

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On 10/31/2020 at 10:55 AM, angelaudio said:

I have a Schiit SYS. It's only $49, but IMO it sounds very sterile like and lifeless. The gain or volume is quite low when coupled to the ST70 I have and I mainly use it sometimes as an attenuator. I get the idea of the placebo effect it has on one's conscience because it's a simple unit. I think the internals are even made in Japan of all places too, but a dedicated preamp like the Erhard will absolutely blow it away. It's no contest when I compare the two and my Aretha has tone control. Obviously the Erhard is many times the price of a Schiit SYS but you'll definitely hear your money's worth with the Erhard. For me, Holger has been great to work with and answers many of my questions and his products are top notch. The phono stage in my Aretha is fantastic too. Great clarity and punch. There's some pics of my Aretha here. 

drD

 

Price does not constitute better and any active pre will sound different than a passive, The decision of weather to use active or passive should be based on your systems efficiency and user preference. Lots of folks do not like passive because they  supposedly add nothing to the sound,  and have no drive like an active . Its all about synergy how each piece works with the next to make a system. I have a sys I use with 3 different amps both Tube and SS it can be overbearing or dull and lifeless. But it sounds fine with my 45 amps.

 

For a Tube Phono Pre. I have heard dozens and my all time favorite and the one I currently have is the Hagerman Trumpet. I have the original version. Jim Hagerman has a new model Trumpet thats much cheaper than the originals and about 1/2 the size. heres a link

 

https://hagerman-audio-labs.myshopify.com/collections/phono-preamps/products/trumpet-mc-vacuum-tube-phonostage

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21 hours ago, Limberpine said:

So, there was a teensy hum when I was using the Schiit sys with the Will Vincent St-70 and was not audible during a song, only in between or when no music was on. but now that hum is WAY louder with the Aretha in all areas. 

 

The Shiit has no gain, the Aretha does, and the 'noise' is amplified. There is likely a noisy tube in your amp.

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4 hours ago, henry4841 said:

Mech is talking about the power cord. The one you plug into the wall. They sell an adapter for those with old 2 prong wiring in their home for this at most any hardware store. Ground loops are notorious in professional bands when not done properly. One question, is your amplifier and the other equipment plugged into the same AC outlet? If not could be the problem.

All cords and outlets are 3 prong. Yes, all plugged into the same outlet.

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Just covering all the bases. Right now it does sound like noisy tube. I think you said it was on both channels. If so it may be a tube that amplifies both channels. In most stereo tube amplifiers there are duplicate tubes for each channel. Is there one tube other than the rectifier that has no mate? If so it could be the culprit. Without seeing a schematic I do not know how your amp is designed. I have seen this problem many times be just a bad connection between the tube and socket. Do try removing each tube and replacing it multiple times. 

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1 hour ago, billybob said:

Until you do the cheater plug test, you will not have done the test on the ground.

Cheater_plug_edited.jpg

Yes, I have one of these. So, put this on the end of the amp plug and plug directly into the wall outlet or the power strip? Right now everything is plugged into the power strip.

 

Thanks!

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1 hour ago, henry4841 said:

Just covering all the bases. Right now it does sound like noisy tube. I think you said it was on both channels. If so it may be a tube that amplifies both channels. In most stereo tube amplifiers there are duplicate tubes for each channel. Is there one tube other than the rectifier that has no mate? If so it could be the culprit. Without seeing a schematic I do not know how your amp is designed. I have seen this problem many times be just a bad connection between the tube and socket. Do try removing each tube and replacing it multiple times. 

It is in both channels. There are 4 power tubes, and 2 driver tubes that all have mates. I can send you a photo of the amp if you want? I have also reached out to the builder to see what they say too.

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43 minutes ago, Limberpine said:

Yes, I have one of these. So, put this on the end of the amp plug and plug directly into the wall outlet or the power strip? Right now everything is plugged into the power strip.

 

Thanks!

Guess either one.. In just a quick test. Make sure unit power is off first.

Do both. Do this first before anything further on

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Try this just for giggles...  Make SURE your speakers are wired correctly.  Yea, yea I know ya know but check things out and make sure you're good.  NOTHING touching to short anything. 

I'm running a Prima Luna and using a Schiit Mani from my Linn table.  Sounds fantastic for $150. 

Double check the speaker wiring for phase and shorts.  Relax and check things out.  Don't stress.  It ain't rocket science.  Go right back to the basics with your set up.  Step at a time.  Start over if you have to and take your time. Cross your fingers too  :)

 

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39 minutes ago, Limberpine said:

It is in both channels. There are 4 power tubes, and 2 driver tubes that all have mates. I can send you a photo of the amp if you want? I have also reached out to the builder to see what they say too.

 

Have you cleaned the tube pins and the sockets in the amp? Dirty pins or tube sockets may be the problem.

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6 hours ago, billybob said:

Guess either one.. In just a quick test. Make sure unit power is off first.

Do both. Do this first before anything further on

Okay, so I got an outlet tester and it appears the the outlet was wired wrong, so the polarity was switched. I fixed that and it tests correct now. Then I plugged it in like normal into the power strip, still a noise, but different, then I plugged into both the wall and the power strip with the outlet adapter and still a noise, but different.

 

Attached is a video of the new noise in the speakers.  

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7 minutes ago, Limberpine said:

Okay, so I got an outlet tester and it appears the the outlet was wired wrong, so the polarity was switched. I fixed that and it tests correct now. Then I plugged it in like normal into the power strip, still a noise, but different, then I plugged into both the wall and the power strip with the outlet adapter and still a noise, but different.

 

Attached is a video of the new noise in the speakers.  

Not everyone has a tester handy like that. Cannot hear a thing but will try again.

And that is the transformer and not through the speakers?

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