Eros is very Noisy

[[email protected]]

Just finished building the Eros a couple days ago and have been playing some records.  I noticed that when close to the speakers, I heard a constant noise while listening with the SEX amp.  I decided to put on my headphones and the noise was very loud (my speakers are 88db so I didn't hear noise as loudly).  I can hear this noise as soon as my SEX amps volume is beyond about 8 o'clock.  When listening to my computer, I hear no noise until about 3 o'clock.  I do not remember my Seduction with C4S being this loud.  I am thinking it was about 12 o'clock when I started hearing noise on the Seduction.  I can't compare the two directly as I had to borrow some parts from it to complete the Eros (accidentally overheated the switch on the Eros as well as two of the RCA females).  Here are the symptoms from power up of Eros.

1.  SEX on and warmed up
2.  Eros turned on
3.  Loud hum for about 4 seconds
4.  Noise in both channels for about 2 seconds.
5.  Noise in left channel stops, then after about 1 second noise in right channel stops
6.  All is quite for about 2 seconds
7.  Noise starts back up in both channels and stays there

Some other factoids:
-Noise is there even when TT is not connected.
-Ground wire makes no difference in noise
-Lots of micro phonics(?), WAY MORE than the seduction.  In fact, the seduction pretty much had none.  I hear micro phonics if touching the chassis, tubes, or input cables.
-Changing out the 6922EH tubes makes no difference in noise
-Voltages and Resistances are within spec

[Paul Birkeland]

Give the EF86's 50-100 hours of burn in time, as they tend to quiet down and settle in thereafter. 

[[email protected]]

Can I do this by just having the preamp on or does a signal need to be going from my TT?

[Grainger49]

Posters often ask about noises at startup.  In the 9 years I have been posting I have often seen someone new to tubes or Bottlehead ask about this.  You should always turn on your system from source to speakers with a 10 to 30 second pause.  You power it down the opposite way but with only 5 to 10 seconds pause.

So what happens for you would be:

1.  Eros turned on
2.  Wait 10 to 30 seconds while the "Loud hum for about 4 seconds, noise in both channels for about 2 seconds, noise in left channel stops, then after about 1 second noise in right channel stops," all happens.  You don't need to listen to this.  I don't.
3.  Turn SEX on and warmed up

This doesn't address the cathode forming noise, but Caucasian Blackplate does.  I don't remember anyone who has had this problem persist after the first 100 hours. 

You have a good question about whether you need to play music or not.  PJ has suggested that a CD player on repeat feeding your turntable inputs would break in a phono section, capacitors, cathodes safely.  I don't remember if he suggested lowering the output or not.

[[email protected]]

Thanks for the advice, I'll plug in my cd player when I get home this evening.  Yes, I usually turn on the Eros prior turning on the SEX amp, just did it backwards to see how noise started.  The Eros/Sex combo sounds pretty good so far and was concerned about the noise as I can hear it over the vinyl noise post 9 o'clock on the SEX.  I'll post my results after 100 hours.

[Doc B.]

It's most likely the need to form the cathodes as suggested. Just leave the preamp on for a few days.

I can hear it over the vinyl noise post 9 o'clock on the SEX.

That doesn't make sense to me. The vinyl noise floor and the preamp noise floor would rise and lower simultaneously as the volume pot on the SEX is turned - that is to say, their relative levels would remain unchanged. The Eros has about 6 dB more gain than the Seduction, so yes, things will be louder at a given volume pot setting using the Eros.

Are you hearing the tube noise at a normal listening level, or just when you turn the volume up past normal listening levels?

[Paul Birkeland]

Thanks for the advice, I'll plug in my cd player when I get home this evening.  Yes, I usually turn on the Eros prior turning on the SEX amp, just did it backwards to see how noise started.  The Eros/Sex combo sounds pretty good so far and was concerned about the noise as I can hear it over the vinyl noise post 9 o'clock on the SEX.  I'll post my results after 100 hours.

I would only suggest doing this if your CD player has a variable output that you can crank way, way down.  Alternatively, an MP3 player on the lowest volume setting fed into the inputs will do just as well.

Forming the cathodes on the EF86's will not require music.

[[email protected]]

It's most likely the need to form the cathodes as suggested. Just leave the preamp on for a few days.
Are you hearing the tube noise at a normal listening level, or just when you turn the volume up past normal listening levels?

Heard at normal listening levels.

I would only suggest doing this if your CD player has a variable output that you can crank way, way down.  Alternatively, an MP3 player on the lowest volume setting fed into the inputs will do just as well.

Forming the cathodes on the EF86's will not require music.

Ok, I'll plug in my iPod in then.  Thanks.

[Grainger49]

One last suggestion:

Even new tube sockets can have some oxidation on them that causes some noise.  Remove a tube, one at a time, re-insert the tube and repeat a dozen times.  Then go to the next tube.  This is the poor man's way of cleaning tube sockets.  I have used it for decades.

Can't hurt, might help!

[Natural Sound]

You could use one of these to break in your phono pre-amp.
http://www.hagtech.com/iriaa.html

[arveedub]

Good luck breaking in your tubes, but don't hold your breath. The ef86 can be noisy. Very noisy. I have a stash of 11 good ones and 9 bad. Pretty poor odds. When I say bad, I mean BAD. Very loud noise, not just a little hiss. The good ones, on the other hand, are quite nice. Just a little noise when I turn the volume up nearly too loud to listen.

If you care for any advice: Don't bother with new production tubes. Unless you trust the seller, don't spend more than $20-$30 a pair on anything either. I bought a lot of eight 6j32p's off ebay & ended up with two pairs of very nice tubes (four dogs, though). They were selling for a couple bucks each. The 6j32p is a russian varient & surprisingly good. Look for the ones with the Soviet markings.

I really like my Eros but I wish I knew about the ef86 beforehand.

[grufti]

My experience with EF86 tubes is exactly the same as arveedub's, except that I have tested quite a few more than 11 by various manufacturers. I ultimately settled on just a few Telefunken tubes. These are some good old production Tesla EF86 available also.

Again with regard to Russian 6J32P tubes my experience is very similar to arveedub's description: about 30 - 50% can be nice, old is good.

It also takes time to evaluate any EF86 variant in the Eros: I have often kept the ones that didn't suck fired up in the Eros for two full days to give them a chance to fully form and settle in. Patience is a virtue in this endeavor. You don't need to run music while the tubes settle in.

Once you find the EF86 pair that tickle your fancy you will need to find a 7308/CCa/... whatever that allows them to shine. I got lucky there.

[Grainger49]

arveedub and grufit, have you two seen this post?

Alternate Pentode For Eros

This opens up more possibilities.

If you are willing to change the tube socket wiring there are some at the bottom of the post that work.

[grufti]

Yes, I did read that post. I even did some follow up.

Don't get me wrong EF86 are great, but like Paul Joppa wrote in a message some time ago [not a literal quote]: "they tend to bring out a person's obsessive personality traits." For better or for worse, once you have found some EF86 tubes that work really well for you, you get great music out of them.

If I made any changes I would probably try C3m tubes [or C3o] in place of the EF86.

[Grainger49]

As long as you are happy.  But you don't seem to be.  I heard the Eros in my system and didn't hear any, ANY noise.  Your system is, of course, different.  Higher sensitivity speakers allow the noise floor to be heard.  for instance Paully has 104dBW speakers.