1. Home
  2. amps-preamps
  3. 1347307740

Screech when turning tube pre on

Hello folks!

Well, after my issues (Cary AE3/AES) yesterday, I finally managed to get the thing working. A few problems though.

1.Turning preamp on causes sharp screeching and distorted noise. After a few short seconds it goes away and music resumes normally.

3.There is static/hissing sound coming from both channels as well, although the noise is only audible when I put my ears right next to the speaker.

4. Raising the volume slightly increases the hissing noise.

Since the hissing increases as the volume is turned, then the problem exists before the Volume dial.

I believe the problem to be a solder joint in the audio selector since the selector came off during shipping. Any thoughts?
youra6
elizabeth
6,726 posts
 
Most tube preamps either have a manual mute switch, or an automatic one, or, the preamp should be turned on, and STABLE, before turning on the amplifier.
That is a well known fact. (ior should be..)So why are you turning on the preamp After the amp?
Just so you can listen to the tubes waking up?
I guess... Tubes making crazy wierd noises starting up is NORMAL.
And the hiss. If you cannot hear it while playing music seated at your listening position at the normal levels you listen at... Then NO PROBLEM.
samhar
1,034 posts
 
From the Stereo Mojo review:

"There was never any hum and only a modicum of faint hiss if you really try to hear it. It was never audible in the listening position."
hifigeek1
770 posts
 
Youra6 what is the sensitivity of your speakers? It's possible the speakers you own are far more sensitive than the reviewers speakers, hence the hiss. Note that with preamps that haven't any mute relay, when they initially power up, it's a good idea to turn the preamp on first, wait a minute then turn the amp on. When shutting off the system, shut the amp off first then the preamp. So, the preamp is first on last off. Hope that helps. I would contact Cary to make sure this is normal..
polk432
1,116 posts
 
HiFi is right. The sensitivity may be over 100 and you'll hear hiss. I have Cary amp and pre. Pre on first and off last is correct.
grimace
624 posts
 
If your pre-amp doesn't have a protection circuit and you turn it and your amp on at the same time - before the preamp is stable as Elizabeth says - you'll get that noise. Learned that one the hard way.
More to discover