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OLDER DECWARE GEAR SUPPORT >> CSP, CSP2, CSP2+ >> Cracking Noise from headphones on startup.
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Message started by Rivieraranch on 01/02/10 at 02:39:22

Title: Cracking Noise from headphones on startup.
Post by Rivieraranch on 01/02/10 at 02:39:22

Lately I have been plagued with a brief cracking noise from the headphones after turning on my home CSP2 and turning the volume knob. I changed rectifiers but the noise persists. I don't think it is good for the transducers in the headphones. I note that the Electro Harmonix 6922 out front has become very microphonic. Could that be the culprit?

Title: Re: Cracking Noise from headphones on startup.
Post by Lon on 01/02/10 at 14:00:16

It could be either of the three non-rectifier tubes, and it's likely to be a tube in my experience. Start some substituting to see if the sound reappears.

I went to 6N2Ps in my CSP2 and I have one that does this, very intermittently. I just grin and bear it because I love the sound and don't have a spare two or three right now.

Title: Re: Cracking Noise from headphones on startup.
Post by Rivieraranch on 01/04/10 at 01:08:33

I substituted a JAN Sylvania 6922 for the EH 6922 in front and still crackling. On to the power tubes.

Title: Re: Cracking Noise from headphones on startup.
Post by Rivieraranch on 01/05/10 at 02:30:02

I changed the left JJ 6922 and started the unit - no crackling sound. This left side power tube was the offender. I removed both JJ's from the CSP2 and sent them to their little JJ boxes with tissue paper wrap and marked the one that crackled. Damn JJ tubes! These were replacements for 2 that just plain died after about 10 hours.

Now I am using the openly microphonic EH6922 in front and 2 6N1P-EV for power tubes. The 6N's are new so they probably need time to break in and sound their best.

Title: Re: Cracking Noise from headphones on startup.
Post by Lon on 01/05/10 at 03:05:17

Well, problem solved!

Happily you have replacements on hand. Tunes continue! :)

Title: Re: Cracking Noise from headphones on startup.
Post by Rivieraranch on 01/06/10 at 12:54:53

And as I predicted, the 6N's opened up and smoothed out with some play time.

Title: Re: Cracking Noise from headphones on startup.
Post by Juan Antonio on 01/20/10 at 20:56:56

Good for you, Jim. For now I'm waiting for the svetlana tubes to spot the problem with my CSP2. If the tubes are ok, the potentiometer may be faulty.

And... Jim, literally your CSP2 has both sides for preamp tubes, not power tubes, obviously :)

Cheers

Title: Re: Cracking Noise from headphones on startup.
Post by Rivieraranch on 02/25/10 at 02:46:21

Now the crackling is back. It was present when I was turning the trim pots at the rear. I couldn't imagine that those 6N1P-EV's went bad after so little time in service. I replaced them with some others and the same problem persists. It seems like the trim pots are causing all this noise.