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CSP2+ Cracking Sound on Startup (Read 4435 times)
Rivieraranch
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CSP2+ Cracking Sound on Startup
02/09/11 at 12:24:27
 
It seems that every time I start the unit I hear a cracking sound briefly from the headphones. I changed the output tubes this morning and the sound persists.
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Steve Deckert
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Re: CSP2+ Cracking Sound on Startup
Reply #1 - 02/09/11 at 16:45:29
 
Most likely it is your input tube, especially if you hear it on both channels...  Could also be dirty tube pins.
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Rivieraranch
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Re: CSP2+ Cracking Sound on Startup
Reply #2 - 02/10/11 at 01:25:19
 
I placed 3 6DJ8's in the amp, after cleaning the pins with steel wool. About 5 seconds after I turned the unit on I heard the cracking and saw a light show in the left power tube. Does this mean the tube is now compromised?

The unit was previously cracking on startup with some RCA 6BQ7's; then with some CBS 6BZ7's.

I put a 7308 in the input position and some 6N1P-EV in the driver positions, started it up and no cracking.

It must be that some of the tubes I have been using are prone to arcing.
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« Last Edit: 02/10/11 at 01:42:25 by Rivieraranch »  

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Rivieraranch
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Re: CSP2+ Cracking Sound on Startup
Reply #3 - 02/15/11 at 23:26:20
 
Now I tested all the 6DJ8's by placing each one in the input position and none crack on startup.

What's cracking?

Maybe it has something to do with the 5Z3 rectifier that I put in using a 4-pin adapter.
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« Last Edit: 02/16/11 at 12:23:01 by Rivieraranch »  

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s1
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Re: CSP2+ Cracking Sound on Startup
Reply #4 - 05/08/12 at 05:49:27
 
The same thing happened to mine last night . After I heard some humming , i tried replacing all OTKs with 3  x Siemens E88CCs . The humming became louder. So I replaced the front tube with 1 OTK , this time the humming was louder on just 1 side , so I switched the left and right tubes . True enough the humming shifted. Since I had one  more E88CC i replaced the right tube.  Immediately on power up the right tube lit up and I heard a distinct popping sound on the headphone.  Turned the amp off and waited a few  minutes and then replaced the right tube. This time the left E88CC tube sparked and i heard the HP pop before I turned the amp off asap.  I  unplugged the headphones before replacing both tubes with the stock OTKs.  Now it is quite again no hum at all. And sound seems ok .  

Should I have the amp checked ?
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Rivieraranch
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Re: CSP2+ Cracking Sound on Startup
Reply #5 - 05/08/12 at 11:58:53
 
I would say no. The amp is most likely fine. These other tubes you are using are not up to the rigors of the SRPP circuit on the back power tube positions. When you say OTK you mean the 6N1P-EV. Not surprising, the amp is designed for this tube.

If you have the headphones on, that popping sound is like a gun going off.
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s1
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Re: CSP2+ Cracking Sound on Startup
Reply #6 - 05/08/12 at 17:58:04
 
Thank you. Glad to know that the amp should be ok. Although I feel bad that my E88CCs =6922 w/c according to the manual can be used on the CSP2+ are probably dead.  I ordered some Mullards to try out and i'm now wary of using them as they might meet the same fate as the Siemens.  Is there a specific way or guide on how to safely roll tubes on the CSP2+?

Like-  front tube only , or all 3 drivers /inputs at the same time?

TIA
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Lon
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Re: CSP2+ Cracking Sound on Startup
Reply #7 - 05/08/12 at 18:12:03
 
You should be able to change a number of tubes at a time, best of the ways I accomplish this is I turn off the machine and let it cool a few minutes, change tubes, make sure all are seated properly, turn machine back on. Haven't had any problems using this method with healthy tubes.
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Lord Soth
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Re: CSP2+ Cracking Sound on Startup
Reply #8 - 05/08/12 at 18:36:27
 
Could your tube rolling problems be due to your choice of Tube rectifiers?
I have tube rolled various types and makes of 6DJ8, E88CC, E188CC and 7DJ8s without any problems.

I have been consistently using a 5Y3GT tube rectifier all the time. My base configuration is a Tung Sol 5Y3GT with a matched pair of Siemens E188CCs for the left and right channels.

Once, I even tube rolled an E188CC in front and and E88CC on the left channel and a PCC88 on the right channel!
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s1
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Re: CSP2+ Cracking Sound on Startup
Reply #9 - 05/08/12 at 22:37:12
 
Thanks everyone for your comments and suggestions. This all very helpful.

Lord Soth,

I am only using a Philco 5U4G rectifier , i tried replacing it once with another 5U4G National Union brand but didn't notice any difference.  I will try to get a Tungsol . Sylvannia or RCA 5y3gt soon.  You mentioned using a matched pair for left and right channels . May I ask what tube you are using for the front ?

Thank you


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« Last Edit: 05/09/12 at 01:16:01 by s1 »  
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Lord Soth
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Re: CSP2+ Cracking Sound on Startup
Reply #10 - 05/09/12 at 16:06:59
 
Hi S1,

Up front, I'm using a Lorenz PCC88 Grey Shields made in Stuttgart Germany.
I have finally settled on this after comparing it with other tubes such as the famous Siemens CCa Grey shields, Valvo Holland CCa Grey shields, Telefunken Tubes and a Frenchmade Philips E188CC amongst many others.
I have a pinched waist Amperex 6922 landing at my doorstep soon. I expect a "Clash of the Titans" to take place very soon. Wink

BTW, I think Steve will be able to comment on the accuracy of my hypothesis. If you refer to the preamp design notes over here, http://www.decware.com/paper56.htm
and scroll all the way to the last paragraph, the CSP preamp was designed such that the 5Y3 rectifier would run your smaller tubes at the lowest voltages. The use of a 5U4 based rectifier would be more taxing on your 3 tubes by running them at a higher voltage.

As I mentioned earlier, I have tube-rolled almost all makes and brands of tubes such as Siemens, Philips, Valvo, Telefunken, Lorenz etc in my CSP2+. The only consistent tube throughout was the use of a Tung Sol 5Y3GT rectifier. I believe that because I have been tube rolling at the lowest voltages, I have not experienced any of the tube arcing phenomenon. This is just my hypothesis and hopefully Steve can verify this?
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s1
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Re: CSP2+ Cracking Sound on Startup
Reply #11 - 05/09/12 at 22:47:37
 
Thank you so much Lord Soth!

I believe this to be one of the most helpful suggestions so far.  And I truly envy your awesome collection of fine tubes.
Good luck with the pinched Amperex . I hope to hear your impressions here.


Now to find some 5Y3 tubes asap!  :)

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