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CSP2+ floor noise and removing the dynamics (Read 1777 times)
bwebster1970
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CSP2+ floor noise and removing the dynamics
10/15/12 at 14:05:41
 
I have owned the CSP2+ for about a year now and I believe I may be experiencing some problems with it.  Maybe I just have a defective unit, but when I turn the output pots up past 3 the floor noise is so noticeable I cannot stand it.  This leads me to say that without these pots this preamp would be very un playable in my system. This has happened since new.  
I am using very sensitive speakers (Klipschorns), but you would expect a sensitive speaker to be used with a set amp. I am also using a VAC 30/30 power amp with 300b tubes (this amp is absolutely dead quiet and completely black by its self).
Another thing I have noticed is; when I bypass the CSP2+ my music is a lot more dynamic and un compressed.  I have tried different tubes with this unit (including a different rectifier tube) and this has altered the sound, but these same characteristics remain. Do I have a defective unit or is this normal?

Thank You
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Lon
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Re: CSP2+ floor noise and removing the dynamics
Reply #1 - 10/15/12 at 14:17:57
 
Welcome!

I wouldn't call this normal. What source are you using? What setting do you have the input gain pots set at?

I have had a CSP2 and now a CSP2+ and I don't have that sort of problem with the output gain turned up. I have the input gain pots turned all the way up, the output about six clicks back from all the way up. My sources put out more than 2V output.

I do notice a bit of weight to the sound compared to my source straight in, and perhaps a diminution of macro dynamics, a different sound, but not worse than straight in overall in my opinion.

I would suggest a call in to Steve about this.
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« Last Edit: 10/15/12 at 14:18:22 by Lon »  

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sberger
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Re: CSP2+ floor noise and removing the dynamics
Reply #2 - 10/16/12 at 00:23:40
 
Have you tried setting the CSP2+ the way Steve advises? I'm using a CSP2 and so I don't know how the input settings which I don't have would apply here but if you turn your amp all the way up, turn the CSP2+ gain halfway up, and turn each output pot up until the overall volume level is as loud as you want it. From there adjust gain using the gain pot on the CSP2+. Perhaps this will at least get you in the ball park overall. I'm using a Torii III amp, and setting that all the all way up I have my output pots set at between 9-10 o'clock which allows me to get my CSP2 gain to 12 o'clock and still have enough headroom if I want to go higher(which most of the time, given 95db efficient speakers and a relatively small room I don't).

Of course, if all else fails give Steve a call and hash it out with him.

Good luck.
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Steve Deckert
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Re: CSP2+ floor noise and removing the dynamics
Reply #3 - 10/16/12 at 04:18:27
 
Welcome to the forum!  I've read your post you may either have a ground loop causing the hum or perhaps it has an issue that happened when it originally shipped to you...  either way, I would not say it is normal.  

The output pots are factory set to about 4 volts (1/4 turn) as all the way up is 30 volts which would be too noisy in most systems.

Steve
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bwebster1970
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Re: CSP2+ floor noise and removing the dynamics
Reply #4 - 10/16/12 at 16:50:07
 
Thanks for the reply's.

I put a transformer isolation box (proAV2) between the pre amp and the power amp last night and the noise was instantly gone. I could turn the pre amp up all the way with no static noise what so ever.  I believe I have a ground loop issue.  I will investigate further tonight by lifting the ground from the power cord. Do you have any other recommendations?

Thanks
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bwebster1970
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Re: CSP2+ floor noise and removing the dynamics
Reply #5 - 10/17/12 at 14:44:17
 
It turns out, my daughter put a cheap splitter plug on the cable line.  The tv was on the same circuit as my stereo.  As soon as I disconnected the tv and cable, the hum/static was gone. I guess this is justification for a dedicated circuit for a stereo.  The pre amp is now very quiet.

Thanks Smiley
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HappyDwarf13
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Re: CSP2+ floor noise and removing the dynamics
Reply #6 - 10/17/12 at 14:59:09
 
I have had similar experiences to your with ground loop gremlins and employed a similar temporary "fix" using a different isolation transformer until I could get to the root of the problem...issues with my surge protector.

In my opinion isolation transformers are a good thing for audio nuts.  I'm building a new house and had a "power purifier" fabricated for me by Controlled Power in Michigan to handle seven 20 amp dedicated lines.  The unit unfortunately weight 168 pounds and has to be mounted on the floor of the garage next to the electrical distribution box.

But to my point...okay, this thing has a large isolation transformer, voltage regulation, EMI filter, RFI filter built in and my contractors cost was only a shade South of $1700 plus freight.  And yeah I still may make my own smaller isolation transformers to place before the surge protector strip at Decware audio equipment BUT how many fancy "power conditioners" can you buy for $1700?  Mine will serve seven dedicated lines.

I'll try to attach a photo of my unit.
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Power_Purifier_copy_copy.jpg
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