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OLDER DECWARE GEAR SUPPORT >> CSP, CSP2, CSP2+ >> New Guy with CSP2+ questions
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Message started by Bobby on 12/06/17 at 23:44:22

Title: New Guy with CSP2+ questions
Post by Bobby on 12/06/17 at 23:44:22

Hello everyone, first post. I have a new to me CSP2+ it sounds great. The person I bought it from sent new tubes with it. (3) 6n1p-ev and1 Mullard GZ34. Got some questions. The output controls if I turn them to the 2nd position I get a very noticeable hum, right and left channels. The input controls need to be at least 2 positions different to balance. I'm running a pc with tidal and a ifi DAC. I've tried both inputs. Is this something normal? Or should I give the new tubes time? Thanks

Title: Re: New Guy with CSP2+ questions
Post by busterfree on 12/07/17 at 00:33:59

Welcome!

Did previous owner label which tube was used for input? Could tubes been damaged during shipping or just worn out?

I would turn the input and output controls all the way down, turn volume up halfway, then adjust input and output control to get to a normal listening volume. I would count the turns to make sure each side is equal. If volume is still off by two steps to be balanced; then, I would power down, rotate tube positions, and try again.

Next step would be to try new tubes. Always good to have a spare set.

You can also check out the manual for the CSP2 on the CSP3 product page.

Title: Re: New Guy with CSP2+ questions
Post by Lon on 12/07/17 at 00:49:18

Very good advice above from Juan. Also, pay attention to cable placement. Three out of four times I've had hum problem it has been cured by routing all power and signal cables carefully as far from each other as possible. Even with shielded cables I would get hum at times with some placement.

Title: Re: New Guy with CSP2+ questions
Post by Lon on 12/07/17 at 00:52:48

Also there's this article by Steve:

https://www.decware.com/paper41.htm

Title: Re: New Guy with CSP2+ questions
Post by Bobby on 12/07/17 at 03:32:39

Thanks everyone for the advice. I will try each step and keep everyone updated.

Title: Re: New Guy with CSP2+ questions
Post by Bobby on 12/07/17 at 20:50:59

I'm thinking that since I live in a apartment I'm picking up the hum from something in the complex since it is in both channels. Main volume does not effect it. I have since moved the 6n1p's around with no effect still low on left channel. Made sure the amp was not the issue changed r&l interconnect no effect. Will be trying to lift the ground as soon as I get a chance. Thanks.

Title: Re: New Guy with CSP2+ questions
Post by will on 12/08/17 at 00:19:27

Most run the input pots high. With most tube combinations, I run mine in the CSP3 at 8. I also run the outputs usually at 8. This will vary according to build, tubes and tastes. Before I upgraded to Jupiter caps and Steve did a mod to make different output tubes work without overloading (mine was one of the first CSP3s), I ran the output pots more like 5-7. The point being ....you should be able to run with much higher gains with minimal to almost no hum.

When you changed around the 6N1Ps did you also rotate the input, or just switch the output positions. I am pretty sure I have gotten channel imbalances with the input being a little off, and any tube can be noisy, especially if it is failing. Rectifiers as much as any can create various levels of hum.

If your system was balanced before, it should be pretty close with the CSP if the tubes and cables are good and suit the setting.

Good luck!

Title: Re: New Guy with CSP2+ questions
Post by Bobby on 12/08/17 at 21:11:29

I emailed Steve today. Got a response back. Steve told me first to get a fresh set of tubes. I'm starting there. You never know. I have been running the controls as sutch. Outputs 1( audible hum at 6 ft. anything above that). Inputs right 7 & left 10. To balance. Thanks.

Title: Re: New Guy with CSP2+ questions
Post by Bobby on 12/08/17 at 21:23:51

Another? Where is the best source for tube? Thanks

Title: Re: New Guy with CSP2+ questions
Post by Lon on 12/08/17 at 22:02:12

I use cryoset.com and ebay.

Title: Re: New Guy with CSP2+ questions
Post by Bobby on 12/09/17 at 01:02:09

Sent some pics to Steve of the amps interior. & just ordered new set of tubes. Its a start.
Vashod 3x 6N1P-EV
Mullard GZ34