Cary SLP 05 - When To Replace Tubes?

I’ll be darned. I swapped back the old tubes and guess what, it wasn’t the tubes after all. Eveything sounded OK again even with the old tubes so I’ll continue using them for now.

So to everyone who said it wasn’t the tubes - you are right!

This is a crazy hobby - I didn’t think that power cord, USB/ SPDIF reclocker break in would have such an effect especially since the power cords were used and I have been running them in for slightly more than a month, albeit with only 20 hours of play in all. It's just weird that things just "clicked" after the tube swap.

Thanks again everyone and apologies for the false alarm...

"Also, when do I need to change the rectifier tube? What are symptoms of its end of life?"

My SLP05 came shipped with a Sino rectifier. When it went bad it blew the fuse when I turned on the power supply. I replaced the Sino with a Create Synergy recifier (twice). When the Create Synergy rectifiers went bad the bass became loose and wooly, the soundstage became indistinct and lacked  focus. The Matsushita rectifier I have installed now has been performing flawlessly and sounds much better than the Sino, Create Synergy, Genelex Gold Lion and Phillips Miniwatt (black base) I had installed before I purchased the Matsushita. 

Jazz

Assuming you are running fully balanced, you can change out the tubes in 2 steps. 1,2,4,5 as a matched quad and 3 and 6 as a matched pair. 

OK i have swapped the tubes.

So far it seems to be the tubes (I still have to swap the old ones back to reconfirm) but what I was getting was a muddier sound overall with less pitch definition which made the deeper bass from the power cords and the USB/ SPDIF reclockers seem boomy. Everything has tightened up now, soundstaging has improved as well as space between instruments and air.

So if I swap the old tubes back and confirm it is the tubes, I am guessing I will have to change all 6 at the same time? Or can I economise and change the ones that need changing by swapping out pairs at a time and replacing only those that are weak and causing the problem? I realise if I have a tube tester it would be easier but unfortunately I do not.

Also, when do I need to change the rectifier tube? What are symptoms of its end of life?

Thanks

I would expect 5000 hours.  You need to get them tested.  The rectifier will last even longer.
Blame the sound on the power cord. They do need break in time.

So just for fun maybe before you start changing out all your tubes try removing the new power cords and USB/Spdif reclocker and see what happens? You can do this immediately and get results plus it's free. Good luck!

The best tube compliment/combination will vary based on the mode of operation.

If single ended from input to single ended output, you only need to concern yourself with tube positions #1 and #2.

If you are running single ended inputs to balanced output, you need to concern yourself with tube position #1, 2, 4 and 5

If you are running balanced inputs to single ended output, you need to concern yourself with tube positions #1,2,3,6

Balanced in to Balanced output you need to concern yourself with tube positions #1,2,3,4,5,and 6

Tube positions 7 and 8 are for the headphones.

I believe that is correct. 

My memory is hazy. Which tubes do I match?

1&2 - left & right channel positive phase gain (1st 2 tubes on front row from left to right)

4&5 - left & right channel negative phase gain (1st 2 tubes on back row from left to right)

3&6 - left & right channel balanced input buffer (3rd column, 2 tubes from front to back)

Correct?

OK so do you suggest I try another set of tubes?

I am running fully balanced and so will need to change 6 tubes.

I have swapped out the rectifier to a Mullard 5AR4.

What you have described does not sound like worn out tubes.  As tubes age, dynamics become compressed and the highs roll off.  

Perhaps the changes to your system is now allowing the tubes to show their true colours, but that is pure speculation.  5 years and the number of hours added to already used tubes, imho, you are due for a tube change. How are you currently running your system I.e fully balanced, as that will dictate which tubes need replacing. 

As as an aside, have you swapped out the horrible JJ rectifier tube in the power supply.