Tube Suggestions Onix SP3

I think the original 5881 tubes in the SP3 are Shuguang (Chinese). Check with av123.com. I have the same amp and replaced the 5881 with a set of JJ/Tesla 6l6gc and have been really happy with the results - much fuller bass response and an overall smoother presentation. They cost about $60 for a quad if I remember correctly. I bought mine from TubeDepot. I'm sure Mcfarland's recommendations are also excellent.

get2it1 - yeah, 6L6GC. There are several people on the av123 forum who second Newbee's recommendation of the SED 6L6. I haven't tried them yet myself but when my Tesla's die on me I plan on giving them a listen. My own experience has been that changing the preamp tubes, 12ax7, make the most impact on the SP3's presentation.

Good luck with your CD player.

Hey get2it1 - the SP3 is not an autobiasing amp, you need to re-set the bias whenever you replace the 5881s. Technically the 6l6gc is not a direct replacement for the 5881 and needs to be biased higher than the 5881. The 5881 bias should be set a 1.15V. Some fellow sp3 owners on the av123 forum calculated the 6l6gc tube bias as 1.60V for the sp3. When I put in my 6l6gc I just biased it at 1.15V with the plan of increasing up to 1.60 but I never got around to it because it sounds good at 1.15 and I figure I'm stressing the tube less.

As for actually biasing the unit you need to get a voltmeter if you don't own one already. You can pick up a digital voltmeter at Radioshack for under $20. Turn your system on and let the amp warm up for 5 minutes or so. Don't play any music while you are biasing the amp, this is important. On each side of the amp you will see 5 holes. Turn your meter on and insert the black lead into the center hole. Insert the red lead into the hole on the far right and check the meter for a reading. Insert a small screw driver in the hole between the leads and turn the screw until the bias reads 1.15V. Once this is done remove the red lead and insert into the far left hole and then adjust the screw between the leads until it also reads 1.15V. You've just biased the two tubes on the side of the amp. Repeat the procedure on the other side and you're done!

One thing to remember is that these tubes take about 24hours of play time to break in and during that time the bias will often drift so you may need to reset occasionaly during this break in period. After this breakin period you should only need to check the bias every 6 months or so.

Good luck!

Are you sure that the reading isn't 1.055? Is your voltmeter set to the right "range"? Try swapping positions of the 5881 tubes and see if the same position gives the abnormal reading. You may want to just get in touch with av123. They've been very good aboout responding to emails/questions. I bought my amp second hand here on audiogon and when I had questions they were great to deal with. Best case scenario is that you just have a bad tube. Good luck, hope you get to the bottom of this!