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bella extreme 3205 tubes

It is time to do a tube replacement/upgrade on my Int. Bella Extreme 3205.
It is an upgraded Jolida 502A that was upgraded by Response Audio in 2006/07.
At the present time I am running4-EH EL34 in the power output, 2-12ax7 Sovtek for the input and 2-12at7 Sovtek as the drivers.
I have about 1000 hours on these tubes and can hear a distinct degrade in the sound quality. I do bias the power tubes about every 100 hours or so.
I can run EL34,6550,and KT88 as power outputs. With the 6550/kt88 it will give me 10 more watts but it is not a necessity to go from 50WPC to 60WPC.
The inputs are what I am more interested in.
I am pushing a pair of Jupiter Audio Europa speakers and a Audio Note CDT transport with a MacCormack DAC-1 with deluxe upgrades.
So what tube would be recommended for this set up? I would like a little more
of an open mid range and the highs a bit brighter. The bass is good and I do have a small sub if I need more bottom end.
Specs can be found here.
http://www.enjoythemusic.com/magazine/equipment/0307/bella_extreme_3205.htm
Thanks Brian
skiezo

Showing 1 response by elevick

elevick
2,636 posts
 
If you have 1000 hours on the amp, the degradation of sound is only due to the output tubes. 12 series tubes easily last 5000 hours and can go up to 10,000 hours. Output tubes will show wear at 1000 hours.
My advice, replace the outputs only and see how it sounds. Before replacing the 12 series tubes, get them tested. You may want to consider NOS tubes for these but tube rolling is the only way to find out.
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