2. amps-preamps
  3. 1353815381

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
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.
josefm
53 posts
 
I have the same or similar amp (mine is the Signature), here is what I am currently using.
GL KT88 reissue power tubes
TS 12AT7 cryoed p-splitters
Baldwin branded 12AX7

I also tried the new GL12ax7, more of a sweet tubey sound. I prefer the Baldwin AX7's sound, more 'neutral' balance.

TS12ax7 (cryoed)+TS12AT7(cryoed) + GLKT77 was the ultimate balance for my taste. Excellent midrange, clean highs, and solid punchy bass. If you go this route request "hotter biasing' GL KT77 quads from your tube dealer, I rec. Jim McShane for the power tubes.
I got the cryoed tubes from Cyroset.

YMWV
skiezo OP
2 posts
 
Thanks for all the help. I just picked up a set of NOS SED 6550 "c" tubes from my local electronics house. He said they have been there for 15 years or so.
They are matched and according to him have about 30 hours on them.
I also found some Baldwin 12ax7 and some black sable 12ax7 that he had laying around. He matched all the tubes for me. All that for less than $100cash.
I will be putting them in this weekend and doing a good burn in of all the tubes
and see what I think.
My old ax12 were tested and one was below the well good bar. So one channel was sounding different.
He said he will look around to see if he can also match some KT88's for me.
I am looking forward to burning these in and giving them a listen.
I will let you know what I think.
Thanks again for the help.
Brian
skiezo OP
2 posts
 
So after about 100 hours on the SED "c"6550 power tubes with some Baldwin AX127 inputs here is my conclusion.

The overall sound is a bit more plump all around, not as colored. The lower octaves have opened and have more depth. The mids are fuller and more pronounced without being "in your face" full. The higher octaves do not seem to roll off as much as with the EL 34. Not quite the "crystal" sound that I was looking for with horns and piano.
BUT
With blues,some old jazz and deep female vocals it is just the ticket.
It has really made the sound more alive without being to edgy.
Stevie Ray has come alive and Stevie Wonder has taken the edge off.
Etta James is killer with her vocals.
Pink Floyd is not as sharp but more dynamic.
So far I am pleased with the sound on this roll.
I have a few other input tubes I will be trying in the near future along with some NOS JJ kt88's.
Thanks for all the help.
Brian
More to discover