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Blues Custom 30, cathode bias or not?

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+1 for re tubing the amp. The stock 12AX7's in the preamp stage aren't too bad but you definitely want to junk the 6L6's in the power stage and replace with a pair of decent tubes.

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I just bought a Blues Custom 30' date=' I'm still in the honeymoon but it seems OK so far. When/if a tube swap becomes necessary, will I have to have it biased or is it self-biasing?




Yep! It's cathode biased. Simply swap tubes (A real GOOD idea). Before you go swapping out the power tubes you might want to listen really closely to the amp. If it sounds slightly "unbalanced" (not getting a smoother or more even distortion) you might want to replace the phase inverter tube first (12ax7 in the 4th position) with a Groove Tubes Matched Phase Inverter (MPI). Here's a link to GT - http://www.groovetubes.com/SAG-AX7-MPI_P1723.cfm

Here's where I bought mine (I got it on sale for $14 - NOT on sale now) - http://www.wwbw.com/Groove-Tube-SAG-AX7-MPI-Matched-Phase-Inverter-Tube-Changing-Kit-219132-i1390286.wwbw


If you're looking for more of a blues tone I would highly recommend the GT SAG-AT7-MPI as it has slightly less gain than the 12AX7 and has a smoother distortion when overdriven.


If you're up for experimentation and have a few extra dollars on hand you may want to try the THD Yellowjackets. I tried them based on a comment from PapaMidnite. These are tube converters for your power tubes. Pull out your 6L6's and plug these in. They will drop your output wattage but the tradeoff is that they are easier to overdrive and much smoother sounding. These really allow the Blues Custom 30 to live up to it's name as a blues amp.


I had originally changed out the Lady Luck speakers in my BC30 for a pair of Celestion G12-65s. After adding the Yellowjackets I went back to the Lady Lucks because they were a bit more clear and didn't break up as soon as the Celestions. I am thoroughly pleased with the sound of the BC30 now. Excellent blues tones and great rock 'n roll tones. It does just as well with the 6L6's but I get smoother overdrive at lower volumes (a big bonus around here). Still enough volume when needed for practice and gigs and when turned up louder it sounds even sweeter.


Since you're a new owner of a BC30 you will benefit from this thread here: http://forums.epiphone.com/default.aspx?g=posts&t=6812


Congrats on your new amp! I really think that the BC30 is a "sleeper" and could very well be a future classic.

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Thanks everyone. I've only had it a week so I'm still getting to know it. I hate to get a new amp and start swapping things around before I get a good feel for it, then I can have a better idea on where to go. I play mostly blues, and I do run a fuzz occasionally. I'm not all that keen on the drive channel so far. Maybe with a little more time I can find a happy medium. I really want to get the speakers broken in a little too.


Thanks again.

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  • 8 years later...
  • 1 year later...

I got a Tung Sol kit from audiotubes via Amazon. It's specifically for the Epiphone BC30. Changing the tubes was not too difficult, wore latex gloves and rubber sole shoes, didn't touch anything but the tube covers and rings to remove screws and pull out Chinese original tubes one at a time, replace with Tung Sol ones and reassemble the retainer rings and covers. The reverb tube (first ax7 on right with the amp upside down) gets the balanced pin one. Rest was a snap to install. The amp sounds smooth and responsive, with no hum. The tone is much better than the original chinese tube based tone. Less harsh, more clarity and even response when using independent eq. Very happy with the result as after ten years, one of the original tubes had blown and I was not willing to trash this beautiful amp.

Edited by baatkarlo
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