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Posts posted by Stugatzo

  1. Many thanks to Layboomo, i now have the schemo!

    So here's my problem, like others, I'm not an engineer.

    What I'm trying to determine is what tube in each position does what.

    So I need to know using a reference point on the amp or looking at the line of tubes, which is which.

    IE...left to right or closest to the power tubes to furthest from the power tubes. Something like that.

    I see references to V1 and Va and b...I don't know what those mean other than i assume V means "valve".

    I know this stuff comes easily for some, just not me!...haha

    Ideally what I'd like to do is open the back, pop off the respective tube and pop in an upgrade or replacement for each.

    Should be easy enough.

    Can a BC30 owner help me there?

  2. This is exactly what i need.

    I want to replace tubes on my BC30...it's just time.

    I need to know from one end to the other which position is which so I know I am replacing in the proper order.

    I will send a PM for the schematic.

    I have no issues taking out the chassis (I did it once to do a clip of resistors with great success).


  3. Guys...thanks x 100!!!

    Just snipped the C5 and C6 caps (one at a time with sound test in between) and WOW!!!

    The difference is tremendous.

    Had previously swapped ou the rectifier and power tubes for mesa 5ax4 and 6L6s respctively, changed the V1 and V2 to Marshall branded Ecc83s...but this mod has sweetened it up even more.

    Thanks for the thread and the useful tips and support.

    Rock on!!!


  4. Hi:


    I am about to embark on the CAP mod to try and cut some of the brightness of my BC30.

    Having read and re-read this thread, I'm still a bit confused about the best way to approach this.


    -Papa says do C6, then C5, then (if still unhappy) C10.


    -Twanger is saying C3, C5 and C6 (but in no particular order).



  5. V1 = CH1 preamp

    V2 = CH2 preamp (fed from CH1 preamp)

    V3 = Reverb in

    V4 = Phase Inverter (PI)

    V5 = Reverb out


    The Czech made JJ tubes (also sold as Tesla' date=' Ruby and perhaps others) are good preamp tubes in the V1, V2 positions. A higher gain tube like the SovTek or Groove Tubes would be good in the V2 position.


    To mellow or sweeten the reverb it would be good to use a lower gain 12AT7 or 12AU7 in the V3, V5 positions.


    For the V4 PI position I would highly recommend a Groove Tubes MPI (Matched Phase Inverter) 12AT7 since their tubes are tested to find which ones are closely balanced in output. It's only a couple of dollars more than a "standard" tube and worth every penny.


    For helpful info on the BC30 you might also want to check out this thread:



    Sorry for my ignorance, but when i open the back and I'm looking at the 12ax7 slots, do i read positions 1 - 5 as starting from the left and moving right?


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