Tube Rolling in an Ampeg SVT-CL

anevilspar7an

anevilspar7an

Well-known member
I'm looking to get away from the JJ's in my new bass amp so I'm asking anyone here familiar if they have any recommendations for me. Before anyone ask why I don't like them, I'm going to preempt that by saying that the top end is a bit dull, these tubes also don't have a lot of mileage on them so I know it's not an age problem. My goal is to make it as hard as possible to overdrive the tubes while keeping a wide clean frequency response. I have done some searching before for this, one of the better options was a new production Mullard in V1 and a new production Tung Sol in V2. My lead guitarist is saying to try Svetlana since he says they are his preferred tube.
 
New Mullards, Svetlanas and Tung-Sols are all New Sensor tubes and most likely made in russia. Haven’t really looked into ’em, but it should be considered they’re made in same factory and post-branded by rating after manufacture. Making only guesses here, but couldn’t it be possible some batches are made in china and just branded with New Sensor labels?

Oh and what version of SVT-CL you have? Some use 12AU7/ecc81 in v2&v3 slots, others use 12AX7/ecc83. So be sure what should be there before going further!
 
Mine has 12AX7 in V1, V2, and V3. 12AU7 are in V4 and V5. I'm not worried about V3, V4, and V5. V3 is the phase inverter, V4 is the positive power amp driver, and V5 is the negative power amp driver.
 
My experience is more with guitar amps but I find JJ "flat", Tung Sol are much more chimey. Those are currently my prefered tubes. Psvanes are also decent and middle of the road between those. Heard good things about the Shuguang but I haven't tried them out yet.
 
I rolled tubes in my SVT-CL when I first got it, I don't remember what I ended up with, I'll have to open it up and see what ended up in there. It is worth mentioning though that my cab (Eden 610) is a bit brighter than the Ampeg 810 fridge, so that makes an impact as well.
 
my experience - with guitar amps at least - is that the V1 position is the most critical and affected by the choice of tube.
(i would recommend starting there first before dropping unnecessary coin on a whole set)
in high gain amps, this definitely still applies, but i’ve found it matters less for subsequent tubes V2, V3 etc.

exception - for the phase inverter stage (or whatever stage is driving the power tubes) - on any amp - i’d be going for something with long plates for maximum low end response. e.g. Sovtek 12AX7LPS

the last time i did a tube rolling sesh with V1, was with a SLO crunch/clean single channel build with x3 12AX7s.
tried jj, ehx, mullard cv4004, svetlana, and a tung-sol.
the tung-sol was a real standout.
had this big bright bloomy character that the others didn’t.

back to your original query though:
anevilspar7an said:
My goal is to make it as hard as possible to overdrive the tubes while keeping a wide clean frequency response.
Click to expand...
assuming you’re talking about replacing 12AX7s
you could try lower gain options:
e.g.
5751
12AT7
etc.

IMG_7310.jpeg
 
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