Reviving this thread because I just picked up one of these today... I managed to get it running decently by replacing a couple tubes that were an "issue" with some I had on hand, but it will be getting retubed and checked out in the near future... I'm also going to be ordering a headcase for it - at any rate, here it is:
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Fender Studio Bass Club!
- Thread starter gjesse
- Start date
That's the guitar version. .... same amp pretty much, with different speakers. Good idea to separate head and cab. You'll get some $$ for the nice speakers if you wanna sell em. The bass version cane with a single EV 15"
Congrats. Great amp!
Congrats. Great amp!
good score man. It's certainly a great bass amp, just make sure to use it with a real bass cab and not the open back guitar cab that its in now. As is, it will work fine at very low volumes, but it just totally kicks a** through a proper bass cab .. sealed or ported. Personally, I like to run my Studio Bass through a Berg NV610 sealed cab. Really brings the big iron, all tube thunder. 
enjoy!
enjoy!
Yeah, I looked into this thread and JohnK's thread before buying it - they were both very informative... I considered stashing away the combo chassis and speakers, but already have an offer for it that would cover the cost of the new headcase - so I'm pretty sure I'm going to do it... Once it's checked out, retubed, and in a headcase - I think it'll be a pretty nice amp - it'll give me a nice alternative to my Mesa Bass 400, and other amps... Thanks for the congrats - I'll be posting updates as they come along...
good score man. It's certainly a great bass amp, just make sure to use it with a real bass cab and not the open back guitar cab that its in now. As is, it will work fine at very low volumes, but it just totally kicks a** through a proper bass cab .. sealed or ported. Personally, I like to run my Studio Bass through a Berg NV610 sealed cab. Really brings the big iron, all tube thunder.
enjoy!
Thanks - I'm almost embarrassed to say what I got it for - after I flip the combo shell and speakers, I'll have practically nothing into it... Once I swapped out the pair of troublesome tubes, I played some bass thru it as is, but already knew enough to take it easy on those open backed guitar speakers... Even that way, it still sounded pretty good - I'll get a chance to play it thru a proper bass cab sometime this week... I'm guessing it'll sound great thru my PH215, or pair of Acoustic 410s - I'd like to score one of those Berg 610s sometime, though...
Curious to know how heavy are other peoples' heads?.
My Head & DIY MDF headcase weighs 35kg or 77lbs. I gig my Hybrid heads coz they are 1/4 of that weight (8kg 18lbs).
Mine sounds great thru my Berg CN212, 20.5kg 45lb. That 215 would sound brutal!
My Head & DIY MDF headcase weighs 35kg or 77lbs. I gig my Hybrid heads coz they are 1/4 of that weight (8kg 18lbs).
Mine sounds great thru my Berg CN212, 20.5kg 45lb. That 215 would sound brutal!
hey, no worries, don't look a gift horse in the mouth (as they say). When I bought mine, the guy sold it to me with NOS RCA and GE 6L6GC power tubes and a set of NOS GE 12AX7, 12AT7 and 12AU7 preamp tubes in near perfect condition. The value of the NOS tubes alone was pretty much equal to what I paid for the whole thing. I took the NOS power tubes out and put them away, and replaced those with a matched sextet of brand spanking new Tung Sol 7581A's. The amp sounds great and now has even a bit more headroom than with the 6L6's thanks to the 7581A's somewhat higher rating and dissipation specs.
enjoy your amp
mine feels pretty heavy too, particularly compared to my 10lb Demeter VTPB-M-800DJ or even my Mesa Walkabout. Mine is in a Mojotone pine headcase and weighs in at about 65lbs. Your use of MDF for the case must be making up the difference.
'S one of the reasons I love the Super Bassman so much. 65lbs and 300w. .. perfect for me in power and weight.
I did love the Studio Bass amp too... but the extra power suited me well
I did love the Studio Bass amp too... but the extra power suited me well
Should sound MIGHTY thru the 215!
I know my Mesa 400 with the KT88s kicks pretty good thru that 215 - and I actually prefer the stacked pair of Acoustic B410s over an SVT810e, so I'm sure it'll sound great thru them, also...
I'm actually considering going the 7581A route, but want to talk to the tech that's going to be servicing the amp 1st... How would you describe any tonal differences between the 7581As and the 6L6GCs???
I'm also deciding on my choice regarding the new headcase - anyone care to weigh in on any differences between The Cab Guy and Mojotone???
no meaningful tonal difference to my ears, but it does seem to stay cleaner at higher volumes. But, I generally don't push mine into the power tube saturation range. I have only used the NOS preamp tubes that came with mine at the time I bought it and have not done any preamp tube rolling. Never felt the need to because it sounds great already.
no meaningful tonal difference to my ears, but it does seem to stay cleaner at higher volumes. But, I generally don't push mine into the power tube saturation range. I have only used the NOS preamp tubes that came with mine at the time I bought it and have not done any preamp tube rolling. Never felt the need to because it sounds great already.
Thanks for the info - I appreciate it
Great to see a thread on these wonderful amps, and to see a tip o' the hat to the late great Ed Jahns. While I've never see his name directly linked to the SB, it certainly looks like one of his designs when you compare it to the 400PS and other that he for sure designed. See the timeelect.com site for more info on that particular arm-stretcher and potential electric-chair.
A couple of technical points if I may; one, the SB as it comes does not have a true bias adjustment, just an "output tubes matching" control, although thankfully not as goofy and asymmetrical a one as a lot of the Silverface ones. One can be added by subbing a 400ohm or so pot wired as a rheostat (i.e. wiper shorted to one end) for the 220 ohm resistor that's right under the matching control on the schematic. That's how Jahns wired the 160PS and the 300PS. Then you have the benefit of both.
Two, changing the plate load resistor on the inverting part of the phase inverter (V4B) to 180k should balance the feed to the output tubes better, a la the "classic" AA864 & AA165 Bassman and AB763 ***Reverb amps.
Third, schematics show the Super Twin and SB with the same OT part#, so 4ohm or 8ohm, should be no problem.
Fourth, for the benefit of those across the pond (or those who are lucky enough to cross it regularly), these come with a dual primary in the PT, so they'll work 110/120 or 220/240 depending on how you hook them up; and if you want to get real slick, wire the PT primaries to a heavy-duty 4PDT switch (and in a perfect world the ground switch and the convenience outlet to a heavy-duty 3PST to take them completely out of the question when operating 220) and you're world-wide with a flick of a switch (well-2). See the right side of the schematic.
And lastly, there's an unused half of a 12ax7 waiting for bright ideas right before the output level control. HO HO!
A couple of technical points if I may; one, the SB as it comes does not have a true bias adjustment, just an "output tubes matching" control, although thankfully not as goofy and asymmetrical a one as a lot of the Silverface ones. One can be added by subbing a 400ohm or so pot wired as a rheostat (i.e. wiper shorted to one end) for the 220 ohm resistor that's right under the matching control on the schematic. That's how Jahns wired the 160PS and the 300PS. Then you have the benefit of both.
Two, changing the plate load resistor on the inverting part of the phase inverter (V4B) to 180k should balance the feed to the output tubes better, a la the "classic" AA864 & AA165 Bassman and AB763 ***Reverb amps.
Third, schematics show the Super Twin and SB with the same OT part#, so 4ohm or 8ohm, should be no problem.
Fourth, for the benefit of those across the pond (or those who are lucky enough to cross it regularly), these come with a dual primary in the PT, so they'll work 110/120 or 220/240 depending on how you hook them up; and if you want to get real slick, wire the PT primaries to a heavy-duty 4PDT switch (and in a perfect world the ground switch and the convenience outlet to a heavy-duty 3PST to take them completely out of the question when operating 220) and you're world-wide with a flick of a switch (well-2). See the right side of the schematic.
And lastly, there's an unused half of a 12ax7 waiting for bright ideas right before the output level control. HO HO!
