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Fender Super Twin Bass Head
- Thread starter johnk_10
- Start date
I don't know that I've ever gotten mine to overdrive the power section!
The preamp will start to growl at about 5 on the "volume" knob, depending on the input signal. I'm using a 4-ohm, 800-watt cab, so it'll handle everything the Super Twin can give it, but it's crazy loud when you start cranking up the "output" knob.
finally took a picture of the supet twin with the mojo box. sitting on a musicman 115 cab about to get new cloth. 400watt ev in it. sounds heavenly....
Question for you guys... The 12AT7 preamp tube in my super twin is original and it says fender on it... Do you guys know who makes the "fender" tubes? Sovtek, GE, RCA? And are they any good? Thanks
- Feb 16, 2008
- 21,240
- 23,636
- Disclosures
- John K Custom Basses
Passinwind
I know nothing.
- Dec 3, 2003
- 23,064
- 45,976
- Disclosures
- Designer/Toaster Tech @ Passinwind Electronics
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They a good tube? I actually switched that tube out for an RCA 12AU7 and I like It
- Feb 16, 2008
- 21,240
- 23,636
- Disclosures
- John K Custom Basses
I'll put it back in... I found that the AU gave me a bit less gain... I dig the big beefy cleans... Probably best to keep it the way its meant to be.
It's fun messing around with that stuff though
Still super happy with my Studio Bass. I'm using it tonight on an alt country/jangle gig. Sounds great with this kind of more vintagey kind of set list. I usually run it into an 8ohm, 15PR400 loaded cab that Don at LDS built for me. It also sounds great through a Berg CN212 when the 2x15 is a bit more than I want to haul.
I got mine in a local CL deal for $375. It's in a Mojotone headcase and it came with original RCA and GE power tubes (one triplet of each) and original Fender labeled preamp tubes in it (7025's, 12AT7 and 12AU7A in the EQ section) which are most likely GE's. I pulled the original power tubes and put them away for safekeeping. They all tested well in spec and I realized that those 6 tubes are worth more than I paid for the amp itself. Funny.
I had wanted to do what johnk_10 did and retube the power section with some nice GE 7581a's but I just could not find any that seemed even close to reasonable (or from a trustworthy source). So, I ended up keeping the original preamp tubes and retubing the power section with matched triplets of TungSol 6L6GC-STR's, and having it rebiased just slightly on the cool side. It has plenty of power and sounds great with the 30w dissipating 6L6's, but it would have been cool to get a bit more out of it with 35w 7581's.
I have to really push mine to get it into the dirty tone zone. I run the pre at 8 or 9 and the Output/Master at 8 regularly and it has bark and punch like crazy, and nice compression, but next to no real dirt. I have to pretty much dime it to get it to really audibly break up. Which is totally good for me, because I want the bark/punch with tube compression, but don't want much(if any) actual dirt in my tone.
Great amp, and its cool to see it posted about and discussed here on TB.
http://www.talkbass.com/forum/attachment.php?attachmentid=387710&stc=1&d=1390082251
here is a pic of it ready to go into action. enjoy!
I got mine in a local CL deal for $375. It's in a Mojotone headcase and it came with original RCA and GE power tubes (one triplet of each) and original Fender labeled preamp tubes in it (7025's, 12AT7 and 12AU7A in the EQ section) which are most likely GE's. I pulled the original power tubes and put them away for safekeeping. They all tested well in spec and I realized that those 6 tubes are worth more than I paid for the amp itself. Funny.
I had wanted to do what johnk_10 did and retube the power section with some nice GE 7581a's but I just could not find any that seemed even close to reasonable (or from a trustworthy source). So, I ended up keeping the original preamp tubes and retubing the power section with matched triplets of TungSol 6L6GC-STR's, and having it rebiased just slightly on the cool side. It has plenty of power and sounds great with the 30w dissipating 6L6's, but it would have been cool to get a bit more out of it with 35w 7581's.
I have to really push mine to get it into the dirty tone zone. I run the pre at 8 or 9 and the Output/Master at 8 regularly and it has bark and punch like crazy, and nice compression, but next to no real dirt. I have to pretty much dime it to get it to really audibly break up. Which is totally good for me, because I want the bark/punch with tube compression, but don't want much(if any) actual dirt in my tone.
Great amp, and its cool to see it posted about and discussed here on TB.
http://www.talkbass.com/forum/attachment.php?attachmentid=387710&stc=1&d=1390082251
here is a pic of it ready to go into action. enjoy!
Attachments
hey, speaking of 6L6 vs 7581a power tubes. My limited understanding has been that 7581a's were originally variants of the 6L6 type that provided "more power" (which I generally understand to be a hyper simplification of the issue of screen grid dissipation and such ).
Per my prior post, I have been looking for some NOS 7581a tubes with limited luck. In the process have seen some current manufactured TungSol 7581a tubes, but when I do some additional research I am getting the impression that the newly manufactured tubes are really just relabeled 6L6's that don't provide the increased power that the original 7851a tubes did (GE, RCA, Telefunken etc.)
Anyone have some experienced, or fact based information on this question ?
thanks
Per my prior post, I have been looking for some NOS 7581a tubes with limited luck. In the process have seen some current manufactured TungSol 7581a tubes, but when I do some additional research I am getting the impression that the newly manufactured tubes are really just relabeled 6L6's that don't provide the increased power that the original 7851a tubes did (GE, RCA, Telefunken etc.)
Anyone have some experienced, or fact based information on this question ?
thanks
no one had any experience seeking/finding good quality NOS 7581a power tubes ? Is this a case where most of the good NOS versions have been hoovered up by tube guys already ?
Like I said, I'm perfectly happy with the Studio Bass as it is today, but it is appealing to try and get as much out of it as I can.
Like I said, I'm perfectly happy with the Studio Bass as it is today, but it is appealing to try and get as much out of it as I can.
hey, just happened to see that there are two Super Twins for sale locally in the SF Bay area (San Jose). Don't see these FS all the time, so I thought I would let you all know.
[Invalid or Expired Link Removed]
[Invalid or Expired Link Removed]
fwiw - these items are not mine and I have no connection to either of these sales or the sellers.
good luck
[Invalid or Expired Link Removed]
[Invalid or Expired Link Removed]
fwiw - these items are not mine and I have no connection to either of these sales or the sellers.
good luck
Kind of OT here, but has anyone tried any of the old Peavey guitar tube amps for bass ? It seemed like Peavey, back in the day, was coming out with their own Fender copies of the Twin, and other tube amps. Just wondered if anyone has gutted a combo and made a head case for the amp for bass.
Just thought I'd post a few pics and info on my new (old) Fender Super Twin amp that I converted to a bass head...
JohnK_10,
Do you have a cooling fan in your Super Twin head cabinet? I read that over-heating in a head cabinet (with 6 power tubes) could be an issue due to air flow constraints (that is almost not the case in a combo).
Do you know when Super Twins had the backplate power socket (and the ground switch) added? On mine (sn #B63085), the chassis has holes to receive the socket and the switch, while the backplate doesn't. Both features are shown in the '180 watt Guitar Amplifier' schematics dated (or numbered?) 012380.
Last one, do you have a shield (24-1/2" wide metal sheet) under the cabinet upper panel, that comes above the chassis? I have one in the combo that is just stappled onto the wood.
Thanks alot for sharing your experience. I am making my Super Twin head conversion and will post pictures when complete.
