Fender Super Twin Bass Head

Discussion in 'Amps [BG]' started by johnk_10, Jul 15, 2008.


  1. johnk_10

    johnk_10 vintage bass nut Supporting Member

    Joined:
    Feb 16, 2008
    Location:
    Thousand Oaks, CA
    Disclosures:
    John K Custom Basses
    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.

    I made the head box cabinet from pine and went over the circuit to make sure that everything was up to snuff. I replaced the bias and filter caps with new Spragues and also installed a bias control (in its stock form, the amp just has an output tube "balance control"). After playing thru it, all i can say is WOW! For some reason this amp sounds alot more powerful and transparent than the previous three fender "Studio Bass" heads that I've had, and they have basically the same circuit. I'm currently running Chinese 6L6GC's ( look like coke bottle KT66's) in it and so far, they are my favorite sounding output tubes in this amp (and inexpensive too). Even with the tone controls set flat, it sounds awesome, and can go from "old school" vintage tones to modern since its EQ is so flexible. Instead of the standard feet, I made some feet out of 1/2" thick sorbothane and now the head doesn't "see" or feel ANY of the cabinet's vibration, even at extreme levels.

    This just might be the best sounding tube bass amp that i have, and that's comparing it to my two SVT's (a '69 and a VR), my Sound City Bass 150, my Sunn 190B and 2000S, and a Traynor YBA200-2. It is super punchy and feels like it's almost as powerful as an SVT (2/3rd's as powerful anyway) so I just put it on the scope and ran a few output tests on it. Just before a 400Hz sine wave distorts on the scope, it is putting out 193.667 Watts RMS at 4 ohms, but it feels like even more.

    To me, these Super Twins are one of the best kept secrets out there for bass and they can be found complete with the 2-12 cabinet for around $500.00 or less. Then you can sell the empty cab and speakers and you'll have about $300 into one of the best bass heads that you'll ever play thru. They also made a Super Twin Reverb, but I didn't want the verb or the extra circuitry for it.

    anyway, here's some pics of it with it's 2-15 JBL K140 cab:

    [​IMG]

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  2. chicago_mike

    chicago_mike Supporting Member

    Joined:
    Oct 9, 2007
    Location:
    Chicago - LA - Rome
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    Endorsing Artist : Genz Benz
    Anything sounds better than a sound *****. Even an old bogus..err...bogen.:bag::ninja::p

    Good find on the fender. Try it thru your sunn 215. that should have jbl d140's yes? Great speakers.
  3. johnk_10

    johnk_10 vintage bass nut Supporting Member

    Joined:
    Feb 16, 2008
    Location:
    Thousand Oaks, CA
    Disclosures:
    John K Custom Basses
    Actually my Sound City sounds easily as good as any of my other tube amps, just a little different flavor. It has a big smooth low end and is super punchy. I'm running four KT88's in it and it sounds HUGE! The only way that I think that people get a bad opinion of them is that they must've heard one that wasn't running properly. Mine sounds almost exactly like a HiWatt 200.
  4. whacker

    whacker

    Joined:
    Dec 5, 2002
    Location:
    Southwest Michigan, USA
    Wow! Nice job on the head cab.

    I remember the Studio Bass combos. Weren't they advertised as a 160 watt RMS deal?

    When were these originally produced, and what's the deal on the speaker cab? You seem to have great facility with all this stuff.

    Someone should try making a bass head out of an old Peavey Mace!
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  6. chadds

    chadds

    Joined:
    Mar 18, 2000
    Sound Citys do sound nice. That head sounds like such a good idea. Beautiful setup.
    Do you actually use another cab with those other heads?
  7. johnk_10

    johnk_10 vintage bass nut Supporting Member

    Joined:
    Feb 16, 2008
    Location:
    Thousand Oaks, CA
    Disclosures:
    John K Custom Basses

    The Studio Bass was made in the mid to late seventies (1977-81) and was also rated at 180 watts (sometimes called 200W). the speaker cab is an old bassman 70 2-15 cab. i just removed the CTS 15's and installed the K140's.

    as far as having a great facility, i've just been doing this for years and actually built the head cabinet for this one at home.
  8. johnk_10

    johnk_10 vintage bass nut Supporting Member

    Joined:
    Feb 16, 2008
    Location:
    Thousand Oaks, CA
    Disclosures:
    John K Custom Basses
    i guess that have alot of cabs. three of them have two K140's in them (a Vox 2-15 Beatle, a Sunn 2-15 and the Fender bassman-shown above). I also have a few 2-10 cabs, an SVT-410HLF, an SVT-610HLF, two 2-12 cabs (vox and fender), and a Sunn 1-18 cab.
  9. pedro

    pedro

    Joined:
    Apr 5, 2000
    Location:
    Madison, WI.

    (pedro standing in awe of folks who actually can build something.)
  10. nysbob

    nysbob

    Joined:
    Sep 14, 2003
    Location:
    Cincinnati OH
    That's as cool a rig as I've seen lately. I'd take that out to the show in a heartbeat. :cool:
  11. johnk_10

    johnk_10 vintage bass nut Supporting Member

    Joined:
    Feb 16, 2008
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    Thousand Oaks, CA
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    John K Custom Basses
    Thanks alot for the kind words guys! I've playing playing thru it for the last couple of days and i have to say that it IS one incredible bass amp. it sounds awesome, even with all of the controls set flat (i.e 5 on all the conventional tone controls and all of the rotary eq's set at 0). every note up and down the neck is extremely full and punchy and it has a completely transparent "fender" sound to it, only with ALOT more rich and full low end subs than a Showman.

    When compared to either of my SVT's, or my vintage Sunn's, (which i absolutely love) they all seem a bit cloudy in one tonal area or another, and you can't dial it out of them with EQ. The ADSR (attack, delay, sustain, release) of every note is truly bitchen, and it makes all of my basses sound as good as i've ever heard them sound.

    this amp is really beginning to spoil me. I spent about 2 hours trying to get my SVT to sound similar to it, but it just can't be done, however i was able to get it to sound a little bit closer to it, and it helped me to get a better tone out of my SVT than i had before. This amp is definitely a keeper for me, as it is now the amp to which all my others are judged. who'd a thought that would happen?????!
  12. moody

    moody

    Joined:
    Feb 1, 2003
    Location:
    Glenbrook (sydney) Australia
    Haven't posted here in a long time, but I just wanted to add a comment.

    I did this last night, not half as pretty (5 pieces of plywood) but functional though a single 15" cab - sounds incredible and feels like way more power than my previous 400 watts solid state.

    I'll eventually get the cab looking nicer, but for the moment I really recommend doing this if you can get hold of one of these amps - as guitar amps they really aren't doing anyone any good and would be much better off with some little 15watt rig in the same place.
  13. staccatogrowl

    staccatogrowl Supporting Member

    Joined:
    Jul 14, 2006
    Location:
    Spinning aqueous sphere
    I used to use a 1976 Fender Super Twin for guitar. In that application it was overpowered enough to be unusable. It had one sound: big fat undistorted clean.

    180 tube watts? I believe it. There was no way to get anything but clean. I was looking for a Fender Deluxe response so that Super Twin found a new home.

    In hind sight I think Fender misbranded that amp. From what you describe and your application, it sounds like a great bass amp. Enjoy!
  14. Jim Powers

    Jim Powers

    Joined:
    Mar 19, 2007
    Location:
    Charlotte, NC
    I played through one of these at an audition last weekend. It looked like someone had taken the amp chassis and mounted it in an old head road case with the faceplate and dials on the outside, ie, a black box. I had never heard of a Super Twin let alone seen anything like this head box. It was on top of a cabinet that had a Sunn grill screwed on, but I found it was actually a Traynor 6-10. This rig sounded absolutely great with my Ric; started to break up in the bottom end after we'd been jamming for a while, but that was very controlable by dialing back the neck pup just a bit. I thought the tone was near perfect and so did the band. I'm a believer, and a shopper!!
  15. MIJ-VI

    MIJ-VI Banned

    Joined:
    Jan 12, 2009
    Nice work! :) What does the head weigh? Will it handle 2 ohm loads?

    If it's light enough, I'd like to do this to a Super Twin Reverb.
  16. johnk_10

    johnk_10 vintage bass nut Supporting Member

    Joined:
    Feb 16, 2008
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    Thousand Oaks, CA
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    John K Custom Basses
    thanks. i'd have to weigh it again to really know, but it is fairly heavy (pretty large transformers). i would guess that its about 55-65 lbs. and no, it only has one speaker out and it is 4 ohms.

    the funny thing is, the Studio Bass was almost the same amp, and it used the exact same power and output transformers, (same part#) and it only had one speaker output at 8 ohms.
  17. rodl2005

    rodl2005

    Joined:
    Jun 1, 2005
    Location:
    Tasmania, Australia
    WELL DONE & CONGRATS on a super looking amp!!! & sounding by he ..err.. sound of it!! How many 6L6GC's does it run-6??? what sort of Chinese 6L6GC's are they btw. I'm tempted to grab a set of ^l^GC's as a replacement for my V4BBH when it needs 'em.
  18. MIJ-VI

    MIJ-VI Banned

    Joined:
    Jan 12, 2009
    That heavy, eh?

    The Super Twin Reverb was very heavy, but I blamed a lot of that on its large speaker magnets. As I recall the STR had a muddier sound than the Twin Reverb, which, in addition to it's weight, made it unpopular with guitarists.

    I'd imagine that prices for members of this long-discontinued 180 - 200 watt family of Fender amps might not be too bad.

    What you've done with your Super Twin may catch on with bassists who are chasing a tube sound. Fender tube amps have a very full & sweet low end, and these units have enough power for bass at club volume levels.

    The idea of having 180 watts of Fender tube sweetness - with the best long-spring reverb I've ever heard - driving a pair of daisy-chained, 300 watt, 8 ohm 12" neo cabs (for use with my 'VI) is very appealing.

    The Studio Bass? Y-e-a-h! I'd forgotten about that one. I recall thinking the first time that I saw one of these that I'd never want a powerful tube bass amp in the same cab as the speaker. (I played with a couple of Twin Reverb-using guitarists who used to drive me nuts with their bassy, blugga-blugga rhythm guitar sound. Their amps had recurrent tube problems.)

    Hmm... I'm no technician, but I'm guessing that Fender just took a different tap off the output transformer? They may have sold an 8 ohm 15" ext. cab to go with the Studio Bass.
  19. johnk_10

    johnk_10 vintage bass nut Supporting Member

    Joined:
    Feb 16, 2008
    Location:
    Thousand Oaks, CA
    Disclosures:
    John K Custom Basses
    the studio bass didn't have an extension speaker jack. just one 8 ohm output jack. here's a pic of one that i converted to a head and sold about a year ago:

    [​IMG]



    what's funny is that i like the super twin head a little better. it seems a little punchier than the Studio bass.

    both of them run six 6L6GC's. for max power, i ran NOS 7581A's i the Studio bass and currently have Shuguang KT66's (6L6GC's) in the Super Twin head.
  20. rodl2005

    rodl2005

    Joined:
    Jun 1, 2005
    Location:
    Tasmania, Australia
    Cool! Great stuff!!!!
  21. andk5591

    andk5591

    Joined:
    Mar 9, 2009
    Location:
    State College Pa
    Wow - I thought I was the only one - You did an amazing job on that - a real sleeper look too. Very cool.
    Mine started as an old chassis laying in the practice room of a band I used to play with 20 years ago. Took it to a tech I worked with. He recapped it, we rounded up a good set of tubes. I built a basic plywood box with aluminum mesh grill, but installed a cooling fan in the bottom. I have been using it off and on since. It sounds great, but the band I am working with now is trying to keep everything small and light, so I am planning to order a Genz Benz shuffle in the next couple days. If I like it, will send the Super down the road...

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