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Bassman 100 channel choice?

Discussion in 'Amps and Cabs [BG]' started by tornadobass, Feb 9, 2006.

  1. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    I'm just starting to play with a Bassman 100 tube head. It has had the usual retube and cap job, etc., so I think it's functionally in good shape.

    The bass instrument channel seems to have less bottom than the normal channel...I think I'd heard this before. And the deep switch makes it sound less deep...seems to boost mids.

    Is it usual to go with the normal channel for bass for a full-range sound?
  2. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    No that isn't really normal but these amps get monkeyed with a fair amount to finding a truly stock one is kind of a crap shoot. Getting it deeper is probably just a matter of changing out a couple of resistors and / or cap's on the tone stack. Maybe a preamp tube depending. You might want to ping Passinwind here at TB and ask about the appropriate values to start with.

    If you haven't tried this yet, jump the normal and bass channels together and play with the tone controls on each and vol levels on each. That may tell you that the bass channel was modded for a reason. My Bassman 30 is that way and with the channels strapped together it's pertty cool.

    You can also plug in to one channel's #1, that the #2 for that channel into an effect (I use my Lexicon MPX-100) and take the output back into the # 1 of the other channel. Cool. Effects loop on a Bassman and the return even has it's own level and tone controls! You could do the same with an EQ or comp or a chain of them ...
  3. Eric Cioe

    Eric Cioe

    Jun 4, 2001
    Missoula, MT
    Jump the channels, for sure. It sounds great. For what it's worth, when I played single-channel on this beast, I did the regular channel.

    The deep boost seems to me to be more of a low mid bump, as you noticed. Great.

    Also, try some different preamp tubes. I wanted something with a bit more finesse than the "USA" 12AX7s that were in it, so I put in some NOS JAN GE 5751s. Jumped together, they get sort of a different drive than the 12AX7s, and singly, they sound very clean. Pretty versatile amp, actually.

    I love mine and it joins the pantheon of amps (two) that I probably won't sell - luckily, I got it right both times I bought heads.
  4. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics

    I'll return a reply to your email shortly. Fender did some arguably goofy stuff (IMHO) with the bass channel on those amps. Mal's Bassman had an especially rare configuration, and after listening to it you could see why. :cool: I think they may have done this with the 2-12 cab in mind, trying to keep it alive.

    As Mal says, you can play with strapping the two channels. There's nothing wrong with using the Normal channel as your go-to, and I know many players who do just that. If you want to change a few things and revoice the Bass channel, it's not too hard to figure out, and it's no problem reverting to stock. You might start with the coupling cap in front of the volume control, which is pretty small and rolls off a lot of low end. I'd start with the value from the Normal channel and see what you get. I generally prefer the smaller value treble cap in the Normal channel's tone stack as well. You could try splitting the difference with 330 or 390pF if you want something different. Or you can go smaller than 250 and have an "air" control. This works really well if you're strapping channels, BTW.

    As far as the Deep switch, just turning down the treble control will actually do a better job than Fender's circuit, again IMHO. I like to use that switch for midrange voicing, so maybe someone else thought that way too? I haven't played through a 100 or 135 for a few years, and I can't really remember what the bass channel sounds like on those, honestly.

    As always: don't try this at home, pro driver on a closed course, lethal voltages are present, do not operate a soldering iron when impaired, if condition lasts more than 4 hours...yada yada!
  5. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    or do like me and just give it to PW. Nice to have him in the neighborhood don'tcha know ...

    By the way I was just bootlegging some bass time for lunch. Dark Star equipped P into the Normal channel and 2x12 cab. Yummy old school but the Altec's in the 2x12 aren't strong enough to deal with it. I see a 2x15 with JBL's on the horizon ... and a couple of more 6L6's than my Bassman has ...
  6. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    Jumping the channels DOES improve the tone alot. They're great heads.
  7. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    I'll try strapping the channels. BTW, this will be going into an Ampeg V-6B 2x15 cab...still has the original Eminence speakers and sounds fine with the Bassman.

    I gave it a try through my Eden 15 cab tonight. Like pudding to the ears :)
  8. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    It IS perfectly normal for the bass channel to have less low end on every two channel Bassman head I've ever used. The "deep" switch fattens up the low mids but you still get more real low end from the "normal" channel. This is also true with the MusicMan HD heads.

    I'm pretty sure the idea was to reduce low end mud, maximize use of the limited wattage and tighten up the sound. It does in fact do all that but if you are after subterranean low end, the normal channel is the way to go.
  9. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Brian...thanks for confirming what I was hearing...adding to my confusion, the deep switch in the up position is actually brighter, sounding, more like the normal channel.

    With the deep switch down, the sound is not as loud and somewhat murky.

    It may sound funny, but to get some perspective, I'm planning to hear the same cab in the same room with the Bassman 100 and my SWR Bass 350, which is the head I'd be using otherwise.

    That'd be a way to sense the overall volume and tone. From an earlier comparison, I recall that the Bassman has more punch than the SWR and, I think, more mids.
  10. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Cab selection will have a huge impact. If I attempt my old BF Bassman 50 watter into a Bag End 2x10, the cab just laughs at it. Into a 2x12 Bandmaster with very efficient old Altec's or into a very effficient ported 1x15 JBL it's a whole other planet.

    You may want to find yourself an older vintage style cab to match up with eventually. Your situation wil be a little different from mine as you have those two extra bottles glowing in there. That will sure help some.
  11. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Agreed about the cab! In fact, running across the old Ampeg 215 cab was what got me going on the tube head.

    I'd love to find a 1x15 or 2x12 of the appropriate width for the Bassman head for smaller gigs.

    It sticks out more than an inch on each side of my modern 24" cabs, including the feet...let's the head vibrate too much.

    OTOH, the Ampeg cab is actually a couple of inches wider than the head...barely gets through the doorway.
  12. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    I used the Bassman 100 for a small but loud gig last night. It did fine! After installing a new tube to replace a temporary older substitute (one new one was DOA), the bass channel without deep was really nice.

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