• Registered: 2007-11-04
  • Posts: 404

Topic: 67 Bassman Odd Harmonics

So I have my fathers 67 Bassman which was pulled out of the head and placed in a combo cab with 2x10 inch webers. 
Awsome amp... Sounds amazing....

My question is when I am playing leads i hear lower notes in addition to what i am playing.  Its almost like I have a octave pedal really low on while i am playing. Its not really loud but it is noticable if you listen and you know what you are listening for. 
Have any of you heard this in older fender amps or any amp for that matter.  Is it normal? or do I need to replace tubes or whatever.

Thanks for your help.

-Jeremy

  • From: Ridgeland, MS
  • Registered: 2009-08-12
  • Posts: 1,248

Re: 67 Bassman Odd Harmonics

Ghost notes can quite often be caused by the amps power supply, especially in an amp with small or relatively small value filter capacitors. The sag that occurs when an amp is pushed (which manifests itself as a sort of compression - which we like!) causes a 120Hz signal from the power supply to modulate the actual guitar signal, resulting in ghost notes. Volume always makes it worse. While adding larger filter caps can help reduce it or eliminate it, you may not want to do this to an amp or may not be able to.

If the amp uses a tube rectifier, the size of the first filter cap has to be kept under a maximum value that the rectifier can handle. This is around 50mF. The first filter in your amp is 47mF, so it is already at the limit. Also, adding more capacitance has an impact on the sound of the amp. While it can increase an amps ability to produce low frequencies, it will make the amp have less sag and may also make the amp sound more sterile. Having a tube rectifier increases sag also.

  • From: Florida, USA
  • Registered: 2008-06-04
  • Posts: 1,420

Re: 67 Bassman Odd Harmonics

My '65 Bassman did this sometimes when playing it through a lower powered 2x12 cabinet/speakers.  When cranked up through a Marshall 4x12 the problem seemed to go away completely.  Might be some cone cry in your speakers....I'd try the amp through another cabinet to isolate the problem.  Cool amps for sure man, I'll NEVER let mine go!

'67 and '74 Fender Twin Reverbs, '74 Marshall 1987 lead mkII, Metro Superlead 100. Pedals from TC Electronic, Ibanez, Dunlop, BK Butler, Electro-Harmonix, Fulltone, Maestro/Gibson, Loopmaster switching, VoodooLab, Boss. Gibson and Fender guitars, Dimarzio pickups.
  • Registered: 2008-10-02
  • Posts: 373

Re: 67 Bassman Odd Harmonics

I have also hear that a bad pre-amp tube can cause Ghost Notes but I would try another cab first. By the way where did you get the 2x10 combo for the bassman I have been thinking of doing that to mine for a long time.

E

  • Registered: 2007-11-04
  • Posts: 404

Re: 67 Bassman Odd Harmonics

My dad bought the cabinet on ebay from "crusty cabinets".  I have to say I hated this amp for years. It had no soul and sounded very dry and ehhh.... 

My dad had a 15 inch speaker in the cabinet for awile and i really didnt like that tone.  Then one day he orders two mismatched speakers recommended to him by Weber who sadly died a few weeks later. Those speakers arrived and he replaced the 15 with those.  The cabinet maker sent him a 2x10 cutout if he ever wanted to change out the speakers. He wired it up and it sounds amazing.

Those 10 inch speakers are killer. He told me he was going to sell the amp and I took it hostage and brought it over to my house. I guess you can say i stole it. Anyhow I love the amp I am really used  to my Vox's and a Fender Twin that did not have the ghost note thing going on.

You can get the 2x10 cabinet made custom from MOJO or tons of other online cabinet builders. Mine looks like it was an original amp made in 1967.  Its pretty cool.

  • Registered: 2009-10-10
  • Posts: 438

Re: 67 Bassman Odd Harmonics

Big E, check out Allen Amps.  He has his own amp line, but he also specializes in old Fender Blackface heads.  He has gone through both of mine (65 Bandmaster & 65 Bassman).  They are now very reliable and he did a very good "plexi" mod on the bass channel of the Bassman.  He also makes all types of combo cabinets for these old heads that look like they are right out of the Fender factory.  I am a very satisfied customer.

  • Registered: 2008-10-02
  • Posts: 373

Re: 67 Bassman Odd Harmonics

Thanks Hooiserock I will check them out. I have a really good tech out here in AZ I just need some cash to get it modded.

  • Registered: 2010-11-09
  • Posts: 1

Re: 67 Bassman Odd Harmonics

Thanks Hooiserock I will check them out. I have a really good tech out here in AZ I just need some cash to get it modded. saving a good deal of time but its very important .

I will saving now just a few days.

john

9 Reply by Abu fateh Bappy (edited by Abu fateh Bappy 2011-01-13 06:52:41)

  • Registered: 2010-12-25
  • Posts: 1

Re: 67 Bassman Odd Harmonics

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