Mods for Re-issue Fender Tweed Bassmans


The Fender has been re-issuing the 5F8A  4X 10 Tweed Bassman for quite some time now and it's one of Fender better amps but it does not sound that much like a original Bassman. It is brighter and harsher sounding clean and the overdrive is not the same. The originals are warm, touch sensitive and smooth sounding clean with a throaty and musical overdrive. This is why they are so loved.  There are number of reason for this and fortunately it can be modded to sound much much smoother, and warmer like a 50's Bassman


Here's are the major issues with the reissues:


1. Voltages:  The reissues run the power tube are about 485VDC but an original would be 440 to 415 VDC.  Higher voltages make the amp cleaner and harder sounding.


2.  Filter Caps: Low quality filter caps (the big grey ones) make the amp sound bad when cranked.
 

3. Bias Adjustment: Some of the re-issues are do not have adjustable bias so the tubes cannot be correctly biased. 


4.  Tubes: The re-issue comes with 6L6GCs instead or 5881 making it brighter, cleaner and harder sounding.  It also uses a 12AX7 where there should be a 12AY7.  It makes the amp harder sounding.


6.  Speaker Wiring:  The speakers are wired like a modern amp rather than to play forward the way a real Bassman is. When wired forward the low end is more apparent. 


7. Output Transformer:  The re-issue output transformer is more like a Blackface or Sliverface Bassman transformer. 

9. Signal Caps: The Polyprop caps are more hi-fi sounding than in the original. 

 

But we can fix it!  There are really two routes to go here: A complete rebuild of the amp or modding the amp with the existing PCB board.  Both methods are effective although a complete re-build will result in the closest possible sound to the original, a shorter circuit path and greatest serviceability.  Budgets can be limited so I offer both mod services.  Below I'll describe each:

Complete Rebuild:  $775 plus return shipping


⦁    Amp hand-wired just like my custom amps and like my version of the 4X10 Bassman the CPC-40T.  
⦁    All parts are upgraded with better caps, a USA made output transformers and other quality parts to get an authentic Bassman sound
⦁    5881's are used in place of the 6L6GCs for a more vintage Bassman sound
⦁    Voltages are dropped to vintage correct levels
⦁    12AY7 is used in the first position
⦁    Speakers are wired to play forwards or instructions are given on how to rewire them

 

PCB Board: $445 plus return shipping

⦁    Amp is modded to sound more like a vintage Bassman without and using the original PCB board.
⦁    Output Transformer is replaced with Classic Tone USA or Hammond (both paper bobbins!)  for richer tone
⦁    Voltages are dropped to vintage correct levels
⦁    5881's are used in place of the 6L6GCs for a more vintage Bassman sound
⦁    A 12AY7 is used in place of the 12AX7 in first position
⦁    Filter caps are replaced with F&Tcaps
⦁    Adjustable bias is added in amps without it
⦁    Speakers are wired to play forwards or instructions are given on how to rewire them

Get yours modded today and I guarantee will be glad did!  Contact  me to arrange sending in your amp. We will fully test your tubes and other parts.  The price may increase slightly if you need additional tubes.  You can either send the whole combo or just the chassis. If you send just the chassis I will instruct you on how to rearrange the speaker wires so the amp plays forward.

 

Use the contact form, email me at carlscustomamps@gmail.com or call 575-640-6833 to get started today! 

 

Customer Comments:

 

"Hi Carl!

We tested the amp! And it's sounding sooooo good and soooo nice!

Thank you! It was a great improvement!!! I'm really happy with that. Both the Bassman and Champ(customer purchased the Classic Tweed Champ)!!! Killer combo!!

My friend was amazed of how it sounded good!

 

Thanks!!"

Lucas

Completely rewired Re-issue Bassman!  The owner is very happy with the mods!! 

Completely rewired Re-issue Bassman!  The owner is very happy with the mods!!