Swapping Components - which ones, brands ,etc . .

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Guy Fawkes, Oct 16, 2008.

  1. Guy Fawkes

    Guy Fawkes Active Member

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    UPDATE/EDIT:
    I would like to increase the headroom out of a fender tonemaster

    I love the clean tone, but I believe that it breaks up too quickly on the clean side

    The treble is hair trigger and can be a bit bright at times

    The gain channel is buzzy, harsh, and dry sounding

    I am getting the merc mag Tonmaster output tranny for starters

    So I guess th inquiry can be distilled into "what caps/resistors, and brands thereof, would contribute towards the above objective and which ones would need to be swapped out" ?
     
    Last edited: Oct 17, 2008
  2. FortinAmps

    FortinAmps Member

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    It depends on the type of amp. Vintage or Modern style?
     
  3. Guy Fawkes

    Guy Fawkes Active Member

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    It's for a Fender Tonemaster, so i guess that would be modern
     
  4. SatelliteAmps

    SatelliteAmps Member

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    Best is very subjective. And everything in the circuit can be considered to affect the tone. Most initial part changes are directly in the signal path. A lot of people like to use good quality carbon resistors, and good quality capacitors, Mallory's, or Spragues to name a few.
     
  5. Guy Fawkes

    Guy Fawkes Active Member

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    So what resistors are usually changed in an amp ?

    WHich ones affect tone, or don't at all?
     
  6. FortinAmps

    FortinAmps Member

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    +1 to that.:AOK
     
  7. FortinAmps

    FortinAmps Member

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    Generally plates, cathodes and interstage attenuation, but you have to consider that everything contributes to it. It also depends on what you are trying to accomplish, more/less gain, brightness, dynamics, etc.

    What would you like to change about your Tonemaster?

    Cheers,
    Mike
     
  8. Guy Fawkes

    Guy Fawkes Active Member

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    Thanks again

    I would like to increase the headroom

    I love the clean tone, but I believe that it breaks up too quickly on the clean side

    The treble is hair trigger and can be a bit bright at times

    The gain channel is buzzy, harsh, and dry sounding

    I am getting the merc mag Tonmaster output tranny for starters

    So I guess th inquiry can be distilled into "what caps/resistors, and brands thereof, would contribute towards the above objective and which ones would need to be swapped out" ?
     
    Last edited: Oct 17, 2008
  9. SatelliteAmps

    SatelliteAmps Member

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    As I already said, start with everything in the signal chain. It's not like there is one or two that will do it specifically. And again, carbon resistors, Mallory or Sprague caps. Start at the input jack and work your way through to the output transformer.

    Honestly, it sounds like the amp isn't what you want. To try and change everything to get both channels to sound better usually indicates a different amp would be easier (and cheaper).
     
  10. Guy Fawkes

    Guy Fawkes Active Member

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    I'll take that under advisement, but I am happy with just using the TM for clean w/o the gain channel and A/B to my V-plex for my marshally stuff

    the lead tone w/the barber red snapper or direct drive is dumbly enough on the clean channel to where I don't mind saving 3G's plus

    getting the dirt channel on the amp going on it would just be a bonus

    I actually like the TM clean alot, but just want more headroom so it's really not as bad as you may perhaps be implying

    Notwithstanding the gain channel tweaks, is the single issue of getting more headroom out of the amp such a monumental task that it warrants selling it and getting another amp ?

    If not, then what are some general suggestions as far as more headroom besides just going to AT's or AU's ?
     
    Last edited: Oct 17, 2008
  11. SatelliteAmps

    SatelliteAmps Member

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    Switching to AT or AU's is an easy way to get more headroom. There are other tricks that could be done inside of the amp, but usually at some cost to the tone of the amp.

    Changing all the parts to better quality won't give you more headroom, but they will alter the tonal qualities of the amp. Might be what you want in the dirt channel. Might also be a lot of time spent on something that isn't what you are after. A lot of the harshness that you are describing in the dirt channel isn't something that will be dramatically changed by changing the brands of parts involved.

    The issue of more headroom isn't so much of a monumental task, but one of value. A lot of money could be spent trying to get more headroom out of the amp, and the value of the amp would be lowered because of all the modifications.

    Also, how much experience do you have at modifying and working on circuit board amplifiers? Is this something you are capable of handling?
     
  12. Guy Fawkes

    Guy Fawkes Active Member

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    I see what you are saying

    I actually have a tech who I am bartering guitar lessons with lately :))

    The amp is all p2p, not pcb

    I opened it once, and it is a rat's nest in there

    I have some suggestions some techs who have done mods on these before

    I'm on the other 'puter right now - will post them later

    Thanks
     
  13. Jackie Treehorn

    Jackie Treehorn Member

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    You might try a bit of global negative feedback. It could solve many of your problems.

    To try it, you would lift the ground connection to where c33 and the 47k phase inverter tail resistor are joined and put a resistor between that connection to ground. The standard Fender blackface value is 100 ohms. Then you would take a wire from the + side of one of the speaker taps, say the 8 ohm tap, and wire it to one side of an 820 ohm resistor, Solder the other end to the junction of c33 the 47k tail resistor and the 100 ohm resistor you added.

    You can also vary the 820 ohm to try different amounts of feedback. You could wire a 2k pot and set it to taste for example.
     
  14. FortinAmps

    FortinAmps Member

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    As far as the gain channel being buzzy and harsh sounding, try introducing some feedback in the power amp section. It is currently running open loop which will give you a very raw sound and some people find it buzzy.
    Cheers,
    Mike
     
  15. Structo

    Structo Member

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    Yes I would first try a lower gain tube in V1 V2.

    This will increase headroom and it will breakup later.

    As far as changing components, I think I would move on to another amp before I started modding an amp that has decent resale value.
     
  16. Guy Fawkes

    Guy Fawkes Active Member

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    TM's don't have great resale value. Not only that, we're back at square one after that:

    Get a 3K plus amp based on forum hype, soundclips, youtube clips, find out you don't like it when you take it to the stage, take a bath and sell it for less

    Nope, I'm gonna mod the sh!t out of this thing. Hasn't cost that much so far, and I'm learning alot from my tech as we're going over it

    The Merc mag transformer has made a big diff so far
     

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