Traynor YBA-2B too bright

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Clapton is God, Dec 3, 2017.


  1. Clapton is God

    Clapton is God Supporting Member

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    Hi all,

    I love Traynor amps, and my newest acquisition is a YBA-2B in fantastic shape. It is an EL84 variant. The schematic for it can be found on this link. It is the last schematic on the pdf.

    I have read several other threads on modding these amps, and I have already made 2 changes. I changed the cap coming off pin 6 of V1 from .1uf to .022uf. I have also replaced R10 (220kΩ) to a more Marshall 33kΩ. However, after these mods, the amp is still too bright. I have the treble knob turned to zero, and it is still a bit harsh and ice-picky at times. Also, the bass control can't go above 2 or 3 without getting unusable. But my biggest concern is the over-all brightness. It could use a little more gain too, but first thing is first. How do I tame the highs on this thing down a LOT?

    I should also mention, besides the 2 changes I made, this amp is bone stock, down to the original speaker.

    Thanks for any help.
     
  2. TimmyP

    TimmyP Member

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    "I changed the cap coming off pin 6 of V1 from .1uf to .022uf." Of which cap are you speaking, the one in the tone stack? You might reverse that mod.

    Get rid of the 10pf after the second gain stage and see what happens to the high end.

    Change the cathode bypass cap of V1 from 25uf to 2.5uf (or smaller).

    Unless you like what it does, get rid of the bright cap (the .001 bypassing the volume control).

    Play with the value of the treble cap (currently 330pf).
     
  3. Tone_Terrific

    Tone_Terrific Member

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    You are reading the wrong schematic.
    Lift the bright cap c5 and/or put a resistor in series to your taste.
    Maybe rebuild the tone stack to Fender DR specs.:)
    Plug in a different (good) speaker, too.
     
  4. Clapton is God

    Clapton is God Supporting Member

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    Thanks! I'll keep this post updated.

     
  5. Clapton is God

    Clapton is God Supporting Member

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    Alright, here's an update. I removed C5, and the tone improved, HOWEVER, now it has an odd issue... If I turn the volume all the way up, keep the treble at 0 or 1 (which is the level of dark I like), and keep the bass low, say 1 or 2, it sounds great, but it's a quiet amp. But as soon as I start to dial up the Bass knob, it increases HUGE amounts of bass AND volume! It seems by removing the bright cap, it has made the bass control and volume control intermingled.

    So what would adding a resistor to where C5 was do exctly? Any idea of what sort of values I should try? I have one of those variable resistor boxes. We talking 100kohms? 1ohm? Thanks.
     
  6. pdf64

    pdf64 Member

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    C5 isn't a bright cap as such, rather it may be seen as setting the upper reach of the bass control's boost; without it, the bass boost upper reach is only really limited by the treble roll off cap C6.
    Really, the whole preamp design seems a bit naff, I would re-build it to something more standard, eg Fender Deluxe AB763 normal channel.
     
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  7. MikeMcK

    MikeMcK Member

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    I'll leave the circuit details to the experts, but can absolutely say this is a key. Those original Marsland speakers were a big part of the reason Traynors went unappreciated for years.
     
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  8. Tone_Terrific

    Tone_Terrific Member

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    Yep.
    The Guitarmates have the tone stack after the first stage, as do Fenders, of course.
    You may have to rebuild to normalize this model.
     
  9. Clapton is God

    Clapton is God Supporting Member

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    Alright, thanks fellas. I should mention that I have been running it through a 2x12 with CL80's. Definitely more efficient, that's for sure!
     
  10. Clapton is God

    Clapton is God Supporting Member

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    Did some more tinkering. As it turns out, one of the lugs from the volume pot was touching the middle lug, which is directly connected to the bass pot. After I fixed that, the volume increase with bass control went away. However, I like the way it sounds better with the C5 "bright" cap installed. It just gets too boom-y without it. I would still like to darken it up, but it's definitely usable, especially with the guitars tone pot turned down to 5. A speaker swap is in its near future.
     
  11. keefsdad

    keefsdad Member

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    So true. I grew up in Toronto and we used them because they could be rented cheaply, but hardly anyone really liked them.
     
  12. Tone_Terrific

    Tone_Terrific Member

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    Yep. When you got a 'real' ;) gig you rented Traynor gear but you really wished for a Marshall.
    A Bassmaster on a full Marshall/Celestion stack would have been pretty cool but I do not recall ever trying one that way.
     
  13. MikeMcK

    MikeMcK Member

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    I did it once... rented a pair of Marshall 4x12s (run in parallel to get 8 ohms) for an outdoor gig. I'm pretty sure I wiped out a local bird species when I cranked it. These days (when the gig's big enough to get away with it) I use a modded YBA-1 into a pair of blackbacks (wish they were greenbacks)
     

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