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Calling Traynor/Schematics Experts

Discussion in 'Amps and Cabs [BG]' started by primussucks9126, Jun 24, 2016.


  1. primussucks9126

    primussucks9126 Supporting Member

    Jan 1, 2008
    Bronx, NY
    Hey all,

    I've got an opportunity to buy a Traynor TS-50. I wanted to know if anyone could tell me the differences between it and the TS-50B?

    I've looked at the schematics, and I've noticed a few minor(?) differences, and just want to know if they would have a major impact on the tone.

    TS-50 schem: http://www.lynx.bc.ca/~jc/781218_TS50.gif

    TS-50B: http://www.lynx.bc.ca/~jc/790713_TS50B.gif

    Obviously the TS-50 has the bright switch and reverb control, but the boost section looks different and so do a few resistor values and voltages on the EQ section.

    I appreciate any and all help!
     
  2. teemuk

    teemuk

    Mar 1, 2011
    Yes, differences in those. Both have the same passive tone stack arrangement with fixed mid-range, and mid-range control implemented differently.

    TS50B arrangement is simplistic: Mid-range control is a passive "notch-T" filter, which introduces a mid-range notch similar to that of the tonestack. The control can -cut only- and its turnover frequency slides in interaction with the dial. As tonestack's source impedance, it will alter overall frequency response some. Tonestack, however, will not be loaded excessively by the 1M input resistor of the following emitter follower.
    "Boost" feature is a simple parallel resistor and "treble bleed" circuit in the feeback circuit of the first gain stage. Effectively the circuit increases stage gain and simultaneously boosts higher frequencies if toggled.

    TS50 is more complex: Tonestack is same, but its lowish 62K+62K load impedance will probably alter its overall frequency response. If nothing else its a voltage divider that attenuates signal to half of its original amplitude. Because the following stage is Traynor's proprietary 3-band overdrive circuit that is not a small detail. Do note that this design, however, does not have significant insertion losses of the passive "notch-T" filter.
    Different to TS50B source impedance driving tonestack is also very low, so there will be some difference in the overall response.
    For mid-range control first gain stage features a gyrator-based resonant band-pass filter. Basically a simulated inductor with parallel capacitor. The parallel cap has series potentiometer for overall control. The circuit, AFAIK, can - both boost and cut - and its turnover frequency does not interact much with the dial, like in case of notch-T filter. Being active, there should be no considerabke insertion losses so that's probably why there's that attenuator following the tonestack circuit.
    Boost's magnitude is slightly lower than in TS50B, but similarly frequency-selective: higher frequencies are boosted more than lower ones. This design also seems to introduce different amounts of stage gain depending on whether you plug to "low" or "high" input while TS50B only attenuates the input signal accordingly.
    Master volume has that treble bleed cap to further enhance higher frequencies at lower volume settings.

    I'm too lazy to calculate turnover frequencies of the two mid-range control schemes, or how much the overall frequency response differs between these two circuits.
     
    Last edited: Jun 24, 2016
    blindrabbit and Jeff Bonny like this.
  3. primussucks9126

    primussucks9126 Supporting Member

    Jan 1, 2008
    Bronx, NY
    Wow! Thanks so much for that!

    Is it safe to say that the heads would sound mostly the same/similar?
     
  4. thumbknuckle

    thumbknuckle In Memoriam

    May 23, 2012
    Westfield, MA
    I've used both a TS50 and a Rusty Box (which is the TS50B circuit). The EQ is a little different but the basic voicing and overdrive is the same. They will do the same kinds of sounds.
     
  5. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    It depends on the age of the amp. Attached is a 1982 revision to the T-50. They made some minor tweeks.

    The power supplies are the same.

    If the amp sounds good, don't worry about. With the schematics, a tech can make any minor changes to convert one to the other if you want it to favor the bass.
     

    Attached Files:

  6. primussucks9126

    primussucks9126 Supporting Member

    Jan 1, 2008
    Bronx, NY
    Hey guys, would you happen to know why, if both power sections are the same, I shouldn't run a TS-50 at 4 ohms, but a TS-50B is ok to run at 4 ohms?

    Despite both heads saying 8ohm minimum, the manual for the TS-50B says 4 ohms is ok. I'm just wondering what the difference is (if there is one) that makes that so.

    I e-mailed Traynor and didn't get a solid answer. Is it just a matter of the new employees not knowing this product well enough and giving me a safe answer?

    I appreciate your help!
     
  7. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    I don't know why Traynor's documentation differs. Perhaps it is warranty related.
     
    Last edited: Jul 28, 2016
  8. primussucks9126

    primussucks9126 Supporting Member

    Jan 1, 2008
    Bronx, NY
    I believe the schematics show the same voltage in the power section as well. Also, this is a solid state amp, so there are no power tubes.

    There is one difference on the schematics. The TS-50B has an additional power switch section, and the voltage listed is 240, but it's free floating and I don't know if or how it actually applies to the circuit. I think it's just showing the difference for an amp sold in a different region.

    Edit: I checked the manual for both and they both say 50 watts at 120 volts AC. The TS-50B manual also says 70 watts at 120 volts AC
     
    Last edited: Jul 28, 2016
  9. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Sorry for the confusion, I fixed my post, somehow I thought that it was a tube amp.

    I checked the power section on the two schematics and they do appear to be the same as do the power supply voltages as you mentioned. One possibility is that the TS-50B might have better heat sinks on the power transistors. If heat dissipation is better in the B revision, that could allow it to run at a lower impedance. You'd have to see the insides to confirm. Schematics don't always tell the full story.

    It could also be that the TS-50 was simply rated more conservatively and that there is no reason why it can't be operated at 4 ohms.
     
    Last edited: Jul 28, 2016
  10. primussucks9126

    primussucks9126 Supporting Member

    Jan 1, 2008
    Bronx, NY
    Thanks so much. I've never seen the inside of a TS-50B but based on how similar everything else is, I doubt there's any additional heat sinking.

    My guess is that the difference is because the TS-50 was a combo amp with only one speaker jack, and the TS-50B was a head with 2 jacks. They probably didn't think about anyone running a TS-50 with a different speaker. I'm gonna give a 4ohm load a shot and see what happens.
     
    beans-on-toast likes this.
  11. BogeyBass

    BogeyBass Inactive

    Sep 14, 2010
    yes exactly that's pretty logical one's a combo one's a head unit. if the manual said 4ohms for the head version it's same transistor output section and if it can handle the heat all good. I'd assume it's large metal can transistors mounted to a heat sink. should handle 4 ohms if manual said.
     
  12. You can always call Yorkville in Pickering Ont. and ask to speak to their tech dept. They're very helpful and always willing to chat.
     
    Al Kraft and blindrabbit like this.
  13. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    May 7, 2021

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