Traynor YSR-1 Headroom?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by AL30, Jul 25, 2006.


  1. AL30

    AL30 Member

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    I have a 1970 Traynor YSR-1 that I recently got up and running. It's a very unique sounding amp and I am enjoying playing it. However, at larger club levels I am having some problems with the headroom (or lack of) in this amp. It also sounds a little "tight"

    I don't really want to mod this amp too much but I need to get the break-up happening much later and the sound to open up. With 12AX7's the break up is around 3. I am now jumpering the channels and running a 12AU7 and 12AT7 for the first two gain stages. It's still too grainy and tight.

    So..

    The Bias Splitter Resistors on this are 100K. Would changing these to 220K open things up a bit? What can I expect to happen if I do this? Do I need to change anything else to ensure a safe operating range?

    The Bias Supply has been changed to an adjustable supply.

    Also, I don't use the tremolo at all - it sounds GREAT too. But, I don't use it and doubt I ever will. Would disconnecting this give a more "pure" amp tone? i.e. is the tremolo loading down my signal?

    http://www.lynx.bc.ca/~jc/moddedYSR1.gif

    I have what appears to be a trasition model (reverb tranny and choke) so my amp doesn't match (exactly) any of the schematics I've seen. The above schem is close.

    Thanks

    AL
     
  2. lanesmat

    lanesmat Member

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    Al, I won't be much help on the tech side of things, but I do own and use a YSR-1 with reverb tranny and choke. Here is my experience with owning this amp for 25 years.

    At least with mine, it's clean and LOUD. I can't imagine playing this thing loud enough to distort. I always use pedals with this rig, even if the venue allows lots of volume. Headroom should be this amps forte'. I always thought the Traynor custom reverb has a more Hiwattish clean tone.

    If I were you, I'd make sure and have the thing completely checked out. I think there is something out of spec for it to have limited headroom.

    Good luck,
    Scott L.
     
  3. AL30

    AL30 Member

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    lanesmat,

    Thanks for that. I have checked out most of the amp. I *think* it's OK. When I got it it wasn't working so I went over the entire amp. It is very possible that I missed something.

    Just curious - what cab and guitar are you using with it? I have a 4x10" and am using a 1990 LP Custom. Both of these may be contributing.

    Thanks again

    AL
     
  4. lanesmat

    lanesmat Member

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    I've used the amp with HBs, teles, and Strats. I either a a closed or open back cab with a 15" Altec Lansing alnico. The speaker I believe is rated around 30 watts, so its robust speaker, but no EV wannabe. I've owned/have several 40-50 watters, including a Fender SFSR, brown-faced Pro, Peavey Classic 50 4x10, and a Rivera Jake. None of these amps come close to the clean headroom volume I can get from the Custom Reverb. I'm not aware of any mods on mine, so I would certainly look at the circuit again, particularly since you got it in non-working condition.

    Good luck,
    Scott L.
     
  5. ES350

    ES350 Member

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    a 4x10"? 2 ohm load? Maybe part of the problem...Mine is very clean with 6CA7's into a 8 ohm Cali 15". Works well into 4 ohm 2x12" as well...
     
  6. AL30

    AL30 Member

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    lanesmat - that's some very useful info. I will definitely take another look at the circuit. I must've missed something. Thank you.


    ES350 - It's an 8ohm cab. No worries on an impedance mismatch.

    AL
     
  7. ROKY

    ROKY Member

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    The LP Custom's pups are going to limit the headroom; moreso than Fender style p/ups.
    OK, that's obvious, but something to keep, strongly, in mind.

    People have always used LPs because of the output[and tone] in driving
    a non-MV amp, harder.

    You might go with a 12AT7 in the PI also.

    I've been using EH6CA7s in my YSR-1 as I like them in that amp better than EL34s

    Depending on what I want to hear, I will usually jump channels, but only
    bring the 2nd volume up "just" enough, to thicken the signal, but still have
    it lean enough so that I get more headroom/less, overall, gain.

    I tend to use teles,strats and lower output minihumbuckers,and P-90s more.
     
  8. AL30

    AL30 Member

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    ROKY - thanks.

    I am running a 12AT7 in the PI slot. I think I may have found some issues causing the lack of headroom. I was comparing schematics with my circuitry. Mine appears to be very late in the game to have the reverb tranny and choke. Because of this (I assume) it has components from several schematics. The two noticeable ones were:

    1) There is a 100K NFB resistor on mine. That is not there (at all) in the early schematics. This would help clean headroom... a lot.

    2) There is a 33K 1Watt resistor near the reverb tranny on the schems. Mine has this resistor (no 30uf/450V cap) but also has the 47K off the plate loads from V1 - the later circuit does not have the 47K. This would be lowering the voltages on the preamps (I think). I'm just guessing at this one.

    There are some differences on the schems which may account for everyone having a diffrent sounding YSR-1.

    AL
     
  9. donnyjaguar

    donnyjaguar Member

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    That amp should blow your ears off before it starts to break up. This is an amp that shouldn't distort much in the low-signal stages. Stick it on an oscilloscope and run it into an 8 ohm load. If you're not getting a clean 1kHz sine wave at 45Watts there's something wrong. Reducing drive by putting the wrong tubes in there isn't going to net you more headroom because the plate resistor values won't be optimum. I see someone has changed the 470R in the phase invertor to 4k7 and this is going to reduce gain through the power amp stage. I wouldn't think twice about changing the 100k bias resistors to 220k, but I would check for HF oscillation after I did it. :)

    Check the 1k resistor feeding the Sgrids. If this has migrated up in value it will reduce the output power.

    DJ
     
  10. AL30

    AL30 Member

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    Will do. Thanks for the info.

    AL
     
  11. ROKY

    ROKY Member

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    I'm [sort of]confused.

    If I use lower gain tubes in V1 and the PI slots, thus giving me more volume
    before breakup, isn't that a gain in headroom ?

    I always thought it was, and I've done that with a number of amps,and
    I've gotten more headroom before clipping.
     

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