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Output transformer tone comparison coming soon to an amp I own.

Discussion in 'Marshall Amps' started by Matthews Guitars, Oct 27, 2020.

  1. scozz

    scozz Well-Known Member Gold Supporting Member

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    Yeah, me too, I’m looking forward to hearing the comparison.
     
  2. Matthews Guitars

    Matthews Guitars Well-Known Member

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    It's going to be a few days. For one, I don't have a recording setup of any kind.

    I'm going to get help from a friend for the recordings. I have to work around his schedule.
     
  3. FogDweller

    FogDweller Well-Known Member

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    I would have also restored it to original specs like you are doing.
     
  4. juniorhifikit

    juniorhifikit New Member

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    Looking forward to hearing the results as well! I love doing these kinds of rabbit-hole explorations. One thing I can add is that if you move the recording mic, even 1/2 inch, the tone will change - a lot! When I do these kinds of A/B comparisons, I use re-amp'd guitars and my OX as a speaker, so there's no variable other than what I'm testing for. Here's a test I did between my Marshall super Bass and a baby clone I built:


    FWIW, I put a Mercury Magnetics OT in the clone, replacing the Hammond that was in there and failed. The Mercury sounds awesome.
     
  5. aberry9475

    aberry9475 Active Member

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    I personally like Hammond transformers, good high quality parts, but I've never had any in a Marshall. At any rate, whether it helps the tone or not in the end, the $35 investment to put a period correct OT in should definitely make the amp more desirable/valuable so good call there. Good to know too that's all it takes to re-lead, that's certainly useful.
     
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  6. Dirty-D

    Dirty-D Member

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    you did the right thing replacing the Hammond. The OT has a huge bearing on tone.I'm guessing the origional was a Dagnall T4145. l have dealt with this personally in the last couple of years with my '82 2203. The OT had shortedand needed replacing.My tech was out of comission and I had to find someone else who tried to sell me on a Mercury Magnetics replacement claiming they just sound better. I explained I didn't want it to sound "better" (which it absolutely wouldn't) I wanted it to sound like it sounds.LIKE A 100 WATT MARSHALL! I wasn't going to go with a newer replacement.I know what sounds good to me and I haven't really heard newer anything that gets me off. Finding an old one was impossible or rediculously expensive.So. . .
    I contacted Heyborer and they unwound it and rewound it exactly the same. Same number of winds , same gague wire, same bobbin material, the origional steel plates(which is crutial) origional bell covers , same color codes everything.So it is the origional OT with replaced wire inside. Cost about $325. A new China made is $125 and MM was $300ish so well worth it.
    Thankfully my guy mended his wounds and was able to do the job. It sounds like it did when I first fell in love with it . There is no substitute for the origional Dagnall IMHO STRAIGHT UP NONE. Sorry 50 watt fans.
     
  7. TM1

    TM1 Member

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    I've known the folks at Mercury for over 30 years and consider them good friends! $35. bucks is a more than fair price. It's a shame though that Magnetic Components is closing as they made good stuff.
    Your Output tranny is 60% of your amps' Tone & Sound. Any new tranny takes at least 20 hours of use to start opening up. I don't mean just having the amp "on", I mean being actually played through. So don't expect it sound sound "amazing" right at the start. You have to put the playing time into it.
     
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  8. Matthews Guitars

    Matthews Guitars Well-Known Member

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    My friend who has his own home studio never got around to getting the comparison done so that isn't going to be happening, sorry.

    But the swap was done and the difference is night and day. The Hammond OT was just flat out choking the life out of the amp's tone.

    It now sounds like a proper killer 2203. A deaf man could FEEL the difference.
     
  9. matttornado

    matttornado Well-Known Member

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    This is interesting. I just replaced the original OT (not sure what brand it is) in my 1974 superlead with a new one from Heyboer and I did not notice any difference in sound.

    I did not do a recording to compare with so there might be a slight difference that my ears did not detect.
     
  10. FleshOnGear

    FleshOnGear Well-Known Member

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    Is it possible that something was wrong with the Hammond? Or that it was the wrong impedance? Just a thought that occurred to me, because my Traynor sounds great with its Hammond trannies. Regardless, I’m glad you’ve restored your amp and that it sounds like it should!
     
  11. neikeel

    neikeel Well-Known Member

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    if it is that different it must have been the wrong specs. If you are running a quad of EL34s the primary impedance should be 1.7k to 2.4k.
    it would be really interesting if you have time to put it on your variac and see what spec the old one was.
     
  12. Matthews Guitars

    Matthews Guitars Well-Known Member

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    Let's be honest. Hammond is a perfectly competent manufacturer of power transformers. But when it comes to output transformers, they're just not it. The lamination stack alone is a quarter inch narrower than the Dagnall that should be in the amp. When buying a replacement output transformer, stick to the companies that know guitar amps and how they sound and that make the transformers that sound good. Drake, Dagnall, Heyboer, Classic Tone, Mercury Magnetics, and my favorite so far, Chris Merren. The Hammond transformer is just one of the cheapest options, and it has the virtue of being readily available, but of the available choices, it's not the best one.


    The Hammond 1750U transformer that was in the amp has an input impedance of 1700 ohms. The specs are available at the Hammond website.

    Incidentally, a note about phasing: The 1750U's primary wires are red and blue with a white CT. The Dagnall that went in to replace it has red, black, and CT is white. So I figured, let's keep red where it is.

    Nope. That's out of phase. The red on the Dagnall is out of phase compared to the red on the Hammond. Might want to make a note of that in your transformer swap notebook.
     
  13. Matthews Guitars

    Matthews Guitars Well-Known Member

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    The tonal difference was so dramatic that I'm wondering if the Hammond OT is defective or was damaged. It really did make the amp sound BAD. I did not like playing it but now, with the proper correct Dagnall installed, I love it. A change that big can only be real. I'll measure the Hammond, both inductance and resistance, and see if it is out of balance or shows other signs of damage.
     

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