5F2A Output Transformer

Discussion in 'Shock Brother's DIY Amps' started by HBamps, May 18, 2020.

  1. dan40

    dan40 Tele-Afflicted

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    Amppartsdirect use to be a Classictone dealer but they have now switched over to Heyboer. I received an email today from them stating that Heyboer is winding and they should be available very soon. Heyboer manufactures some great iron for many builders and dealers and they also supply most of the iron that Mojotone sells. Just another option if all else fails.

    https://shop.amppartsdirect.com/collections/apd-custom-by-heyboer
     
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  2. HBamps

    HBamps Tele-Meister

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    Thanks for this. Man, there are so many choices. I was set on Calssictone and when I found they are not available, it started the mad search.

    I'm considering;
    - Mojo 771
    - Weber W022905M
    and now this
    - Heyboer 15 watt one

    Will I make a mistake with any of these?
     
  3. Nickfl

    Nickfl Tele-Afflicted

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    I used the Weber 022905m OT for a 5b2/5c2 inspired build a couple of years ago and it made a very good sounding amp. That is still probably the best sounding single ended amp I've built, so I wouldn't hesitate to recommend it.
     
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  4. jimgchord

    jimgchord Tele-Afflicted

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    A 275 v pt with a sovtek 5y3 will give a plate voltage of around 300. Which is perfect in my opinion
     
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  5. King Fan

    King Fan Poster Extraordinaire

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    I see in another 5F2a thread you wisely touch base with Hammond expert @jsnwhite619 who noted he got good results with a Hammond 275-0-275 PT using a JJ rectifier. When I input 275 on the calculator you link above, with 1 power tube, 1 preamp tube, and SE operation, I get B+ ~340V, which you note is your target. And you say you have a Hammond that does 275 in your parts bin?

    You seem to know your way around these things; 275 seems do-able to me. You probably know this too, but a reasonable way to find target voltages for the 5f2a is to use the schematic Fender produced when they changed its name (momentarily, at the end of its life) to "6g10 Harvard." And then recall they were running 110V, not 120, out of the wall.

    Harvard schematic with voltages.jpg


    Finally, I agree with your research: The *BF* Champ 330-0-330 has come in "too hot" in some 5f2a builds -- though the amp would probably work fine. In general, the target voltages on a number of older Fender amps seem to suggest original PTs with HT voltages in the range of 290-310, a less common range on modern PTs. Mojo and other *tweed* Champ PTs can be a nice fit for the obvious reason the original 5F2a use a 5F1 PT. And yes, per Murphy's law, this one is temporarily out of stock. But Mojo is wound by Heyboer, who are apparently reopening as mentioned, so you might see if they have a timeline. And AmpPartsDirect, linked above, is rolling out their Heyboer-wound line and are eager to build market share -- they were very helpful when I contacted them.


    upload_2020-5-20_8-13-51.png
     
    Last edited: May 20, 2020
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  6. Tele Slacker

    Tele Slacker Tele-Meister Silver Supporter

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    I had heard on the TAVA podcast interview with Chris Benson (Benson Amps) that Triad was starting back up with guitar amp amplification (he mentioned he was testing some). Anyone heard further?
     
  7. tubedood

    tubedood Tele-Meister

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    I pondered this a bit on my 5F2-A build, went with Allen Amps TO11S. Beefy as heck, great with a 6V6 on the 8 ohm tap and on the 4 ohm tap will be fine for a single ended EL34. I might try a SE Plexi with it next.
     
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