Mable Audio 5F6A Transformers

Discussion in 'Amp Tech Center' started by MrCoolGuy, Jul 22, 2020.

  1. Wally

    Wally Telefied Ad Free Member

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  2. MrCoolGuy

    MrCoolGuy Tele-Holic Silver Supporter

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    Yes, this is something I have noticed too. I also like the feel of solid. These mable transformer's definitely feel/ sound hollow.
     
  3. Nickfl

    Nickfl Friend of Leo's

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    So what exactly about those caps made them obviously trash?

    I get peoples saying stuff like this about switches and jacks. You can feel cheapness in a cheap switch and to a lesser degree you can tell with jacks although with those I don't think you really know until you use them for a while and find out if they maintain good tension. But capacitors? Really, you can tell just by looking at that a capacitor or a resistor is low quality?

    Same thing with transformers, how do you know that it's good or bad quality by looking at it? I can't help but notice that sometimes people who comment on xxx kits having good or bad parts couldn't tell you what half of those parts actually do...

    I think a lot of people on internet forums confuse shiny / pretty /expensive for good. They can tell that sprague atoms and sozo coupling caps are pretty and they cost them a bunch so they assume that they're good.

    Which is not to say that there aren't some smart people here with valid or at least well thought out reasons for their opinions why one transformer is better than another but the conventional wisdom that get spouted off about components iis often just parroting based on nothing more that confirmation bias and opinions that are more loud than valid.
     
    Last edited: Jul 31, 2020
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  4. MrCoolGuy

    MrCoolGuy Tele-Holic Silver Supporter

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    You're right and that was the whole point of this thread: discerning the difference between shiny / pretty and actually good. If you read the previous posts, you'll see me trying to find good reasoning behind why some name brand transformers are better than others.
    With the Mable kit... like you said, you can feel that the switches are cheap junk (not to mention experience I have with those switches) and the jacks don't appear that bad at first look, but I've been warned about their quality from people I trust. That being said, the main reason I wouldn't use them is simply because you can get high quality Jacks pretty cheap. When it comes to the capacitors, first, I had been warned about them. Second, the first thing you see when you Google "elon electrolytic capacitors" is a page about counterfeit capacitors and countless accounts of people having bad experiences with them. Third, the one I tested was out of the 20% tolerance it was supposed to have and in further testing, was leaking before any extensive use.
    I try not to parrot information. I never confuse shiny and expensive with good.
    That's why you see this thread. And I'm glad I posted it, too, because I've learned a little about transformers.
     
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  5. Nickfl

    Nickfl Friend of Leo's

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    I've heard of the fake capacitors before but I've never seen those pictures that's interesting. If they measured out of spec that's a very valid reason too. It's not totally clear if Elon was the perpetrator or the victim there though and that post was from almost 10 years ago so who knows if that's still a common situation. I've heard stories of Sprague atom caps just being cheap East Asian caps wrapped in a bigger case as well so it may not be limited to just the cheap brands. I've also heard a lot of people dump on Illinois branded capacitors as being no good which I understand to be a hangover from of the "great capacitor plague" of the early 2000s, when there was a widespread electrolytic capacitor manufacturing flaw affected a lot of consumer electronics. As best as I can tell there's no longer a valid reason to say one shouldn't use that particular brand of capacitors, although there may be a reason to doubt the reliability of any you find that may have been put in equipment before 2008 or so.

    As far as posting this thread I think you're on the right track with asking "why" rather than just "is it any good". Definitely some good information about transformers from @tubegeek, and you got a testimonial from someone who had actually used those transformers as well. You also got some generic "I don't trust the Chinese" responses which I don't think are particularly helpful, even though we have all likely experienced something somewhere along line to make us understand that sentiment.

    I definitely didn't mean to come off as suggesting you shouldn't have started the thread, you've mostly attracted good information here and that's always welcome. I'm just a little cynical about these threads because they too often have people posting forceful opinions that turn out to be based on nothing other than having read someone else's opinion elsewhere on the internet.

    I can't count the number of times someone has said x component or kit or whatever is "the best" and the only thing you should use and then for it to become apparent later on that person is basing their opinion on the sum total experience of having built one amplifier and they're just saying that because it's the only brand they have any experience with.

    To paraphrase one notoriously prickly longtime member here, the problem with the Internet is you never know who's opinion you're getting, it could be a respected expert in the field or it could be a 12 year old who likes to troll.
     
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  6. tubegeek

    tubegeek Friend of Leo's

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    na-internetu-niko-ne-zna-da-ste-pas.png
     
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  7. MrCoolGuy

    MrCoolGuy Tele-Holic Silver Supporter

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    The cap thing is interesting, and I sure don't know if Elon as a brand is to blame or is maybe a victim... it seems like if one were to trying to counterfeit caps, they would go for a more recognized brand name. I can't even find any information about Elon caps online.
    Illinois caps are fine by me and I'm glad to see them in newer amps.

    Yes, the internet can be a tricky thing. That is why I'm getting specific in my questioning. It helps weed out the uninformed responces. But I appreciate your input as well as people like @tubegeek who has helped me a lot recently.

    I still haven't decided if I'm going to use these Mable transformer's. I would just sell them, but I don't think I could even get much for them...
     
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  8. Nickfl

    Nickfl Friend of Leo's

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    Have you tested them at all? I would say that if they have appropriate specs for the amp you want to build you should use them, but with a questionable kit supplier you shouldn't assume the specs are correct. Even reputable transformer suppliers like Classic Tone have a tendency to fudge "close enough" specs on PT voltages and OT impedance and have been known to recommend the same transformer for a whole range of amps that have significantly different voltage and impedance requirements.

    If I were you I would check to see what voltages the PT is actually putting out and test to see what the winding ratio on the OT is and go from there.
     
  9. tubegeek

    tubegeek Friend of Leo's

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    How-to figure out the ratios:
    https://www.tdpri.com/threads/ot-transformer-and-rectifier-tube-questions.1038261/#post-9982784
     
  10. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    The one they sold as the W025130, and rarely seems to be in stock anymore? I bought one of those 10-11 years ago for an amp project and have been really pleased with the selectable 120V/125V primary and 540V/680V secondary. Just the thing for today's higher wall voltages! And it supports 3-amp rectifier tubes like the 5U4, so you can do a lot with it. Might be my favorite power transformer. :cool:
     
  11. wabashslim

    wabashslim Friend of Leo's

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    I've never studied the subject, nor have I read the whole thread at this point, but I will state that transformers are inductors, and as such they offer ever-increasing impedence as frequency rises, so frequency response is a major factor for OTs. Their inductance, like pickups, is dependent upon how they're wound - coil size & shape, gauge & type of wire & insulation, grade of iron, number of laminations (more=better) and any number of subtle variations that affect response & damping factor besides wattage.
     
    Last edited: Jul 21, 2021
  12. MrCoolGuy

    MrCoolGuy Tele-Holic Silver Supporter

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    I've put a lot of time, thought and effort into this since I created this post. I guess it's only fair to admit that different transformers have a huge effect on sound/tone. But from what I've noticed (at least with the comparisons I've done), cost isn't the determining factor.
    Furthermore, it's very hard to find multiple manufacturers that make the same transformer. There is always small differences. This makes true comparisons hard. And to answer my original question, mable transformers seem to be fine. That being said, I did end up switching the output transformer for a heyboer and prefer its sound.
     
  13. 2L man

    2L man Tele-Holic

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    I used toroidal transformers on my 5F6A build for 6V6 power tubes. I had used toroid PTs few times before and had built one Single Ended guitar amp using Toroid OT but using Toroid OT for a Push Pull was first. It sound very interesting when tube distortion comes clear so I will use more on coming builds.

    Toroid OTs are known to saturate when tube pair is not properly matched and there comes current imbalance so I built bias circuit which also has a balance potentiometer. So I have been able to turn bias about 70/30% and I can see its effect using an oscilloscope and also hear when playing but it does not change the sound necessarily worse, just distorts low frequencies more. Same happen when EI core OT is used and tube pair has imbalance.

    If you are interested you have Antek in USA and I think

    MP-15W50 15W OUTPUT TRANSFORMER

    Has best potential for guitar amplifiers. It has 5000 ohm impedance when 4 and 8 ohm speaker load is used. It is rated for 15W HiFi watts so it will produce at least double using Guitar frequencies and cost $55.

    This is how my 5F6A "iron" side looks. Between transformers there is 10uF/400V russian PIO capacitor which filters OT current hoping it makes sound warm ;) PHOTO-2021-05-01-17-33-38.jpg
     
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