Do output transformers "saturate"

[Mike K]

Every source from actual winders of OTs says this is not the case, and I think when they truly do, you start to get a lot of unpleasant fizz. So I'm forced into a conundrum here re: Teemu's book on SS design. Pg. 269, Fig. 6.77. He talks about a Peavey "transtube" circuit which "was to simulate the output transformer’s saturation that takes place during high gain overdrive and is excited by the DC component of the clipped wave." I'm now questioning his credibility in understanding what is actually going on in a tube amp, but perhaps this is just a matter of words. Perhaps what he means is the transformer is being driven TOWARD saturation and becoming bandwidth limited.

The accompanying figure of the circuit, which I didn't confirm is correct, shows a strong mid boost centered around 700-800Hz that tapers off rapidly around 300Hz and 2kHz. This is the effect that I hear most in an overdriven tube amp, but have never seen any real explanation for the attribute that causes it. But to me, no matter how scooped the amp is, it always sounds more mid-strong the more power tube distortion is present. So I tend to believe, at least empirically based on my ears, that some kind of mid-boost is happening in the output stage interactions. But what is the real cause of the effect? I believe this to be the effect that is heard most with different transformer designs.

[loudthud]

I purchased a small Peavey practice amp at a pawn shop that had the Transtube badge on the front. The preamp had minor amounts of even order distortion but only reached just over 1% THD before clipping. Most tube preamp circuits reach about 10% THD before clipping. For the most part, output transformer saturation is a myth propagated by non-technical people that wouldn't know it if they heard it.

[Chuck H]

re: Teemu's book on SS design. Pg. 269, Fig. 6.77. He talks about a Peavey "transtube" circuit which "was to simulate the output transformer’s saturation that takes place during high gain overdrive and is excited by the DC component of the clipped wave." I'm now questioning his credibility in understanding what is actually going on in a tube amp,..

Actually what Teemu did was reiterate the intention of the designer of the discussed circuit and this has nothing to do with Teemu's understanding of what is happening in tube amps. You should be careful about denigrating members or their printed efforts here.

but perhaps this is just a matter of words. Perhaps what he means is the transformer is being driven TOWARD saturation and becoming bandwidth limited.

And this is my point above. Teemu didn't mean anything. He was discussing the intention of another designers circuit. This has nothing to do with his understandings.

You opened here on the forum by telling us about our profound lack of experience. To your credit you backed that sort of behavior off pretty fast. But you still seem quick to discredit, offensively, any technical position that disagrees with your personal, and often non technical experience. But perception isn't always reality. It's entirely probable that some of your perceptions can be explained by technical aspects other than what you thought. You would do well keep these inquiries amicable and without inference of incompetency or inexperience directed toward other members.

[Mike K]

Actually what Teemu did was reiterate the intention of the designer of the discussed circuit and this has nothing to do with Teemu's understanding of what is happening in tube amps. You should be careful about denigrating members or their printed efforts here.



And this is my point above. Teemu didn't mean anything. He was discussing the intention of another designers circuit. This has nothing to do with his understandings.

You opened here on the forum by telling us about our profound lack of experience. To your credit you backed that sort of behavior off pretty fast. But you still seem quick to discredit, offensively, any technical position that disagrees with your personal, and often non technical experience. But perception isn't always reality. It's entirely probable that some of your perceptions can be explained by technical aspects other than what you thought. You would do well keep these inquiries amicable and without inference of incompetency or inexperience directed toward other members.

I'm sensing quite a double standard here. I'm not denigrating anything, I'm calling into question what is actually meant here and the bold claims of said publication. My intent is not to discredit Teemu, I don't know him personally, but I was instructed to read his book by another member who questioned something that was directly in print in his book, and acted like I was some kind of idiot for even suggesting it as a valid method. Pretty rude if you ask me. Perhaps some people should be a little more humble in their suggestions or criticisms, eh?

Anyway, I'm actually curious what Peavey is trying to accomplish. Peavey engineers are not stupid. They've produced some of the most convincing SS emulations of tube amps out there, they obviously understand this stuff better than most. The question is what is this real effect on a tube amp? And perhaps, if we could understand it, a humble and honest author would revise the next version of their book to make the content more accurate.


Listen, I've read hundreds of text books. I can't think of one that doesn't have at least one error. No one is perfect, but let's learn from it, and not get offended by it. I'm only offended when people who have very singular thoughts think they have all the answers for everything. That is not creative thinking. One should research something for themselves before immediately dispelling what someone else claims. Perhaps there's something they might not know. I'm keeping an open mind, but again, I don't get that from many members here. Don't play favorites in terms of this to protect long standing members. That's the curse of every forum and stifles any kind of meaningful conversation.

[Chuck H]

Don't play favorites in terms of this to protect long standing members. That's the curse of every forum and stifles any kind of meaningful conversation.

Just so you know, I'm absolutely going to do that. So now you can be prepared. This isn't a matter of long standing only but also a matter of long term, appreciated contribution and the seniority and respect that come with it. If cursory cultural models of earned respect are bad for forums then damn the torpedoes. We'll sink. Thank you for the suggestion of how we should be operating. I'll be ignoring it.

That said I do recognize that one of our members has been a bit short and snarky of late. With me as well for what it's worth. Being relatively new here you wouldn't know that he usually displays a little more patience and just keeps to the facts. Those members with a long history of successful, peaceable discussion that have the sort of technical and/or practical experience that has always been the foundation of this forum are invariably going to get preferential consideration. Sorry not sorry.

[Mike K]

Just so you know, I'm absolutely going to do that. So now you can be prepared. This isn't a matter of long standing only but also a matter of long term, appreciated contribution and the seniority and respect that come with it. If cursory cultural models of earned respect are bad for forums then damn the torpedoes. We'll sink. Thank you for the suggestion of how we should be operating. I'll be ignoring it.

That said I do recognize that one of our members has been a bit short and snarky of late. With me as well for what it's worth. Being relatively new here you wouldn't know that he usually displays a little more patience and just keeps to the facts. Those members with a long history of successful, peaceable discussion that have the sort of technical and/or practical experience that has always been the foundation of this forum are invariably going to get preferential consideration. Sorry not sorry.

I'm sorry but if you are going to claim to be a technical forum, you have to side with the technical. People are going to disagree and sometimes those that have experience are wrong.

I admit I purposely challenge people and some find that intimidating. But I'm not doing so to be a troll, I'm doing so to try to gain a deeper understanding for both parties. I don't wish it to become uncivil, but all too often it does. But if someone's published claim cannot be challenged as being "credible", then I'm out. That is not science, that is dogma.



PS - I don't want the end. I think Helmholtz is an excellent EE and full of knowledge. I value his knowledge and experience. I value yours as well Chuck, and I hope I've made that clear. Everyone, even beginners, have some experience that is worthwhile.

[Chuck H]

I'm sensing quite a double standard here. I'm not denigrating anything, I'm calling into question what is actually meant here and the bold claims of said publication. My intent is not to discredit Teemu,

Well...

I'm now questioning his credibility in understanding what is actually going on in a tube amp

Did I misinterpret that? You're full of shit. Stop trying to edit your social clumsiness post script. It doesn't work.

[Mike K]

Well...



Did I misinterpret that? You're full of shit. Stop trying to edit your social clumsiness post script. It doesn't work.

I do - does he understand what Peavey is actually trying to do? Do I? I do not. I'd like to understand better. From the science I know, transformer saturation is not a desirable result in tube amps.

I don't know how I'm editing it? There's a claim, whether it's from Peavey or Teemu, I don't care. I have no vested interest in the personal nature but he did publish it, so he takes the heat.


Also, you might think I'm cherry picking or some shit. I literally read 10 pages out of the book and found that. It seemed relevant to something in another thread and didn't want to drift it more, so I asked. Is it a credible claim? Is the effect real - sounds like it to me, but I have no data. Can we focus on that?

[Chuck H]

I do - does he understand what Peavey is actually trying to do? Do I? I do not. I'd like to understand better. From the science I know, transformer saturation is not a desirable result in tube amps.

I don't know how I'm editing it? There's a claim, whether it's from Peavey or Teemu, I don't care. I have no vested interest in the personal nature but he did publish it, so he takes the heat.


Also, you might think I'm cherry picking or some shit. I literally read 10 pages out of the book and found that. It seemed relevant to something in another thread and didn't want to drift it more, so I asked. Is it a credible claim? Is the effect real - sounds like it to me, but I have no data. Can we focus on that?

And yet you said:

I'm now questioning his credibility in understanding what is actually going on in a tube amp

Are you one those people that can't be wrong. You clearly have practiced tactics for dealing with it. I'm not discussing the technical matter in this thread. I'm addressing your manner on behalf of the forum and in the interest of having your threads and topics achieve success instead of rancor.

[Mike K]

I'm not sure what you're gunning at here.


Yes, I'm questioning his understanding. I question my understanding. Why are you so fixated on the fact that I do not take his, or Peavey's claim, as dogma? It goes against what I have learned, I've stated that multiple times, but there's obviously some effect there.

[Mike K]

For the most part, output transformer saturation is a myth propagated by non-technical people that wouldn't know it if they heard it.

So why is it cited as so in this book? Why can you make this claim, which seems to disagree with Teemu's publication but I'm being bullied by the moderator of this forum for saying essentially the same thing?

[Chuck H]

I admit I purposely challenge people and some find that intimidating. But I'm not doing so to be a troll, I'm doing so to try to gain a deeper understanding for both parties. I don't wish it to become uncivil, but all too often it does. But if someone's published claim cannot be challenged as being "credible", then I'm out. That is not science, that is dogma.

There are ways to question findings and interpretations without using phrasings that imply overall incompetence. If this sort of tactic is intended to be provocative then know you are achieving that. But you're not provoking technical discussion. No one is intimidated. Just offended.

[Mike K]

There are ways to question findings and interpretations without using phrasings that imply overall incompetence. If this sort of tactic is intended to be provocative then know you are achieving that. But you're not provoking technical discussion. No one is intimidated. Just offended.

I think you're reading into that.

So by saying "output transformer saturation is a myth propagated by non-technical people that wouldn't know it if they heard it." is a better way?


If someone can't take criticisms of works, they should not publish. I did call into question his understanding of a tube amp, because what he says directly contradicts it. It was not meant to convey overall incompetence, I was very much focused on that one aspect and why I questioned it. It should seem obvious that one can understand different aspects of a system to different degrees. And that's why I put words after that. I meant to clarify that maybe he just chose poor words. But I still question the credibility. I stand by that 100%. It does not question the whole book, just that one section. One can disagree with one section of a technical paper and accept all others. I haven't read the whole book, so I won't be able to comment on anything else.


I'm sorry you're offended by it. Please let me know how I can modify my criticism of this subject and not offend you, or Teemu. Again, if it's something he misrepresented or doesn't fully understand, I hope he modifies it to be more clear and precise in the next revision.

[Chuck H]

So why is it cited as so in this book? Why can you make this claim, which seems to disagree with Teemu's publication but I'm being bullied by the moderator of this forum for saying essentially the same thing?

loudthud did not say the same thing as you. He did not say Teemu was non technical. He said output transformer saturation was largely a myth perpetuated by non technical people. You said Teemu's credibility and understanding of what's going on in a tube amp is questionable. One is a personal slur and the other is not. You are practicing diversionary tactics by noting that loudthud disagrees with output transformer saturation and now repeatedly implying that you were questioning Peavey's position on the matter. Own up. You made a social error in an attempt to be provocative. Especially so because your exact phrasing incorrectly implied that Teemu was responsible for any questionable technical considerations. Making this a falsely derived personal attack. This is not an effective way to stimulate technical or scientific discussion.

[Mike K]

loudthud did not say the same thing as you. He did not say Teemu was non technical. He said output transformer saturation was largely a myth perpetuated by non technical people. You said Teemu's credibility and understanding of what's going on in a tube amp is questionable. One is a personal slur and the other is not. You are practicing diversionary tactics by noting that loudthud disagrees with output transformer saturation and now repeatedly implying that you were questioning Peavey's position on the matter. Own up. You made a social error in an attempt to be provocative. Especially so because your exact phrasing incorrectly implied that Teemu was responsible for any questionable technical considerations. Making this a falsely derived personal attack. This is not an effective way to stimulate technical or scientific discussion.

I'll boldly claim that Teemu is propagating that same myth in his book by not clarifying. Why can you not accept that?


Listen, you're defending Teemu, not the idea. I'm attacking the idea which was propagated by said author - his name is only attached to said idea by authorship. If an author cannot claim responsibility for what is published, then they should not publish. End of story. I don't know how much experience you have with publishing technical papers, but you want to convey it a certain way. And you continue to do so.


I don't know Teemu, I didn't know he was a member of this forum, I have NO vested interest in him or discrediting anything but what I wrote.