I am interested with a transformer where you can adjust the proximity of the cores. (I understand that it changes the specifications if you changes the distance between the cores with the primary and secondary) But I am into sound coloration and distortion; and want to explore the possible effects. So if you have any ideas or starting points or pros/cons it would greatly appreciated.
How would design a transformer that had adjustable cores? (for saturation and de-saturation)
- Thread starter s wave
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i have never heard of anything like that before.
First of all I want to say that I have learned massive amounts of knowledge and wisdom from your posts. A variable core? I always work on projects that are way out of the box. Most fail - but the ones that work are like gold. When I start making the prototypes I will post images/results - ty CJ! oh quick quote I like; Ford - give me all the people that don't know a V-8 can't be made... (of course it wasn't the first V-* but it was the 1st one that worked very well).
why not just apply variable dc?
Well there are tuneable transformers in IF circuits,
i like outside the box stuff too. I always wanted to build a guitar amp with two transformers in series to reduce turns ratio, like I stead of a 36 to 1 you could have two 6 to 1 transformers which would reduce capacitance and maybe leakage inductance.
I do like the idea of having control over spacing between winds, if for nothing else but to study the effects on the sound.
i like outside the box stuff too. I always wanted to build a guitar amp with two transformers in series to reduce turns ratio, like I stead of a 36 to 1 you could have two 6 to 1 transformers which would reduce capacitance and maybe leakage inductance.
I do like the idea of having control over spacing between winds, if for nothing else but to study the effects on the sound.
Matt Syson
Well-known member
I suppose a custom wound transformer on a large pot core with different 'slugs' could be a start but putting such a device in a circuit to make it useable would be fun.
Matt Nolan
Well-known member
Because there is a risk of magnetising the core laminations so that even when you remove the DC the saturation remains, so it is no longer as variable. Different materials may be better or worse in this respect, I'm no expert.
We better tell Rupert! Oh wait...
Depending on the application I guess things change rapidly. A passive motor ribbon mic output is DC and it varies. Increasing the current has been fairly well explored - and this project is more about changing the magnetic field properties for sound characteristics. Changing the core field distances will greatly impact the sonics (color/distortion) in a hurry I am guessing - but this is the 'edge' I am looking for - where it distorts from possibly a brown sound to a normal sound to an overdriven/saturated sound. (I am also interested in changing the magnetic flux field by using adjustable magnetics to infuence it - but I think that is another discussion lol). Thx!
This too it seems ty.
Hmmm... I think the OLD am car radios had em? guessing here. Here is a what looks like an ancient thread but they were 'staged' transformers? https://maker.pro/forums/threads/455khz-if-transformers.73096/
I the Marshall JTM 45/100 prototypes had 2 transformers? https://ampgarage.com/forum/viewtopic.php?t=11018 and https://www.fuzzfaced.net/marshall-jtm-45-100.html But you meant in series. I like your idea/possibilities.
Yes I want to study the effects on sound here too.
(Back story - years ago I posted a pic of a couple of teenagers in a experimenting room, it's location was in NJ, and there was some old amps/electronics. I will have to try to dig up that pic again. Anyway, I asked if anyone knew who these guys were; I actually got a response from from one of the guys. He said the guy with his back turned was Eddie Van Halen. And the amp was the old Marshall used for the famous undervolted brown sound - I recollect him saying something like they undervolted it to 80+ volts etc.)
Just looked at the old info on these. Super cool - they were AC/DC and yea they are too big for small audio signals I would think. But thx it gave me some ideas.
Disco Volante
Well-known member
I guess someone else mentioned it first: Old-style welding transformers control the power (current) by using a split bobbin with a gap between them and inserting a block of lams more or less with a long screw arrangement.
It would be reasonably simple to do this on a smaller core. Some M-laminations have a bit wider room for the bobbin...
These days, welding machines are mostly SMPS...
Keep us posted;-)
It would be reasonably simple to do this on a smaller core. Some M-laminations have a bit wider room for the bobbin...
These days, welding machines are mostly SMPS...
Keep us posted;-)
freshtapescent
Well-known member
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Get a guitar or other magnetic pickup…drive your signal through a coil of some kind, proximity of drive and transducer coils will determine field strength & tone.
A transformer with movable cores will only give you more or less inductance, not more or less distortion.
Could you use a very high frequency AC bias to rob magnetic headroom from the transformer stage? Core could quickly cycle between saturated and unsaturated so as to avoid permanent magnetism effects of DC bias?
We built a huge power transformer about 6 feet tall that had a circular core, all the lams had to be cut to a different width, there were some gaps in the corners that got filled in with hardwood, as there was a limit to how many sizes we could order,
Round coils might sound better than square coils, never tried it,
You can have PRI and sec wound on two different bobbins, great for isolation but lots of leakage. This is how iso transformers are wound.
Round coils might sound better than square coils, never tried it,
You can have PRI and sec wound on two different bobbins, great for isolation but lots of leakage. This is how iso transformers are wound.
Disco Volante
Well-known member
That's exactly how those welding transformers are wound. Pri on one half of the bobbin, then the movable core, then the sec on another half bobbin. I just took one apart last week, forgot to get pics of it. It was all molten plastic and aluminium wire, but a nice big core...
Newmarket
Well-known member
No expert either. But isn't this where gapped/untapped cores come into it ?
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