thefragger
Certified Crazy.
OK, good tip, but the stackup of those three pieces are to be of equal volume of the core?
Like this? (quick sketch)
Scott 130 power transformer fix revised.
- Thread starter stanko
- Start date
OK, good tip, but the stackup of those three pieces are to be of equal volume of the core?
Like this? (quick sketch)
The wood model for winding a bobbin has the same outside dimensions as the core of the transformer iron, the part the windings will be wrapped around after assembly. You can certainly use wedges, but a thin piece of wood sandwiched between two thicker ones is a lot easier to manufacture correctly and will work fine. You won't have any trouble driving the center piece out if you keep it small and don't wrap everything too tight. Remember, the bobbin will shrink as it drys anyway, or will at least try to. I hope I am explaining correctly. I didn't make a bobbin so I don't have any pictures of doing it. I do have some extras around here from other transformers, I'll try and find them.
thefragger
Certified Crazy.
Ooh, ok, I get what you mean about the three pieces now. I had the location incorrect.
Does the thickness of the wood bits matter?
Sorry for going so far off-topic!
I don't think you're off topic at all. The post is to show people they can rewind a transformer. Best Regards to you and thanks for all the questions. Makes me glad I bothered to take the pictures. Wasn't sure anyone cared .Ooh, ok, I get what you mean about the three pieces now. I had the location incorrect.
Does the thickness of the wood bits matter?
Sorry for going so far off-topic!
thefragger
Certified Crazy.
Oh, I'm excited that you shared!
I'll need to trundle down to the machine shot and make my own winder like your purchased one (with the threaded carriage + pulley setup), but maybe build a single/double idler in so I can reverse the direction during winding.
:scratch2:
Wood goes on the narrow ends, right, like this?
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audiodon
Addicted Member
Moderators:
I nominate this thread to be a sticky. I do wonder the following though:
1. If stanko would like to retitle it. Essentially it's a transformer winding overview and the title is misleading of where the thread has gone.
2. It's a good question whether it should be a sticky here in tubes or perhaps in DIY.
This is one I'd like to be able to refer to later.
I nominate this thread to be a sticky. I do wonder the following though:
1. If stanko would like to retitle it. Essentially it's a transformer winding overview and the title is misleading of where the thread has gone.
2. It's a good question whether it should be a sticky here in tubes or perhaps in DIY.
This is one I'd like to be able to refer to later.
Some pictures of a hand wound quick core (Bobbin to some) for winding. I didn't use glue, just wanted to show the procedure. This shows the proper orientation of the wood. You want to be able to see all the pieces while winding, an end view sort of speak in the drafting world. I just grabbed two pieces, three is easiest to take apart later.
Attachments
I don't know how to do any of those procedures.
thefragger
Certified Crazy.
Super job Stanko! Proof's always in the puddin'.......
No doubt we've all got some transformers we could "repurpose" for better use. Your thread shows just what is possible, and with the wisdom from practical experience to boot. Thanks for sharing what you've learned, and passing on your tips!
Dave
No doubt we've all got some transformers we could "repurpose" for better use. Your thread shows just what is possible, and with the wisdom from practical experience to boot. Thanks for sharing what you've learned, and passing on your tips!
Dave
s-petersen
Scott
How close did you come to the desired voltage?Looks fantastic!
My calculations pointed to around 91 or 92 winds for 15 volts at the filament series groups. I had room and wire for about 105 so I put them all on there. I ended up with 18 volts which I reduced to 15 by using 2 10 ohm resistors instead of 1.35 ohm and 12 ohm as called for. I could have gone with calculated but I'm very happy with a little extra to drop across the filter networks. I suspect my ripple is much less than original while maintaining original voltages in the circuit.
chinacave
Its Like a Jungle Sometimes; It makes me Wonder
A quick glance at this article seems like a good adjunct to Stankos' description (?)
Possibly worth a read.
Rewinding a transformer article - EICO ST-84 Pre (Tronola site)
Possibly worth a read.
Rewinding a transformer article - EICO ST-84 Pre (Tronola site)
Destructor
Super Member
Somewhat off topic, I have a 130 in generally good condition. I’ve replaced nearly every Pyramid cap with OD’s. Unfortunately it’s never quite worked correctly, mostly a volume imbalance and intermittent hum in the phono section. I did have a tech go through it years ago and get it working relatively well but the imbalance remained. It certainly worked well enough to realize that the 130 is a great sounding preamp. Maybe I should just bite the bullet and bring it to someone who will thoroughly go through it and do what is necessary to bring it up to par.