can I get a trasnformer re-wound?

[pula58]

My pro reverb output transformer is blown (wires inside are shorting). Who can do a good job re-winding it?

[Groovey Records]

Mercury Mag will do it

They also have the replacement Tranny for a whole lot less do re mi $


FBFPROR-O

[donnyjaguar]

Find a transformer winder who is up for a challenge. My buddy used to wind transformers as part of his job at a manufacturer of commercial HVAC equipment. They could re-wind anything including interleaving and bi-filar and did small to large lam stacks.

[Prairie Dawg]

My pro reverb output transformer is blown (wires inside are shorting). Who can do a good job re-winding it?

What you can do is get yourself a replacement transformer with the same dimensions and carefully remove the end bells (if that's what it has) or the frame by unfolding the tabs on the bottom that secure the transformer body and putting the frame on your new one, and Bob's yer uncle.

[mark norwine]

I'll catch hell for this, but I worked at a transformer manufacturing facility for 6 years:

With this size transformer, there's no such thing as a "re-wind".

Dissection of a transformer:

1.) remove the bells. They can be reused.

2.) the lams get cut off with a bandsaw because they're either welded or glued (or just plain rusted) together. Can't re-use those!

3.) the 10 cent bobbin (if bobbin wound) or the former (if paper) is "chucked"...i.e. mounted on a freely-rotating arbor.

4.) the wire......miles of it......thin & intertwined, is pulled off. It is virtually impossible to salvage it, and even if you could get it off in one continuous length, you'd never get it back on. Not happening. I call BS to anyone who says otherwise. It goes out for recycling. And remember: it's bad to begin with! That's why you're having it "re-wound" in the first place.

After disassembly, what are you left with? 75 cent end bells & a 10 cent bobbin.

No, folks, there's no such thing as a "re-wind". There's only "Make a new transformer using old end-bells"

[WesKuhnley]

No, folks, there's no such thing as a "re-wind". There's only "Make a new transformer using old end-bells"


Classic. :bow

[OlAndrew]

Sort of like 'jack up the radiator cap and install a new Ford'.

[SatelliteAmps]

I'll catch hell for this, but I worked at a transformer manufacturing facility for 6 years:

With this size transformer, there's no such thing as a "re-wind".

Dissection of a transformer:

1.) remove the bells. They can be reused.

2.) the lams get cut off with a bandsaw because they're either welded or glued (or just plain rusted) together. Can't re-use those!

3.) the 10 cent bobbin (if bobbin wound) or the former (if paper) is "chucked"...i.e. mounted on a freely-rotating arbor.

4.) the wire......miles of it......thin & intertwined, is pulled off. It is virtually impossible to salvage it, and even if you could get it off in one continuous length, you'd never get it back on. Not happening. I call BS to anyone who says otherwise. It goes out for recycling. And remember: it's bad to begin with! That's why you're having it "re-wound" in the first place.

After disassembly, what are you left with? 75 cent end bells & a 10 cent bobbin.

No, folks, there's no such thing as a "re-wind". There's only "Make a new transformer using old end-bells"

I don't think you will catch hell for this. If you call any of the decent transformer companies, they will all back up what you are saying.

[Trout]

You know who might be a great person to send it to?

Matt at Music Power Supply (http://musicalpowersupplies.com/index.html).
He makes custom transformers, and does great work without beating you up in the wallet.

If it only has a shorted lead inside and CAN be fixed, he is more than qualified.

[Hacksaw]

sort of like 'jack up the radiator cap and install a new ford'.
lmao!!

[pula58]

well, I could get a new transformer and use the ends bells and frame of the old one...but...I keep askin gmyself why? Given that the OT is blown, I may as well get a new one (A Merc or heyboer) and just leave it at that. When I sell the amp (If I ever do) I will just have to take the price hit due to the fact that the amp doesn't have all original trannies. Oh well!

[pula58]

Well, afte some contemplation, I'm gonna get a new Merc Mags OT. I figure that the amp is no longer "all original" anyway...so..might as well get a tranny that has some appeal in case I want to sell the amp at some point. Then, maybe I can check into a re-wind at some point later on down the road. The idea of putting a new OT into the old frame and end bells sounds like a potential path to dishonesty if I ever sell the amp...don't want to go there...!

[gldtp99]

I think you've made a sound desicion---- a new OT is the best way to go IMO---many companies make great sounding iron these days............gldtp99

[Baxtercat]

Plus, Pro Reverbs had too-small trannies anyway. Get one w/ more guts and get a better sound.

[Prairie Dawg]

Well, afte some contemplation, I'm gonna get a new Merc Mags OT. I figure that the amp is no longer "all original" anyway...so..might as well get a tranny that has some appeal in case I want to sell the amp at some point. Then, maybe I can check into a re-wind at some point later on down the road. The idea of putting a new OT into the old frame and end bells sounds like a potential path to dishonesty if I ever sell the amp...don't want to go there...!

It's only dishonest if you deliberately misrepresent what is there.

[zzmoore]

I'll catch hell for this, but I worked at a transformer manufacturing facility for 6 years:

With this size transformer, there's no such thing as a "re-wind".

Dissection of a transformer:

1.) remove the bells. They can be reused.

2.) the lams get cut off with a bandsaw because they're either welded or glued (or just plain rusted) together. Can't re-use those!

3.) the 10 cent bobbin (if bobbin wound) or the former (if paper) is "chucked"...i.e. mounted on a freely-rotating arbor.

4.) the wire......miles of it......thin & intertwined, is pulled off. It is virtually impossible to salvage it, and even if you could get it off in one continuous length, you'd never get it back on. Not happening. I call BS to anyone who says otherwise. It goes out for recycling. And remember: it's bad to begin with! That's why you're having it "re-wound" in the first place.

After disassembly, what are you left with? 75 cent end bells & a 10 cent bobbin.

No, folks, there's no such thing as a "re-wind". There's only "Make a new transformer using old end-bells"

Does the iron "core" get thrown out in this process?

[Slunderfungus]

It's only dishonest if you deliberately misrepresent what is there.

:agree

[mark norwine]

Does the iron "core" get thrown out in this process?

Yes. Step 2: The lams get cut off with a bandsaw

[AL30]

You know who might be a great person to send it to?

Matt at Music Power Supply (http://musicalpowersupplies.com/index.html).
He makes custom transformers, and does great work without beating you up in the wallet.

If it only has a shorted lead inside and CAN be fixed, he is more than qualified.

:eek: Wow !! Those don't cost much at all. Do you have any experience with these transformers? How do they compare (construction and sound) to others? (hammond, heyboer etc). Sorry, don't mean to hijack you can PM me if you like.

AL

[Trout]

:eek: Wow !! Those don't cost much at all. Do you have any experience with these transformers? How do they compare (construction and sound) to others? (hammond, heyboer etc). Sorry, don't mean to hijack you can PM me if you like.

AL

Actually yes, I have bought a few transformers from him for various repair projects. They sound on Par with Heyboer, simple open frame construction, nice leads, and so far have been very durable.

Its my understanding that he does these as a hobby, so he might not have every model in stock at any given moment.
I like them, some of the projects I get in guys are looking for fast low cost fixes, when guys need something specific or high end, I buy accordingly.

Bang for the buck I give him an A-

[AL30]

Thanks for the info Trout. :wave


AL

[zzmoore]

I'll catch hell for this, but I worked at a transformer manufacturing facility for 6 years:

With this size transformer, there's no such thing as a "re-wind".

Dissection of a transformer:

1.) remove the bells. They can be reused.

2.) the lams get cut off with a bandsaw because they're either welded or glued (or just plain rusted) together. Can't re-use those!

3.) the 10 cent bobbin (if bobbin wound) or the former (if paper) is "chucked"...i.e. mounted on a freely-rotating arbor.

4.) the wire......miles of it......thin & intertwined, is pulled off. It is virtually impossible to salvage it, and even if you could get it off in one continuous length, you'd never get it back on. Not happening. I call BS to anyone who says otherwise. It goes out for recycling. And remember: it's bad to begin with! That's why you're having it "re-wound" in the first place.

After disassembly, what are you left with? 75 cent end bells & a 10 cent bobbin.

No, folks, there's no such thing as a "re-wind". There's only "Make a new transformer using old end-bells"

I am going to revisit this, because I still do not understand. In step #2 why are the lams being cut with a band saw? That is the core. It is the windings that need to be removed from the lams, and then the core is re-usable.
Why even bother to put the laminations through a saw? That destroys them. Why not just throw the transformer away while it is still in one piece?
Thank You

[mark norwine]

Tell me what you don't understand.

The lams are glued or welded together.....they're not going to come off without a fight, and as such are not reuseable. Bandsaw is fastest.

I might have you confused because these are not the steps to take for a rewind [which I still contend "there's no such thing'].....these are the steps for dissection, as if you wanted to count windings or study construction, etc. If there's no need to dissect a dead tranny, then yes...simply through it away.

mn

[zzmoore]

Tell me what you don't understand.

The lams are glued or welded together.....they're not going to come off without a fight, and as such are not reuseable. Bandsaw is fastest.

I might have you confused because these are not the steps to take for a rewind [which I still contend "there's no such thing'].....these are the steps for dissection, as if you wanted to count windings or study construction, etc. If there's no need to dissect a dead tranny, then yes...simply through it away.

mn

Hey Mark -
You know way more about this than I do. Are we mostly talking about shell core (or does it even matter) transformers? That is the type I have been trying to visualize. Other than separating the "I" lams from the "E" lams, is it necessary to do much to the laminations? For some reason, I thought you could just separate the two different lams, slide in the new windings, insulation, leads, etc. and then put the two lams back together.
But now I realize I do not even understand what holds the "I" and "E" together. So I guess that is my first question, how do you get those two apart? I suppose I am starting to get a glimpse of the problems you were discussing.
Another question.... would it be easy/easier to rewind a hollow core (if that is the right term) tranny? With one of those, could you just remove the windings, and rewind each side of the core, without having to de-laminate anything?
I realize this gets pretty involved. Don't want you to spend an hour typing a answer. I will be happy to take the dumbed down version.
I appreciate your time.
Thank You

[Prairie Dawg]

Tell me what you don't understand.

The lams are glued or welded together.....they're not going to come off without a fight, and as such are not reuseable. Bandsaw is fastest.

I might have you confused because these are not the steps to take for a rewind [which I still contend "there's no such thing'].....these are the steps for dissection, as if you wanted to count windings or study construction, etc. If there's no need to dissect a dead tranny, then yes...simply through it away.

mn


Jeez, Mark. Do you mean to tell me the Emperor ain't got any clothes on??

[davemccarthy707]

Get a nice 70's (cheaper) Bassman tranny to stick in there. You won't be disappointed!

[mark norwine]

Other than separating the "I" lams from the "E" lams, is it necessary to do much to the laminations? For some reason, I thought you could just separate the two different lams, slide in the new windings, insulation, leads, etc. and then put the two lams back together.
But now I realize I do not even understand what holds the "I" and "E" together. So I guess that is my first question, how do you get those two apart? I suppose I am starting to get a glimpse of the problems you were discussing.

They were never assembled with the idea that they'd be taken apart.

To begin with, understand that the lams, while made of metal, are coated so that there is no metal-to-metal contact in the final transformer. This insulation prevents eddy currents.

The lams are glued, varnished (cooked on) or sometimes welded in place, and after years of use are simply not going to come apart in any fashion that would render them reusable. So unless you want to go through the excersize of disassembly for the sake of education, there's little point in doing anything other than cutting them apart with a bandsaw.

Another question.... would it be easy/easier to rewind a hollow core (if that is the right term) tranny? With one of those, could you just remove the windings, and rewind each side of the core, without having to de-laminate anything?

You're over-thinking this. There are no parts of a small-sized transformer (aside from the endbells) which can be disassembled and easily reused.

My suggestion: go find an old, useless transformer.....heck, I'll mail ya one!....and take it apart. You'll see what I'm talking about very quickly.

[Roundtone]

I'll catch hell for this, but I worked at a transformer manufacturing facility for 6 years:

With this size transformer, there's no such thing as a "re-wind".

Dissection of a transformer:

1.) remove the bells. They can be reused.

2.) the lams get cut off with a bandsaw because they're either welded or glued (or just plain rusted) together. Can't re-use those!

3.) the 10 cent bobbin (if bobbin wound) or the former (if paper) is "chucked"...i.e. mounted on a freely-rotating arbor.

4.) the wire......miles of it......thin & intertwined, is pulled off. It is virtually impossible to salvage it, and even if you could get it off in one continuous length, you'd never get it back on. Not happening. I call BS to anyone who says otherwise. It goes out for recycling. And remember: it's bad to begin with! That's why you're having it "re-wound" in the first place.

After disassembly, what are you left with? 75 cent end bells & a 10 cent bobbin.

No, folks, there's no such thing as a "re-wind". There's only "Make a new transformer using old end-bells"

Refreshing and honest...

[MKB]

There is supposed to be a guy in Texas (unfortunately I can't recall his company) that would rewind transformers if you paid him enough. This was told to me by an old transformer designer I used to work with also based out of Texas back when I was into high current inductor design for work.

Rewinds could have some usefulness as the special steel in the laminations of old output transformers can be different than what is available in laminations today, and the steel formulation is very important for the tone of the transformer and thus the amp.

I have taken several transformers apart for reverse engineering as well as rewinding the secondary of one for a different voltage (although it was for a low voltage with not many wire turns, and the transformer was not varnished). Many transformers are not varnished or welded, and can be easily disassembled in a way it may be later reassembled. So it can be done but with varying degrees of difficulty.

If your transformer isn't varnished or welded, you stand a very good chance of getting it rewound by someone who knows what they are doing and is willing to do it. If the transformer is varnished, you may be able to take it apart but it would involve heat and maybe solvents to break down the varnish, making it a harder job. If it is welded, you're out of luck as you will have to cut it apart and this will destroy the laminations.

[Mike9]

I just ordered a new Heyboer OT for my Blackface Deluxe through Weber. I ordered Heyboer's version of a Fat Stack with 4, 8 & 16 ohm taps for like $55 - now that's hard to beat. I'd love to try an MM, but not for an extra $100 for what amounts to the same thing.

[pula58]

Hi Mike9,
Now that Ted W is gone, who helped you to order that OT at Weber? How much bigger is a fatstack than the normal OT?

Thanks!

{.