Replacing Transformer in 5E3 Tweed Deluxe

[jjmantele]

The extra wire would need to be insulated and connected to nothing if an exact original heater wiring plan is what you want. You have 3 altenatives:

Use exact original wiring (most hum potential.)

Use grounded center tap (green/yellow) wiring for reduced hum potential. This requires changes to other wiring.

Use virtual center tap wiring for reduced hum. Must Add 2 resistors and this requires changes to other wiring.

[iReally]

Ok, thanks. So the extra wire is basically there so it can be wired in to reduce hum. But if I'm not too worried about the hum factor (I guess I can always change my mind later), I can wire it up the original way without using the Green/Yellow wire and everything will be fine. Someone correct me if I'm wrong.

Anyone know about the nuts that came on the transformer that I asked about in my last post? They definintly look like they should be used to attatch the transformer to the chasis, especially with the rubber washers under them. I just don't understand the sticky amber colored stuff that seems to be sealing the nuts on...

[zook]

ignore, accidental post.

[zook]

Originally Posted by iReally

Ok, thanks. So the extra wire is basically there so it can be wired in to reduce hum. But if I'm not too worried about the hum factor (I guess I can always change my mind later), I can wire it up the original way without using the Green/Yellow wire and everything will be fine. Someone correct me if I'm wrong.

Anyone know about the nuts that came on the transformer that I asked about in my last post? They definintly look like they should be used to attatch the transformer to the chasis, especially with the rubber washers under them. I just don't understand the sticky amber colored stuff that seems to be sealing the nuts on...

The Green and yellow wire is probably the center tap for the 6V heaters. You can just ground it along with the Red/Yellow center tap for the B+. I'd wire them to the ground of the first filter capacitor..

The sticky stuff on the nuts is the equivalent of nail polish. It's there to keep the nuts from backing off. You could take the nuts and lock washers off and mount the transformer. I would look first, however to see if there's a second set of nuts in the package. Usually you would leave the one set of nuts on the bottom of the transformer and use another set to mount it. The nuts are likely #8 32.

Winnie

[Rick S]

Originally Posted by zook

The Green and yellow wire is probably the center tap for the 6V heaters. You can just ground it along with the Red/Yellow center tap for the B+. I'd wire them to the ground of the first filter capacitor..
Winnie

This amp has one end of the 6V winding on the chassis. DO NOT connect the center tap, unless the heater circuit is rewired to lift the existing chassis grounds. Loop it, shrink wrap it and carefully tie it out of the way.

Regarding the nuts, you need new nuts, or you can probably harvest the nuts from the old transformer. If you try to take the nuts off of the new transformer, the bell will likely not fit the hole in the chassis properly. Proper installation will have 8/32 keps nuts on both sides of the chassis.

[iReally]

zook and Rick S,

Thanks for your speedy replies.

I'm going to go ahead and leave the Green/Yellow safely tucked away, at least for now. I can always unwrap it later if I decide to do some changes.

The transformer didn't come with any extra nuts, and I'm glad I asked about that because as much as the nuts on the transformer looked like they would work for mounthing, they also looked like they weren't supposed to be removed. The nuts from the old transformer do work for this task, good idea Rick.

[zook]

Originally Posted by Rick S

This amp has one end of the 6V winding on the chassis. DO NOT connect the center tap, unless the heater circuit is rewired to lift the existing chassis grounds. Loop it, shrink wrap it and carefully tie it out of the way.

Regarding the nuts, you need new nuts, or you can probably harvest the nuts from the old transformer. If you try to take the nuts off of the new transformer, the bell will likely not fit the hole in the chassis properly. Proper installation will have 8/32 keps nuts on both sides of the chassis.

ooops that's correct.

Winnie

[Silverface]

I'm jumping in real late.

I honestly think those who are being kind and trying to assist you because you keep insisting you want to do this yourself are doing you a great disservice.

There is SO much more to "fixing" an amp than hooking up wires in the right place.

"although none are blistered and they all apear to be ok in the opinion of my buddy that looked at the amp. I'm sure they are not working "like new" but I don't mind if the amp sounds old because, well, its old."

A good example of "over your head" - "appear to be OK" means exactly nothing. Your buddy may have NO qualifications. Not working "like new" and "don't mind" are utter naivete. When they don't work "like new" they are in danger of blowing...and that may be exactly why a transformer was replaced to begin with, because ONE blown cap can take out a transformer.

When you install the transformer you decide on, how will you run the filament wires? Do you know how and where to twist them, and what direction/distance they need to be from other components? Do you know which wires are kept long and which are kept very short?

Do you know ANYTHING about "lead dress" or even the term?

Have you had at least a high-school electronics course? Can you look at a resistor and know the value by the color bands?

I can really appreciate wanting to do this yourself, and wanting to learn. But those are two different things. This amp IS NOT a good "teaching tool".

IMO you need to do some heavy reading first - Funk, Mitchell, Weber - all those books are good and bad, and you need to read all of them to LEARN what's fact and what's opinion.

But the simple fact is you have no idea what you are doing, and are just going about this from a "hook up wires to the right place" angle, which iss completely invalid. Proper lead dress is critical, or you'll end up with an amp that will hum, hiss, shut down due to high-frequency instability...and you will have no idea what's happening or how to fix it.

I do not mean to sound harsh, but you really need to stop. You stand a good chance or cooking a classic, collectable amp, and you are, IMO, taking the wrong approach.

Read some books. Take an electronics class. Build a Champ kit next. Acquire the proper tools (multimeter, signal genrator, scope, dummy load). THEN start doing heavy-duty reapirs like transformer replacement - here you need to find out what happened in the first place.

I've been working on tube amps for 40 years, and I rarely replace transformers, as I don't feel I have the proper test equipment to determine why it blew in the first place.

I hope you do learn all you can about amps and become capable of ding at least some of your own repairs - but you are not qualified in any way, nor is advice given on an internet forum by well-meaning folks (where you have no idea of THEIR experience) sufficient for you to undertake this project.

I have a strong feeling you will completely ignore this. But I think it needed to be stated, if only so others will have an idea what they might or might not be capable of fixing.

Good luck.

Jim

[Wally]

The green/yellow should be the center tap for the heater filament. Was there no wiring diagram with the transformer?

[CoolHandDuke]

This amp has one end of the 6V winding on the chassis. DO NOT connect the center tap, unless the heater circuit is rewired to lift the existing chassis grounds. Loop it, shrink wrap it and carefully tie it out of the way.

I'm going to go ahead and leave the Green/Yellow safely tucked away, at least for now. I can always unwrap it later if I decide to do some changes.

MAKE SURE it is shrink wrapped and taped COMPLETELY outta the way

last thing you want is a loose wire end exposed and causing an electrical arc

[CoolHandDuke]

Jim-

I honestly think those who are being kind and trying to assist you because you keep insisting you want to do this yourself are doing you a great disservice.

There is SO much more to "fixing" an amp than hooking up wires in the right place.

very solid points

"although none are blistered and they all apear to be ok in the opinion of my buddy that looked at the amp. I'm sure they are not working "like new" but I don't mind if the amp sounds old because, well, its old."

i think his point is he wants to get to minimum working order and go from there

A good example of "over your head" - "appear to be OK" means exactly nothing. Your buddy may have NO qualifications. Not working "like new" and "don't mind" are utter naivete. When they don't work "like new" they are in danger of blowing...and that may be exactly why a transformer was replaced to begin with, because ONE blown cap can take out a transformer.

very good points. you seem to know what you are doing.

When you install the transformer you decide on, how will you run the filament wires? Do you know how and where to twist them, and what direction/distance they need to be from other components? Do you know which wires are kept long and which are kept very short?

Do you know ANYTHING about "lead dress" or even the term?

Have you had at least a high-school electronics course? Can you look at a resistor and know the value by the color bands?

excellent questions

I can really appreciate wanting to do this yourself, and wanting to learn. But those are two different things. This amp IS NOT a good "teaching tool".

IMO you need to do some heavy reading first - Funk, Mitchell, Weber - all those books are good and bad, and you need to read all of them to LEARN what's fact and what's opinion.

how would he know whats good and whats bad without some advice from one who knows

But the simple fact is you have no idea what you are doing, and are just going about this from a "hook up wires to the right place" angle, which iss completely invalid. Proper lead dress is critical, or you'll end up with an amp that will hum, hiss, shut down due to high-frequency instability...and you will have no idea what's happening or how to fix it.

I do not mean to sound harsh, but you really need to stop. You stand a good chance or cooking a classic, collectable amp, and you are, IMO, taking the wrong approach.

Read some books. Take an electronics class. Build a Champ kit next. Acquire the proper tools (multimeter, signal genrator, scope, dummy load). THEN start doing heavy-duty reapirs like transformer replacement - here you need to find out what happened in the first place.

could he not get all the info from very knoweldgeable guys like yourself here?

I've been working on tube amps for 40 years, and I rarely replace transformers, as I don't feel I have the proper test equipment to determine why it blew in the first place.

so you have been doing amp work for 40 years without the proper test equipment?

how has it worked out for you? respectfully

I hope you do learn all you can about amps and become capable of ding at least some of your own repairs - but you are not qualified in any way, nor is advice given on an internet forum by well-meaning folks (where you have no idea of THEIR experience) sufficient for you to undertake this project.

I have a strong feeling you will completely ignore this. But I think it needed to be stated, if only so others will have an idea what they might or might not be capable of fixing.

Good luck.

Jim i hope my ?'s arent seen as disrespectful

but rather than tellling someone who is obviously headstrong not to do it because they dont know how why not explain how?

someone told you right?

you seem to have a vast knoweldge that a teenager could learn a lot from

most people have quite a few things to say about kids today and yet here is one who seems to realize the great value in self-reliance, learning, seeking advice from those more expeirienced, etc.. and i would think many would appreciate those values here


again very respectfully Silverface

[Silverface]

CHD - thanks for making some good points.

Regarding test equipment, I don't do "heavy" work any longer (i.e. transformers or analyzing an unknown chassis) because I *no longer* have a scope and the other stuff. I used to, but didn't use them often enough. and sold them. Cap jobs, biasing and basic service I can do without those. But he's into a "serious" job requiring the right equipment.

"could he not get all the info from very knoweldgeable guys like yourself here?"

Honestly? No. Not at this level. Anybody taking this type of job has to already know all the little things - biasing an amp, proper lead dress, wire length/type, knowing that caps "looking good" is meaningless...analogy: he's going from riding in cars to asking "how do I drive an F1 car, I want to do it tomorrow?" without ever getting a driver's license or taking driver's training...which you can't do on an internet forum.

The problem is not so much the job that he's doing - it's WHY he HAS to do it. What caused the problem? He has no clue how to look for signs of....anything. He doesn't know what to test, nor HOW to test. Is the transformer defective? Did it blow because of a bad cap? Is there a speaker load issue? Bad insulation and a short? A power surge? Did a power tube flip a plate? Is a critical resistor open?

You don't ever simply replace a blown transformer - you find out WHY it blew first. That's not an optional task, it's required, or you stand a good chance of blowing one all over again.

I question whether or not he can check the plate voltage and bias the amp - and without those two tiny things, he's apt to be buying another transformer...and another. If his plate voltage is out of balance, too high, too low, if the bias is on a "runaway".....this is what qualified techs get paid to do.

You don't start *here*. You start with 1) learning the safety requirements, and 2) replacing tubes and learning how to bias. Baby steps.

When the question came up regarding a 3-prong plug I flat knew the original poster was in WAY over his head. That kind of stuff is common knowledge to the most inexperienced of amateur techs.

I see him putting himself in danger and wrecking an otherwise good amp. It's not a job for someone at that level, and the knowledge required can't be gained here. He needs to be well-grounded (pun intended) in the basics first.

Edited to add - I GREATLY respect what he wants to do, and his straight-ahead attitude. But sometimes wisdom needs to be respected more than desire...and this is such a case. I hope he takes the advice, learns from the resources given and becomes a monster tech...but you have to start small.

[TC7]

I don't know... I think if the young enthusiast has a burning desire to learn this stuff, it's not all that hard to learn and he'll have it forever.

It's really not that big a deal if he blows up his amp... even if it is a nice old amp. He'll probably remember the explosion the next time he gets a nice old amp. Or he'll regret it, like every one of us regrets all the guitars and amps we let get away for stupid reasons.

I don't think we can save his life by telling him to not do the work because he might be killed.

When I was 19, if you told me something I was doing would DEFINITELY kill me, I'd keep doing it ...because 19 year olds are a little bone-headed. (I been one, I raised two!)

I think... after we give him all the obligatory warnings... it sort of becomes our duty to help him out as much as possible.

I think he'll be fine because he's been warned and will now also have a ton of help from the good folks here.

No time like the present. No end like the deep end.

[geoffreysnow]

i'm surprised this thread wasn't closed by the mods a long time ago.

this kid obviously has no idea what is what inside an amp and it's just a matter of time before he seriously shocks or even kills himself. then his next of kin will hear how we "encouraged" him to dig inside the amp and next thing you know there's a lawsuit.

last I checked there's no disclaimer posted loud and clear on this forum like some of the other amp builder forums. open target for someone to sue...

or if it's not this guy then it's the next guy who picks up a project amp thinking he can get as much support as he needs to get it going again from an online forum even though he has no background in the electrical field.

If it's someone asking what so and so sounds best in an amp, that's fine. if it's someone asking what goes where and detailed step-by-step-guys-on-the-forum-know-what-they're-doing-so-if-something-goes-wrong-it's-their-fault-kind
of questions are the ones who will point fingers and have a case against this forum.

[zook]

Oh Christ here we go... give the kid a break and get down from your high horses.

iReally try going to AX84.com, you'll find a less pompous crew there

Winnie

[iReally]

geoffreysnow,

I've been nothing but completely respectful to everyone in this forum, even those who don't approve of my project. However, I really don't appreciate post like one you just made. Saying "this kid obviously has no idea what is what inside an amp and it's just a matter of time before he seriously shocks or even kills himself" is not productive at all and is very rude. I understand your view (because you stated it before) and now I feel like your just here to complain. There will be no law suit. No one is encouraging me to do this, they are just answering my questions. It has been made very clear that there is danger involved in this project. I am respectively requesting that you don't post in this thread anymore unless you have something productive to say. As always, I mean everything I say with respect and I'm not trying to start any trouble. I'm here to learn and ask questions. I am in no rush to complete this project so I have plenty of time to figure it all out.

TC7,

Thanks a lot for your support! I'm learning a lot and I plan to continue doing so. I really appreciate people like you who want to help me learn rather than telling me to give up.

Silverface,

I'm glad you found this thread because you really seem to know a lot about amps. I understand where you are coming from because I don't seem qualified to take on this project, especially to someone with a lot of experience working on amps.

However, there are a few things I want to clear up:

- The part I posted about the capacitors "looking ok" is old. I have read up more about capacitors (and have been advised by the fine people of this forum) and now realize that there is a good chance that some of the capacitors are shot even if they "look ok." I am trying to learn how to test them, I believe I read that they can be tested using a multi-meter (I found one that I can borrow from my dad). I still have a lot of reading to do on that, but I certainly am aware that the caps are an issue that needs to be investigated further. (as a side note: upon further inspection, one of the caps does have a blister on the bottom so even with "useless" visual inspection it seems that one of them is shot)

-As far as resistors, I don't have the values of the color bands memorized, but I have found charts online for that.

-I know nothing about "lead dress" but as soon as I'm done typing this reply I will go look it up. Thanks for mentioning it because no one else has yet. If you have any pointers for me they would be greatly apprectiated.

-"I do not mean to sound harsh, but you really need to stop. You stand a good chance or cooking a classic, collectable amp, and you are, IMO, taking the wrong approach."

While I greatly respect this opinion, it is the approach I want to take. The way I look at it, it is a classic, collectable amp that has already been tainted. The tweed was completely ruined and someone else has already hacked it up before me. The original speaker is in terrible shape and the original transformer is missing. The original handle is also gone. The original rectifier tube caught fire (possibly because of the incorrect transformer that was used by the previous owner?) and the other original tubes have been removed and will be kept for a later time.

At this point, my approach on this amp, is that if I am now planning on changing out the capacitors, most parts that can be destroyed have been or can be replaced.

I'm sure as a long time vintage amp enthusiast it probably makes you cringe to think of me playing such a collectors piece, but it's my amp and this is the direction I have chosen for it.

-Find the reason the original transformer blew is certainly at the top of my priority list. If that wasn't made clear before (which it might not have been) I would like to make that clear now.

-"I have a strong feeling you will completely ignore this."

I certainly am not ignoring you (I guess that is obvious) but, in fact, I am doing quite the opposite. I am very glad to have your advice and I hope you will consider checking this thread periodically to maybe help me out with some of my questions.


- I realize this is a large task, but I am in no rush to complete it. I'm going to take it one step at a time.

CoolHandDuke

Thanks for bringing up strong counter points in my defence as well as sorting through the information to let me know what parts Silverface brought up that I should be considering for my project. He seems very knowledgable, just a little over the top.

zook

Thanks for being an all around helpful guy and letting me know about that other site. I will certianly check that out.

[Silverface]

ireally - Thanks for that post, you clarified a lot of issues.

First, I commend you for looking up everything you find on here that's new to you - most don't have the patience (or brains!) to do that.

Also, now that I know exactly what you have - a "project" amp with little vintage value except as a "player" (i.e. a non-original, non-collectable) I see it as the perfect platform to learn some things on. I did the same thing MANY years ago with a Super Revrb.

But - (you knew it was coming... )

I still firmly believe you need basic electronics knowledge before touching a thing. If nothing else, a basic US Navy radio training manual or any "Electronics 101" from a trade school library would be a start. I think the lawsuit thing is pretty silly (precedents have been set that would cause such a case to get tossed out instantly) but basic electronics knowledge is invaluable - and look up everything you can find about discharging electrolytic caps - to reiterate what was said earlier, those things can kill you even if the amp is unplugged and has not been used for months!

Seeing that transformer outside the "box" with all the wires connected scared me, honestly. Don't do that. Make sure things are properly mounted BEFORE testing - there are ground issues you may encounter that could knock you across the room.

ONE HAND inside the amp at a time. Always.

If you want to poke at parts, move wires, etc, use a wooden chopstick or small dowel rod. NEVER a hand, screwdriver, or even plastic part you're unsure of (some plastics are conductive).

So please, do some more reading and don't touch anything until you have a firm grasp on what each of the major components does, which direction the current flows, and REALLY understand grounding issues. Then we can get down to things in a specific sequence that might get you somewhere.

You'll still probably need a tech since there's still the "what happened?" question...but once that's determined you seem smart enough and methodical enough to get through this. As I said before, it's flat impossible to post every detail you need to know, which is why you HAVE to do your homework - and you certainly didn't pick the easiest way to get started - but by the time you're done you'll be miles ahead of most "bedroom techs".

And I'm actually not "over the top" - I'm careful in what I advise to ensure I'm not throwing guys into an alligator pit. "Cautious" would be the correct term (and I think most truly qualified techs would agree with 99% of what I asked).

So - what's the next question?

[iReally]

Silverface,

-Thanks for the practical list of safety precautions. I am familiar with most of what you said but it certainly never hurts to go over basic safety. I appreciate that.

-As far as my next question, I have a lot of reading to do for now. You covered a lot of things that I am not entirely familiar with so I will be reading up. I guess my next question would be- What book should I start with? The internet has provided me with a lot of good information but I know from previous projects that it is hard to beat a good book.

-I am also going to be talking to my uncle who has a degree in electronics. He has been an electronics technician for many years and a guitarist for even longer. I'm not sure how much experience he has with working on tube amps, but he will be able to answer all my basic electronics qustions.

Thanks for your help!

[geoffreysnow]

Originally Posted by iReally

geoffreysnow,
However, I really don't appreciate post like one you just made. Saying "this kid obviously has no idea what is what inside an amp and it's just a matter of time before he seriously shocks or even kills himself" is not productive at all and is very rude.

i'm stating the obvious. plain and simple. I'm a contributing member at this forum and i like it a lot because people here are willing to help. but when some kid comes in and says screw everyone's advice about having it professionally looked, especially when you have no idea what you're looking at, I get a bit upset. you'll get tons more help if you do your homework first. ask questions and learn. don't come in and say help me fix this.


looking back at an older post of yours to show even more of your ignorance of amps:

Originally Posted by iReally

I understand that if most people had this amp they would want it to be professionally restored, but I'm not most people. I want to get this amp in working order so that it sounds good to me. Not necessarily exactly the way it sounded 50 years ago, but so it sounds good to me. I don't mind if the amp sound old and imperfect. I like that. I am excited about this amp as a project almost as much as I am excited about playing it.

that makes no sense at all. explain that one to me. i think you have no idea what it sounds like or can sound like. a safe and properly working amp should sound a certain way - good. your posts drip with ignorance.

In no way am I saying that you shouldn't ever work on amps. I'm just saying this is a big project and you have zero experience.

In regards to my previous post, people have sued for smaller things. I heard s2 amps is getting sued by someone who tried to make their kit. I just don't want to see this place fall victim.

[iReally]

geoffrysnow

Please just stop. I have found a bunch of people here that are willing to help me with my project. If you don't like what is happening in this thread, find another one to read. I don't doubt your knowledge of amps, but we just aren't right for each other.

I have heard these amps, I know what they sound like.

I can assure you that neither I nor my family will be sueing anyone as a result of this thread.

You are suggesting that I do my homework first and then ask questions. I am here to ask questions so that I know how and where to do my homework.

I'm sorry if this thread or my methods are upsetting to you, but don't lose too much sleep over it. It's all good buddy.

As always, I don't mean any of this out of disrespect.