Modifying a Chandle Tube Driver to work on 220v

[Tubetec]

They do tend to make the swappover easy and try to prevent any chance of miss wiring the primary by accident .

 

[lead_coda]

Hey guys, thank you so much for the help. I looked a lot of online info, with what you guys said, and I'm pretty sure I got it now! That being said, I think the top picture of the rack can be misleading, the pin 3 PCB link is between 1 and 2. So I want to confirm I understand properly, with an image of the top and bottom well identified. Numbers represent the pins, letters the PCB trace. The letter B is the one that is misleading.

Black wire stays the same.
Break the link between the 1 and 3 (on the PCB top, red cross on my drawing)
And then change the white wire so it's not connected to 4 (which is already link to 2, I added a red line in the drawing but the link is already there), I could connect it to B.

Does that make sense? If anything in my drawing is not clear please ask.

Cheers

 

[Walrus]

I also agree with Tubetech and Ian.
In your new pictures, cut the links between a & b, and between c & d. Then put a link
between b & c.

 

[scott2000]

d is also feeding pin 4 under the board?

 

[ruffrecords]

The mains comes in on 1 and 4. I am sure this was designed so this would not have to be changed when setting links for different mains voltages. So I think you need to start with that assumption.

Cheers

Ian

 

[lead_coda]

HAhahahaha, my god this morning I thought I understood, now I'm more confused a bit. Here's a graph of the transfo, the first is how it's wired right now. And the second, option one is what I understood it should be, but option two is how Ian, Tubetech and pretty much everybody is telling me to do. Wouldn't this be wrong because of the polarity of the transformer, the dots? So I just want to double-check before I do something I regret.

Thanks for spending time helping me understand, appreciate it!

Cheers

 

[scott2000]

I messed up and posted the wrong picture of the windings I guess. Not sure how that happened.....
1 datasheet says one thing

http://www.thordarsonmagnetics.com/selectorPages/14-PFC-Series.pdf
and another says a different thing

https://www.datasheetarchive.com/pd...c119133c31d735eec1abbcfe36&type=O&term=PFC242

 

[lead_coda]

Oh shit, that makes more sense! It's weird, though, first thing I posted I had a chart like that but the polarity point were like the other one. But if it's like the one you just posted, all everybody was saying makes so much more sense!

That being said... does this mean the polarity of how it's wired now is wrong? Like 1 connected to 3 (two neutral) and 2 to 4 (two positives)?

 

[scott2000]

That being said... does this mean the polarity of how it's wired now is wrong? Like 1 connected to 3 (two neutral) and 2 to 4 (two positives)?

I'm not clear on this description.... Looks like your option 2 is the correct way to go...Just like everyone else has been saying all along.
Sorry for the confusion...Kinda ticks me off about the datasheets bc it was stressing me out too...not sure what that's all about... I'd much rather learn from my mistakes without other variables making that trickier. Still not convinced I am not seeing something correctly...I mean, are there 2 different versions floating around?

 

[Tubetec]

Follow the simple legend on the pcb , its idiot proof ,
You dont need to swap wires , dismantle the pcb from the housing or worry about pinout or phasing the windings correctly , thats been done for you ,
two cuts ,one wire link ,

 

[lead_coda]

Tubetec, it makes sense; you're right. I'll do what is written on the PCB and then I'll keep you guys posted. Thank you so much.

It was a bit confusing for me as my skills are really those of a hobbyist. But I like to understand things and not just ''do it''. Also the unit had already been tempered by the previous owner, so that also added to my confusion. But with all your help, I think I understand more the principle and I'll also be able to modify my spring reverb.

Cheers guys

 

[ruffrecords]

Oh shit, that makes more sense! It's weird, though, first thing I posted I had a chart like that but the polarity point were like the other one. But if it's like the one you just posted, all everybody was saying makes so much more sense!

That being said... does this mean the polarity of how it's wired now is wrong? Like 1 connected to 3 (two neutral) and 2 to 4 (two positives)?

No, that is a normal parallel connection which is what you need for 115V. For 230V you need the two in series as described by Tubetec. Like said before, the mains is wired to 1 and 4. You want to leave that as it is.

Cheers

Ian

 

[lead_coda]

Hey, good morning, everyone,

I wanted to keep you guys updated. The surgery was a success. Everything seems to work, the unit sounds fantastic. Thank you so much. My only issue at the moment and I have a really hard time figuring if it was like that before, but I don't think so. The unit now physically buzzes a little bit, not super loud but enough for when it's silent to hear it. Anything I should be concerned with or even something fixable, in your opinion?

Cheers

 

[scott2000]

The unit now physically buzzes a little bit

Could be the transformer working hard for some reason. What kind of voltages are you getting at the heaters or op amp power supply pins?

 

[Admiral-dk]

I suspect that the original transformer is wound for 110/220Vac. - the PCB text suggest this to be true ...!

That is more often than not, a problem in modern day Europe, as the EU harmoniced the voltage to be 230Vac. all over Europe in 1993.
The result is that all Transformers wound with as few Primary turns as possible for 220Vac. actually sligthly saturates when you apply 230Vac. to them => Stray Magnetic Flux outside the Core ... and this is one of the cases where a Toroidal Transformer will give you much more grief than an E-Core ---- admittedly not your problem - but the E-Core will also be noisier ...!

If you are lucky - you can still obtain / find a 230Vac. Transformer with the correct data and simply replace the original -> problem solved.
But these are getting rather hard to find today

Per

 

[lead_coda]

Could be the transformer working hard for some reason. What kind of voltages are you getting at the heaters or op amp power supply pins?

I did not have time to check that yet, as my work got back to me in force this week.

I suspect that the original transformer is wound for 110/220Vac. - the PCB text suggest this to be true ...!

That is more often than not, a problem in modern day Europe, as the EU harmoniced the voltage to be 230Vac. all over Europe in 1993.
The result is that all Transformers wound with as few Primary turns as possible for 220Vac. actually sligthly saturates when you apply 230Vac. to them => Stray Magnetic Flux outside the Core ... and this is one of the cases where a Toroidal Transformer will give you much more grief than an E-Core ---- admittedly not your problem - but the E-Core will also be noisier ...!

If you are lucky - you can still obtain / find a 230Vac. Transformer with the correct data and simply replace the original -> problem solved.
But these are getting rather hard to find today

Per

Other than the noise, is there any danger? Will this in the long run break my unit, burn my house down or create a black hole?

Cheers

Pat

 

[ruffrecords]

I suspect that the original transformer is wound for 110/220Vac. - the PCB text suggest this to be true ...!

That is more often than not, a problem in modern day Europe, as the EU harmoniced the voltage to be 230Vac. all over Europe in 1993.
The result is that all Transformers wound with as few Primary turns as possible for 220Vac. actually sligthly saturates when you apply 230Vac. to them => Stray Magnetic Flux outside the Core ... and this is one of the cases where a Toroidal Transformer will give you much more grief than an E-Core ---- admittedly not your problem - but the E-Core will also be noisier ...!

And because he is in the UK the mains voltage is actually 240V. And 50Hz rather than 60Hz only makes saturation that bit closer. The harmonised spec says something like 230VAC plus or minus 10%. UK mains voltage always has been 240V. There was no way the entire UK network was going to change to 230VAC when harmonisation occurred but it meets the spec. It is unfortunately true that mains transformer designers always fly close to saturation.

Cheers

Ian

 

[Admiral-dk]

I would be VERY surpriced if it can burn the house down - unless you change the Fuse to one with a MUCH higher rating ...!
If you are very unlucky - you might have the Transformer melt itself ....
Not likely, if my experience can be used here. I have changed a number of Mains Transformers over the years - the majority in (Guitar & Bass) Tube Amps (and a bigger number of Output Transformers) and the wast Majority has been the result of either Bad Output Tubes or defect BIAS Circuits. Then there has been a (much) smaller number, where I'm quite sure that they wheren't big enough from the Factory -> Overheating to more then the 'Warnish/Lacquer' on the Copper Windings can stand. Some are most likely the result of a Lightning hitting the Mains Grid. And the remaining where absolutely not possible to guess (without an Ortopsy) - here there might be a few that is the result of being 220Vac. Primary running on 230Vac.

All that said - considering the huge amount of old Fender, Marshall and other 220Vac. Amps still playing without any problems - don't worry.

I know from my Brother in Law - that there are 3 very old English Powerplants that are actually 250Vac. - always where and still are on your Grid ...!... that only has influence on their local area. I just Googled and found UK Mains Voltage.
I do agree on 50/60Hz. - but since it is wound to accept both 110Vac. and 220Vac. - I'm pretty sure that 50Hz. is OK.

 

[scott2000]

The datasheets, both of them,
say it's rated 230V, 50Hz

https://www.datasheetarchive.com/pd...c119133c31d735eec1abbcfe36&type=O&term=PFC242
http://www.thordarsonmagnetics.com/selectorPages/14-PFC-Series.pdf

 

[Admiral-dk]

True - but the text on the PCB suggest that your unit is old enoug to have been made before the EU standard of 2009 and that the Transformer is 220Vac. (unless there is a text on itself saying 115/230Vac.) .... and sometimes we still see the same sparepart numbers afterwards (maybe with an appendix to it).