C2x running hot (continuation)

[dsmart705]

Had a chance this evening to finally check the "no load" secondary voltages of the transformer. Although the line and phono transformers physically look different (line appears to be a slightly larger unit) and have very different resistance coils the no load voltage is very similar.

Line transformer secondary - 51.4vac
Line transformer centre tap - 25.7vac

Phono transformer secondary - 55.4vac
Phono transformer center tap - 27.6vac

The line transformer got hot after 10 minutes of being plugged in while the phono transformer remained at room temp when it was plugged in. I will be placing a parts order tonight (might as well recap too while it's all apart) and will make a new thread on the conversion process. Based on these voltage numbers I will be going with the same transformer as the other fellow used which is the Amgis L-01 6364 25vA. Although I was initially pretty bummed about this situation it has pushed me to learn something new. I am concerned that moving to a toroidal transformer might have some negative impacts on the sound but I really do not have another choice.

 

[Sparkplug]

Had a chance this evening to finally check the "no load" secondary voltages of the transformer. Although the line and phono transformers physically look different (line appears to be a slightly larger unit) and have very different resistance coils the no load voltage is very similar.

Line transformer secondary - 51.4vac
Line transformer centre tap - 25.7vac

Phono transformer secondary - 55.4vac
Phono transformer center tap - 27.6vac

The line transformer got hot after 10 minutes of being plugged in while the phono transformer remained near room temp when it was plugged in. I will be placing a parts order tonight (might as well recap too while it's all apart) and will make a new thread on the conversion process. Based on these voltage numbers I will be going with the same transformer as the other fellow used which is the Amgis L-01 6364 25vA. Although I was initially pretty bummed about this situation it has pushed me to learn something new. I am concerned that moving to a toroidal transformer might have some negative impacts on the sound but I really do not have another choice.

Great job. Did the transformer get really hot as you experienced before? Any changes in secondary voltage due to heat? Did you do your experiment with heat gun? Sorry for multiple questions … just wondering.
I think that’s what you meant anyway but recapping best be done after all transformer issues have been dealt with and squared away, otherwise it’ll be a nightmare to troubleshoot.
Generally, the Xformer and the magnetic flux running through its core have the biggest effect on audio quality, so there will be a change in audio signature … how much, you will know after the change.

 

[dsmart705]

Great job. Did the transformer get really hot as you experienced before? Any changes in secondary voltage due to heat? Did you do your experiment with heat gun? Sorry for multiple questions … just wondering.
I think that’s what you meant anyway but recapping best be done after all transformer issues have been dealt with and squared away, otherwise it’ll be a nightmare to troubleshoot.
Generally, the Xformer and the magnetic flux running through its core have the biggest effect on audio quality, so there will be a change in audio signature … how much, you will know after the change.

1. Yes the transformer reached the same temp as when it was mounted in the C2x (confirmed by temp gun)
2. Negligible change in secondary voltage once it was hot (over 40 degrees)
3. Didn't bother with the heat gun again as the transformer was already hot.
4. Yes the transformer situation will be dealt with before any other parts are changed.

Not sure where the heat is coming from. One would think an internal fault would show as a noteable change in resistance or voltage (especially when hot) but they stay relatively stable.

I have read many differing opinions (as with all audio stuff) about the difference between EL and toroidal transformers. I feel like it could go either way with the change sound quality. Either way its better than using the C2x as a door stop.

 

[Sparkplug]

1. Yes the transformer reached the same temp as when it was mounted in the C2x (confirmed by temp gun)
2. Negligible change in secondary voltage once it was hot (over 40 degrees)
3. Didn't bother with the heat gun again as the transformer was already hot.
4. Yes the transformer situation will be dealt with before any other parts are changed.

Not sure where the heat is coming from. One would think an internal fault would show as a noteable change in resistance or voltage (especially when hot) but they stay relatively stable.

I have read many differing opinions (as with all audio stuff) about the difference between EL and toroidal transformers. I feel like it could go either way with the change sound quality. Either way its better than using the C2x as a door stop.

Okay, I can’t say I’m surprised because today after reading this I did what I should have done at the beginning, search the Japanese blogs on C-2x to see what they say.

LOL, the first one, almost right off the bat, was wondering if there was something wrong with his amp due to heating, LOL again, it seems you’re not alone. I really think the Japanese version all have this issue to some degree.

Sorry for the long post but I think it shows a workflow that’s relevant should you decide to replace transformers. Then I came across a second much more detailed blog of this guy who wasn’t getting any voltage out of one of the secondaries of his Xformers. He opened up the monster to investigate. He noticed two 330Ω resistors had heat discoloration, you may want to check that at some point, he didn’t mention R numbers …


Then he noticed he had no voltage out of the phono transformer so used a similar enough transformer he had laying around to see if that would work …


Hooked up the wires and shamelessly turned on the power …


It worked, with center tap voltages at ±25V. He even played Music with no problems. Then he opened up the C-2x transformer box and realized there was not a heck of a lot he could do in the way of repairs, he also mentioned internal fuses of one of the transformers having been blown (didn’t know there were any) …

So he ordered two toroidal transformers with similar almost the same specs …

It seems he went through much pain to make the transformer mounting plates fit but he did it, I have a feeling that kind of thing would be very much down your alley (mechanical stuff ) …

Then after running wires and soldering that involved some more pain, he used the 125V input of the transformers and insulated the unused 100V probably because he needed the higher secondary output of 24V, he didn’t explain.
He also tied up the middle wires of the secondary windings to use as center taps. After hooking up and powering on, he got ±20V going into the bridge diode (I think, he didn’t say). The rest was listening tests of various kinds which were all successful with no noise or anything out of ordinary. So the point of all this is that you most probably won’t notice much difference in audio quality updating your transformers. Also, I think the 25VA transformer is the right choice.
Again apologies for the long post.

 

[Shade Ruff]

Okay, I can’t say I’m surprised because today after reading this I did what I should have done at the beginning, search the Japanese blogs on C-2x to see what they say.

A huge tip of the hat to Sparkplug for this outstanding forensics find. This is but the latest example of this great forum's worldwide appeal and utility. As demonstrated here, Sparkplug's foreign-language proficiency and knowledge of where to search in that language paid big dividends!

Shade

 

[Sparkplug]

A huge tip of the hat to Sparkplug for this outstanding forensics find. This is but the latest example of this great forum's worldwide appeal and utility. As demonstrated here, Sparkplug's foreign-language proficiency and knowledge of where to search in that language paid big dividends!

Shade

Thank you for you kind words.

 

[Vint Age]

A huge tip of the hat to Sparkplug for this outstanding forensics find.

I couldn't agree more, for this one and for his other outstanding forensic finds posted elsewhere!!!

 

[Sparkplug]

I couldn't agree more, for this one and for his other outstanding forensic finds posted elsewhere!!!

Master … master … I’m not worthy …
If it helps someone, that’s all that counts for me.

 

[dsmart705]

Master … master … I’m not worthy …
If it helps someone, that’s all that counts for me.

I really appreciate all the support you have offered for my situation. I also commend everyone else who has contributed as I would not have had the confidence to see this through without all the help. My parts order came in this yesterday so I might just get a chance to start on things this weekend. I do think you are right (Sparkplug) that the transformer issue, at least with the 100v units, might be a common...or at least a known problem overseas. This might be a factor for those looking to import a C2x. On the bright side the 120v conversion is a surprisingly inexpensive endeavour...although I expect a significant amount of trial and error to get it all mounted and wired to my liking.

I noticed something in a previuos picture I posted. You can actually see the heat pattern leaving the transformer enclosure and going out the vent hole. I think the heat pattern (brownish dust) is epoxy particles that are baking out of the transformer housing. There are afew other spots on the trace side of the circuit board where the dust accumulates.

 

[Shade Ruff]

I do think you are right (Sparkplug) that the transformer issue, at least with the 100v units, might be a common...or at least a known problem overseas.

So, this all begs the question of what leads to C-2x Japanese model (100V) transformer malfunctions - something in the model's electronics or an issue with the transformer's design/manufacture?

 

[Vint Age]

or an issue with the transformer's design/manufacture?

From the forensics so far I'm thinking it's the X'fmr ...

 

[Sparkplug]

So, this all begs the question of what leads to C-2x Japanese model (100V) transformer malfunctions - something in the model's electronics or an issue with the transformer's design/manufacture?

As @Vint Age also pointed out, my money is on a bad Xformer although I have no proof, just a hunch. Furthermore, C-2x (J) may be internally different than C-2x export models, I know my C-6 (J) is, however, I seriously doubt that would cause any Xformer heating. I guess (no proof again) that Yamaha might have screwed up on these Xformers for the Japanese version. As a Japanese saying goes, “even a monkey falls off the tree once in a while …”. LOL.

 

[theophile]

The following thread got updated today. Go to the last post.

Yammy C2x gets hot

PLEASE HELP ME........... Haven't played in a couple of days now and noticed something weird.:scratch2: My C2x pre is hot, about 35-40 deg C, when it's not even turned on.:sigh: Is this something that requires attention or is it normal. I have only had this for a few months now and it's...

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