5f6a being a real pain.

[martin manning]

So the question is, is this an old transformer the OP is dealing with? Either way it would be worth some investigation to see if it has a center tap or not. Maybe a refund or a replacement could be had.

[stretch2011]

I just bought this transformer a few weeks ago. I will definitely be calling Weber tomorrow about a replacement.

[Firestorm]

Not to be pedantic, but you've got an amp that had a bad PT, then another maybe bad PT, and a bad cap and a blown OT and a blown speaker. And you said that when you first powered it up, it didn't work right. Before you install any more expensive stuff, triple and quadruple check your wiring.

With your main filters in series, if one cap shorts you'll still have 80uF @ 450V and the amp should work. If one cap goes open and you have 220K balancing resistors, the amp should still work but your voltages will be way low (and you might burn a 220K).

I suspect another, as yet undiscovered problem.

[stretch2011]

You are fine.
I have rechecked everything but I will do it again. The last time I powered up the amp I took out the two 80uf caps and replaced it with the standard two 22uf in parallel. That was when I found out I have 350ish volts ac and 350ish v dc at the 5u4.
I know it's not the 5u4 because it worked fine In another amp.
When the current limiter was hooked up it seemed to work fine. Then off the limiter it made the standard tube amp hum, just the rectification issue.

[Firestorm]

With a rectifier, if you don't have a reservoir cap connected to the rectifier output (or if the cap cathode isn't grounded or is out of whack in some other way) the AC volts on the rectifier plates will equal the DC volts on the rectifier cathode. You're seeing the RMS voltage, rectified to ripply DC. When there's a cap present, it can charge to the peak AC voltage (with no load). So if you see only the DC equivalent of the AC RMS voltage, something is not connected right.

[stretch2011]

Wonderful, I'll double check the caps and the wiring. I'll try to dig into it either tonight or tomorrow and I'll report back afterwards. Thanks for all the help guys.

Don't you love how those scrap parts builds can turn into a a nightmare for the mind and the wallet.

[sunnydaze]

With a rectifier, if you don't have a reservoir cap connected to the rectifier output (or if the cap cathode isn't grounded or is out of whack in some other way) the AC volts on the rectifier plates will equal the DC volts on the rectifier cathode. You're seeing the RMS voltage, rectified to ripply DC. When there's a cap present, it can charge to the peak AC voltage (with no load). So if you see only the DC equivalent of the AC RMS voltage, something is not connected right.

Exactly right. Learned this one the hard way - chasing my tail for awhile thinking I had bunch of bad rectifier tubes....

[stretch2011]

WELL GUYS!!!!!

I got in touch with weber. They said it looks like their entire line of the W025130 International transformers don't actually have a center tap. That the HT secondaries are 50v off from the "center tap"

[JazzGuitarGimp]

WELL GUYS!!!!!

I got in touch with weber. They said it looks like their entire line of the W025130 International transformers don't actually have a center tap. That the HT secondaries are 50v off from the "center tap"

I guess they figured since the vendor couldn't get it right, they'de just leave the CT out. "Change the fscts to conform to the evidence." LOL

[pdf64]

It's disappointing that the exact same issue keeps recurring for them.

[johnnyreece]

Yeah, I had an issue with their general purpose multitap transformer. Almost none of the voltages were what they were supposed to be. And, all the ones they had in stock had the same issue. I e-mailed back and forth with their tech, Gene, and eventually I just decided to deal with it. Glad you at least discovered the problem! That's half the battle.

[stretch2011]

Well I got the WO25130, wired it in, and completely unloading the power transformer hums pike crazy. Called Weber and they are sending a new one.

This is becoming way more of a hassle than it should be.

[JazzGuitarGimp]

Well I got the WO25130, wired it in, and completely unloading the power transformer hums pike crazy. Called Weber and they are sending a new one.

This is becoming way more of a hassle than it should be.

I use only Mercury Magnetics iron. I know a lot of people knock them for one reason or another - cost being the biggest issue. But I've done enough business with them that I am on the best pricing tier, short of signing up for an OEM account. I don't build anywhere near enough amps per month to do that. But the pricing I am getting now is reasonable, given their quality and sonic performance.

[stretch2011]

I usually get classictone transformers but I was trying to get the best price. I honestly didn't think that a power transformer was that hard to produce but I'm being proven wrong time and time again on this amp.

I do plan on trying some edcor and heybors out in the near future.

[RWood]

Weber lost all my business when they hinted that my skills were in question when the standup endbells they sent would not fit in a Chinese PT they sent. The bells measured much shallower than the stock laydowns. They never made good on the deal and the bells got screwed onto the end of my bench as a reminder. That PT also was also unbalanced, but only by 8 volts.