Overhere it's 240Vac only sometimes =>
Transformateur R-CORE à fixation sur châssis 30VA - 2 x 12V - Transformateurs R-CORE pour châssis
(Been shopping there before the web. Fun shop, Wink-Wink-Nodge-Nodge on the parking lot, by folks with various nation license plates, each time I drop by)
For 120-120 in any size, Japan. (Used medical channels for those in the past. Rather well connected in that area)
The primaries are also wound on both bobbins, so 120Vac + 240Vac primaries is not in the book.
Transformateur R-CORE à fixation sur châssis 30VA - 2 x 12V - Transformateurs R-CORE pour châssis
(Been shopping there before the web. Fun shop, Wink-Wink-Nodge-Nodge on the parking lot, by folks with various nation license plates, each time I drop by)
For 120-120 in any size, Japan. (Used medical channels for those in the past. Rather well connected in that area)
The primaries are also wound on both bobbins, so 120Vac + 240Vac primaries is not in the book.
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I'd settle for 240/24-24 but they don't seem to have that.
Do you use soft recovery rectifiers or capacitors bypassing them?
Transformateur R-CORE à fixation sur châssis 30VA - 2 x 24V - Transformateurs R-CORE pour châssis
Speedy and Soft, a Snubber and a Snart.
Speedy and Soft, a Snubber and a Snart.
That just indicates you know what you are doing. (Although you might Google snart!)
Ed
Sorry for posting them again but these two may help you while testing anything that has to do with main’s trafos.
A -non galvanically isolated- interface for main’s voltage waveform monitoring on the scope (or recording)
http://www.diyaudio.com/forums/analog-line-level/146693-john-curls-blowtorch-preamplifier-part-ii-3454.html#post3361980
A B-H curve tracer (testing for core saturation).
http://www.diyaudio.com/forums/equipment-tools/134065-b-h-curve-tracer.html#post1671925
If you raster the chassis surface and probe with close spaced test leads each small area, then writing in each cell the leakage measurement and probe orientation, you will have a rough map .
Can you tell me which trafos were pictured in the 3rd, 5th and 6th attached FFTs ?
George
Not for IC's at least in our case (we sell LOTS of stuff to Huawei and ZTE), in fact we got the Chinese Gov. to stop some copy cats.
Do a simple frequency response test on the transformers. You will find the toroids are very wide band. E-I with split bobbins would be lower pass-thru. A few decades ago, I measured the BW of a Hafler DH500 power amp supply transformer (E-I) and it was -3db at 60Khz. They are pretty much as you would expect a 50/60 Hz (audio) operation transformer to be transparent at audio freqs on the incoming ac line.
Thx-RNMarsh
Thx-RNMarsh
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Here ! Here ! ....... Not to be OT, but that's why they
make dandy audio output xfmrs .
The list of items are for finished goods... I know it seems like an IC is a finished goods but not how it is meant. Its a part of/in a finished good item. A part in a finished good (product) which is directly safety related is listed as required to meet standards for safety.
-RNM
Richard, thanks for the info on the DH500 transformer, I still have a DH500 with your front end cascode mod from TAA.
To my knowledge, Richard was the first guy to measure the alarming bandwidth of toroid power transformers. Later, we realized that the high internal cap coupling was the reason that the bandwidth was so high. That is why we switched to R-core or at least split bobbin, if we could in recent years.
Flawless till 100KHz, Menno told me at the dinner table.
Standard series toroidals as output transformers, sounded so wonderful that I have goose bumps, recollecting the moments.
(OK, so I had a number of brewskies and emptied a bottle of Bourbon, with the 2nd one underway. Recollect I told the lady I was bucknaked, and she could come in now, while Guido was switching the tune)
Standard series toroidals as output transformers, sounded so wonderful that I have goose bumps, recollecting the moments.
(OK, so I had a number of brewskies and emptied a bottle of Bourbon, with the 2nd one underway. Recollect I told the lady I was bucknaked, and she could come in now, while Guido was switching the tune)
Attachments
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I hope things have improved there, as your experience is probably much more recent than mine. I too, was marketing component devices, in my case, very fast Lithium Niobate optoelectronic modulators for backbone fiber-optic networks.
Yes I suspect some of it is. UL is next to useless for sales around the world. Many countries are also different Korea sends plant inspectors yearly, Europe is CE, china is also different. Like Richard says multiple copies required. Our XS amps are out for safety now, we will receive a smoking hulk maybe one working amp and a piece of paper all for $20,000.
Best tube amps I've heard had toroidals at the output (inspired by Vanderveen's work). 😉
Re trafo test
Ed: “Now, I am running out for you, for some may not have heard Salt Peanuts.
Wait for the boom and accent the pea. You see, you must accent the pea Not the nuts. I want only Peas tonight!”
Dizzy Gillespie - Salt Peanuts _ Live - YouTube
But the peanut gallery is far more imaginative
Jeff Hamilton and Steve Smith - SALT PEANUTS - YouTube
George
Ed: “Now, I am running out for you, for some may not have heard Salt Peanuts.
Wait for the boom and accent the pea. You see, you must accent the pea Not the nuts. I want only Peas tonight!”
Dizzy Gillespie - Salt Peanuts _ Live - YouTube
But the peanut gallery is far more imaginative
Jeff Hamilton and Steve Smith - SALT PEANUTS - YouTube
George
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Back on phono stages...
nowadays we have analog and digfital as emanicipated sources in audio systems. But compared to phono a digital source deliver higher signal output (≥ 2Vrms) to the line stage. What about designing the phono stages with more gain to have equal signal levels?
nowadays we have analog and digfital as emanicipated sources in audio systems. But compared to phono a digital source deliver higher signal output (≥ 2Vrms) to the line stage. What about designing the phono stages with more gain to have equal signal levels?
It's easy to make the gain higher, but what do you pick as your reference level? How do you accommodate signals (and undesired noises) which can exceed the reference level by 20dB?
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