I’m building my first chip amp. I guess you could say I’m a “chip amp virgin”.
My questions are where do you buy your transformers from?
And
How do you figure out the right size? Do you guesstimate or is there a formula for it? The only specs I have is the volt/amps for the transformer and the total watts for the amp, which is 80 X 2 and 160 X 1. I know the amp has to use more power than that for that output. I’m lost on the transformer size. I’m in the US if that helps.
Power Transformers
I have and will continue to use Antek Inc. for power toroids.
Whenever possible I will use the AS- series toroids since they have a mylar static shield between the primary and secondary windings.
If your amp will do 80Wx2 then I would choose AT LEAST a 200VA toroid.
I always kind of figure for 50% efficiency in an amplifier so I take the amout of total watts output and multiply by 2 to get the VA's I need.
With your 160x1 then I would get a 300VA toroid for a monoblock or a 400VA for a stereo pair.
Some may say it is overkill but I would rather have too much than too little if the budget allows.
Antek transformers are designed for 50hz mains power and they say that their transformers will put out 20% more VA's at 60hz that the U.S. has.
In this case I would say that a 300VA toroid would do you just fine since by their logic it should be good for 360VA at 60hz mains power.
To get the volts that you need from the toroid, take the volts the device needs, add 2 volts and divide by 1.414 if you are using full wave bridge rectification.
I have and will continue to use Antek Inc. for power toroids.
Whenever possible I will use the AS- series toroids since they have a mylar static shield between the primary and secondary windings.
If your amp will do 80Wx2 then I would choose AT LEAST a 200VA toroid.
I always kind of figure for 50% efficiency in an amplifier so I take the amout of total watts output and multiply by 2 to get the VA's I need.
With your 160x1 then I would get a 300VA toroid for a monoblock or a 400VA for a stereo pair.
Some may say it is overkill but I would rather have too much than too little if the budget allows.
Antek transformers are designed for 50hz mains power and they say that their transformers will put out 20% more VA's at 60hz that the U.S. has.
In this case I would say that a 300VA toroid would do you just fine since by their logic it should be good for 360VA at 60hz mains power.
To get the volts that you need from the toroid, take the volts the device needs, add 2 volts and divide by 1.414 if you are using full wave bridge rectification.
The VA was listed on the different torrids I looked at, the 26 volts was listed on the amp board.
This company will ship them to your door. The price includes shipping. With the transformer kit you can wind whatever voltage you need. It comes with the information as to wire size and V/turn data. Also it comes with polyproylene film tape to insulate the secondary after you wind it and mounting hardware. With the kit, you can easily add an auxilary seconday to power op-amps and control circuitry.
If I can just ask a question here than start a new thread - anyone know where I can get Thai Lin transformers? My Meier Corda Cantate.2 blew its TL99-0100-030 encapsulated transformer last week, which I suspect is my faulty voltage regulator that just blew the amp on my active monitors a few hours ago.
Dr. Meier told me there's a Talema equivalent also as the pin placements are identical, but I have to be honest, I'm no engineer so I can't even tell what indicates their sizes (it's a tight fit on the amp's PCB so it has to be an exact fit). I couldn't find any Thai Lins on Mouser or even through Google; I came across some Talemas but even if its the same size the output specs are different.
Also, as I am not an engineer, my amp was diagnosed by the tech of a local hi-fi store. They have a network for parts, but none of these; they're more into tubes - whose transformers of course are huge although they can direct me to a local company that makes custom transformers even on small orders, as well as a guy who does custom-wound audio-grade transformers for DIY tube amps. However, I'd rather get either the original Thai Lin or the Talema equivalent.
Anyone know where I can find the replacement transformer online? I live in the Philippines but I can buy from the US and have it shipped to California where friends can ship it to me along with other audio equipment we don't get locally (this time mostly parts), or maybe better, fly in with them in their carry-on luggage. (Yeah, the FAA, but from my experience they opened up my check-in bag since a PCB showed up on the X-Ray, so we'd all rather have them on hand and not have anyone drop them while going through bags)
Dr. Meier told me there's a Talema equivalent also as the pin placements are identical, but I have to be honest, I'm no engineer so I can't even tell what indicates their sizes (it's a tight fit on the amp's PCB so it has to be an exact fit). I couldn't find any Thai Lins on Mouser or even through Google; I came across some Talemas but even if its the same size the output specs are different.
Also, as I am not an engineer, my amp was diagnosed by the tech of a local hi-fi store. They have a network for parts, but none of these; they're more into tubes - whose transformers of course are huge although they can direct me to a local company that makes custom transformers even on small orders, as well as a guy who does custom-wound audio-grade transformers for DIY tube amps. However, I'd rather get either the original Thai Lin or the Talema equivalent.
Anyone know where I can find the replacement transformer online? I live in the Philippines but I can buy from the US and have it shipped to California where friends can ship it to me along with other audio equipment we don't get locally (this time mostly parts), or maybe better, fly in with them in their carry-on luggage. (Yeah, the FAA, but from my experience they opened up my check-in bag since a PCB showed up on the X-Ray, so we'd all rather have them on hand and not have anyone drop them while going through bags)
Oh I thought a part number would be sufficient. They were about to close shop at the time so I just took a quick snapshot with my smartphone; will drop by this weekend to pick up the blown transformer.
An externally hosted image should be here but it was not working when we last tested it.
Yep I know; the thing is if I do get another brand, how do I know it'll drop right in? Pin layouts might be in the data sheet but I can't tell if they'll be the same size.
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