We're always open to partners to help us expand our business and product coverage.
If you are specialize in certain technology, or handcraft, or any work that is related to HIFI or audio industry, please contact us and tell us more how we can cooperate and benefit one another.
You can be - equipment manufacturer, gadgets maker, or even transformer manufacturer, we can work something out to benefit ourselves, as well as our customers.
Examples:
1. You are amplifier manufacturer - we can cooperate by supplying you transformers.
2. You are HIFI gadget designer - we can cooperate by sharing technology and product ideas.
3. You are CNC house, or capable of metal stamping, bending and such.
4. You are a supplier of parts (electronics, electrical, irons, pre-fabricated chassis, transformer cases, transformer frames and etc).
5. You are transformer manufacturer - we can cooperate by covering one another product gaps. There are some product segments that J&K do not cover, we can pass those business to you, or act as bridge; and vice versa. There are some geographic regions that is too far to ship J&K products to (too expensive, or not covered), and vice versa, we can leverage each other's network.
We had outsourced some of our low end transformers to our partners previously as the pricing that our customers looked for were just too low for us to manufacture here. If we like your audio gadgets, we may even help you market it under your brand, or under our brand.
6. You have idea on transformer design that you would like to design (by us, or by yourself), manufacturer, and sell (by yourself or by us), we can work out a deal.
Ideas are limitless! Complicated or simple.
Email us and we shall discuss more. We are open to all ideas - no ideas are stupid ideas.
J&K Audio Design
28/4/2020
Tuesday, April 28, 2020
Sunday, April 26, 2020
VA versus WATT
Often users ask us, how do I estimate the size required for the power transformers the circuit requires? How do I know if the power transformer size is sufficient for my circuit, for my amplifier or for my equipment?
To them, it is always Watt that they heard mostly and learnt in secondary school, or even university. How do they use Watt versus VA? What is the best method to power transformers? What are the differences between VA and Watt? Some often see that we usually up-rate the transformers per the Vdc and Idc they use on their tube amplifier and they wonder why.
How do I properly size my power transformers? How do I properly size my isolation transformer?
First, we've to know what is the distinction between VA (Volt-Amp) and Watt. For equipment, the power consumption, or the actual power drawn by the equipment, is usually expressed in Watts. For transformers, usually they are rated in VA, which is also known as "apparent power", and is simply Vac x Iac.
For resistive loads, such as bulbs with filament, heater with heating elements, and many more, the VA rating and Watt rating are the same - this is because the "Power Factor" is 1.0. For power supplies with capacitor-input, choke input supply, switch mode power supply (SMPS) and etc, the "Power Factor" is <1.0, such as 0.6 - 0.8, and therefore the VA rating and Watt rating will be different. Google for "power factor" if you're unsure what it is - we will postpone this for another article - hold on first.
The Watt rating has to be divided by the "Power Factor" to get the actual VA rating required for the equipment in use. Or, the VA rating must be multiplied by the "Power Factor" to get the Watt rating.
Alright, enough with the theory, cut the crap, how do I order the d*mn transformer?
Ok, ok, here's the simplified version, easy for non-technical people to follow. It's not super accurate, but is good enough for ordering use:
Example #1: Consider the case of a equipment that consumes 260W from the wall on average.
To them, it is always Watt that they heard mostly and learnt in secondary school, or even university. How do they use Watt versus VA? What is the best method to power transformers? What are the differences between VA and Watt? Some often see that we usually up-rate the transformers per the Vdc and Idc they use on their tube amplifier and they wonder why.
How do I properly size my power transformers? How do I properly size my isolation transformer?
First, we've to know what is the distinction between VA (Volt-Amp) and Watt. For equipment, the power consumption, or the actual power drawn by the equipment, is usually expressed in Watts. For transformers, usually they are rated in VA, which is also known as "apparent power", and is simply Vac x Iac.
For resistive loads, such as bulbs with filament, heater with heating elements, and many more, the VA rating and Watt rating are the same - this is because the "Power Factor" is 1.0. For power supplies with capacitor-input, choke input supply, switch mode power supply (SMPS) and etc, the "Power Factor" is <1.0, such as 0.6 - 0.8, and therefore the VA rating and Watt rating will be different. Google for "power factor" if you're unsure what it is - we will postpone this for another article - hold on first.
The Watt rating has to be divided by the "Power Factor" to get the actual VA rating required for the equipment in use. Or, the VA rating must be multiplied by the "Power Factor" to get the Watt rating.
Alright, enough with the theory, cut the crap, how do I order the d*mn transformer?
Ok, ok, here's the simplified version, easy for non-technical people to follow. It's not super accurate, but is good enough for ordering use:
Example #1: Consider the case of a equipment that consumes 260W from the wall on average.
If we conservatively assume (yes, assume, since we do not know what's inside, we will take the worst case) 0.6 Power Factor, then the calculation would be as follow for the transformer VA to order:
VA = 260W / 0.6 = 433VA
(Some will use rule of thumb of doubling the VA required versus the power consumption in Watts.)
I would expect users to do some additional de-rating as well since transformer is not a perfect device - there may be losses. Also, if it is an amplifier, then the power consumption may actually be more since amplifier is dynamic, drawing different power at different point of time due to the volume versus music nature, which is dynamic and unpredictable. Therefore, double or triple of that is nothing surprising for amplifiers.
*** If you prefer cool-running transformers, de-rate it further - do note that de-rating requires readjustment of the primary/secondary ratio since the secondary voltage will be higher than normal when under-load. *** Inform us if so when you're ordering, so that we can set the right voltage for you.
Example 2: Order power transformer for an amplifier. Assuming you need Vdc of 400V at Idc of 200mA, using a bridge with capacitor input power supply (important note: different circuit calls for different formula).
Vac = V-average-dc x 0.9 = 360Vac
Iac = Idc x 1.61 = 0.322A
VA = Vac x Iac = 116VA
If you do not know the calculation method, you can go for simple calculation:
P in Watts = Idc x Vdc = 0.2 x 400 = 80W
Power factor = 0.6
VA = 80W / 0.6 = 133VA
Above is just for a single winding. If there are multiple windings in a power transformer, add them all up, and add additional margins for multiple windings since efficiency will drop further with more windings in a single transformer.
Some will use rule of thumb (again) of doubling the power (Watt) required for the VA rating, for a quick check.
Do not forget to take losses into consideration, which is not included in this guide, especially tube rectifier / diode drops. D.C. regulator requires voltage margin for stable operations too and is dependent on the type of circuit used. Also, consider mains voltage drop/hike too in your calculation. Some will add additional buffer for lower operating temperature since there shall be copper losses and core losses that will generate heat and cause temperature to rise.
Alright, here's your calculation example for how to order a power transformer, and how to differentiate VA and Watts during transformer ordering. Keep this in mind when you order. If you do not know how to calculate, let us know and we can help you estimate.
J&K Audio Design
26/4/2020
:
Saturday, April 25, 2020
COVID-19 Update
Hope all are well, alive and kicking!
Movement Control Order has extended but we've slowly begun our operations and catching up with the orders in the past few months - we'd like to take this opportunity to apologize for the hiccups in production.
Kindly send in your new orders to avoid long delays as materials shortage won't be something that can be resolved in a short term as most materials manufacturers have stopped operations, or in a 50% or less capacity, same with us.
Take care and live strong!
J&K Audio Design
26/4/2020
Movement Control Order has extended but we've slowly begun our operations and catching up with the orders in the past few months - we'd like to take this opportunity to apologize for the hiccups in production.
Kindly send in your new orders to avoid long delays as materials shortage won't be something that can be resolved in a short term as most materials manufacturers have stopped operations, or in a 50% or less capacity, same with us.
Take care and live strong!
J&K Audio Design
26/4/2020