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
Wednesday, March 18, 2020
Halt operations from 18th MAR till 31st MAR 2020 due to COVID-19.
J&K Audio Design has to halt operations from 18th MAR till 31st MAR 2020 due to COVID-19 outbreak measures from the government.
Apologies for all the delays. We still check and respond to emails.
Take care and stay well everyone!
J&K Audio Design
19/3/2020
Apologies for all the delays. We still check and respond to emails.
Take care and stay well everyone!
J&K Audio Design
19/3/2020
Thursday, February 27, 2020
Value for money output transformers
Best bang of the buck output transformers! Value for money
output transformers! Good sounding output transformers! Good things need to
repeat 3 times!
Hope everyone is well in terms of the COVID-19 outbreak, as
well as the current stock market correction period. In such treacherous period
of time, what’s better than staying home and do some self-improvement reading, market
research/analysis and new product design!?!?
Who’d like to have a best bang of the buck output transformer?
Please raise your hand! We’ve surveyed the market of output transformer makers,
list out some of the popular names such as Lundahl, Tango, Hammond and etc to analyse
what’s good, and what’s to be had.
The picture shows our rating based on our own criteria –
take it with a cup of salt.
What are the critical parameter for output transformer?
- Primary
impedance ~2.5K to 3.5K (common impedance for most tubes)
- Primary
DC 100mA at minimum (suitable for 2A3, 300B, KT88, KT100, KT120 till KT150)
- Primary
inductance of ~6H per 1K Ohm (for better low frequency loading/response)
- Secondary
0 – 4 – 8 Ohm (suits most speakers out there)
- Output
power 30W (decent, but not too low)
- Frequency
response of at least <20Hz and > 20kHz (for full HIFI bandwidth)
- Tolerance
of +/-1dB (where human ears could hardy differentiate a 1dB difference)
- Decent
headroom/core volume >= 1KG per 10W SE
- Decent
price <$150/pc
With all the above criteria in consideration, we have come
up with 2 output transformer designs to satisfy most users needs. We cannot do
an All-In-One output transformer as the design trade-off is just too much.
Therefore, one (JK Fighter P-OPT) is designed more for
Pentode (KT88, EL34, EL84, KT120, KT150, and etc).
- Higher
primary inductance to cater for higher tube Rp (Pentodes in general)
The other (JK Fighter T-OPT) is designed more for Triode (50,
300B, 2A3, 45, 71, R120, 300BXLS, PX4, and etc).
- Lower
primary inductance to cater for lower tube Rp (genuine Triodes in general)
- Additional 16 Ohm secondary for high efficiency speakers
For those that wish for a warmer sound, they can use JK Fighter
P-OPT with Triodes or even Pentodes. For those that want a more high fidelity
sound, JK Fighter T-OPT is the one to go.
Expected availability ~June 2020. If you’ve feedback on the
design for improvements, or you happen to be looking for one for your design(s)
– let us know before we finalize the design. Email us! If they are valid and
genuine, and doable within the budget, we will include them.
To keep the price low, they are all fixed design. If you
need to customize, it will have to be on standard customize price. Custom made version
will be more expensive, and will have better dynamic headroom too.
We have no plans to release Push-Pull versions since those
have lower demand. If there are a lot of queries, or even OEM requests, we may consider
doing so – let us know.
Thank you for your support!
Take care everyone!
J&K Audio Design
28/2/2020
Monday, February 17, 2020
Vacuum Tube Repair
Good health to all J&K readers, supporters, and most importantly customers!
Just a little update on the COVID-19 outbreak - latest news is that some of our suppliers will resume work on 24th FEB 2020 - hope that situation improves that much to enable them to resume production.
Now back to our agenda here - vacuum tube repairs, or vacuum tube revivals!
I believe, transformers repair is nothing new to our followers. We've repaired hundreds, if not thousands of them over the past many years.
Another critical part of the solution chain would be on vacuum tube repair and revival, especially on those exotic NOS tubes that cost quite a considerable amount of money. We now offer vacuum tube repair or revival service to our customers through our long time partner (a tube maestro).
Do note that not all vacuum tubes can be repaired or revived. Some are dead for good. For some that are still having some life in it, or failed prematurely, or even fail as DOA, maybe they could be repaired. In some cases, some even be buying those expensive exotic NOS tubes that are dead at a dirt cheap price, and sending them to us for repair! If by any chance those dead exotic NOS tubes can be repaired, they could save thousands of dollars comparing to buying good exotic NOS tubes. Those that are worth repairing are those Western Electric signal or power tubes, Genelax / Gold Lion signal or power tubes, or even any old big power tubes that worth fortunes.
Since repairing or revival could a 50-50 or worse kind of odds, one may need to weight the pros and cons before sending for repair. Vacuum tube repairs or vacuum tube revival starts at U$100 per piece, and could be more depending on the type of tubes and illnesses.
Loose base, no connection at tube pin due to broken wire or cracked solder, or broken pin can be easily repaired by base replacement or re-connection internally at the base. Broken filament, could possibly be repaired, on case by case basis.
Here are some things to be considered before sending vacuum tubes for repairs or revivals:
1. Are they worth the trouble or worth the price? Repair price could be more than buying them new or or buying NOS.
2. Mechanically broken vacuum tubes are not repairable - such as broken glass or vacuum loss (inside appears all white).
3. Severely broken tube internally (massive internal structure failure, broken plates for example).
For other cases, please send us some pictures and descriptions and we shall see what we can do.
Examples for some cases on vacuum tubes that could possibly be repaired:
1. Crackling noise
2. Keep blowing fuses
3. Filament shorted
4. Internal pins shorted
5. Open connections
6. Intermittent operation
7. Missing base / base repair / base replacements
8. Oxidized tube pins / internal wires
9. Weak tubes
10. And etc... can't list all since there could be other illnesses
Contact us, if unsure.
Now, go dig your storeroom and see if there are any vacuum tubes you'd like to be repaired. Better still, go ask all your tube audiophile friends for used tubes, broken tubes that they do no longer use, and see if they are worth repairing or reviving! They could save you a fortune, or make you some good money after being repaired!
Tubes that are worth repair, for example, could be 212, 4212, 211, 4211, 4300B, 300B, 2A3 single plate, 2A3 double plate, 801A, PX4, AD1, 53KU, 52KU, U52, EL156, KT88, KT66, Telefunken, Western Electric, Genelax, and various other expensive exotic tubes.
Vacuum tube dealers, sellers, shops owners - if you have tubes that you think are worth repairing, please contact us and we may be able to repair them for you for re-selling later. The same 3 rules above apply.
Start digging! You may encounter a few gold mines! Don't let the exotic tubes go to waste - recycle them!
J&K Audio Design
18/2/2020
Just a little update on the COVID-19 outbreak - latest news is that some of our suppliers will resume work on 24th FEB 2020 - hope that situation improves that much to enable them to resume production.
Now back to our agenda here - vacuum tube repairs, or vacuum tube revivals!
I believe, transformers repair is nothing new to our followers. We've repaired hundreds, if not thousands of them over the past many years.
Another critical part of the solution chain would be on vacuum tube repair and revival, especially on those exotic NOS tubes that cost quite a considerable amount of money. We now offer vacuum tube repair or revival service to our customers through our long time partner (a tube maestro).
Do note that not all vacuum tubes can be repaired or revived. Some are dead for good. For some that are still having some life in it, or failed prematurely, or even fail as DOA, maybe they could be repaired. In some cases, some even be buying those expensive exotic NOS tubes that are dead at a dirt cheap price, and sending them to us for repair! If by any chance those dead exotic NOS tubes can be repaired, they could save thousands of dollars comparing to buying good exotic NOS tubes. Those that are worth repairing are those Western Electric signal or power tubes, Genelax / Gold Lion signal or power tubes, or even any old big power tubes that worth fortunes.
Since repairing or revival could a 50-50 or worse kind of odds, one may need to weight the pros and cons before sending for repair. Vacuum tube repairs or vacuum tube revival starts at U$100 per piece, and could be more depending on the type of tubes and illnesses.
Loose base, no connection at tube pin due to broken wire or cracked solder, or broken pin can be easily repaired by base replacement or re-connection internally at the base. Broken filament, could possibly be repaired, on case by case basis.
Here are some things to be considered before sending vacuum tubes for repairs or revivals:
1. Are they worth the trouble or worth the price? Repair price could be more than buying them new or or buying NOS.
2. Mechanically broken vacuum tubes are not repairable - such as broken glass or vacuum loss (inside appears all white).
3. Severely broken tube internally (massive internal structure failure, broken plates for example).
For other cases, please send us some pictures and descriptions and we shall see what we can do.
Examples for some cases on vacuum tubes that could possibly be repaired:
1. Crackling noise
2. Keep blowing fuses
3. Filament shorted
4. Internal pins shorted
5. Open connections
6. Intermittent operation
7. Missing base / base repair / base replacements
8. Oxidized tube pins / internal wires
9. Weak tubes
10. And etc... can't list all since there could be other illnesses
Contact us, if unsure.
Now, go dig your storeroom and see if there are any vacuum tubes you'd like to be repaired. Better still, go ask all your tube audiophile friends for used tubes, broken tubes that they do no longer use, and see if they are worth repairing or reviving! They could save you a fortune, or make you some good money after being repaired!
Tubes that are worth repair, for example, could be 212, 4212, 211, 4211, 4300B, 300B, 2A3 single plate, 2A3 double plate, 801A, PX4, AD1, 53KU, 52KU, U52, EL156, KT88, KT66, Telefunken, Western Electric, Genelax, and various other expensive exotic tubes.
Vacuum tube dealers, sellers, shops owners - if you have tubes that you think are worth repairing, please contact us and we may be able to repair them for you for re-selling later. The same 3 rules above apply.
Start digging! You may encounter a few gold mines! Don't let the exotic tubes go to waste - recycle them!
J&K Audio Design
18/2/2020
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