DIY Audio....or how many solder burns have you had?

[Puffin]

I am a keen DIYer and have been for many years. Over that time the resources available to the Audio Diyer have exploded. However it seems that the numbers getting their hands dirty are much less than say 30 years ago?

Mind you the main cost now in making an amplifier with a linear power supply is the transformer given the cost of copper. Most Class D amps will run perfectly well with a switch mode PS as these have come on greatly in the past few years and prices are quite keen from some sources. Even Nelson Pass advocates the use of SMPSs with some of his Class A amps.

Some may say that they want something to look like a commercial offering rather than a bag of spanners. This is achievable if you have some imagination and utilise things that aren't specifically made to house electrical components. If you have your kit in a dedicated room then this maybe not so important.

What would put you off putting an amp or other audio equipment together?

[walpurgis]

I'm always tinkering with something. Doesn't necessarily have to be Hi-Fi though, but I do have another passive pre-amp to assemble and a Class D amp and speakers, if I ever get around to any of it all :).

As for solder burns, I've had a few. More likely to end up bleeding than burnt though, I get a nick or gouge a couple of times a week :rolleyes:.

[Puffin]

I was at minor injuries about 4 weeks ago after a "stanley knife incident" I was convinced my left hand was nowhere near where I was about to cut....well in fact I was trying to get an old paint run out of some fancy architrave prior to painting. Scored down and whoomp! I thought I had taken the top off my L hand index finger. Finger immediately went numb, hurt like hell but bleeding was not what I was expecting.

Had it cleaned and steristripped and was told that any numb areas are unlikely to get any sensation back:eek: Still it is only a very small part of the top of the finger between the tip and the first joint. I had said to myself in the past after cutting myself that if I were using such a knife I would wear one of the thick leather gloves like they used to sell in Poundland. Hmmm.... its seems like I am only thick element in these accidents.

Which chips are in the Class D amps? I have 2 TPA3116 amps and 2 IRS2092s one is dual mono and the other an integrated....oh yea and recently a Sure/Wondom TPA3255 said to do 300w into 4 :Ohms :D yea... I didn't have to put it together. It was very expensive though...£23.00 from Aliexpress.

https://www.aliexpress.com/item/1005004895645420.html?spm=a2g0o.order_detail.order _detail_item.3.40b9f19cknJ0ad

They vary in price every day.

[walpurgis]

Which chips are in the Class D amps?

It's another TPA3116. Semi integrated, V/C & rotary switched input selector, but a beefy and very quiet external SMPS in separate box.

[struth]

when i worked in the trade i got burnt often :eyebrows: whats worse tho you oft got little...and BIG shocks too.... wish i had a quid for every one.. mains was worst but a discharge from a crt hurts too..often flung you across the room:lol:

[Macca]

last used a soldering iron in 1995. Got burnt by it a few times but that's the game isn't it? Like if you have a motorbike you're going to come off it sometimes.

Only been electrocuted once unless you count pushing each other into those electric fences you get on top of stone walls in the countryside to keep the sheeps in. And not done that since school. Mind you never built electronics only speakers. And someone more capable always made the cabs for me.

[Barry]

Built a few amplifiers in my youth, both valve and solid state, because I could not afford manufacture built ones.

Nowadays, I only make up cables and in fact made up a pair only a week ago. Had very few burns or shocks. The only 'accident' I had was in wiring an electrolytic capacitor the wrong way around by mistake - that made an impressive bang with steam shooting out from one end, leaving a big fluffy mess! :doh:

[Barry]

Recently made a pair of XLR terminated cables to connect between my TEAC DAC and the preamp:

https://i.postimg.cc/cJQHKHPr/013.jpg

I did this for a number of reasons:

[1] The available space behind the DAC was limited

[2] The cable length is chosen to be as short as necessary, for the sake of neat and tidy cable dressing

[3] I have complete control of the neatness and quality of the soldering and assembly. Commercial ready-made cables are often very poorly made.


If you look carefully, you will see the cable entry to the right-angle XLR connectors is at 45 degree to the orientation of the pins. This is because the space behind the DAC is extremely limited, so I needed to use connectors where the cable gland can be orientated in any one of 8 ways.

Here are the connectors fitted in situ, showing the very limited space available:

https://i.postimg.cc/L4bFkStD/014.jpg

https://i.postimg.cc/wMKPPqwY/015.jpg

[Puffin]

Nice job.

[Puffin]

I built a dual mono IRS 2092 Class D amp a few years ago which sounded fine but as I was building quite a few Class D amps at the time it got pushed to one side. I recently plundered some of the power supply for another project. A bigger PS did not make for a better sounding amp and so I put the 2092 PS back together.

Switched the amp on and one channel was oscillating :D ....bum. The 2092 requires a split rail supply and I had only taken bits to make a single rail supply. As I was poking around the reference 0v lead which should have been securely soldered to the capacitor bank popped off. Soldered it back and the bad board is now fine. Quite why one board oscillated and the other didn't I have no idea, but it was good that I didn't have a duff board to replace.

The amp boards are tweakable. There is a small pot for adjustment of the PWM switching frequency which really needs a oscilloscope for accuracy. However some on DIYaudio helpfully added that the higher the switching frequency the hotter the amp will run. Experimenting can get you to the sweet spot and it there is now quite a marked improvement in SQ. The amps had been running really cool as most Class D's do, but now they are pretty warm as is suggested would happen. Some kind of Class A electrickery?:lol:

[Pete The Cat]

Back in the '80s I took a belt from the mains when I was rewiring a joint box. I'd done it many times before and knew the drill but had left the mains plugged in. Idiot! :doh:

Funny thing is how time slows and your brain tracks what's happening astonishingly well. In that split second I was able to recognise that my screwdriver hand felt momentarily stuck to the screw I was attempting to turn and I realised what I'd done, before a combination of jerking and being thrown back across the room. Good news is that the only injury was the bump from the fall.

Pete

[shane]

Last time I got a belt off the mains was replacing a single socket with a double in our kitchen. Our old house where we lived for 30 years had (very vey old) fuses for upstairs and downstairs rings. The new place has a row of fancy RCBs. I carefully switched off the downstairs ring RCB, not noticing another one marked Kitchen…

Haven’t had any notable burns recently but the forefingers and thumbs of both hands have been regularly imprinted by the hot pins of 5-pin DIN plugs in that race between the solder solidifying and the pain becoming unbearable!

[walpurgis]

the forefingers and thumbs of both hands have been regularly imprinted by the hot pins of 5-pin DIN plugs in that race between the solder solidifying and the pain becoming unbearable!

Yes, I know that one! :)

[Barry]

Use a table top vice. It's almost impossible to solder up connectors to cables without one.

[shane]

Perfectly possible, I’ve done hundreds. Painful though.

[Barry]

Perfectly possible, I’ve done hundreds. Painful though.

I said "almost" - OK if like to burn your fingers and/or risk 'dry joints'.

[Mr. C]

Being around soldering equipment every day, very, very rarely do I receive burns, thankfully. Although the odd cut around the lab in inevitable just a fact of electronics lab life.

With regartd to SMPS, I design a great many of these for various applications, the main pluses are PDF (Power density factory) high power for lower space, COST and for our US cousins less real estate to take up.

With the newer techniques involved with SiC & GaN switching and much better EMI supression and power distribution network (fancy way of saying psu micro controller lol) You see all of these are controlled in real time, with precise control on of input V&I, switching times, PWM lengths, current supply against output requirments. Coupled with the biggie these days efficiency if over 80%+ in many circumstances oh did I mention the cost.

This is why a few amplifier manufactures are heading in this direction, I mean even Sugden uses SPMS in their design.

Oh wait both Sugden & Pass are class 'A' that permantly on transistor current drenched electricity consuming monsters just what the world needs right now ? :eyebrows:

[Puffin]

I don't know if Nelson Pass designs his amps with SMPSs in mind but he advocates their use with his amps...all his amps?.....well his ACA amps of which I have built 4. His ACA Mini is a seriously good amp. I use a Meanwell 5A 24vdc.

[Mr. C]

It you are happy with it Rob thats's all that matter then :)

[Macca]

Being around soldering equipment every day, very, very rarely do I receive burns, thankfully. Although the odd cut around the lab in inevitable just a fact of electronics lab life.

With regartd to SMPS, I design a great many of these for various applications, the main pluses are PDF (Power density factory) high power for lower space, COST and for our US cousins less real estate to take up.

With the newer techniques involved with SiC & GaN switching and much better EMI supression and power distribution network (fancy way of saying psu micro controller lol) You see all of these are controlled in real time, with precise control on of input V&I, switching times, PWM lengths, current supply against output requirments. Coupled with the biggie these days efficiency if over 80%+ in many circumstances oh did I mention the cost.

This is why a few amplifier manufactures are heading in this direction, I mean even Sugden uses SPMS in their design.

Oh wait both Sugden & Pass are class 'A' that permantly on transistor current drenched electricity consuming monsters just what the world needs right now ? :eyebrows:

You can't leave a class A powered up all the time so I'd suggest they actually use less power than a B or AB or even a D if that amp is left powered up all the time.

Also world is moving to electric vehicles which in terms of power consumption make a big class A amplifier used say 20 hours a week look like nothing. Please don't encourage the 'green' virtue signallers who have to tell us they are abandoning class A 'For the planet'. They are so tiresome - and wrong.

SMPS have lower noise than an LPS assuming both implemented properly, is that not true?

[willbewill]

I keep an Aloe Vera plant handy for solder (and other) burns, works a treat - just cut a piece off and rub the inside goo over the burn.

[Barry]

SMPS have lower noise than an LPS assuming both implemented properly, is that not true?

My only experience with SMPS is with the little triangular 'wall warts' used to charge mobile phones. I have one plugged into a double socket along with the bedside radio (analogue). If the phone is being charged, there is a background noise on the radio. This does not occur if I use a charger plugged into a socket on the other side of the bed. I don't know if the interference is mains borne, or if it is RFI.

[Macca]

My only experience with SMPS is with the little triangular 'wall warts' used to charge mobile phones. I have one plugged into a double socket along with the bedside radio (analogue). If the phone is being charged, there is a background noise on the radio. This does not occur if I use a charger plugged into a socket on the other side of the bed. I don't know if the interference is mains born or if it is RFI.

Possibly the problem is with the radio's PS not filtering very well? Hard to draw any definite conclusion without testing the specific application.

I use a mobile phone charger to power a DAC and there's no noise I can hear even up close to the speaker. It's plugged into the same multi-way block as the pre-amp and transport. I can't discriminate it from the other DAC I own, which has twin built-in LPS.

[Barry]

It has just dawned on me that my TV (a Sony) uses a SMPS, but clearly it does not affect the picture.

Even if an LPS did improve matters, I'm not going to bugger around in trying.

[Bksabath]

Same of My fingers don't burn any more :)

[Barry]

Possibly the problem is with the radio's PS not filtering very well? Hard to draw any definite conclusion without testing the specific application.

I use a mobile phone charger to power a DAC and there's no noise I can hear even up close to the speaker. It's plugged into the same multi-way block as the pre-amp and transport. I can't discriminate it from the other DAC I own, which has twin built-in LPS.

Agree, it is difficult to ascertain if the interference is mains-borne, or if it radiated. It doesn't seem to matter how close the phone is to the radio, nor does playing around with the radio's telescopic aerial alter the effect. So that would exclude RFI, whereas moving the charger to another socket solves the problem, which suggests the interference is mains borne.

The radio is an old Roberts radio, designed and manufactured long before digital and SMPS became prevalent.

[Mr. C]

Well Martin

I spend maybe 30% of my week working on PDN's / IoT / medical and other switching power devices which the key criteria’s are lower more efficient power with a smaller footprint which is the correct way forward. However, to obtain a real quality low noise smps then the use of many methods is employed including specialist materials, careful high side layout and magnetics, low side with linear tracking regulators, in depth DC<>DC filtering (post smps).

Have tried many very well thought out smps designs on a few audio amplifiers (and RF ones lol) it works perfectly fine and with proper consideration can pass the UKCA/CE Cisper regulations.

90% of my lab bench power supplies are linear I have one half and half a Rohde & Schwarz smps with linear tracking regs, it’s the same size and the equivalent LPS but half the weight. and 2.5 times the amount of ripple noise.

only very, very few clients are specifying class 'a' designs these days for a multitude of reasons one being the physcial size, the weight of the unit, the power consumption and sheer heat they generate.

Lets look @ your Krell KSA50S it takes pretty much 345Watts of power @240Vac at idle which is roughly 450Va which for a quoted genuinely 50W class 'a' device is on the money at more realistic volume levels this isn't going to rise to much as the devices (FET's) are 100% duty cycle as in on permanently all of the time.

So, in 20 hours you will have used 0.35 of Kwh x 20 so around the 7Kwh @ the capped rate of 0.34p per Kwh gives you £2.38 for the amplifier total electrical use (plus whatever the rest of the system uses in that period) so compared to a EV being charge at bollock charge between £40-£70 yes its relative indeed.

A class a/b amplifier is around 55-65% efficient so you could reduce that outlay by a further 25-30% and with a class 'd' style amplification by at least 100%, this is not about which one sounds better purely on consumption.

Also you have a small amplifier in terms of most of the current class 'a' units which are out there, recently visited a cleint who use the older big krell mono's with the meters on them, you could literally wtach the electric meter jump to warp when he switched them on.

Although the big Gryphon Colosseum’s idle around 3.2Kw each and double up as house heaters but do sound superb.

https://onahighernote.com/wp-content/uploads/2017/07/Colosseum_Solo.jpg

Personally class 'a' has never worked for me, plenty of others yes most are overly safe and somewhat nice which is why the big fad for class 'a' was kicked off in the mid 80's due to the slew of forward, hard sounding glut of average solid state amps but a multitude of manufacturers.

Back to would I use a correct smps in any audio products like amps, maybe one or two designs would lend themselves to this for sure (would it sound better or worse or yes, but as I mentioned cost is the key here), however for myself and the designs we create not yet Martin.

[Mr. C]

SMPS have lower noise than an LPS assuming both implemented properly, is that not true?

For very small psu for IoT and wearable tech work I would say yes, simply due to the nano size, we have devices that 'sleep' using pico (One million millionth (10-12) of an ampere.) or femto amps, (One quadrillionth of an ampere. An ampere being the SI base unit of electric current. 1 Femtoampere = 10-15 amperes. 1 pA = 0.000 000 000 000 001 A.) microscopic amount of currents.

Yes you can easily measure the amount of both radited and conducted rf noise from any electrical device with a quality spectrum analyser/ A/C power analyser/ H & E field probes and for current a good DVM with mA and pA ranges all calibrated. You may also require emc tent/ testing chamber etc.

All of this has to checked and tested by an approved CE / UKCA testing facility for the relevent standrards according to each product being sold.

For higher currents and lower noise then LPS is the way to go if you wish to spend the money. remeber with a traditional LPS then you only have here in the UK 50 cycles @ second in which to fill that capacitor with a smps you can have upto 250K times a second to fill it, hence why they are much smaller caps on a smps but MUCH more RF noise. You have to kill the noise for both conducted and radited emmissions along with some form of dc filtering.

[struth]

must be some pricey EV charger to be that amount.. mine is under £20 for full charge.



so compared to a EV being charge at bollock charge between £40-£70 yes its relative indeed.

[Mr. C]

Overnight charge yes Grant I would suggest so, but stopping at a 'ev station for a fast charge is more'

I'm not getting into whether EV's are better or worse, (I also design many items that are used on EV's including power train products) we have to do everything we can to reduce our all emcompassing emmissions yes, but this is going to require a conserted effort ALL round for many aspects of life.

Not convinced by EV's for many reasons, this is my view they are many others who do not share this. back to smps
V's LPS

[Macca]

Hi Tony

Thanks for the comprehensive replies.

Regarding Class A amplifiers my point is the small number in circulation added to the fact that they are only switched on when in use means their contribution to emissions isn't worth considering. Likewise cost in use, at least for a little one like mine, is pretty much negligible. (I maybe get about 6 hours a week on mine).

I don't claim any advantages in sound quality compared to other amplifier classes. I am thinking about getting a Class D but only to get much higher power output. But it probably won't happen since I'm not sure I really need it anyway.

What were you using at Cranage? Belles? Which model was it? (In truth I'd rather have those TAD loudspeakers).

Regarding SMPS, well as I said I use one for the DAC, I don't perceive any problems. If it ain't broke....

[Barry]

only very, very few clients are specifying class 'a' designs these days for a multitude of reasons one being the physcial size, the weight of the unit, the power consumption and sheer heat they generate.

Lets look @ your Krell KSA50S it takes pretty much 345Watts of power @240Vac at idle which is roughly 450Va which for a quoted genuinely 50W class 'a' device is on the money at more realistic volume levels this isn't going to rise to much as the devices (FET's) are 100% duty cycle as in on permanently all of the time.

So, in 20 hours you will have used 0.35 of Kwh x 20 so around the 7Kwh @ the capped rate of 0.34p per Kwh gives you £2.38 for the amplifier total electrical use (plus whatever the rest of the system uses in that period) so compared to a EV being charge at bollock charge between £40-£70 yes its relative indeed.

A class a/b amplifier is around 55-65% efficient so you could reduce that outlay by a further 25-30% and with a class 'd' style amplification by at least 100%, this is not about which one sounds better purely on consumption.

Also you have a small amplifier in terms of most of the current class 'a' units which are out there, recently visited a cleint who use the older big krell mono's with the meters on them, you could literally wtach the electric meter jump to warp when he switched them on.

Although the big Gryphon Colosseum’s idle around 3.2Kw each and double up as house heaters but do sound superb.

https://onahighernote.com/wp-content/uploads/2017/07/Colosseum_Solo.jpg

Personally class 'a' has never worked for me, plenty of others yes most are overly safe and somewhat nice which is why the big fad for class 'a' was kicked off in the mid 80's due to the slew of forward, hard sounding glut of average solid state amps but a multitude of manufacturers.



One of the reasons why I stopped using the Mark Levinson ML-2 monoblocks (into Quad 57 ESLs). They are big, heavy, very inefficient and run hot (so much so, the black anodising of the heat sinks had started to bleach).

In theory class A amplifiers can never be more than 50% efficient. The ML-2s are true Class A designs, wherein the mean audio output power doubles for each halving of the load impedance. Specifically the ML-2 provides 25W into 8Ω; 50W into 4Ω; 100W into 2Ω, and 200W into 1Ω - that is, provides a constant rms voltage of 20V, although given the power supply current capacity of 7A, the power into 1Ω should be taken cum grano salis. The power consumption from the mains (described as "idling" power consumption) is "around" 400W, or 8x the audio power into 8Ω, that is an efficiency of 12.5%.

So for the Krell KSA50S 50W/channel amplifier, the idling power of 345W implies an efficiency of 29%; more than double that of the Levinson design.

I now use a pair of Quad 510 monoblocks (or a pair of 'monoblocked' Quad 405 amplifiers (upgraded to Keith Snook level 3) and with improved power supplies). Whilst legend has it that the combination of Levinson ML-2 amplifiers with the Quad ELS was a "match made in heaven", I can say that the replacement of the ML-2s has not resulted in a degradation of sound quality.

[Puffin]

I built a Class A Pass F2 about 10 years ago and that ran as hot as a very hot thing!. At the time I used it with a pair of monster BLH (Back Loaded Horns) with either Fostex or Lowther FR units. The F2 was 5w per channel with a massive linear supply. Of the Pass amps I have built in the last year the ACA Mini a Class 5w "power house" is by far the best and if you could tell it was only 5w I would give it to you! It gets quite warm but the heatsinks are so small it's effect on global warming is negligible IMO. If you can get to hear one you would be amazed at the SQ. Cost of build including PCB and quality parts was £120. Power supply was £30 (SMPS)

[Mr. C]

Barry

From the majority of my experinaces here with this amplifier technology, its around the 35% mark for class 'a' efficiency, not having looked at a great many manufuctures 'a' class models. Although one or two do dip below the that efficiency point to obtain big power numbers, hence why the heat sinks are way over the top!

That is exactly the power consumption coming out of the wall this morning after 15 minutes 'warming up' time lol I also measured the idling of a Puresound A30 class 'a' 30 watt valve amplifier those was 272W @ idle zero load.

Another method would to calaculate the heat loss, a thermal camera can come in handy here, just check the top cover for constant temprature see how many are over 55C

The last class 'a' design I was involved with was absolutely rock stable @ 98Wrms into 4 ohms @ 290W Rms @ 1 ohm from a claimed 30W rms unit with 1.04% distrortion. Ultra low impedances right across the frequency spectrum and a very robust power supply.

Apologies about the table layouts

Output Impedance (re. 10.0W into 8ohm @ 1Khz and 20Hz it was still producing over 53Wrms) =

0.004ohm @ 20Hz 0.004ohm @ 21Hz 0.004ohm @ 23Hz 0.003ohm @ 26Hz
0.003ohm @ 30Hz 0.004ohm @ 33Hz 0.004ohm @ 37Hz 0.004ohm @ 42Hz
0.004ohm @ 47Hz 0.004ohm @ 53Hz 0.004ohm @ 59Hz 0.004ohm @ 66Hz
0.004ohm @ 74Hz 0.004ohm @ 83Hz 0.004ohm @ 94Hz 0.004ohm @ 105Hz
0.004ohm @ 118Hz 0.004ohm @ 132Hz 0.004ohm @ 149Hz 0.003ohm @ 167Hz
0.003ohm @ 187Hz 0.003ohm @ 210Hz 0.003ohm @ 236Hz 0.003ohm @ 265Hz
0.003ohm @ 297Hz 0.003ohm @ 334Hz 0.003ohm @ 375Hz 0.003ohm @ 420Hz
0.003ohm @ 472Hz 0.003ohm @ 530Hz 0.004ohm @ 590Hz 0.004ohm @ 670Hz
0.004ohm @ 750Hz 0.004ohm @ 840Hz 0.004ohm @ 940Hz 0.004ohm @ 1060Hz
0.004ohm @ 1190Hz 0.004ohm @ 1330Hz 0.004ohm @ 1500Hz 0.004ohm @ 1680Hz
0.004ohm @ 1890Hz 0.004ohm @ 2120Hz 0.004ohm @ 2380Hz 0.004ohm @ 2670Hz
0.004ohm @ 3000Hz 0.004ohm @ 3360Hz 0.004ohm @ 3780Hz 0.004ohm @ 4240Hz
0.004ohm @ 4760Hz 0.005ohm @ 5300Hz 0.005ohm @ 6000Hz 0.005ohm @ 6700Hz
0.005ohm @ 7600Hz 0.006ohm @ 8500Hz 0.006ohm @ 9500Hz 0.007ohm @ 10700Hz
0.007ohm @ 12000Hz 0.008ohm @ 13500Hz 0.009ohm @ 15100Hz 0.010ohm @ 17000Hz
0.012ohm @ 19000Hz 0.013ohm @ 21400Hz 0.016ohm @ 24000Hz 0.018ohm @ 26900Hz
0.021ohm @ 30200Hz 0.025ohm @ 33900Hz 0.030ohm @ 38100Hz 0.036ohm @ 42700Hz
0.042ohm @ 47900Hz 0.050ohm @ 54000Hz 0.059ohm @ 60000Hz 0.069ohm @ 68000Hz
0.079ohm @ 76000Hz 0.089ohm @ 85000Hz 0.099ohm @ 96000Hz 0.108ohm @ 100000Hz


We can measure ANY attribute on the incoming a/c mains both single and three phase and calculate pretty much what ever you you wish for. We have four methods of doing this via various test equipment. This morning I used the Tektronix PA3000 which is accurate to 0.04% after warm up, has some nice features like start up current measurment, idle power over time, draw charactoristics over time, transient repsonce etc.

We also have the R&D scope Teledyne Lecroy Wavepro which has a full power analysis suite and even three phase vector plotting/ harmonic & spectrum analysis at the same time. Gain accuarcy of 0.5% due to a 12 bit Adc scope

However I draw the line at paying £500 for a UK mains break out box, so I built my own lol!

If you guys wish to check this yourself, then the item in the last image is a great way for sensible money to enable you to perform these measursments you can use a normal multimeter providing it's CAT II rating or above and a simple hall effect current clamp to go around the squares in the device cost is about £30 from memory


https://coherent-systems.co.uk/wp-content/uploads/2023/07/TPAb1.jpg

https://coherent-systems.co.uk/wp-content/uploads/2023/07/TPAb2.jpg

https://coherent-systems.co.uk/wp-content/uploads/2023/07/TPAb3.jpg

https://coherent-systems.co.uk/wp-content/uploads/2023/07/basic-waveform-meas-00004.jpg

Industry explanation (https://learn.keysight.com/bench-power-supply-basics/lesson-3-linear-vs-switching-power-supplies)

[majex45]

An engineer I worked with suggested rubbing instant coffee on iron burns. It works, a bit.

[struth]

An engineer I worked with suggested rubbing instant coffee on iron burns. It works, a bit.

green coffee beans ground very fine is supposedly the best for serious burn wounds.. dunno about instant tho.

never tried it tho