Hi all
Not for me to say but I have started the conversion work will take same time and it is down to Patrick to say when he is happy.
Looks good for now.
On other point got my Trafos yeterday wimp nexd door moaning because of the weight.
As Usual the postman waits around the corner for evveribody to get out before showing up.
Those are 1000VA twin sec at 24V with a tap at 20V bit hi voltagge for Patrick design but would do for F5 and Aleph J.
I had not time to plug them in and roast them a litle bit just to find out about the noise
they don't look like piltrons but preaty shure they be god.
Those are custom made supose we could ask for 500 600 VA at 12 14 16 V secs to my suplier Again this to be arranged troug the forum.
Group buy any one?
Al
Not for me to say but I have started the conversion work will take same time and it is down to Patrick to say when he is happy.
Looks good for now.
On other point got my Trafos yeterday wimp nexd door moaning because of the weight.
As Usual the postman waits around the corner for evveribody to get out before showing up.
Those are 1000VA twin sec at 24V with a tap at 20V bit hi voltagge for Patrick design but would do for F5 and Aleph J.
I had not time to plug them in and roast them a litle bit just to find out about the noise
they don't look like piltrons but preaty shure they be god.
Those are custom made supose we could ask for 500 600 VA at 12 14 16 V secs to my suplier Again this to be arranged troug the forum.
Group buy any one?
Al
12 / 15 / 18v would be more suitable to different First watt projects. IMO.
That is more people interested.
OK Patrick. Followed your method
Here are some new results.
I took 2 resistors at random from the bag. I measured current and voltage with 2 meters at current levels around 1A and 2A.
For both resistors I get roughly a 3mOhm increase in resistance between 1A an 2A
I then parralleled the two resistors and measure current and voltage and I get less than 1mOhm increase between 1A and 2A.
These CPF3 resistors range between $0.80 and $1.20 each depending on where you buy them.
How well matched do these resistors need to be?
See attached results.
Edit: I still need to double check these on another voltmeter. The meter used to measure voltage looks like it is from the 1980's. I suspect it is ok but need to double check, using the Agilent. I used the Fluke to measure current.
Here are some new results.
I took 2 resistors at random from the bag. I measured current and voltage with 2 meters at current levels around 1A and 2A.
For both resistors I get roughly a 3mOhm increase in resistance between 1A an 2A
I then parralleled the two resistors and measure current and voltage and I get less than 1mOhm increase between 1A and 2A.
These CPF3 resistors range between $0.80 and $1.20 each depending on where you buy them.
How well matched do these resistors need to be?
See attached results.
Edit: I still need to double check these on another voltmeter. The meter used to measure voltage looks like it is from the 1980's. I suspect it is ok but need to double check, using the Agilent. I used the Fluke to measure current.
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Hi Bobodioulasso
Anitink you like as long as we get enough to get the price down
PS will need to listen to the one I got as dont want to disapoint any body.
Hi thanh1973
You are doing a god job and your effort is much apreciated but may be worth looking at wheatstone bridge as gives results down to .0001.
It is used with straing gauges (nothing buth a 120 Hom resistor) pressure aplied to the resitor causes the filament to strech and change the resistance.
I have seen few grams pressure and a 25mm 25mm Iron block give a reliable reading.
Just cek Wikipedia.
Al
Anitink you like as long as we get enough to get the price down
PS will need to listen to the one I got as dont want to disapoint any body.
Hi thanh1973
You are doing a god job and your effort is much apreciated but may be worth looking at wheatstone bridge as gives results down to .0001.
It is used with straing gauges (nothing buth a 120 Hom resistor) pressure aplied to the resitor causes the filament to strech and change the resistance.
I have seen few grams pressure and a 25mm 25mm Iron block give a reliable reading.
Just cek Wikipedia.
Al
indeed it is my friend. i'm gonna build this too if posible, we should go in on a conrad order for it
> How well matched do these resistors need to be?
Not better than your MOSFETs, which means 10mV at bias (2A), which means 5mohm.
I am sure you can also make a good measurement with a wheatstone bridge. My point is that to be sure, you should do your measurements under working conditions. Matching done that way leaves no doubts. Of course you can compare a range of methods and conclude that they all gives you consistent results, and then you can choose the easiest one.
I shall stick to my principle -- matching under working conditions.
Patrick
Not better than your MOSFETs, which means 10mV at bias (2A), which means 5mohm.
I am sure you can also make a good measurement with a wheatstone bridge. My point is that to be sure, you should do your measurements under working conditions. Matching done that way leaves no doubts. Of course you can compare a range of methods and conclude that they all gives you consistent results, and then you can choose the easiest one.
I shall stick to my principle -- matching under working conditions.
Patrick
> we should go in on a conrad order for it
You guys are sometimes really very impatient.
Variac is discussing with us on behalf of the forum the possibility of manufacturing for them a small batch of a semi Hi-End housing for building Class A amps. We have submitted to him a draft design which will take 300W dissipation at ease (that works out to about 100W Class A output). Will do 2 channels nicely. (Hope you don't mind Variac.)
This proposed design has 2 Conrad MF35-151 heatsinks, 15mm solid aluminium front plate, 8mm AL bottom plate, 4mm AL top and rear, with stainless steel handles, feet, and push button. Weighs about 15kg, which is probably the problem. 15kg Aluminium costs money, so is shipment.
You'll have to wait till we come to an agreement first before I publish the design. I can only tell you that it does look gorgeous even by my standards.
Patrick
PS We retain ownership of the design !!
.
You guys are sometimes really very impatient.
Variac is discussing with us on behalf of the forum the possibility of manufacturing for them a small batch of a semi Hi-End housing for building Class A amps. We have submitted to him a draft design which will take 300W dissipation at ease (that works out to about 100W Class A output). Will do 2 channels nicely. (Hope you don't mind Variac.)
This proposed design has 2 Conrad MF35-151 heatsinks, 15mm solid aluminium front plate, 8mm AL bottom plate, 4mm AL top and rear, with stainless steel handles, feet, and push button. Weighs about 15kg, which is probably the problem. 15kg Aluminium costs money, so is shipment.
You'll have to wait till we come to an agreement first before I publish the design. I can only tell you that it does look gorgeous even by my standards.
Patrick
PS We retain ownership of the design !!
.
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For those who cannot wait and would not want to spend money on cosmetics, here is an example of a commercial solution :
Kühlkörpergehäuse 008.37 (VE=1Stück)
4mm AL front, 2mm steel plates all round. About same size heatsink.
Patrick
Kühlkörpergehäuse 008.37 (VE=1Stück)
4mm AL front, 2mm steel plates all round. About same size heatsink.
Patrick
I may have news on this front as well.
I'm waiting for a delivery of a Conrad MF35-151 based solution. It's semi custom made. The seller has a base set of materials and one tells him how to modify the parts. I've seen the pictures of the one I ordered, I should have it in hand in a week or so.
The individual's goal is to turn this into a DIY service.
I'm waiting for a delivery of a Conrad MF35-151 based solution. It's semi custom made. The seller has a base set of materials and one tells him how to modify the parts. I've seen the pictures of the one I ordered, I should have it in hand in a week or so.
The individual's goal is to turn this into a DIY service.
> we should go in on a conrad order for it
You guys are sometimes really very impatient.
Variac is discussing with us on behalf of the forum the possibility of manufacturing for them a small batch of a semi Hi-End housing for building Class A amps. We have submitted to him a draft design which will take 300W dissipation at ease (that works out to about 100W Class A output). Will do 2 channels nicely. (Hope you don't mind Variac.)
This proposed design has 2 Conrad MF35-151 heatsinks, 15mm solid aluminium front plate, 8mm AL bottom plate, 4mm AL top and rear, with stainless steel handles, feet, and push button. Weighs about 15kg, which is probably the problem. 15kg Aluminium costs money, so is shipment.
You'll have to wait till we come to an agreement first before I publish the design. I can only tell you that it does look gorgeous even by my standards.
Patrick
PS We retain ownership of the design !!
.
You will not tempt me into disclosing the design until the agreement is through.
If it does not work out, it will remain secret forever.
You know me by now. I only do 100% perfect solutions.
And this will be special offer to the forum, and they then offer them to you for a profit to keep this place up.
(assuming what we offer is what they would like in their product range)
Patrick
PS 2x Conrad MF35-151 weighs in at about 5kg.
Each of them is sufficient for 1 channel F5X.
.
If it does not work out, it will remain secret forever.
You know me by now. I only do 100% perfect solutions.
And this will be special offer to the forum, and they then offer them to you for a profit to keep this place up.
(assuming what we offer is what they would like in their product range)
Patrick
PS 2x Conrad MF35-151 weighs in at about 5kg.
Each of them is sufficient for 1 channel F5X.
.
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...that this works out as planned!
Let's do a poll perhaps ......
How many of you would like a gorgeous looking enclosure (more comparable to PL than to FW in terms of design sophistication) ?
And how much are you prepared to pay ?
(Do bear in mind that 50 other guys would have the same design as you ....)
To give an example, the Origen H6 HTPC Enclosure which has 8mm AL front plate and rest thin sheet metal is selling for something like 250 to 300 Euros.
Looks gorgeous, but does not weigh 15kg. And sheet metal stamping rather than CNC machining.
Patrick
.
How many of you would like a gorgeous looking enclosure (more comparable to PL than to FW in terms of design sophistication) ?
And how much are you prepared to pay ?
(Do bear in mind that 50 other guys would have the same design as you ....)
To give an example, the Origen H6 HTPC Enclosure which has 8mm AL front plate and rest thin sheet metal is selling for something like 250 to 300 Euros.
Looks gorgeous, but does not weigh 15kg. And sheet metal stamping rather than CNC machining.
Patrick
.
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