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Salas low shunt Group-design by Salas

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qusp

qusp

Member
Joined 2009
actually I hadnt noticed it had doubled and now that it doesnt have sense lines and doesnt seem to be taking in any of the good suggestions made, in fact there is no indication that they are even being considered, so I agree it does not seem a GB to me at all. PCBs do not cost that much, especially large numbers and from vietnam, our PCB for the D1 IV made in canada was less than this and I can tell you it is higher quality than the last QH salas board. so I too am removing myself from the list until I see the finished design has taken into consideration the wishes of the group.

for what its worth AndrewT, to me the power fets would be better on the side, in the middle really limits heatsinking options

1 - TFAN69 - 1set
2 - pop music - 2 set
3 - Royalbee - 2 set
4 - h-wan - 3 set
5 - rothay - 3 set
6 - ben-jam-in-3 set
7 - Superluca71 - 2 set
8 - suburra - 2 set
9 - Joshua_G – 2 set
10 - dbratny - 4 sets
11 - rpeter - 3 sets
12 -Sunsun22: 2sets
13 - Sergelisses: 1 set
14 - Studiostevus: 2 sets (shipping after 15 january)
15 - Kuka: 2 sets
16 - Ferrari: 4 sets
17 - cerfer: 2 sets
18 - leejh: 2 sets
19 - drspence: 2 sets
20 - albrerta: 1 set
21 - Bernie: 1 set
22 - Chul: 2 sets
23 - dggs: 2 sets
24 - luvdunhill: 1 set


And ,
Please Update the list not get last PCB:

1. stephen1212 (ordered 10 received 0 need 4 sets )
2. fitzfish (received 1 set, still need remaining 3 sets)
3. ramallo
4. claudio
5. kp93300 ( 2sets)
 
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D

drspence

Member
Joined 2005
AffirmAudio.com
I withdraw my order until the pricing and board design is better defined.
drspence

1 - TFAN69 - 1set
2 - pop music - 2 set
3 - Royalbee - 2 set
4 - h-wan - 3 set
5 - rothay - 3 set
6 - ben-jam-in-3 set
7 - Superluca71 - 2 set
8 - suburra - 2 set
9 - Joshua_G – 2 set
10 - dbratny - 4 sets
11 - rpeter - 3 sets
12 -Sunsun22: 2sets
13 - Sergelisses: 1 set
14 - Studiostevus: 2 sets (shipping after 15 january)
15 - Kuka: 2 sets
16 - Ferrari: 4 sets
17 - cerfer: 2 sets
18 - leejh: 2 sets
19 - albrerta: 1 set
20 - Bernie: 1 set
21 - Chul: 2 sets
22 - dggs: 2 sets
23 - luvdunhill: 1 set


And ,
Please Update the list not get last PCB:

1. stephen1212 (ordered 10 received 0 need 4 sets )
2. fitzfish (received 1 set, still need remaining 3 sets)
3. ramallo
4. claudio
5. kp93300 ( 2sets)
 
Joshua_G

Joshua_G

Member
Joined 2008
gomeh.com/
I also withdraw my order until the pricing and board design is better defined.

1 - TFAN69 - 1set
2 - pop music - 2 set
3 - Royalbee - 2 set
4 - h-wan - 3 set
5 - rothay - 3 set
6 - ben-jam-in-3 set
7 - Superluca71 - 2 set
8 - suburra - 2 set
9 - dbratny - 4 sets
10 - rpeter - 3 sets
11 -Sunsun22: 2sets
12 - Sergelisses: 1 set
13 - Studiostevus: 2 sets (shipping after 15 january)
14 - Kuka: 2 sets
15 - Ferrari: 4 sets
16 - cerfer: 2 sets
17 - leejh: 2 sets
18 - albrerta: 1 set
19 - Bernie: 1 set
20 - Chul: 2 sets
21 - dggs: 2 sets
22 - luvdunhill: 1 set


And ,
Please Update the list not get last PCB:

1. stephen1212 (ordered 10 received 0 need 4 sets )
2. fitzfish (received 1 set, still need remaining 3 sets)
3. ramallo
4. claudio
5. kp93300 ( 2sets)
 
A

AndrewT

R.I.P.
Joined 2004
Strosek said:
Does anyone from the first GB have a board in hand that they would be so kind as to sell me? Even just a single positive rail would be great! I need higher current then the second GB will allow...

Thanks and PM if anyone would be so kind:)
Click to expand...
Hi, how much higher current?
Quanghao quotes <=1300mA.

I have a 5C/W sink on the CCS mosFET and 830mA as the CCS current fed from a 12vac transformer and the Tc is well over 100degC. Tj is getting close to the maximum of 175degC for an irf9140. irf9240 would be above SOA rating due to max Tj=150degC.

I don't think heatsinks in the middle of the PCB allow sufficient space for very high current CCS.
 
noSmoking

noSmoking

Member
Joined 2010
A Little help Please,
I built 2 of the 5 to 35v boards the pos and neg, Parts on the boards as silked,I have 40 volts ac,trans rated around 5 amps, going in, about 43dc at R1(22R) ,I have a 1k trimmer ,I get 4 to 12.96 output by adjusting the trimmer,do I need to change parts to get to higher outputs? trimmer need to be 5K? I need 15 vdc. I am new to FET power supplies,,,,,BUT learning fast,,,,,
both board doing the same ,
Thanks,
 
S

Strosek

Member
Joined 2009
AndrewT said:
Hi, how much higher current?
Quanghao quotes <=1300mA.

I have a 5C/W sink on the CCS mosFET and 830mA as the CCS current fed from a 12vac transformer and the Tc is well over 100degC. Tj is getting close to the maximum of 175degC for an irf9140. irf9240 would be above SOA rating due to max Tj=150degC.

I don't think heatsinks in the middle of the PCB allow sufficient space for very high current CCS.
Click to expand...

Thanks for the heads up! I'm thinking about 800mA but my heatsink is quite large... I looked a up it up and it's at very least 7C/W so hopefully that will do the trick!

I wish I had heat problems....LOL I'm still waiting for some kind member to sell me a board.:) Fingers crossed!

Thanks for the input!
 
qusp

qusp

Member
Joined 2009
well if you read above AndrewT states that he is right on the limit of dissipation with IRFP9140 and a 5C/W heatsink, with only a 7C/W sink you will be over without a doubt. 7C/W is WORSE/smaller than 5C/W not better. with this rating smaller numbers are better, yours will be almost 40% hotter by my reckoning (inside cavernous head math based on similar dissipation target to andrew). with a larger sink you'll get there, as Andrew said, but you have to stop the fet from vaporizing
 
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S

Strosek

Member
Joined 2009
qusp said:
well if you read above AndrewT states that he is right on the limit of dissipation with IRFP9140 and a 5C/W heatsink, with only a 7C/W sink you will be over without a doubt. 7C/W is WORSE/smaller than 5C/W not better. with this rating smaller numbers are better, yours will be almost 40% hotter by my reckoning (inside cavernous head math based on similar dissipation target to andrew). with a larger sink you'll get there, as Andrew said, but you have to stop the fet from vaporizing
Click to expand...

My mistake.... I tried to look it up on digikey but the pictures they use are not all actual size in this case... I'm clearly not sure what the C rating is but my heatsink is HUGE for this package size. I'll do some more research in efforts to find out it's actual rating but I suspect it will do fine.

Thanks for the clarification.
 
noSmoking

noSmoking

Member
Joined 2010
gee no one answered ......

Why don't you cool them with ammonia or freon,I guess you could water cool them but that would be too easy,get a water cooled heatsink for a processor and mount it,It's smaller too and if you get a refrigerated cooler like they sell at home improvement stores,heat would not longer be a factor, supercool those FET's !!!!!!!!
If you want sub 250 or so several people are cooling power supplies with freon,it squirts freon directly on a small spot inside the enclosure inside the heatsink, MEGA amps and no heat !!!!!
Just my 2 cents......
 
noSmoking

noSmoking

Member
Joined 2010
Heatsinks

I am using these ,no heat problems yet.they run about 85 F @.400 ma
got them at a aluminum surplus and cut them to length,got about 50 for 10.00 bucks.
 

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G

gabanyayaya

Member
Joined 2008
noSmoking said:
I am using these ,no heat problems yet.they run about 85 F @.400 ma
got them at a aluminum surplus and cut them to length,got about 50 for 10.00 bucks.
Click to expand...

noSmoking

that's from the first GB. Is there any problem in terms of voltage stability with the current version?

What about the heat, would it be too hot when using a much smaller size heat sink????
 
noSmoking

noSmoking

Member
Joined 2010
hi,

I haven't ran a new board yet,,,,,I did find a stability problem on the one in the pic, you have to give them a minute to get to temp and then under a load if you blow on the heat sink it will change the output,my solution is to put them in a enclosed box and vent it, so it will not get any unwanted airflow,
I have read about using a zener to reg,but not tried it yet,I don't think that the drift maters that much, the most has been about .03 volts,
I've got 2 built and will put them in service soon,,,,,
I built the boards to spec on the silk ,I am putting 40 ac in but the most I get out is 13.0 vdc....Do I need to chance some parts I haven't gone digging yet but will have some time soon....

Regards:),
 
merlin el mago

merlin el mago

Member
Joined 2009
Paid Member
noSmoking said:
I haven't ran a new board yet,,,,,I did find a stability problem on the one in the pic, you have to give them a minute to get to temp and then under a load if you blow on the heat sink it will change the output,my solution is to put them in a enclosed box and vent it, so it will not get any unwanted airflow,
I have read about using a zener to reg,but not tried it yet,I don't think that the drift maters that much, the most has been about .03 volts,
I've got 2 built and will put them in service soon,,,,,
I built the boards to spec on the silk ,I am putting 40 ac in but the most I get out is 13.0 vdc....Do I need to chance some parts I haven't gone digging yet but will have some time soon....

Regards:),
Click to expand...

The LEDs are lit to be sure CCS is going on well? Have you connected the remote sense wires? It's really strange this reg is solid as a rock...
 
G

gabanyayaya

Member
Joined 2008
I have compares the shunt board by QH and the shunt I'm using by Oliver for his TDA dac. There's not much different in circuit except the transistors. With some little over voltage at the psu the regulator works just fine except the IRFP9240 is hot (like 70°C something). I haven't yet getting any hiccups from it.

I wonder are you experiencing the same thing with QH shunt board noSmoking??

This week I might change the traffo to a smaller.
 
noSmoking

noSmoking

Member
Joined 2010
hi merlin,

merlin el mago said:
The LEDs are lit to be sure CCS is going on well? Have you connected the remote sense wires? It's really strange this reg is solid as a rock...
Click to expand...


all LEDs are burning ,4 of them,I have a 22R and a 1K trimmer,.47 uf and a 220 uf, I did connect the sense wires to the output pads,I have loaded the output with a 300r and a led,I can adjust the trimmer from about 4.o to 13vdc I have 43vdc at r1,I did check the big fets out of board there good,I am going to do the sk170 next,all the parts are new,,,
both 5 to 35 board are doing exactly the same so If i screwed up I have done it 2 times,lol
Thanks for all your help this problem is probably something I have cause but it will get fixed I am sure...
 
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