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Interest for potential GB for UDNess PCBs and matched FETs.

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#81
ItsAllInMyHead 1 set - Option 2 Obviously
Mark Johnson 1 set (+ as many as possible)
AnthonyA 1 set
OtisCampbell 1 set - Option 2
bullittstang 1 set +(3+ xtra sets, & let me know if you have extra transistors) - Option 2
myl 1 set - Option 2
yoaudio 1 set - Option 2
hirscwi 1 set
mordikai 1 set - Option 2
zchopper 1 set - Option 1
jens r. 1 set - Option 1
astromo 1 set - Option 2
----------------------------------------------------------------------
mordikai 1 extra PCB, 1 extra set parts
myl 3 extra PCB sets
Touchdown, 1 set
samoloko 1 pcb set - Option 1 (pcb set only), would take 1 additional pcb set
Billyk 1 Set
BuzzLiteYr 1 pcb set (would take 2 extra sets pcbs for a total of 3 sets)
manniraj 1 pcb set (Option 2 with matched FETs)
 
#82
ItsAllInMyHead 1 set - Option 2 Obviously
Mark Johnson 1 set (+ as many as possible)
AnthonyA 1 set
OtisCampbell 1 set - Option 2
bullittstang 1 set +(3+ xtra sets, & let me know if you have extra transistors) - Option 2
myl 1 set - Option 2
yoaudio 1 set - Option 2
hirscwi 1 set
mordikai 1 set
zchopper 1 set - Option 1
jens r. 1 set - Option 1
astromo 1 set - Option 2
----------------------------------------------------------------------
mordikai 1 extra set, will take some unmatched transistors
myl 3 extra PCB sets
Touchdown, 1 set
samoloko 1 pcb set- Option 1 (pcb set only), would take 1 additional pcb set
Billyk 1 Set
BuzzLiteYr 1 pcb set (would take 2 extra sets pcbs for a total of 3 sets)
manniraj 1 pcb set (Option 2 with matched FETs)
meanie 1 pcb set option 2 with matched FETs.
 
#83
I don't think you got the message.
To keep the temperature constant, you need as much thermal mass as you can get.
We use 10kg of aluminium and then thermal control.
I don't think you will get much mass with a CPU cooler.

This is what I consider minimum :
H S MARSTON-43DN-01000-A-200-HEAT SINK EXTRUSION | eBay

And then on top of that a fan is a good idea.
But you should keep it continuously blowing onto the fins.
And I presume you can keep your room temperature constant during the time you do your matching, to say +/-1°C.

And I already said that it is not a must to match the MOSFETs.
UDNeSS, or You don't need Semisouth's


Patrick
 
#84
I‘m probably late to the party, but...

ItsAllInMyHead 1 set - Option 2 Obviously
Mark Johnson 1 set (+ as many as possible)
AnthonyA 1 set
OtisCampbell 1 set - Option 2
bullittstang 1 set +(3+ xtra sets, & let me know if you have extra transistors) - Option 2
myl 1 set - Option 2
yoaudio 1 set - Option 2
hirscwi 1 set
mordikai 1 set
zchopper 1 set - Option 1
jens r. 1 set - Option 1
astromo 1 set - Option 2
----------------------------------------------------------------------
mordikai 1 extra set, will take some unmatched transistors
myl 3 extra PCB sets
Touchdown, 1 set
samoloko 1 pcb set- Option 1 (pcb set only), would take 1 additional pcb set
Billyk 1 Set
BuzzLiteYr 1 pcb set (would take 2 extra sets pcbs for a total of 3 sets)
manniraj 1 pcb set (Option 2 with matched FETs)
meanie 1 pcb set option 2 with matched FETs.
Myleftear 1 set with matched FETs
 
#85
EUVL said:
I don't think you got the message.
To keep the temperature constant, you need as much thermal mass as you can get.
We use 10kg of aluminium and then thermal control.
I don't think you will get much mass with a CPU cooler.

This is what I consider minimum :
H S MARSTON-43DN-01000-A-200-HEAT SINK EXTRUSION | eBay

And then on top of that a fan is a good idea.
But you should keep it continuously blowing onto the fins.
And I presume you can keep your room temperature constant during the time you do your matching, to say +/-1°C.

And I already said that it is not a must to match the MOSFETs.
UDNeSS, or You don't need Semisouth's


Patrick
Click to expand...

Patrick - Once again, I truly appreciate the patience and support. All clear now. I had read the post you linked previously months ago, but I could not open .asc files (I don't know what program they're for. I assume LTSpice), so I had asked someone for some help.

GB Participants - my humblest of apologies. From the onset I tried to be clear that I am a noob, I wanted to give back a bit, and I could only do this if time didn't become a deciding factor. Sadly, my time is even more limited these days. I was trying to be flexible, but I also definitely can't meet the criteria for matching described above even if it's not strictly necessary.

As it stands. Option 2 (waiting for me to match) is off the table. I'm just not comfortable with it. It is absolutely true that I am not grasping this to the full extent. So, do you guys really want me doing this? 😀 I've read every thread and everything Patrick linked. In the most recent message it was -

"But for the purpose of the UDNeSS,
J113 -- match Vgs at 6mA
2SK209GR --match Idss and optionally Vp
FQA9P25 -- match Vgs at 1.3A"

So that is what I was going by. I can only imagine what I'll run into for questions once I start trying to use the CCS etc. In short, I had no idea what I was signing up for. I know Patrick (EUVL) didn't sign up for tech support 😀 He's been very gracious.

Summary -

If you'd still like boards - The expectation of the donation to DIYA on your honor still stands. Shipping is on me. I'll ship USPS tracked. I will not be sending out unmatched J113, 2SK209, or the MOSFETs I matched with the incorrect method.

If you are on the initial list - within one week (based on the time of posting) - PM me with:

Full Name as it should appear on your shipping label
Address as it should appear on your shipping label
​

For those outside the US, as previously stated - I'll work with you individually re: your shipping.

There is no need to update the list in this thread.

For those on the waiting list. After the week has passed - if there is room, then you're in. I'll PM you in order to let you know if you're in. Once I've reached 12, we're cut off, and I'll post back here to notify everyone. So, no action needed on your part at this time.

Once again, I appreciate everyone's interest and patience. I hope I didn't delay anyone's plans to build what I'm sure is a fabulous amp.

For those that build it, I can't wait to hear how it turns out. I based my interest off of Morde's comments, and I still plan on giving it a try. Once I get up the nerve, I'll consider posting a walkthrough of how I wind up matching parts. Based on the number of PMs I got, I think it will be of interest.

Wishing you all the best.

Patrick
 
Last edited:
#88
Thanks very much, Dennis. I wish I could have matched the parts, but I have ordered the heatsinks Patrick recommended, and I'll experiment with that and other things. I have to build the CCS and learn to match the other components also. So, step-by-step. Once I get it down (and verified with a trusted person that can make sure I didn't goof it) - I may send out some care packages. I have a ton of parts. 😀
 
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