I'm putting together my order and Digikey offers 8 different versions of the LT3092, does it matter which one? If so please let me know. I didn't see it in the kit thread BOM.
I haven't read all 49 pages yet, maybe it was dropped??
thx 😉
I haven't read all 49 pages yet, maybe it was dropped??
thx 😉
option 1 kit is including all smd parts soldered on board, meaning - LT3092 is there, too
option 2 kit - same, plus all parts going on pcb, for you to solder
and - small alu pcbs for LU are in bag, too
option 2 kit - same, plus all parts going on pcb, for you to solder
and - small alu pcbs for LU are in bag, too
^ If ZM doesn't get back to you, I'd start here.
https://www.mouser.com/datasheet/2/609/lt3092-2036966.pdf
My suggestion would be to first read the sheet and determine what those segments of the part number denote.
Then, I'd choose the package size that fits the boards you have.
Then, if you're curious about at least one other piece of the puzzle, maybe do an internet search re: what you're looking for. If that is a bit tricky, I found this in <5s.
https://ez.analog.com/power/f/q-a/163816/temperature-grade-reliability
Then, if a solution is not certain, maybe post back.
I think that X package with X grade will work well, and I am fortunate to have found it in stock, so I have picked X part linked below. Is that okay? Or... order a kit for certainty.
Just suggestions. It's fun (for me) to learn what some of the mumbo jumbo means on spec sheets and parts numbering nomenclature, maybe it will be for you.
https://www.mouser.com/datasheet/2/609/lt3092-2036966.pdf
My suggestion would be to first read the sheet and determine what those segments of the part number denote.
Then, I'd choose the package size that fits the boards you have.
Then, if you're curious about at least one other piece of the puzzle, maybe do an internet search re: what you're looking for. If that is a bit tricky, I found this in <5s.
https://ez.analog.com/power/f/q-a/163816/temperature-grade-reliability
Then, if a solution is not certain, maybe post back.
I think that X package with X grade will work well, and I am fortunate to have found it in stock, so I have picked X part linked below. Is that okay? Or... order a kit for certainty.
Just suggestions. It's fun (for me) to learn what some of the mumbo jumbo means on spec sheets and parts numbering nomenclature, maybe it will be for you.
dunno, don't care for suffix
what I'm looking regarding LT3092 is : preferably SOT223 case, if not available then TSOT-23-8 case
recently I resorted to make all pcbs containing ref. CCS with 2 options - instead of onboard CCS, there is small Daughterboard soldered with 2 fat pins to main board , and then it can be either LT3092 (normal case and ultrasmall SMD) or LM334
LM334 still much easier to obtain than LT3092
frankly, dunno where I posted all related info, but Codyt's build is with Daugterboards, just go back few posts to see his pics
onboard LT3092 reserved strictly for future Babelfish XA252, nasty xconductance of pucks needing every ounce of predictability in biasing circuit, at least when my OCD is deciding factor
what I'm looking regarding LT3092 is : preferably SOT223 case, if not available then TSOT-23-8 case
recently I resorted to make all pcbs containing ref. CCS with 2 options - instead of onboard CCS, there is small Daughterboard soldered with 2 fat pins to main board , and then it can be either LT3092 (normal case and ultrasmall SMD) or LM334
LM334 still much easier to obtain than LT3092
frankly, dunno where I posted all related info, but Codyt's build is with Daugterboards, just go back few posts to see his pics
onboard LT3092 reserved strictly for future Babelfish XA252, nasty xconductance of pucks needing every ounce of predictability in biasing circuit, at least when my OCD is deciding factor
found few posts with daughterboards presented
https://www.diyaudio.com/community/threads/the-marriage.390965/post-7140688
think I'm going to take another trick from Pa - need to have spreadsheet documenting what I made, recently is happening that I'm seeing new things in my old posts
last night I was searching through one ("my") thread on Baby DiyA, just to see renders of line stage I was working month or so back, and totally forgot about
https://www.diyaudio.com/community/threads/the-marriage.390965/post-7140688
think I'm going to take another trick from Pa - need to have spreadsheet documenting what I made, recently is happening that I'm seeing new things in my old posts
last night I was searching through one ("my") thread on Baby DiyA, just to see renders of line stage I was working month or so back, and totally forgot about
After installing more caps to cap-mx output, and running only one channel at a time, same thing (though i guess not unexpected).
I went to comparing spice and real pcb thermals. Spice says irf510 and bc139 should be dissipating 500mW each, that would get kind of toasty. Yet mine i cannot even tell are even warm (30C or less).
Maybe there is reason for suspicion here even though i get ~-1.345V on Lu gate that spice says
I went to comparing spice and real pcb thermals. Spice says irf510 and bc139 should be dissipating 500mW each, that would get kind of toasty. Yet mine i cannot even tell are even warm (30C or less).
Maybe there is reason for suspicion here even though i get ~-1.345V on Lu gate that spice says
Or if there is 0.65 V across R9, check if R9 is not 220 Ω or more. That would explain nicely problem with driving LU input capacitance at higher frequency.
Yup, there is 0.65V across R9, but it is 29 ohms measured. Sim says this is normal for 22 ohms as well?
I must be missing something
I must be missing something
Definitely.
IRF510 and BD139 should be hot and require heatsinks if CCS operates as it should at 30 mA.
Did you measure R18 on your PCB (R9 from the sim) without de soldering? There is a BC550 base to emitter junction that could skew measurement. Try with reversed positions of ohmmeter probes.
What is voltage across R11 on the PCB?
nature of the beast ( ring of two CCS) is that there is always one Vbe across R9 ( designation from yor LTSpice pic)
30mA isn't carved in stone, but more the merrier
be sure that you have 22R there
and, again, no reason that is having anything with wiggly Freq.
30mA isn't carved in stone, but more the merrier
be sure that you have 22R there
and, again, no reason that is having anything with wiggly Freq.
another check of voltage shifter Iq
your LTSpice pic : check voltage across R8
it must be (0V65/22R)*61R
(where did you found 61, dunno)
I remember my value is 68R
your LTSpice pic : check voltage across R8
it must be (0V65/22R)*61R
(where did you found 61, dunno)
I remember my value is 68R
If only several mA flows from the CCS, that has everything to do with wiggly fr. response.
was referring to (possible) 27R, measured as 29R
of course there are all reasons why hefty 30mA must be there ....... say 10mA of difference not being much worse ........ but with less than 20mA I would feel uncomfortable
of course there are all reasons why hefty 30mA must be there ....... say 10mA of difference not being much worse ........ but with less than 20mA I would feel uncomfortable
Ah, all clear. 🙂
As is a saying “Too many cooks spoil the broth” I hope there will be no confusion and Dendrobium will find what’s wrong.
As is a saying “Too many cooks spoil the broth” I hope there will be no confusion and Dendrobium will find what’s wrong.
Ok, so i took off pcb and de-soldered and replaced bc139 and bc550 for different one (expect this to make 0 difference but desparation)
While they were off measured this R9, now without bjt Rbb effect and still 29 ohms, but given how critical it is i changed it and now it is 24.5 ohms (ok, not perfect, 27mA instead of 30, but if it's that it should show some improvement at least and then i know where problem lies)
Measured this one at 66..another check of voltage shifter Iq
your LTSpice pic : check voltage across R8
it must be (0V65/22R)*61R
(where did you found 61, dunno)
I remember my value is 68R
1.73V measured across this..ok pretty much correct, (0.65/24)*66
On gate of LU now is 1.172V
DC offset needed retuning, so hopeful now things are different
Thank you guys for all help
As you maybe remember my previous forum name was Zbunjen, maybe i should have kept it (and you know why, we are all same region)
EDIT: no change, though now the IRF is warmer, but ok, this was worthy sidequest
It is actually interesting but output curve is identical down to minute detail
Maybe its just factory reject Ali LD1014's, what else could it be?
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Yeah, azure is new modified right channel, red is old unmodified left.
In reality they are perfectly overtop each other, i just clicked "separate traces" in REW so you can even see two.
Cue my embarassment when amp is fine and it is somehow recording setup..but then makes no sense everything i ever measured was flat, except with this.
All corrections that were made were necessary. CCS had too small current (cool semiconductors) and you didn’t add capacitors at the Cap mx output for nothing. Check this if you haven’t already:
https://www.diyaudio.com/community/...-at-the-capacitance-multiplier-output.389938/
That’s weird. Both channels measuring the same, mean two semi-defective LD1014D in a row.
If LU's are main suspects, I can send you for free a matched pair soldered on aluminum PCB adapters. They have nice triode curves but that is DC measurement. Who knows how they work at AC.