Quad Eight AM 10 Layout

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dogears said:
There’s a pretty substantial difference in their performance in LTSpice between +/-15 and +/-28V supply. Just as a heads up.

Also curious. Any details could be helpful, as most of us are probably considering 500 series applications.
 
Ricardus said:
I thought there would have to be. But what is LT spice showing you? What types of differences?

This is where we discussed this previously:

https://realgearonline.com/post/239713/thread
 
justinheronmusic said:
Seems the conclusion is that there is no perceivable difference, just on paper.


I don;t know that we came to that conclusion, I questioned it.  I have not listened at both voltages, and what I have are AM-3's or something, 5 transistor version. 
 
Hi all

Hi all
Does any of the 560/550 have to be matched pair !?

Thanks
F
So, Yes, the one's in the center marked 2x550 should be matched...

Another thing, I want to put a 'spacer' under the 2N4036/2012... it's not an easy piece of hardware to find this days...

I have a 3D printer at home, so I could make it, but does that transistor getting really warm ??? --> PLA will twist, then melt around 180°c... and it's messy°°°
what's your thoughts ?

thanks
F
 
Last edited:
None of my original AM-10s have any kind of spacers or heat sinks on the TO-5’s. Never had an issue with heat doing any real damage. A little discoloration but nothing more. It’s a larger footprint than 2520, but even so I don't think it’d be a problem on that smaller board.

But if you’re really set on the idea, if you’re just talking about the old (usually) white plastic spreaders/spacers in TO-5 footprint, I still have hundreds. I’m in the US but PM me if you’re desperate and i’ll send you a bunch for shipping cost. i was thinking about putting the whole lot up for sale here anyway.
 
Hi. New to the board, not new to soldering tiny electronic things.
Bought a bunch of DOA kits from CAPI and built 'em...The garAM10 didn't work, everything else did.
While the diode boo-boo I did make (fixed it, the silkscreen and diode conventions could be much better here), from reading other posts, that's not my issue.
I use a Variac to bring up the voltage slowly. On this and only this one, a loud hum would occur...
Doing a diode check on diodes and transistors shows no shorts.
All transistors+diodes are in their proper positions and orientations.
All resistors are the proper value and in the proper places. Capacitors aren't shorted.
Looking at the PCB and measuring from the pins, I get conductivity where I'm supposed to, and can't find any bridges that shouldn't be there.
Now, I ask ya...What transistors would be turning on that would cause this? I'd love to fix this, or at least turn it on and not hear the blasted hum of death.
Thank you, metalockpick
 
Hi all


So, Yes, the one's in the center marked 2x550 should be matched...

Another thing, I want to put a 'spacer' under the 2N4036/2012... it's not an easy piece of hardware to find this days...

I have a 3D printer at home, so I could make it, but does that transistor getting really warm ??? --> PLA will twist, then melt around 180°c... and it's messy°°°
what's your thoughts ?

thanks
F
Once the proper TO-5 etc sized spacers dried up, we bought a large jar of buttons on eBay. Buttons like for your clothes. They made outstanding standoffs for small transistors. It took a couple tries to find the right size/style we wanted.
 
There are still plenty of TO-5 mounts and spacers available. Here are some that are currently available on Digi-Key:

1678313992847.png

1678314048131.png

Be sure to check out this website:

https://www.bivar.com/component-har...perm-o-pads/?bz-page=1&bz-results-per-page=10
And, the entire 17-page set of files that "SmallButFine" had posted containing the AM-10 and other QUAD-EIGHT related schematics are all contained in an enlarged and easier-to-read version in the attached "QUAD-EIGHT AM-10 & Other Schematics" PDF file.

Other TO-5 mounts and spacers datasheets are shown in the other PDF files.

ENJOY!!!

/
 

Attachments

  • QUAD-EIGHT -- AM-10 & Other Schematics.pdf
    1.3 MB · Views: 1
  • BIVAR -- PERM-O-PAD TO-5 3-PIN MOUNT - PN - 520-021.pdf
    38.4 KB · Views: 0
  • BIVAR -- PERM-O-PAD TO-18 MOUNT - PN - 100-095.pdf
    46.8 KB · Views: 0
  • KEYSTONE -- TO-5 Socket 3-Pin - 4590.PDF
    188.8 KB · Views: 0
  • KEYSTONE -- TO-5 Socket 4-Pin - 4591.PDF
    188.5 KB · Views: 0
  • KEYSTONE -- TO-5 Socket 8-Pin - 4592.PDF
    191.3 KB · Views: 0
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