soundguy

quad eight mic pre [pics]
« Reply #40 on: November 10, 2005, 12:29:40 AM »
its a pain in the ass to get them out but a really secure way to get them in and have them stay there.

remove the four bolts in the transformer.  Replace with a bolt about an inch or whatever longer.  Drill four holes in your chasis to line up with the holes in the transformer.  Slide new longer bolts through the chasis.  Put a plastic (you may need to use a metal standoff for the one position with the ground trace) standoff on the bolt, 1/4" will probably do.  Now mount the transformer and the pcb back onto the bolts and screw the nuts down on top of the transformer.  thats the way I mount all that type of stuff horizontally.  Its a bit of a production when you need to remove the amps to fix or swap components but its a great roadworthy solution, once you bolt it down, it aint going nowhere.

dave

chips are good with dip...


b3groover

quad eight mic pre [pics]
« Reply #41 on: November 10, 2005, 12:55:41 AM »
So the one hole with the ground trace needs a metal stand-off so that it's grounded to the case?

soundguy

quad eight mic pre [pics]
« Reply #42 on: November 10, 2005, 02:27:24 AM »
if I remember right it should make its way to ground somehow.  Its been a while since I looked at those.  I forgot my picture was sitting at the top of this page, thats how those are mounted in the chasis, like I described.

dave

chips are good with dip...

b3groover

quad eight mic pre [pics]
« Reply #43 on: August 06, 2007, 04:15:26 AM »
Holy sh*t!  After having this project on the back burner for at least 3 years (if not 4), I finally got all 8 of my Quad Eight cards racked up.  I just finished a few minutes ago.  Unforunately, I have one bad card, but I think it is the pair of diodes on the rails... should be an easy fix.

Check it out:



It's been so long since I started this project, I've misplaced four of the knobs!  Hopefully I can find them or I'll have to buy more.  D'oh!

The two holes under channels 1 & 2 are for Joe's direct input kits, however the 1/4" jack's threads are not long enough to go through the thick front panel.  I'm still figuring out a way around that.



Lots 'o iron in this bad boy.  It's whisper quiet, too, thanks to putting the power supply (one of Joe's kits, naturally) in a separate case.  



My wiring is kind of a mess, but hey... it works!



Here's the power supply.  I'd like to say I came up with the idea of using an old computer PSU case, but I saw it on the web somewhere.  I have a million of these damn things lying around and not only do they have a lot of extra wires that can be used for short hook-up runs, but they make a great case for a small power supply.  You've already got a mounted IEC jack and a power switch!

I'm headin out of town for a week starting Tuesday so I won't have time to do any real tests, but I'm really anxious to try these on drums!  WOO!

quad eight mic pre [pics]
« Reply #44 on: August 06, 2007, 03:02:41 PM »
Yeah!  I just started doing the final layout for my QE's too.  These were among the first DIY parts I picked up 4 or 5 years ago.  I just need to order up a couple of Joe's DI kits, drill the back panel and wire away.

b3groover

quad eight mic pre [pics]
« Reply #45 on: August 06, 2007, 05:18:30 PM »
Poo-ey... replaced the diodes on the bad card and now it is getting juice but it induces a nasty noise into the entire system and doesn't pass audio.  Something is wrong... hopefully bad caps?

The other 7 channels are working great and sound sweet!  Miko, Joe has a new go-between kit where you can mount the input transformer directly on the card.  I wish he would've had those when I ordered my kits, but again, it took me so long to rack these things up...

gang of elk

quad eight mic pre [pics]
« Reply #46 on: August 06, 2007, 11:13:44 PM »
sweet!!

rattleyour

quad eight mic pre [pics]
« Reply #47 on: August 07, 2007, 12:28:07 PM »
That 8 pack of QE's is staggering... I LOVE my humble pair of them.

Enjoy!

CJ

quad eight mic pre [pics]
« Reply #48 on: August 07, 2007, 06:19:54 PM »
hmmm, no Memorex tape on Miko's avatar, what up?
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

b3groover

quad eight mic pre [pics]
« Reply #49 on: August 07, 2007, 11:21:13 PM »
Well, right now it's a 7 pack because I have one card that isn't working.  I hope I can fix it.  I've had these cards for years and never tested them until the other night.  7 of them are exactly the same, the 8th one (the one that doesn't work) had different diodes on it and some handwriting on it.


SonsOfThunder

quad eight mic pre [pics]
« Reply #50 on: August 07, 2007, 11:33:41 PM »
Well at least its not the other way 'round!

Seriously, laying out a good one and taking voltage measurements from it should help you find the fault(s) on the bad one, eh?

HTH!
Charlie
"The sow would rather have her ear than a purse." - PRR

b3groover

quad eight mic pre [pics]
« Reply #51 on: August 10, 2007, 02:01:16 PM »
Yes, that's a good idea.  I just hope it's not the output transformer.

emrr

quad eight mic pre [pics]
« Reply #52 on: August 16, 2007, 02:16:54 PM »
Ohm out the output and see; doubtful IMO.  Also see if you can get a current measurement on the individual module to compare.    

I've got a similar 8 banger waiting to build, but with these two channel CA-727 cards.  They are same as the earlier AM-3 five transistor CA-127's, but two on a card and no attached output trans.  Here's an example of a pair I did FS, with Edcor outputs.   I've got just enough of some older Jensen outputs for my keepers.  Mine are a fairly rare variation that Ken Hirsch of Orphan Audio / Quad Eight Electronics LLC had to ID for me.

Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

rattleyour

quad eight mic pre [pics]
« Reply #53 on: August 16, 2007, 04:11:15 PM »
Hey Doug, where did you get those cool QE badges?

I saw them in some otehr pics you posted.

emrr

quad eight mic pre [pics]
« Reply #54 on: August 16, 2007, 06:28:29 PM »
I made them.    Labels are all old style faux-decal stickers with laquer coating, ala antique WE, military, etc gear.
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

CJ

quad eight mic pre [pics]
« Reply #55 on: August 29, 2007, 05:05:21 PM »
whats this?
is that the stock transformer?
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

emrr

quad eight mic pre [pics]
« Reply #56 on: August 29, 2007, 05:47:47 PM »
That's the stock output transformer found on cards that use them.
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

CJ

quad eight mic pre [pics]
« Reply #57 on: August 29, 2007, 06:06:48 PM »
i see.
i have a 1500,uf instead of 470.
is that an option?
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

hitchhiker

quad eight mic pre [pics]
« Reply #58 on: August 29, 2007, 08:02:02 PM »
Hey CJ!
 
  1500 uf is the stock output on the CA-127. The next v is the CA-137 and it has the 470 uf.

Sure be cool to see one of these output transformers put through the paces.
 
Lance

CJ

quad eight mic pre [pics]
« Reply #59 on: August 29, 2007, 08:29:12 PM »
thanks!
I SAW A 2200 UF ALSO.
Cj
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html