Have you guys seen this before?
http://lowpowerlab.com/blog/2013/02/11/diy-smd-metal-stencils-the-definitive-tutorial/
Reflow Toaster Oven with Bells and Whistles RAYSHOBBY.NET
http://lowpowerlab.com/blog/2013/02/11/diy-smd-metal-stencils-the-definitive-tutorial/
Reflow Toaster Oven with Bells and Whistles RAYSHOBBY.NET
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That solder paste stencil looks like a neat alternative to a solder syringe when doing multiple boards. I'll have to try that.Have you guys seen this before?
DIY solder stencils from soda cans | Hackaday
Reflow Toaster Oven with Bells and Whistles RAYSHOBBY.NET
Lets start with cfa-x #post 701 .
I must leave now i'm one step before fire test "calor gold".A class A amplifier by Dr Borivoje Jagodic
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MJE340/350's do not really affect OPS performance when used as predrivers.
THD is slightly higher and the CFA IPS's slew a bit slower when these are used
as VAS devices.
I have both the 340/350's and the 1381/3503's on hand. Gain wise, both (340/350's)are
100+ current gain. 1381's are higher (e =200+) , and most of the 3503D's are <140.
We aren't getting a match anyhow - NO 3503 - e's(mouser does not stock them).
Dang , for a symmetric VAS ... like the CFA's - spooky , I might use the 340/350.
At least they match (gain wise).
Symasui and wolverine are designed to compensate for the 1381e/3503d "mismatch" .
(wolverine and symasui are both "upside down" - positive CCS/level shifter).
OS
.
THD is slightly higher and the CFA IPS's slew a bit slower when these are used
as VAS devices.
I have both the 340/350's and the 1381/3503's on hand. Gain wise, both (340/350's)are
100+ current gain. 1381's are higher (e =200+) , and most of the 3503D's are <140.
We aren't getting a match anyhow - NO 3503 - e's
(mouser does not stock them).Dang , for a symmetric VAS ... like the CFA's - spooky , I might use the 340/350.
At least they match (gain wise).
Symasui and wolverine are designed to compensate for the 1381e/3503d "mismatch" .
(wolverine and symasui are both "upside down"
- positive CCS/level shifter).OS
.
What I meant with the wolverine/symasui -
Since they are "un-symmetric " to begin with , the mismatch really does not
matter. If you wanted to be anal , you could adjust the gain of the active side
(the 3503's Re) to compensate for the gender differences.
The CFA's "like" a better match. (In simulation) , my "Kypton-C" CFA's servo
has to provide more feedback with a mismatched VAS pair.
Lazy cats SMD CFA uses very closely matched devices - he don't need no servo.
Through hole has it's limitations... (especially with a {non-servo'ed}CFA).
OS
A good start , but by SMD ... I mean ALL SMD.
- ALL the semi's can be SMD , even the higher Ic VAS one's.
-all diodes -SMD. -all resistors -smd , even the big Zener shunt ones.
- Large caps , trimmers, euro-terminals would be the only through hole devices.
....shrink it down to 76mm X 35-40mm (3 X 1-1/2")
OS
Hi OS it is useful if you can post a complete list for all IPS where needed matched trans.in VAS.MJE340/350's do not really affect OPS performance when used as predrivers.
THD is slightly higher and the CFA IPS's slew a bit slower when these are used
as VAS devices.
I have both the 340/350's and the 1381/3503's on hand. Gain wise, both (340/350's)are
100+ current gain. 1381's are higher (e =200+) , and most of the 3503D's are <140.
We aren't getting a match anyhow - NO 3503 - e's
Dang , for a symmetric VAS ... like the CFA's - spooky , I might use the 340/350.
At least they match (gain wise).
Symasui and wolverine are designed to compensate for the 1381e/3503d "mismatch" .
(wolverine and symasui are both "upside down"
OS
.
A good start , but by SMD ... I mean ALL SMD.
- ALL the semi's can be SMD , even the higher Ic VAS one's.
-all diodes -SMD. -all resistors -smd , even the big Zener shunt ones.
- Large caps , trimmers, euro-terminals would be the only through hole devices.
....shrink it down to 76mm X 35-40mm (3 X 1-1/2")
OS
We need an SMD designer soon
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Just think about it !! "Needed" might be a overstatement. "Preferred" would be
appropriate.
The servo is quite the little helper
. For example , the "spook" - VFA , just a few tenth's of a milliamp DC feedback will correct a unbalanced VAS.
CFA-X will need a few turns on one of the trimmers to do the same.
They all still work in these conditions , but they work better without.
OS