la2a PCB design

[Gustav]

Someone was working on a PCB version of an la2a clone at some point. Did that ever happen ?


Gustav

 

[CJ]

OT: Just to bump this great work by Cayacosta:

http://www.vacuumbrain.com/docs/la2.html

 

[Scenaria]

you guys need to stop being scared of point to point

its not very difficult and somethings just seem like they should be old school

 

[Gustav]

[quote author="Scenaria"]you guys need to stop being scared of point to point

its not very difficult and somethings just seem like they should be old school [/quote]

hehe..I wish I werent scared m8...I wish....

(Bangs head against table to try and forget schweeeeet la2a vocal compression)

Gustav

 

[kiira]

[quote author="Gustav"][quote author="Scenaria"]you guys need to stop being scared of point to point

its not very difficult and somethings just seem like they should be old school [/quote]

hehe..I wish I werent scared m8...I wish....

(Bangs head against table to try and forget schweeeeet la2a vocal compression)

Gustav[/quote]

Ha ha I like P2P better because I cannot lay out a circuit board to save my life.

The way I learned is by making guitar amps and using a Fender style method... the tubes on one side, the inputs and pots and ground bus on the other and a long strip of turret board in between them. Then you can just kinda "string" the resisters and caps between them on the board. It's actually pretty easy... it has to be otherwise I wouldn't be able to do it.

 

[cannikin]

I have to agree

Point to point was actually a ton of fun (building the Bloo). It is also very educational if your new to DIY because you can visually trace the circuit and understand whats going on.

 

[Arrigotti]

I am of the PTP beginnings too.

I was actually scared of PCB's when I started here. That's why I did an LA2A first.

The other cool thing about PTP is that you can compare the schematic to your work really easily. It help you understand all the sections.

Just Do it! ...as Nike says

 

[CJ]

Also, I find that DIY circuit boards do not take kindly to component replacement. Two or three swaps at best. Then the pads start to disappear magically. And re-appear on the leads of that .1 cap you just pulled. :evil:

 

[daArry]

i do remember a thread not long ago with a pcb layout

 

[Bluzzi]

I also have chosen the LA2A specifically because of P2P. Its the only wiring I've done. PCBs scare the hell out of me. I use to supply military parts. Some were boards that had layers sandwiched within the board including top and bottom layer traces!

Jim

 

[electronaut]

Here's the thread:

http://www.groupdiy.com/index.php?topic=6131

 

[Guest]

i dunno , i can point to point very well ,

but pcb layouts are so challenging , making it simple for the builder is where time and care come into play.

not to mention making it sound likle the original ,

my la-2a pcb frequency plots are identical to the ua reissue.

pink noise / multi tone/ frequency sweeps / noise floor / white noise,

( with compression / w/ out compression / some copmpression , the same)


not to mention it only to me 30 minutes to populate the board
20 to solder ,

heh , world record on building an la-2 , 50 minutes

 

[Guest]

 

[mcs]

[quote author="Gustav"]hehe..I wish I werent scared m8...I wish....[/quote]
Scared of point to point? Try building some p-to-p UHF stuff - then the tube stuff will look very easy :grin:

I actually built a small UHF amp for receiving TVDanmark a couple of years ago (I didn't want to spend any money on the project - Danes will understand why :wink. So I made an amp complete will stop filters and channel-pass filters. That's very good p-to-p and circuit layout training :grin:

Best regards,

Mikkel C. Simonsen

 

[electronaut]

[quote author="Scenaria"]you guys need to stop being scared of point to point
[/quote]

I don't know Scenaria... driller45's PCB LA2a looks pretty bad ass. An LA2a in an hour????? Hard to beat...

 

[Bauman]

just great really!! :thumb:

 

[Guest]

im not sure if i like the small little daughter boards ,

except for the power , thats okay , and makes isolation much easier.

the metering and audio in/out are gonna go back onto the main board ,

efectivly eliminating a couple more on/off board wires.

the diy silkscreen worked out good , (damn that lettering is hard to silk)

the heaters connect on the bottom with twisted wire like on the p2p

version .

no noise from dem heaters.

a bit more to do on the silk layout. making it so my sister can build one.

driller. :thumb:

 

[Guest]

was hoping someone knew how to replace a Pot with a resistor(s).

ive been tying to figure out this formula , but it's a little above

my pay level and i get freaked out and confused :shock: :

" R1A = WP ∙ R1

R1B = ( 1 - WP ) ∙ R1"

something like that ,

simply so i could replace the stereo adj pot and limiter response pot

with a fixed value.

i know these two knobs are useful in calibration , but as a mono compressor , they both seem to sit at clock wise (full 1 meg? since their one meg ohm pots)),

so i figure their just taking up space and need to get chopped.,

ive searched the forum on this , but no luck.

any help ?

 

[Milkmansound]

I not your sister but are you gonna make these PCB's avialable?

 

[Scenaria]

[quote author="electronaut"][quote author="Scenaria"]you guys need to stop being scared of point to point
[/quote]

I don't know Scenaria... driller45's PCB LA2a looks pretty bad ass. An LA2a in an hour????? Hard to beat...[/quote]

to me part of the fun is the time it takes to build something.. the thought that goes into laying out the wire and such...

also it helps on the budget... if you build things soo quickly its easy to run out of money to build the next thing

to each their own I guess...