point-to-point vs board: difference in SQ?

[rickcr42]

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I've built a few of them and unless you keep the wiring to an absolute minimum and keep it short and tidy it acts as an antenna and tunes into radio OG (oscillation god) The LM6171 is one instance where P2P must be very well thought out and very well implemented

a potential 'workaround' for high speed layout is to use the tiny manufacturer evaluation boards as kinda an "opamp module" and then do the rest of the layout open and PTP.This is more like the old modular designs where you just replaced a single module block instead of the entire board.
another "plus point" in my mind for open construction and boardless where possible is for those with constant upgraditis.Not just the opamp swaps but the passive part swappers who by heating and reheating circuit boards end up with a damged board and the copper foil lifted or gone totally from the location of the part.

More than one way to go at things and an open mind is step #1 or you limit yourself to "same old" .

 

[PinkFloyd]

Quote:

Originally Posted by rickcr42 a potential 'workaround' for high speed layout is to use the tiny manufacturer evaluation boards as kinda an "opamp module" and then do the rest of the layout open and PTP. .

The "other" option is to buy a PCB / Kit.

 

[dr_digits]

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Originally Posted by rickcr42 if DIPs are used dead bug is an option for the adventurous.

And for those slightly less adventurous, you can p2p with dip sockets. It is a lot harder to lose a leg on a nice socket. Sockets are also quite a bit cheaper. If I had a digi-cam I would post some pics of a p2p cmoy and a p2p opa627 + buf634 multi-loop that I did.

Now that I think about it, one major advantage of PCBs is the resulting product is better suited to handle vibration and shock. Not that anything I've built has broken in transit, but it is a concern with some p2p designs.

 

[rickcr42]

Quote:

Now that I think about it, one major advantage of PCBs is the resulting product is better suited to handle vibration and shock. Not that anything I've built has broken in transit, but it is a concern with some p2p designs.

that is exactly why earlier in this thread i recommended terminal boards and chassis mount tie points.
Absolutely rock solid stable and the match of any circuit board.The tie points I use are single posts that bolt directly to the chassis with a kinda mini shock absorber in between the "tie" and chassis.

I also use wood board mounts a LOT internally.Especially when i add line transformers.trasnsformer to capacitor clamp to pine board mounting surface to metal chassis.

I take no chances with either vibration or durability though to be honest I am thinking USPS can wreck the best of designs no matter how well designed and implemented.

 

[erix]

Hey rickr - thanks for the Welporne!

I'd never seen that amp before now - it looks kinda like something on my bench!

This is Pete Millet's SRPP amp for AKG K1000's. I initially decided to build it point-to-point but, after seeing some guitar amp **** I decided to go turret boards. These views of are the boards about 80% done.

psst! Wanna make your own turret boards?
Here's How:
You can get G10 Garolite (the board material) in 1/16" & 1/8" thicknesses from www.mcmastercarr.com. Pretty cheap - 12" x 12" x 1/8" for <$30.

You can get the turrets from www.hoffmanamps.com (as well as boards) and an installation tool. These are awesome parts - buy 100.

The G10 machines like butter. Use a bandsaw or tablesaw to cut it and a sander for the edges. It also drills easy without tearing out.

The turrets are quite cool to work with - wrap the components around them and run wires from the insides to the tube pins - (note, these are hollow as opposed to Welbornes).

Enjoy!
erix

 

[rickcr42]

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Hey rickr - thanks for the Welporne!

Hey stranger,you're welcome.

I have been doing the point-to-post-to-terminal board-to-point construcion method for a long time and will never go back to any other way.It suits me and has proven reliable over time.

but man,that wellborne is just too good looking and i just like to LOOK at it

 

[dr_digits]

Quote:

Originally Posted by rickcr42 The tie points I use are single posts that bolt directly to the chassis with a kinda mini shock absorber in between the "tie" and chassis.

Hi Rickcr, I was wondering if you would share where you get these tie points. I would like to try them out.
Thanks.

 

[skyskraper]

rick or anyone else, is there a book or link you can reccomend that will help me develop my p2p skills? i mean im sure it's not hard to translate a schematic to a perf board layout, but i would like to get a knowledge start before i attempt it, and then when i do attempt it, to do it right

found a cool simple discrete HP amp in jones & shea's book "transistor audio amplifiers" that i would like to play around with and get working nicely

 

[Dreamslacker]

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Originally Posted by amb All valid points, but I should also point out that a "designed" PCB allows such things as ground planes or power planes. These have performance benefits in some circumstances that cannot be realized with p2p wiring.

 

[amb]

Dreamslacker, LOL. Nelson Pass has you beat, however. Check out the prototype of his A40 power amp. Look at the photo on the last page of this PDF file.

 

[Dreamslacker]

Quote:

Originally Posted by amb Dreamslacker, LOL. Nelson Pass has you beat, however. Check out the prototype of his A40 power amp. Look at the photo on the last page of this PDF file.

Damn!! LOL...

I just find it intriguing that few people bother to do true PTP these days.. LOL. Coming up with a design and accomodating it such that all the leads connect to each other w/o use of wires is fun.. LOL..

 

[rickcr42]

Quote:

rick or anyone else, is there a book or link you can reccomend that will help me develop my p2p skills?

PTP requires an understanding of the schematic and sigal flow more than any other method but if you think in PC Board terms think of the wires as the copper trases but just not attached to the board and like with a pcb shoot for wires not crossing other wires or straying too close to AC.

It is also way easier to get the ground right when you have a single point and a single wire for each ground from the part or group.

I always do a mockup by placing the actual parts on the chassis where they will go then i draw a pencil and paper sketch of the wiring until it is right and then build the actual device using my sketch as the wiring guid.

Maybe a good read would be this for layout ideas :

http://www.magnequest.com/2a3_diy/Se..._Manual_v1.pdf