Breadboarding Method Concept

[Gregwor]

Hey guys,

I thought I'd share an idea I'm trying out. It might be dumb but might be great. Either way, I want to find out.

The reason this idea came to me was because I didn't want to be limited to fixed terminal strips. I want to be able to easily move my circuit around or even build it in sections to be swapped in/out. I've collected a lot of pictures of existing breadboards to get ideas as so many of them are great. I am taking on a very large circuit I'm designing and I'd love to breadboard it to tweak things before I design the PCBs.

I bought a bunch of barrier terminal strips, a 2'x4' sheet of plain 18 gauge cold rolled steel, and some small neodymium magnets. I lucked out in that when I cut one lip off of the side of the terminal strip, it just happened to be damned near exactly the depth of 2 stacked magnets. So I used some JB Weld to fasten the magnets to the strips. I realize that 450+VDC with only a thin piece of polyamide 6 might be an issue so I will probably (unless you guys think it might be okay) reserve the terminals at either end of the strip to low voltage or ground connections.

I did a test with just one strip to see if 2 magnets on each end of a barrier strip would hold well enough for me to feel safe breadboarding with them and it certainly was! Moving it around caused the strip to flex which gave me confidence in the concept. I can remove the strip by lifting it straight up but it takes a fair amount force to do so.

I modified 9 barrier strips before bed tonight and I've attached a picture of that. I hope I can find time soon to wire something up. I'll keep you posted but would love to get some feedback from you guys.

Greg

[Gregwor]

Success, so far!


I didn't think I'd get to it this quick, but I couldn't resist. I got these items hooked up and tested.

- Toroidal transformer leads
- Plate node
- Screen node
- Phase inverter node
- Bias circuit with both pots


Everything is working as expected with no errors so far.  Some things I need to address:

- A solid ground to the sheet --> I'm waiting to get my 100W iron back from my dad that I also need in order to wrap up a restoration of a clients Silverface
- Some perforated angle iron to mount some hardware
- I want to add some magnets to the bottom of my power tube sockets
- I need to do some fabrication to mount my preamp tube sockets
- I need to pick up some white paper straws so I can dye them and cut them into small rings to label my component leads which will help me keep track of what is what
- I would like to find a good way to label my first strip so that when it comes time to move the beast (ideally a 2 person operation) further than across the room, I can efficiently disconnect/re-connect the transformers
- Figure out the best way to mount my clip-in reservoir cap (I've just taped up the connections for now to protect me when probing)


Some notes after my first day with it:

- These barrier strips are great, but as expected, it's not a seamless operation.
- Lift directly up to remove the strips as I broke the set of magnets off one end by lifting it up on one side.
- Make sure the component lead isn't pushed into the crack between the insulation and connector.
- After making a termination, use some pliers to tug on all leads to make sure they're secure.
- For a couple components with very small diameter leads, I added a coat of solder to enlarge them which seemed to work.
- For MOSFETs I bent the leads such that I was able to use the middle gate lead as the one that I pushed into the barrier strip. For the Source and Drain leads, I had to extend them with a bit of wire.
- For each section added, spend time thinking about the best way to populate the strips. Luckily it's pretty darned easy to adjust.
- Reserving the outer most connections for ~ground is actually nice so far.


Please chime in if you have any ideas I could apply. Right now I'm just winging it.

Greg

[Willabe]

Everything is working as expected with no errors so far.

And if you do have an error?

And it's all on a metal 'grounding sheet? 

This is all a very, very, unsafe/dangerous idea. 

[pullshocks]

Shooter uses that style of barrier strips, in much more solid fashion.

[Gregwor]

Everything is working as expected with no errors so far.

And if you do have an error?

And it's all on a metal 'grounding sheet?

This is all a very, very, unsafe/dangerous idea.

I appreciate the comments. I am curious how else I should tackle this. Please advise.

Each little step of the way I’ve been very slowly bringing up the voltage with my variac. I have a current limiter and fuses on the primary and all secondaries. If there is a wiring error, I’ll find it and remedy the wiring. The barrier strips are very solid. It takes a lot of effort to move them.

As for the metal sheet, how is this different than a point to point circuit in a steel amp chassis? My chassis has earth ground and circuit ground just like a ‘real’ amp. With my 32 years of electronics experience and post secondary electronics education, I’ve felt extremely safe breadboarding on this contraption.

I’m not arguing here, rather dealing with concerns as my safety is priority.

Short of creating pcbs what other approach do you suggest?

Thanks!

Greg

[Willabe]

.... I am curious how else I should tackle this. Please advise.

The barrier strips are fine. But you need to screw/bolt them down. And it should be on wood or plexi, something non conductive.

Those barrier strips come in 2 different voltage ratings, 300 and 600. When I built my bread board I found this and bought the 600v strips.

Here, read these threads on breadboards;

My breadboard build part 1;

https://el34world.com/Forum/index.php?topic=18922.msg194833#msg194833

Part 2;

https://el34world.com/Forum/index.php?topic=18354.msg187427#msg187427

Slivergun's breadboard;

http://el34world.com/Forum/index.php?topic=15445.msg148808#msg148808

Silvergun's son of breadboard

http://el34world.com/Forum/index.php?topic=16551.msg163203#msg163203

Dummyload and RichardD had big bread board called ProtoZilla? And Dummyload built a 2nd bread board. I can't find anything on them other than a pic or 2 of them. Those pictures are in those thread links above. 

Both are great bread boards. 

[Willabe]

As for the metal sheet, how is this different than a point to point circuit in a steel amp chassis?

It's very different. In an amp everything is soldered and bolted/screwed solidly in place.

On a bread board everything is floating, it's temporary. 

[Gregwor]

The strips are 600V ones. Altech HE4HNWPR/12 to be exact.

I appreciate the replies guys. I think I will continue on this path knowing the potential hazards. I feel as though you are underestimating the power of these magnets. To put it into perspective, it takes about 10 pounds of force to lift these and they certainly don't slide around very easily either. As for the connections themselves, like I said, I grab each component leg with pliers and tug on them good and hard to make sure they're solid.

If you're concerned about others copying this unsafe idea, please PM me and feel free to delete this thread. As my first post stated, this is an experiment to see if it would work to breadboard/tweak my complicated circuit before designing the PCB.

Thanks again!

Greg

[Willabe]

It's not just the magnets. You have everything on a conductive metal sheet. Your playing with fire.

As far as complex circuits all of the breads board links I posted can build anything you want.

You asked what we suggest, look through the links I posted.   

[Willabe]

... As for the connections themselves, like I said, I grab each component leg with pliers and tug on them good and hard to make sure they're solid.

This helps defeat the purpose of a bread board, being quick to test circuits and quick to change components.

Takes extra time to tug on every component lead.   

[Gregwor]

... As for the connections themselves, like I said, I grab each component leg with pliers and tug on them good and hard to make sure they're solid.

This helps defeat the purpose of a bread board, being quick to test circuits and quick to change components.

Takes extra time to tug on every component lead.   

This is unavoidable with these strips when I populate them with some small component leads mixed with larger component leads. If you use these same strips, I'm sure you have the same problem at times. I'd rather take my time to ensure things are solid and wired properly.

Once I do some more work with this sheet and see how things come together, I might move over to a piece of wood and screw the strips in. We'll see. Right now this is working awesome.

Greg

[Willabe]

This is unavoidable with these strips when I populate them with some small component leads mixed with larger component leads. If you use these same strips, I'm sure you have the same problem at times. I'd rather take my time to ensure things are solid and wired properly.

My bread board has the same strips and I have never had any trouble with the leads.
 

[Willabe]

The transformer's are supposed to be fastened down and their fly leads should be connected to the strips.

Pretty much everything your doing is not safe.

Did you even look at the links on bread boards that guys here have built? 

[Gregwor]

Yes, I've searched high and low for years to find the best breadboard approach. I have a Google Drive folder littered with breadboard pictures and URL links (including all of the ones you linked above).

I appreciate your warnings of safety, but I'm well versed with this stuff as I've worked professionally in the field for my entire adult life. I also recognize your many attempts to change my course and again, provided things line up as intended, I will. My time is limited right now so I'm doing things totally temporary so that when I can't be at this bench, I can be brainstorming and prepping for a different approach. Also, note that the strips aren't being moved around. Things are stationary and when energized, I'm not touching anything other than a probe. Again, I can't see how this sheet is any different than a chassis. And compared to many many vintage point to point amps I've worked on over the years, this thing is far from the dangerous spaghetti mess that those amps are. Provided nothing touches the grounded plane, I should be safe.

Regarding the small diameter leads, it's only on a couple 1/2W resistors. But I don't mind taking the 5 seconds to tug on the leads to ensure they're seated.

Greg

[Willabe]

I appreciate your warnings of safety, but I'm well versed with this stuff as I've worked professionally in the field for my entire adult life.

If you were as "well versed with this stuff" as you say, you wouldn't be doing this.

Again, I can't see how this sheet is any different than a chassis. And compared to many many vintage point to point amps I've worked on over the years, this thing is far from the dangerous spaghetti mess that those amps are. Provided nothing touches the grounded plane, I should be safe.

And there's 1 of the problems, you can't see the difference. I explained the difference to you.  You think your idea is the greatest thing since sliced bread. You seem to think your the only 1 who has thought of this. There's reasons nobody else has tried this before you or stayed with it. Surly other people have and instantly saw the dangers and rejected the idea. But you think "this is working awesome."

It's your pride that won't let you admit your wrong and it's a very, very dangerous idea.

You can lead a horse to water, but you can't make him drink.

[Willabe]

                  ------    Announcement   ------

In no way does this forum endorse anything that is being posted in this thread on Gregwor's bread board. It is NOT SAFE in any way. Do NOT build it or use it!

[EL34]

I am for free speech, so chime in how you feel about this buildIs it safe?

[kagliostro]

I wouldn't see much difference in a breadboard or a regular chassis (turret/eyelet/ptp)

In any case, anyone who approaches repairing or building an amplifier must pay attention (a lot of attention) to what they are doing

But this doesn't mean giving up

If there is a wish for a bread board copy a proven and sure one

But only if you are experienced enough to know exactly what you are doing
 
Franco

[Willabe]

K, did you look at this bread board?

This is not a normal bread board, the terminal strips are held by magnets on a metal sheet. 

[Willabe]

I wouldn't see much difference in a breadboard or a regular chassis (turret/eyelet/ptp)

There is a BIG difference, everything in a chassis it held solidly in place.

[kagliostro]

I was posting but as I'm using the phone instead of the PC there was a send before I finished to write the whole post


May be this gives a wrong interpretation on what I would like to say


K

[kagliostro]

A safest Bread Board (also if a bit less versatile), can be this one (if I remember correctly Manhattan method)

The components are soldered, so sturdy fixed

Franco


BTW: Bread Board calls that way because the first expementers used a real Bread Board whose material was wood, an insulating material

[RoadShow]

Here's how I went about it, allowed me to make quick set up changes and do scope hook ups to understand what went on.

Main transformer driven from variac to allow me to set the level for different designs, a 6.3v supply and an OT.

Hopefully it's not too bad or dangerous.

[acheld]

I rather like the idea of magnet mounted terminal strips.

I think if you glued down a sheet of formica (or something similar) over the sheetmetal, it would be safer. 

At work (in the distant past), I've used whiteboard that had a ferrous backing -- I'd bet that the plastic coating would be sufficiently non-conductive as to be safe enough.  It certainly was durable.

Breadboarding is ALWAYS less safe than a standard build.   You have to assume (or hope, anyway) that folks know this.

[mresistor]

Here's how I went about it, allowed me to make quick set up changes and do scope hook ups to understand what went on.
Main transformer driven from variac to allow me to set the level for different designs, a 6.3v supply and an OT.
Hopefully it's not too bad or dangerous.

That breadboard is pretty cool and really not a lot of dough.  https://www.mouser.com/ProductDetail/Global-Specialties/PB-104M?qs=MLItCLRbWsxdhA04ESNcJg%3D%3D
What are the plug in tube sockets?
Here's a cheaper one that has rubber feet  https://www.amazon.com/dp/B0824W99L2/

[RoadShow]

Here's how I went about it, allowed me to make quick set up changes and do scope hook ups to understand what went on.
Main transformer driven from variac to allow me to set the level for different designs, a 6.3v supply and an OT.
Hopefully it's not too bad or dangerous.

That breadboard is pretty cool and really not a lot of dough.  https://www.mouser.com/ProductDetail/Global-Specialties/PB-104M?qs=MLItCLRbWsxdhA04ESNcJg%3D%3D
What are the plug in tube sockets?
Here's a cheaper one that has rubber feet  https://www.amazon.com/dp/B0824W99L2/

The plug in tube sockets, I got a bunch of them off of ebay seller t_blizzard back in 2019 for about $10 each.  I bought a bunch of 9-pins, some 8-pins, and some others.
I just checked, he doesn't have them listed anymore.

Close up of the 8-pin attached

[Gregwor]

I apologize for causing a ruckus here. All the responses did not fall on deaf ears.

I liked the concept as I stated in the initial post. Ultimately, I did not know where to place the strips like on other examples -- it seems most of them are quite different from one another. So, I've continued on my path and completed the entire power amp section which runs as noise-free as any other amp I've played. This has revealed a lot of layout questions/concerns I've had. I think after I build one other critical part of the amp, I should have enough data to move to a safer breadboarding solution.

Having said that, I do not want to tarnish my reputation here as I adore the forum. I will delete this thread (assuming I can do so) in a few days after some members have seen this reply.

Thank you all again for the input!

Greg

[acheld]

No, no, don't delete!  Worthy discussion with different points of view.

Early in my personal journey with amp building, my thought process (if your could call it that) was to think in terms of modules that could be laced together to build an amp. At the time, Merlin Blencowe was selling his B9A development boards (http://www.valvewizard.co.uk/developmentboard.html) and those worked out well for my purposes.

The B9A boards are long gone . . . but you could easily have some made up at low cost.

You can see these boards in action at RobRob's website (https://robrobinette.com/ValveWizard_B9A_development_board.htm)