Ground balance add on board for Mini pulse .

[godigit1]

Thanks Guys.

I doubt Ill be able to get anything together that fast.
I decided to take the bare minimums to SC with me so Ill at least be able to follow along and catch up quickly I hope.
Ill try to get the rest of my board popuated and fired up see if it even works.
I designed it for rev E but have populated it for rev d so at least Ill be on the same page.
When I get it working I will still put together a piggy back pcb specifically for rev D and E so anyone can add it to their previous Pcbs.
Thanks again for all the help on this.

[geoscash1]

If you guys can do the hard graft of making an add-on board for the MPP Rev-E (a stripboard would be more than suitable) and prove that it works to your satisfaction, I'll volunteer to layout a new PCB. Then [hopefully] Silverdog will be able to offer kits for an MPP Rev-F version, and anyone else can get their own boards made up as well.
Too busy at the moment to really get involved, but I expect this could take you some time anyway to thrash it into shape.

Hi George, thanks for offering that support..

I'm going to try to kludge something together on perf board and connect it to an mpp I have setup on my bench as a test board and see how it works out. According to Digger429 it sounds as if it seems to be working with the way he set it up so will try to get this together over the next days and see if it will be useable. The ground here in nor cal is pretty hot and littered with hot rock as well so it is something definitely needed. Hopefully this can be something that will help even with some depth loss or sensitivity loss.

I have been working on the other primary project so been spending time on it with a couple new coils I made for it.. working good too just as is...

[Qiaozhi]

If you guys can do the hard graft of making an add-on board for the MPP Rev-E (a stripboard would be more than suitable) and prove that it works to your satisfaction, I'll volunteer to layout a new PCB. Then [hopefully] Silverdog will be able to offer kits for an MPP Rev-F version, and anyone else can get their own boards made up as well.
Too busy at the moment to really get involved, but I expect this could take you some time anyway to thrash it into shape.

[geoscash1]

Your welcome and Im glad your working on this as well it totally helps to have someone to bounce ides off.

So Im obviously not a engineer either but have allot of fun with it any ways.
I may play with a new board but I think 4 layers would be in order to keep the same board size.
I only have the free dip trace so I will have to change board size totally copy Georges layout as much as possible trying not to mess up signal traces.

That should keep me busy!!

So here is what I was thinking for the switch.[ATTACH]44802[/ATTACH]
If we tie The 0 v in at a single location it will shut down the whole circut.
Maybe a couple diodes at the transistors but that might slow things down too much???
Hopefully someone with engineering knowledge can help answer that one for me .
Pretty Please

That looks like it will work perfect, it would kill all voltage to that side of the circuit.. My brain dont work as good as it use to, didnt even think of shutting off voltage to it like that.
I think youre right as far as diodes at the switches, that would change the timing if Im thinking correct..

Nice job...

Im probly not much help, just been feeling better so gettin back in to the swing of things...

It would be nice to hear from one of the gurus though, maybe just to help sort out these little details.

I dont think having the board a little bigger will matter to much. Even at 4×4 or a little longer one direction it will still be a decent size..

[godigit1]

Your welcome and Im glad your working on this as well it totally helps to have someone to bounce ides off.

So Im obviously not a engineer either but have allot of fun with it any ways.
I may play with a new board but I think 4 layers would be in order to keep the same board size.
I only have the free dip trace so I will have to change board size totally copy Georges layout as much as possible trying not to mess up signal traces.

That should keep me busy!!

So here is what I was thinking for the switch.
If we tie The 0 v in at a single location it will shut down the whole circut.
Maybe a couple diodes at the transistors but that might slow things down too much???
Hopefully someone with engineering knowledge can help answer that one for me .
Pretty Please

[geoscash1]

I was thinking a two pole switch on lines c and d to completly cut off c and d transistors.
But this leaves the timing active??
Im was also thinking maybe just a switch at -VG but i was going to try to play with that.
Im not sure if the circutry needs isolated so as not to effect the regular timing
Or if left running would effect the regular operation.
Seems like completly killing the signal would be a good option as it would also consume less power.

By the way, thank you for posting this, I like what you did with your addon board, that helped a lot.. That should work nice.

You are thinking exactly the same thing I am. I am really unsure of exactly how to do it.. I had also thought, maybe a logarithmic on/off pot at the R11 but am not sure if that will disco the C & D lines and leave the original portion of the circuit working the way its supposed to either. I'm just not an engineer (well, maybe a garage engineer... lol) so really don't have enough smarts to know what will let the primary circuit work the way its supposed to and shut off the addon portion without screwing anything else up.

Yeah, I was thinking to just add Digger429's design right into the mpp revD schematic, it just seems it would make more sense to me and would make it easier for anyone new to building one. Instead of trying to fit another board or have another separated board for troubleshooting in case of issues, just have everything all on the mpp board. I really like my mpp but as mentioned it isn't so good on hot ground so if this will give it a better chance even with some depth loss, I'll take it.

I would love to do some boards with the GB added on but someone would have to take the hand kludged schematic and make new files. If someone is willing to do that, then you bet, I will do a board order no problem and do an order for as many as everyone may want and any help with funding would be fine with me..

Here is what I did to it so far, but this is by no means a working schematic, I just redid Digger429's circuit images and drew them into the mmp schematic with all of the changes to the parts, it would have to be checked over and redrawn with new reference for R components, C components and Q components in the addons sections.

[godigit1]

I was thinking a two pole switch on lines c and d to completly cut off c and d transistors.
But this leaves the timing active??
Im was also thinking maybe just a switch at -VG but i was going to try to play with that.
Im not sure if the circutry needs isolated so as not to effect the regular timing
Or if left running would effect the regular operation.
Seems like completly killing the signal would be a good option as it would also consume less power.

Your way ahead of me as far as having a good direction with your build and thank you beacuse you have made me re-think things a bit.

I have to go to Santa Cruze for a couple weeks on the first so I wont be able to finish for a while.
Ill have time there to work on a pwb though so i will make a piggy with your scematic for the Rev D.
Are you going to make a whole new pwb Or add components to you existing pwb ?
You had stated you did not want a piggy back board. so i was curious. If your making a new pwb I would go in halves or better on a pwb order.
Just Thinhing.

[geoscash1]

Disregard that last "on off switch" attachment, it is incorrect. I deleted it but somehow its still showing.

[geoscash1]

Hi Geoscash1.
Im really not sure about what Digger 429 had going. Its kinda vague( hopefully he will chime in) but what I was doing was for the rev e beach. Basically i copied the whole pulse generator and was going to figure things out from there.
I have reject and gain on my board but they can be panel mounted , r37 or r6 for the rev d is on board.
So the green at r6 is on board then you have your reject pot that would be pl 3 on the scematic. I have added this to my piggy back board I dont know if I will really need it or not.
Im assuming the lower green circled pot is what is on the rev e scema as the gain pot. I added this also on my board but all can be wired to the panel if necessary. Im not totally sure but I think digger was using dual gang pots for these.
Looking at the rev e scematic may help figure things out.
The blue and red circles are where he connected the new transistors on the back of his board Im not sure if he just drew them wrong or he actually has pots there.
I figured I would get my board running and then add the pots if needed to do any fine tuning and then do a final pwb design.
I have to revisite his post and refresh myself before going too much further.
I hope Ive helped im a little confused about that as well .

Hey thanks for the reply godigit....

Ok, that makes sense.. I guess I should have went back and reread what he wrote in his first post.. got to busy staring at the drawings...

So, went back and read everything. I kinda just redrew what he had but added his ideas and changes for more clarity for myself. I removed the schematic references numbers on the changed parts and added the IC mc14538's as (U8-a/b and U9-a/b respectively to keep them in an orderly fashion) new parts. Attached is how I did it and will be adding it to my mpp. The only thing I kinda dont understand is how would you add a switch to turn off the GB when there are going to be GB-C and GB-D 2 (sets of wires) unless of course you add a switch for each but how and where would it be best to do that or put it in?

Here is what I did to it with Digger429's changes added to try out. I just need to figure out how to add a switch to be able to turn it on/off.

[godigit1]

Geoscash 1,
Digger 429 wrote
I also put a dual gang potentiometer for the outputs that go to C and D to control the ground balance strength. With field testing I think I'll throw that out and just put a switch, because the potentiometer at R11 does the same job.

So no pots at c and d I think, this is also where I wanted to add a switch to turn gb on or off when needed.

[godigit1]

Hi Geoscash1.
Im really not sure about what Digger 429 had going. Its kinda vague( hopefully he will chime in) but what I was doing was for the rev e beach. Basically i copied the whole pulse generator and was going to figure things out from there.
I have reject and gain on my board but they can be panel mounted , r37 or r6 for the rev d is on board.
So the green at r6 is on board then you have your reject pot that would be pl 3 on the scematic. I have added this to my piggy back board I dont know if I will really need it or not.
Im assuming the lower green circled pot is what is on the rev e scema as the gain pot. I added this also on my board but all can be wired to the panel if necessary. Im not totally sure but I think digger was using dual gang pots for these.
Looking at the rev e scematic may help figure things out.
The blue and red circles are where he connected the new transistors on the back of his board Im not sure if he just drew them wrong or he actually has pots there.
I figured I would get my board running and then add the pots if needed to do any fine tuning and then do a final pwb design.
I have to revisite his post and refresh myself before going too much further.
I hope Ive helped im a little confused about that as well .

[godigit1]

Thanks waltr,
Ill look at your build beeen thinking about using pics but im not code savy.
I actually have a Hammerhead timing circuit allready built for another project i may revisite my hammerhead after this Mpp build. Also have a chance and cuda to do so will be busy.
Thanks for your project.

[geoscash1]

try and get the 4011 working and to trigger first , they need everything working at 100% to trigger. I made Davors cct. but did not put it into MPP.

You lost me 6666, What 4011 ??? ... the mpp doesn't have a 4011 nor does the GB circuit from digger429 that is being used here.

My questions still stand as far as a couple of digger429's connections on his schematic, cant tell if they are just resistors to -5v or if they are supposed to be trimmers, also the pot after/around the 22k resistor, I think that 22k can be eliminated and a 50k panel pot used in that position but I could be wrong.

I want to work digger429's circuit into the mmp full schematic that way I can just have a board made with all components on it instead of using an addon board. I love my mpp but it is terrible in hot ground so am hoping this may help it out a bit even if losing some depth/sensitivity. I have the circuit drawn up but want to make sure of a few of his connections before doing a board for it.

[6666]

try and get the 4011 working and to trigger first , they need everything working at 100% to trigger. I made Davors cct. but did not put it into MPP.

[geoscash1]

I was just drawing this up to do the same thing.. After looking at digger429's drawing had some question on a couple of his wiring.
I'll edit the pic so it's easier to answer here shortly.

Are the pots in green circles front panel?
Is the connection in blue circle to 5v or -5 and is it a trimmer?
Is the one in red circle a trimmer?