Max1044 - You are the bane of my existance

[Toney]

That layout is a bit hard to look at for too long think its the contrast or something might be me.
Anyway, it sounds like you have successfully verified it in the past?

[chromesphere]

Worked it out.  

I replaced one of the max's in the RG with an LT1054.  I put the last remaining working MAX in a charge pump on the buzzaround.  power them both up, this time the max in the buzzaround heated up and died!  Its when i have 2 charge pumps one dies....Not sure about the order though only ever had the max closest to the power supply....why the !@#%!?

Edit: tested my RG with an FSH infront which as i mentioned before has an LT1054 in it.  No problems.
The max must be drawing extra current / voltage or something when you plugged in another charge pump (or the LT1054).  I've had enough problems with the max, im not buying them anymore...

Edit again: oh this just keeps getting better and better.  I also had my boneyard in the lineup (boneyard -> FSH -> RG).  I wasnt getting any output, i was sure there was an LT in the boneyard..."must be another problem" so i let it be and focused on the RG & FSH which worked fine as i said.  ok so i just opened it up.  Bang, its a max.  Bang its now dead.  and thats madbeans layout...

Is there something inherently wrong with my layout which is pretty much, the road rage?

Paul

[chromesphere]

Ok, i just tested a max with an LT WITHOUT my booster in the chain and it didnt heat up and die...so there is something wrong with my layout...

I've checked it versus madbeans, its exactly the same (-9v section)...except obviously the charge pump and effect are on the same board...

Any help would be GREATLY appreciated..Im off to cry.

Paul

[Earthscum]

Is the negative voltage somehow oscillating and causing the MAX circuits to overload? Or maybe the LT draws enough current powering up, then suddenly stops and causes a spike to hit the MAX?

ETA: Maybe try the CMOS trick and put a 100 Ohm or so in line with the MAX input?

[chromesphere]

But wait! Theres more!

Tried another of my RG boards with the a max and another charge pump (FSH with an LT) together, No problems.   Cut out the board inside the pedal that i'd been testing and tried that with the buzzaround + MB roadrage, no problems....what the hell?  It looks like everything works, until it goes in the enclosure...checked over the offboard wiring, there is nothing wrong with it...

I'll try wiring up another one and see if it does the same thing...(new enclosure, new board)

This has got to be one of the lowest points in my diystompboxing history...it's been a total nightmare.

Going to look into it some more before i post again, cause it's turning into the ramblings of a man thats lost his mind. (me)

Paul

[derevaun]

What does your 9v source's voltage read without a load? Maybe there's not enough current draw for it to operate close enough to "spec?"

ETA: maybe observe the voltage on the source when you add+powerup a circuit with the LT?

[chromesphere]

Im getting 9v output from the power chain unloading and about 8.75v with a pedal or 2 connected.  But i dont think thats the problem...i just wired up another now, and its got no issues...i cant find anything wrong with the other.  Wow all this BS and it may have been an (invisible) wiring issues....?  i need to do more testing. 

What exactly can cause a max to burn out?  Over voltage and over current?  Wonder how i managed to over volt / current the other one...

Paul

[add4]

Chromesphere .. i'm not sure it can help, but i also got heating issues with charge pumps, but i was using the 7660s.
Turned out i made an error in my layout and the IC dangerously overheated (i melted one breadboard ... and one finger).

the thread linked to my experience with it is here :
http://www.madbeanpedals.com/forum/index.php?topic=3533.0

turned out i made a wrong connection of one of the caps..

hope that can give you food for thoughts...

Regards,

[chromesphere]

Hey add4!  Didnt know you were a DIYSB'er

I think maybe the tc1044 and lt1054 have some sort of internal protection to stop the "finger burning" experience.  If you stuff something up, they are ok, but the max just burns out....thats my current position on the issue.  It was strange though that i was burning out max's IN OTHER PEDALS (from a fault in the offboard wiring or something).  That kind of scares me.  I'm going to order 15 LT's and use those / replace all my max's.  It doesnt guarentee against errors in wiring / layout, but atleast the chip doesnt explode if there is a problem...I'm still of the conclusion, the max is just too fragile for diysb'ing...(for me anyway).

Paul

[pinkjimiphoton]

dumb question, but couldn't you just use a 7809 or something (9v reg) before the charge pump to limit it to 9v and isolate the charge pumps as well?

i've been having issues with charge pumps too with some of my circuits...intermittently. they work great, sound great, but usually about the third set i can smell something getting crazy hot...
.
i build madbean's take on the dipthonizer (honeydripper) and that has an icl7660cp in it ... but in certain combinations, it doesn't like to play well if it's on the same power supply as my klon(e),,,

but only if certain pedals are in between.

if i have fuzz face, honeydripper/wah/klon it works fine.

if i put either of my tone benders (one "my" ge/si hybrid toneblaster, the other a guitarpcb "pumped up" toneblaster) between the dripper and the wah, chaos ensues. sometimes it works fine until i kick on the dripper, then it's like dead...unpatch, and it's fine. use the dripper by itself, fine.

take the tonebender out, no problem....i can feel your frustration, believe me!!!!

[chromesphere]

WOW that sounds exactly like the issues i was having! 

I'm order 10 LT1054's today.  I wonder if its a positive ground issue, or a positive ground with MAX1044 issue...I think ill just get some LT1054's and try them. 

Although im not 100% on this, it seemed that the only charge pumps that burned out for me where max's.  If i had a max and an LT, the max would burn out. Didnt matter on the combination, it was always the max. 

Although im not cluey enuf with electronics to confirm this, i have a feeling the LT has some internal protection against (buring out) where as the max doesnt.  Thats the only conclusion i could come up with out of the absolute chaos that has been the last 2 weeks of my life.

Paul

[Jdansti]

I may be missing something (not too surprising), but if you need negative 9V, could you just use a conventional bipolar power supply such as this:

http://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf

I've had good success with this. Instead of integrating a transformer inside the enclosure, I powered the rest of the system with a cheap AC wall wart that was at least a few volts above the regulated voltage.

You've probably already thought of this or know that it won't work for your needs, so my apologies if I'm way off track here.

[chromesphere]

The problem with your suggestion jdansti is that its far too simple and effective. 

Unfortunately for me, I would like all my effects to run off the same power supply as i think thats why most people go down this path.

Thanks for the suggestion though.
Paul

[Jdansti]

Aha!  That makes sense. I've placed label tags on the end of all of my PS cords near the plugs showing the voltage, AC/DC, and polarity. For anything above 9V, I also write the name of the effect. I also make sure I have the power jack on the pedal labeled too.  I'm the only one messing with my pedals, but I'll probably blow something one day when I plug a 20VAC PS into a pedal that's expecting 9VDC. 

[chromesphere]

It seems "blowing stuff up" is part and parcel of positive ground circuits   I have a pile of MAX's here that can testify.
Paul

[pinkjimiphoton]

the charge pumps work great, usually. the reason to put everything on the same power supply is to help cut ground loops/noise and simplify life...

but it doesn't always work that way, and charge pumps suck a lot more juice than without generally.

[Paul Marossy]

The average guitarist of today has been "educated" by net-blather that if you take pedals designed to run on 9V batteries and power them with 12V, 15V, 50V, whatever, it will magically make their fingers play guitar better. 

Works the opposite way for me. The higher voltage exposes my flaws more better. 

[Jdansti]

Sorry to get a little off topic.  Since I have a pedal that uses +/- 15VDC, another that uses 12VDC, and a bunch that use 9VDC, I've toyed with the idea of making all of them capable of running on a 20VAC wall wart.  If I accidentally connect a 9V supply, it shouldn't hurt anything.  This would probably not be a good idea for someone who makes pedals for other people, though.

I don't know how it's done, but I have a rechargeable electric razor the allows you to connect any voltage, AC or DC, from 12V to 120V. If you use DC, the plug polarity doesn't matter.  It would be cool if you could do it cheaply for pedals without hum issues.  The down side might be that you'd be back to charge pumps.