(Nearly) Complete LXH2 Full PCB

[GuitarLord5000]

If anyone's interested, I have finally completed the LXH2 PCB in its entirety.  Since Im using DIY Layout Creator, the circuit is WAY too big for the program, so I divided the PCB up into modules consisting of:
1. The Marshall Amp Sim
2. The Cabinet Emulator
3. The Peak MFB Filters
4. The Dip MFB Filters

And here they are:
Amp Sim:

Cab Sim:

Peak Filters:

Dip Filters:



If anyone can see any mistakes, let me know, and I'll fix it.  Also, if anyone decides to verify this PCB, PLEASE let me know.  Just as soon as I can figure out how, I'll be uploading these PCB's to the DIY Layout Creator site.

The only thing that is really missing at this point is the +/- 9v power supply.  If anyone has a PCB for this or would like to throw one together to really complete this project, please post it here.

The schematic is here:
http://home3.netcarrier.com/~lxh2/marsh.html

[km-r]

some effort dude! kudos!
it looks complicated to me though as i always prefered the lxh2 using DUAL op amps... so the pcb was a lot "linear" and quite easy to trace problems [if any]
now you just need someone to verify your work...

[jrc4558]

guitarLord, man, check you email, I sent you what you asked several days ago.

[GuitarLord5000]

some effort dude! kudos!
it looks complicated to me though as i always prefered the lxh2 using DUAL op amps... so the pcb was a lot "linear" and quite easy to trace problems [if any]
now you just need someone to verify your work...

Wow km-r, I couldn't even fathom trying to do this project with Dual Opamps!  That would be a WHOLE lot of packages and supply rails to deal with.

guitarLord, man, check you email, I sent you what you asked several days ago.

Constantin, I looked over your Fender LXH2, and I have to say, it's a shame that it didnt work for you.  Its a beautiful piece of work!  When I first started designing the Marshall PCB, I attempted to line all the Opamp packages up down the middle like you did (it makes putting the supply rails in VERY easy!)  But I just couldnt do it, as the Marshall sim has too many opamps.  I also worried that putting the + and - rails that close together might introduce a lot of noise.  If I ever get the gumption, I'll probably do the fender sim.  But after finishing this one, I've lost a lot of the drive to do PCB's of this complexity.  Im probably not even gonna do this project for a while, as Im tired of looking at it already!

BTW, guys, How exactly do you power your LXH2's?  Are you using a transformer to give you +/- 9v or are you able to use the Max1044 chip?

[MetalGuy]

Congrats for the effort!

[km-r]

some effort dude! kudos!
it looks complicated to me though as i always prefered the lxh2 using DUAL op amps... so the pcb was a lot "linear" and quite easy to trace problems [if any]
now you just need someone to verify your work...

Wow km-r, I couldn't even fathom trying to do this project with Dual Opamps!  That would be a WHOLE lot of packages and supply rails to deal with.

BTW, guys, How exactly do you power your LXH2's?  Are you using a transformer to give you +/- 9v or are you able to use the Max1044 chip?

indeed dude, and for the other reason that i have tons of dual op amps around...
i placed it in a large enclosure together with a +/- 12V supply regulated down to 9V using 7809 and 7909...

[kusi]

my versions;
Schematic

TopLayer

BottomLayer

mfg kusi

[MartyMart]

Great effort and no wonder that you want to get away from it for a while !!
I did mine on veroboard - without the spkr sim and it was a beast to do, but I only had a
10 minute de-bug !!
Tried it out again a week or so ago and it sounded most excellent .. MM

[MetalGuy]

my versions;
Schematic

TopLayer

BottomLayer

mfg kusi

Good job but I can't help to make a note. Double layer PCBs are not DIY projects friendly. Personally I never design double layer PCBs and skip automatically any projects containing such but in this case it's not fatal.

[GuitarLord5000]

Great effort and no wonder that you want to get away from it for a while !!
I did mine on veroboard - without the spkr sim and it was a beast to do, but I only had a
10 minute de-bug !!
Tried it out again a week or so ago and it sounded most excellent .. MM

Wow, a 10 minute debug.  Most Excellent!

So how do you power YOURS Marty?
I'm curious because i've never messed with anything other than 9v stompbox power supplies.  Messing with transformers is something that I really dont wanna get into at this point.
I dont think the Max1044 would have enough ass to power all these opamps.  Does anyone agree?  Disagree?
Are there any +/- 12 volt wall warts available?

[rody82]

What about building a simple +- 9 V power supply?
There's a project at ggg.
http://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf

[GuitarLord5000]

What about building a simple +- 9 V power supply?
There's a project at ggg.
http://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf

Yeah, I'd seen that.  But....

Messing with transformers is something that I really dont wanna get into at this point.

Unless of course, there are no other options.

[GuitarLord5000]

Oh, and a big thank you to you rody, for attempting to verify this for me.  From the mistake you found, I have generated this:


Thanks again!

[MartyMart]

Wow, a 10 minute debug.  Most Excellent!

So how do you power YOURS Marty?
I'm curious because i've never messed with anything other than 9v stompbox power supplies.  Messing with transformers is something that I really dont wanna get into at this point.
I dont think the Max1044 would have enough ass to power all these opamps.  Does anyone agree?  Disagree?
Are there any +/- 12 volt wall warts available?

I simply used 2 x 9v batteries, one on input jack and reversed on output jack ( craig anderton style )
It's lasted several hours and is still going strong, PSU is a better solution and 12v/15v will offer more
lower gain headroom I think.
MM.

[rody82]

Finally got some parts today, and built the power supply. (based on ggg bipolar project).
What bothers me, is that i have exactly 9V on the + output, but only -8.77 on the -.
The 7909 was made by another manufacturer (it was labeled with an S, and CZ on the bottom right corner).
I ordered 2 of them, so i soldered in the other one, but got the same result.
Will this have a negative effect on the sound? Should i buy some quality 7909?

thanks,
Rody

[rody82]

And it seems they have output voltage tolerance of about 4%... 
I used a 150ma 12V transformer.

[MetalGuy]

And it seems they have output voltage tolerance of about 4%...

This difference is normal and can be even bigger. I'm using mainly 7812 and 7912 regulators and I never get exactly + or - 12V out of them no matter of the manufacturer. The 7812 usually produces 11.8V the 7912 -12.2V but that's not a problem and it's not fatal at all.

[rody82]

ok then, i'll try it. If it sounds good then i wont care.
Got some new regulators though

[rody82]

What did you use for C1? A ceramic or a film cap?

GuitarLord: That trimpot location could be improved. The bottom 2 legs were ok, but the top leg was way more far away, at least + 2 holes. It seems trims here in europe are so big.

I've built the first section, still waiting for my pots to arrive, and could not decide what to use for C1...

[GuitarLord5000]

GuitarLord: That trimpot location could be improved. The bottom 2 legs were ok, but the top leg was way more far away, at least + 2 holes. It seems trims here in europe are so big.

Wow!

Sorry rody!
When I designed the PCB, I did it based on the trimpots found at smallbear.  While they are somewhat physically large, the lugs are very compact.  They are really great trimpots!  The truth is, trimpot sizes vary so much, there's no way I could possibly account for all of them.  I chose the smallbear model because smallbear is widely used amongst folks from this forum.  I guess that anyone building this particular project would either have to purchase from Steve at smallbear, or else modify the .DIY file to suit the trimpot that they have available.
Keep us posted on how the build comes out.
And thanks again for verifying the project!

Dave