(Nearly) Complete LXH2 Full PCB

rody82 · October 28, 2007, 11:14:45 AM

wired it up, but have some problems

I have a gating sound at the output of opamp 6.
Wonder what causes that. Rechecked the layout, and
component values before that output. Everythings
seems fine. The signal at opamp 6's input is a
loud distorted signal, sounds ok.

rody82 · October 28, 2007, 12:39:25 PM

Some more details: I've disconnected the rest of the circuit after opamp 6, to
localize the problem. Nothing changed, so it must be somewhere around opamp6.

rody82 · October 28, 2007, 04:19:17 PM

Problem went away by using 2 fresh 9V batteries..
seems my ggg bipolar ps could not handle so much
opamps.. (i'm using a 160ma 12 V tranny)

GuitarLord5000 · November 01, 2007, 01:22:04 AM

Hey Rody,

So, everything is good with the layout? No problems that you noticed?

How does it sound?
Should I just bit the bullet and build the thing?

Thanks again for verifying the build rody.

Peace!

Dave

rody82 · November 04, 2007, 11:05:18 AM

Yep, the main sim layout seems fine. I've built the CabSim part,
and the sound seems much better now, except its have a gating
effect again. Do we know how much power this circuit eats?
Cause i think its a power related problem again...

I've made some small changes on the cabsim and filter layouts.
It'd be nice to include some more resistor spaces, because
there are many values that are not standard. I've eliminated
some jumpers too. The problem is that the DIY Layout Creator
is useless on such huge circuits. It takes ages to do some small
modifications.

km-r · November 05, 2007, 02:41:03 AM

wow, this would come verrrrry handy for others who want to build this.

did you have noise issues?

rody82 · November 05, 2007, 11:34:49 AM

No it doesnt seem too noisy, but that gating effect is a big problem. As i dont have a well
working bipolar supply around it'll take time to get or build a good one.
It doesnt work with batteries either, wonder how much current a battery can supply...

With 8 more opamps, the +/- 9V dropped to about 7-8 volts. This must be the root
of the problem, isnt it?

GuitarLord5000 · November 07, 2007, 03:58:52 AM

Quote from: rody82 on November 05, 2007, 11:34:49 AM
With 8 more opamps, the +/- 9V dropped to about 7-8 volts. This must be the root
of the problem, isnt it?

It very likely is the problem. I believe that most folks that run the dual batteries with the LXH2 are running the Fender Sim without the filter section. There's far fewer opamps in that kinda scenario, so it may not be such a big deal. Since there are so many more opamps with the Marshall sim, two 9v batteries probably just aint cutting it. I'd be very interested to know how well it operates with a transformer based +/- 9V supply.

Rody, could you please send me your revised layouts so that I may compare them? If you do not still have my email address, please PM me, and I will give it to you.

Dave

rody82 · November 07, 2007, 10:44:09 AM

I'll try it with 4 batteries.
I suspect my ggg bipolar supply doesnt work well, because my tranny is only 120ma,
and propably i could've used better regulators.

PS: GuitarLord, i've sent you the files.

rody82 · November 07, 2007, 04:44:53 PM

Found it

You missed the last 1k resistor on the cabsim layout, so the
very last opamp was misbiased. I had to cut the trace, but
there was enough space, so no problem.
Now it works fine, sounds cool

Its a bit noisy, but not much more than any other unboxed
distortion pedal. My wiring is a bit chaotic now, and i used no shielded
cables, so i guess the housing will improve it a lot. Maybe some
coupling capacitors would help too?
Anyway i'm satisfied now, and looking forward to build the
filter sections. i'll make it switchable with a dpdt.

GuitarLord5000 · November 07, 2007, 09:02:56 PM

Okay, so here's where we stand...
1. The Amp Simulator is functional.
2. After adding in the 1k resistor (thanx again rody), the Cab Sim is functional.
3. At present, the Amp/Cab simulator is a bit noisy, however not incredibly so. With shielded wire, and an enclosure, the circuit should have lower noise?

I added the 1K resistor into the original Cab Sim file. So, if everything looks good, I'll go ahead and release the Amp and Cab Sim files to everyone. Anybody care to help me with this? Perhaps someone would be willing to put them into a Gallery? I have already uploaded them to the DIY Layout Creator site here:
http://www.storm-software.co.yu/diy/index.php?project=layouts
And they should be available for download before very long.

Rody, keep up the good work! From what I understand, the filter section should improve the sound even more. Once everything is done and in order, can we expect some sound clips? :-)

Peace,
Dave

km-r · November 07, 2007, 10:03:26 PM

i could use your cabsim layout guitarlord...
what enclosure did you guys use? im planning for a non-stompbox type enclosure.

you could ask aron for your own layout gallery if you want to.

GuitarLord5000 · November 07, 2007, 10:56:57 PM

Quote from: km-r on November 07, 2007, 10:03:26 PM
i could use your cabsim layout guitarlord...

Drop me a PM with your email address. I'd be happy to send it to you.

Quote from: km-r on November 07, 2007, 10:03:26 PM
what enclosure did you guys use? im planning for a non-stompbox type enclosure.

I havent built this yet. However, I planned the PCB based on a rack type enclosure. This is not really a stompbox effect per se. It is designed to input directly to a mixer for live playing or recording (if I read the website correctly). Trying to pack this monster into a stombox enclosure would be a severe chore.

Quote from: km-r on November 07, 2007, 10:03:26 PM
you could ask aron for your own layout gallery if you want to.

I really dont want to go that route. There are others on this site who have very nice galleries, and who take great pride in them. I'd just as soon place this in one of those galleries. I dont have the time or the desire to have my own gallery. If nobody wants to do that, then once it is all finished, the files can be easily downloaded from the DIY layout creator website.

rody82 · November 08, 2007, 01:56:51 AM

I think i'll box it in a rack enclosure, or maybe something smaller, like those old big Electro Harmonix pedals.
And I'll post photos and soundclips.

Do you think its a good idea to twist the wires to the pots?

GuitarLord5000 · November 09, 2007, 07:46:41 AM

Quote from: rody82 on November 08, 2007, 01:56:51 AM
And I'll post photos and soundclips.
Do you think its a good idea to twist the wires to the pots?

I cant think of any problems with twisting the wires. And I look forward to seeing the pics and hearing the soundclips!

Dave

rody82 · November 22, 2007, 02:01:56 PM

I've built one of the filters, and etched the other. Hope i can build it this
weekend, and can report the results.
Still need a nice box to put it together and wire up neatly.

By the way, is it possible to record directly from this box to
the soundcard? Is the signal level high enough to plug in a
headhone?

Morocotopo · November 23, 2007, 10:40:14 AM

Constantin, i have some news for you...
I downloaded the LHX2 fender sim from your gallery, made it...

AND IT WORKS!!!!

With a little correction to your layout

You reversed the plus and minus supply on the dual opamp....

I made a layout for the fender cab sim, not built yet.

Interested boys? I can post it.

Just saw this thread by pure chance, almost missed it.

Morocotopo

rody82 · November 25, 2007, 01:07:25 PM

Some photos about the current state of this project:

http://img118.imageshack.us/img118/7501/pb250063hs1.jpg
http://img119.imageshack.us/img119/1320/pb250064cs7.jpg

As you can see, its already boxed

I have some problems after wiring up the filter sections.
If i pick the strings hard it sound ok for a while, then,
as the volume decreases there's that gating effect again.
I've measured +8.3 and -7.3 Volt at the opamps.
Do you think its power related, or something at the filter
section?

GuitarLord5000 · November 25, 2007, 01:45:54 PM

I'll take a look again at the filter sections. I ran through those fairly quickly, as they are pretty much all identical in everything except parts values. Still, there could be something I missed. Gimme a day or so to pick through it really good.

Thanx for posting the pics! You dont know how nice it is for me to see this thing all put together and "boxed" up! Now, if we can work out the last of the kinks, I'll really be thrilled!

Thanx again,
Dave

jrc4558 · November 25, 2007, 02:09:38 PM

Quote from: Morocotopo on November 23, 2007, 10:40:14 AM
Constantin, i have some news for you...
I downloaded the LHX2 fender sim from your gallery, made it...

AND IT WORKS!!!!

With a little correction to your layout

You reversed the plus and minus supply on the dual opamp....

I made a layout for the fender cab sim, not built yet.

Interested boys? I can post it.

Just saw this thread by pure chance, almost missed it.

Morocotopo

Post it for sure! Did you have hissing noise in yours? Cuz mine hissed like hell. I thought its due to the crosstalk between the op amps within the dual one (i used it for the first and the last cascade).

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(Nearly) Complete LXH2 Full PCB