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Old 16th July 2003, 04:46 AM   #1
jimminy is offline jimminy  United States
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Default need schematic for laney amp pedalboard

I have a Laney pro session 120-reverb from maybe the seventies, but the foot controller is long gone. Does anyone know where I can get the schematics so I can make one?
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Old 18th July 2003, 12:25 AM   #2
jimminy is offline jimminy  United States
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Or just as good-maybe someone can tell me how to figure it out, it's probably not that complicated, being that it's proably 20-30 years old.
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Old 18th July 2003, 07:33 AM   #3
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Hi,

I don't know anything about the Laney pro session 120-reverb or the foot controller, but I agree that you can figure it out if you carefully observe what goes out of the amp through the footcontroller plug .... what kind of plug is it? Stereo/mono Jack? What should it do ? Disable reverb, add boost, or complete channel switching (in the 70's hmmmmmm)
.. keep us posted, we might be able to help...

regards,
Thijs


PS
Be very carefull with tube amps, disconnect powercord, etc etc..
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Old 18th July 2003, 05:18 PM   #4
jimminy is offline jimminy  United States
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GREAT! Thanks for the help. Here's what it is to the best of my (meager) knowledge.

The connection is a standard (5 pin) MIDI connector, but don't be confused, it isn't a MIDI device, it just happens to be the very same connector.

I'm not entirely sure what controlls are switchable using the footcontroller, but the unit has 2 seperate channels, there is a switch on the face that allows to switch it such that ch1 goes into ch2, and there is a reverb. each channel has a preamp and a boost on/off button and each channel has 3 additional buttons, one to turn the channel on and off, one to turn the preamp on and off, and one to give the channel reverb. Each channel has an EQ section too, parametric if I'm not mistaken.

These are the potential footswitches as I see it.

Channel 1
-channel on/off
-preamp on/off
-pre boost on/off
-reverb on/off

Channel 2
-channel on/off
-preamp on/off
-pre boost on/off
-reverb on/off

Master
-Channel 1/Channel 2 toggle
-ch1 into ch2 toggle
-Master mute (doubtful)

I suppose it's also possible there was an input for an expression pedal since the EQ would allow for a wah effect.

Seems like it'll take a lot of experimenting, and I'm a little nervous about frying something, though it's not a tube amp. Maybe someone can tell me how to experiment without breaking it, and I suppose these things all pretty much worked the same way, though I might be totally wrong on this point. I could take a picture of the front & back if it'll help.

If you can help, I'd really appreciate it. This is a great sounding amp, and I would love to add it to my live rig.

Thanks,
Jimminy
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Old 22nd July 2003, 08:27 PM   #5
jimminy is offline jimminy  United States
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OK, OK, I suppose this looks a little too complicated to figure out considering my last post.

So I'll make the question easier.

Is it more likely on a unit as old as this one that it would use a momentary, normally open (or closed), switch to toggle the control (say preamp on), or would it more likely be a single throw switch, alternately passing current or not.

Also, is it fair to assume that each of the 4 remaining pins (assuming one of the 5 pins is (+) current) is going to toggle one control, or is it more likely that the switching is more complicated than that, and that its a matter of combinations of the remaining 4 leads, or maybe even altering the voltage when switched?

Does anyone know how other footswitches from this era worked?
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Old 23rd July 2003, 08:20 AM   #6
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Sorry jimminy,

I had a busy week.

Yes the amp and switching arangement is more compluicated than I was hoping for but don't dispare.. You seem to know electronics from you last question.. good question! I really don't know anything about this amp but this is wat I would do:

get a nice multimeter/voltmeter and be carefull

Check if there a pin directly connected to ground, shield?

Check if there's any AC voltage on the pins when playing? Any DC volts?

Check if touching any pin with the voltmeter probe makes a popping sound (turn the amp down a bit.. )

post your results and /or go ahead and try to hardwire some pins or some pins to ground give the results

You could also op[en up the amp and check where the wires of the pins go to... but if it's a SS amp this could get complicated...

Goodluck, keep us posted,
Thijs
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Old 24th July 2003, 03:51 PM   #7
jimminy is offline jimminy  United States
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I did a little test. I know a little about electronics, but just enough, usually, to keep from getting electrocuted, but not enough to really do much besides poke around. so I poked around, here's what I found.

it's a 5 pin DIN connector on the face of the amp. the middle pin carries +5V DC (I think it's DC). shorting the current to either of the 2 pins to the right turns on one of the 2 channels. I can turn both channels on and off with a 2 button footswitch, or I suppose I could switch back and forth with one footswitch.

oddly though, the other 2 leads don't seem to do anything. I do get some clicking when I touch those though. I'm suprised it doesn't either switch on the preamp boost, or the effects loop. why would they use only 3 of the 5 leads? especially when a more simple A/B arrangement would switch back and forth between channels. Maybe somethings fried in there. I wish I know what the original footswith was.

That's what I know so far. thanks for the input tschrama.
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Old 24th July 2003, 06:56 PM   #8
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Good to hear you made progress... Maybe you could check if there's a audio signal on one of the other pins, maybe reverb, maybe a boost by shorting a feedback resistor to ground or something else.. I'm sure you're gonna make a good footswitch if you're carefull, you're half way on the design part...

Quote:
the middle pin carries +5V DC (I think it's DC). shorting the current to either of the 2 pins to the right turns on one of the 2 channels. I can turn both channels on and off with a 2 button footswitch, or I suppose I could switch back and forth with one footswitch.
Nice.. ..Switching back and forth with one footswitch would be very nice, buy a good foot-stomp-switch and go on making a nice case. Those really strong foot-stompo-switches can be expensive

Quote:
I do get some clicking when I touch those though. I'm suprised it doesn't either switch on the preamp boost, or the effects loop. why would they use only 3 of the 5 leads?
Maybe they recuire a audio AC input, one is a 'send' and one is a 'return' .. perhepts reverb or boost or effects loop....


Regards,
Thijs
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Old 29th July 2003, 11:13 PM   #9
jimminy is offline jimminy  United States
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yeah, interesting. Can you tell me how to test this please?

In the meantime, I'll probably just patch in and see if any voltage appears at either of the leads. Fun.

On a side note, I found the other person in the world who has this amp, and he's done exactly the same thing and came up with a switching pedal for his, however he is using 2 switches to turn each channel on and off. the problem with this is that you end up with both channels on before you can turn one of them off if you want to switch back and forth. I wonder if there's a way to build this thing so you can switch from and 'either/or' setup to a 'both/and' if you know what I mean. It would be nice to have an option to toggle ch1 to ch2, or to toggle ch2 on/off while keeping ch1 on. a nice way to add a boost or tone change.

Thanks,
Jimminy
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Old 7th August 2003, 08:47 AM   #10
TG is offline TG  Ukraine
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Greetings,

Try to contact Peavey Tech Support at
http://forums.peavey.com:8080/~parts

Once I needed a schematics for their Rockmaster preamp. I had left a message on Parts forum, and the next day I had this schematics in my mailbox.


Good luck!
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