Pedal Preamp overdrive Marshall Valvestate VS30

[ANDYEFFECT]

I'm looking to build the sector preamp overdrive Marshall Valvestate VS30 to turn into a power transistor.

there is some possibility for someone to mount PCBs only the Preamp OVERDRIVE of Valvestate vs30? :?:

I like the overdrive / distortion of this project.

thanks
Andre


http://www.drtube.com/schematics/marshall/vs30-60-02.pdf

[CASTOR]

Hello! see if I got it right:
You want to build a project where you put the overdrive section of this amp inside a footpedal, dont you?
You have to keep in mind a couple hints though. Even if its not impossible to do, you will find it easier to build a pedal that sounds similar like the Guvnor or some other.
The preamp section on a guitar amp usually runs on a higher voltage than an ordinary stompbox. On this case it should be 12 to 15 volts (im just guessing, maybe the schem has more info on that) so if you run it on 9 volts it will sound different (tamer that is).
Also you will have to separate the "clean" stages from the "drive" which means redrawing the schem to include just what you want to copy. Dont forget there is a power amp in there too, you want only the preamp so this part should not be included.
Have fun and please excuse me for my terrible English !

[ANDYEFFECT]

Hello! see if I got it right:
You want to build a project where you put the overdrive section of this amp inside a footpedal, dont you?
You have to keep in mind a couple hints though. Even if its not impossible to do, you will find it easier to build a pedal that sounds similar like the Guvnor or some other.
The preamp section on a guitar amp usually runs on a higher voltage than an ordinary stompbox. On this case it should be 12 to 15 volts (im just guessing, maybe the schem has more info on that) so if you run it on 9 volts it will sound different (tamer that is).
Also you will have to separate the "clean" stages from the "drive" which means redrawing the schem to include just what you want to copy. Dont forget there is a power amp in there too, you want only the preamp so this part should not be included.
Have fun and please excuse me for my terrible English !

yes friend, I want to separate stages "clean" and stage "overdrive", I will only use the preamp stage of "overdrive" channel.

I wanted to help separate stages.

hugs
ANDRE

[Ice-9]

This is very possible to do. The only real obstacle is the 30v power you wil need to run it. This also can be done from a 9v battery using voltage doubling/ tripling circuitry. Try a search for  30v from 9v or similar. If you want any help redrawing the circuit i can help there.

[ANDYEFFECT]

This is very possible to do. The only real obstacle is the 30v power you wil need to run it. This also can be done from a 9v battery using voltage doubling/ tripling circuitry. Try a search for  30v from 9v or similar. If you want any help redrawing the circuit i can help there.

I think there is no need to be 30V,
the preamp is powered by 15v, that is easy to solve,
I want to mount is the only sector Preamp overdrive, you can help?
thanks
andre

[Ice-9]

Iv'e checked the schematic, and its powered by 30v. It has a +15. 0 and -15 split rail power supply, but you could alter the circuit to use a different voltage.

[Ice-9]

I have redrawn a schematic of the overdriver preamp section including the 2 band tone stack and contour controls. I have also added a voltage divider for single rail power instead of the +- 15v split rail. either could be used.
i will have to wait till i finish work to get home and take a photo to upload. hope this is of some help.

ps the circuit is very simple once it has been redrawn.

[Ice-9]

What is interesting about this circuit is the use of the dual input single output switched op amp used for chanel switching. If all you want to do is build the overdrive channel into a pedal there is no need to use M5201as IC2 (from the link schematic). i would replace it with a standard op amp chip and change the schematic to suit. and use true bypass wiring. I will redraw the schematic and post it to show these mods later tonight.

here is a link to the data sheet for the M5201. It states that it is a http://pdf1.alldatasheet.com/datasheet-pdf/view/896/MITSUBISHI/M5201L.html

also for a pedal version you will want a cap on the input and output, i quite fancy tring this circuit on breadboard at some point.

will post schematics in a couple of hours.

[ANDYEFFECT]

What is interesting about this circuit is the use of the dual input single output switched op amp used for chanel switching. If all you want to do is build the overdrive channel into a pedal there is no need to use M5201as IC2 (from the link schematic). i would replace it with a standard op amp chip and change the schematic to suit. and use true bypass wiring. I will redraw the schematic and post it to show these mods later tonight.

here is a link to the data sheet for the M5201. It states that it is a http://pdf1.alldatasheet.com/datasheet-pdf/view/896/MITSUBISHI/M5201L.html

also for a pedal version you will want a cap on the input and output, i quite fancy tring this circuit on breadboard at some point.

will post schematics in a couple of hours.

very interesting!
there is no need to switch.
is the only channel for that matter overdrive, with the controls stack.
I await your project.
hugs

[Ice-9]

Ok here is the re-draw made from the original schematic which has the M5201 dual in single out switched op amp. I have drawn the schematic so it is easy to understand. As the op amp is used to with another of the same type elsewhere in the circuit to switch between the clean and dirty channel it can be replaced with a single op amp in a pedal.


there is one mistake in the schematic. The 22uf cap going to the 30v rail and the output diodes i have drawn upside down ( the + side of cap goes to 30v)

I will redraw and post the modified op amp next.

[ANDYEFFECT]

Ok here is the re-draw made from the original schematic which has the M5201 dual in single out switched op amp. I have drawn the schematic so it is easy to understand. As the op amp is used to with another of the same type elsewhere in the circuit to switch between the clean and dirty channel it can be replaced with a single op amp in a pedal.


there is one mistake in the schematic. The 22uf cap going to the 30v rail and the output diodes i have drawn upside down ( the + side of cap goes to 30v)

I will redraw and post the modified op amp next.

Ice-9

great work, hope to be continued here, to see the final result.
great support!

[Ice-9]

Here is the schematic modified to use only the needed op amps (no need for switched between channels )I think i might give this one a try at some time soon.



I'm quite sure this will operate at 9v with possibly a couple of mods but to get the same sound and dynamics 30v or +-15v split rail will be needed.

[slideman82]

This distortion really kick ass!!!!!!!!

[ANDYEFFECT]

Here is the schematic modified to use only the needed op amps (no need for switched between channels )I think i might give this one a try at some time soon.



I'm quite sure this will operate at 9v with possibly a couple of mods but to get the same sound and dynamics 30v or +-15v split rail will be needed.

you can mount PCBs in DIY layout creator?

[alex frias]

Hard to believe...

[Ice-9]

Hard to believe...

Just wondering Alex what is hard to believe

[alex frias]

The expression "Help me?" was used in place of "Could you do all those things for me?".
Someone did the same in a braziliam forum.
Good luck, the project looks promising...

[Ice-9]

  Yeah i see, If i decide to put this one on a PCB it will have to be after the New Year anyway. Dunno if everyone is like me but i get side tracked by getting too excited by too many projects at once and not all them make it to completition. But this looks like an interesting little circuit so i might make it to the pcb.

[DougH]

Interesting... Two separate tone stacks in series, one fixed except for mids and the other vice versa.

You guys might want to take a look at the Guvnor. It is similar in some ways but slightly simpler, and is tuned more for pedal use. The VS30 preamp lacks some of the filtering the Guvnor has, as it is designed for an amp preamp instead of a pedal.

[slideman82]

Be carefull! op amps work with dual 15V supply, not single 30v!