orig schema for Marshall Shredmaster??

[rx5]

anyone got links or diagrams of original schem

Ive got 2 here but dont work.... just gives me some nasty feedback and howling.....

:x  :x

[Mike Nichting]

I have a shredmaster schematic from 1994. Is that the original??

Email me and I will send it to you.


mike

[Gus]

Check the links section.  

http://users.chariot.net.au/~gmarts/ampovdrv.htm

The links aron has posted are good links.

[petemoore]

...and its Schredding   !!!... used it last night at the gig!!

[rx5]

Gus, Ive done the marshall shredder from GMARTS....sadly , it doesnt work as expected......i expect howling/feedback at high gain.... something is really wrong.... and im not near my guitar amp....Im meters away from it.....

[Gus]

What is wrong with your build?   I did not understand it did not work? or it does not have the gain you wanted?

[AllyP]

I havent got the original but check out the schematics directory on my pics:


http://uk.briefcase.yahoo.com/toad_boy1983

I made one from this but it sounded awfull.....but the stock retail one i tried sounded great.....?!?!?!?!   Does anyone have any sound samples of one theyve built? (petemoore? :wink:)

Could you email me one?   u1m32 at keele dot ac dot uk

[rx5]

@Mike

sent an e-mail already

@Gus
 
 85% to full setting of GAIN, and it will self-oscilate... try building one and see for yourself.... Even Allp commented "It sounded awfull" ... seems you cant get the Correct diagram .... :?

@Allp

 was your problem the GAIN also?? it squilled like hell when near high gain??

[rx5]

@Allyp

that link you gave me WAS my second copy of Marshall Shred Master..... yup, sounds terrible...... same as from the Gm Arts site.....

:cry:  

Guess I will wait for Mike to send me one....  :lol:      

AND there is a difference in schema between GM ARts and from the link you gave me...... which one is which.... oh well.... :roll:

[AllyP]

I built the one in my scheme section.....

I didnt get the squeeling but it sounded absolutely full of bass and the gain wasnt 'breaking through' the sound....

It sounded NOTHING like the stock version I played....

The differences seem to be that rather than the inverting input of the first gain opamp being connected to ground, it is connected to the bias......with the resistor and cap before the gain pot reversed.....does this give the same effect?

Any chance of Mike or RX emailing me this other scheme?  

Id like to compare.....I will try them out next week on my proto board...

Ive taken a weeks holiday just for my DIY stompies :wink: .....Maybe I should go somewhere....but hey.....id just be thinking about my unfinished projects

[rx5]

@Allp

I think Ive got it all ironed out... Ill send you a copy of a working version of it... give me 3 days or so.....

got A 3rd copy by Mike Nichting (thanks a lot , Mike).....

comparing  the copy you have and  Mike's , the diagram you have seems to lack a resistor and a cap in betwenn .068uF,8.2K (missing R,C) then pin 6 of 2nd op-amp ...refer to your diagram...those two values SHOULD BE in between them... or else you will get a real overdrive that it sounds like a feedback.... the diagram you have IS correct... only it lacks the issing resistor and capacitor... Im currently asking Mike for those values....

he gave me a PS but cant read the values...too small to read....cant ZOOM in on it...Im using Ghostscript to view PS files....

Ralph

[AllyP]

rx......any chance of you doing a sound sample then?  Just a couple of seconds would be enough...I dismantled mine before I took a sample....I figured the circuit just plain sucked :S


Thanks,I eagrly await your mail

[rx5]

do you mean the bias of the 1st op-amp connected to Vbias? you connect it to Vbias (1/2 supply) you would STILL get distortion sound...but the correct connection is to the ground.... MG Arts showed its connection to Vbias while the diagram you have shows its connected to gnd (.047&3.3K) ...... minimum gain setting sounds like a simple gain amp w/out dist...while adjusting it to MAX would give you the dist effects you want.... maybe youve just missed out a part or something...

meantime try makign it again...its just a simple circuit... Even my circuit is constucted in breadboard..... havent done the final PCB yet....

the values Ive stated that are missing (res & cap) can be experimentally replaced by 10K res.....

Again, The diagram you have IS correct , just a missing res an cap....

Ill send a soundclip if I got time ..... still waiting for the values of those res and cap....

till then.....

Ralph

[AllyP]

Cheers Ralph!

It might be simple for some.....but it was only my second circuit :wink:  Im only on my third now

Thanks for sorting out the bias/vbias thing for me...i was just tryin to get my head round it yesterday

I s'pose i must have missed something....I'll try again!!!


Are you designing your own PCB?  Or have you found one somewhere when i wasnt looking :wink:

Thanks again,



Ally

[rx5]

ok here is the corrected part...refer to the diagram you have.....

here it is:

.068uF -> 8.6K -> connection for bypass sw ->8.6K -> 0.068uF -> pin #6 on 2nd op-amp......

rest of diagram is correct.... I havent done ANY pcb's YET... All the diagrams i get from the net, I always resort to breadboard....for tweaking/debugging porpuses..... I make a PCB when Ive really finalized it....

Ill send the WAV if I got time....

go build one now... just to make sure, do it slowly.... refer to the diagram from time to time.... I always build mine , section by section(input,gain,tone section,distortion section,output section,etc...)

just take your time....

[rx5]

         

paging Mike.....

Ive sent a second and 3rd mail to you....still no response....
         

thanks


RALPH

[rx5]

 
thanks for the fast reply , Mike....

"R8=4.1mF , C6=100nF................."

you mean R8= 4.1K   right?? :lol:

:wink:  :wink:

Allp,

change those BOLD .068uF and 8.6K Ive mentioned.... the true values are stated above..... thanks to Mike

I just made up those (.068uF/8.6K) ...but at least it works...  :lol:

nyway's...make yah shreddah now....

I love this forum!!!!! IT REALLY ROCKS!!!! :twisted:    

[AllyP]

Ok....Ive made an updated schematic on my yahoo account(look up at one of my first replies to this topic....)

Its called marshredAPCORRECT.jpg


Does this look right Ralph? :?

I'll have another go at building it in sections! :wink:  I hope it works better this time :wink:


I'll be your bestest buddy if you could supply a WAV.....  I'll even give you my favorite pokamon cards 'n' everything  :lol:  :lol: :wink:

[rx5]

Allyp,

THATS EXACTLY IT!!!!! nice one.....

go build one... maybe Ill send the WAV this friday...got classes on thursday.....

and dont send me pokemon, just carling switch...hehehehehe joke :lol:  :lol:  :lol:

cya

Ralph

[AllyP]

Great does anyone wanna host this updated schematic?


Aron....do you wanna link to it?