Hi I have got the Valvestate 65 schematics: they should be similar. Send me an Email if you want them...
An Hint: post this on http://www.firebottle.com/fireforum/fireBB.cgi?cfg=ga&enter=go
Maybe there you'll find them...
An Hint: post this on http://www.firebottle.com/fireforum/fireBB.cgi?cfg=ga&enter=go
Maybe there you'll find them...
thank you guys.
I also have VS65 and 8080,8100 but I need VS100R's schem.
Someone has done some mods in it and I'd like to repair it.
The problem with other schems is that the component numbers are not the same.
For example a pot named VR2 isn't the same with the VR2 on VS65 schem.
And I think that there are some differences in the preamp stage of VS65 and VS100.
I also have VS65 and 8080,8100 but I need VS100R's schem.
Someone has done some mods in it and I'd like to repair it.
The problem with other schems is that the component numbers are not the same.
For example a pot named VR2 isn't the same with the VR2 on VS65 schem.
And I think that there are some differences in the preamp stage of VS65 and VS100.
!!!!!!!!!!!!
Thank you Enzo,
Seems that is what I needed!!
The only difference is that on my PCB there's a different code number...V100-60-00 for the preamp unit instead of V100-60-02...I don't have the other PCBs in front of me.
But the circuit looks exactly the same.
I don't know why but the previous owner is...
!!!
IC6 is missing!!!!!!!!!!!
What kind of IC is this? M5201?????
It isn't a normal op-amp.It's sth like a mixer op-amp!?
Any good marshall dealer in Europe?So I can order some parts?
I need three pots and this strange op-amp.
As I can see from the other op-amps on the PCB,it's a mitsubishi 5201A.
I ask my local surplus store for this but...nothing.He told me that I can order it only from a Marshall dealer.
Seems that is what I needed!!
The only difference is that on my PCB there's a different code number...V100-60-00 for the preamp unit instead of V100-60-02...I don't have the other PCBs in front of me.
But the circuit looks exactly the same.
I don't know why but the previous owner is...
!!!IC6 is missing!!!!!!!!!!!
What kind of IC is this? M5201?????
It isn't a normal op-amp.It's sth like a mixer op-amp!?
Any good marshall dealer in Europe?So I can order some parts?
I need three pots and this strange op-amp.
As I can see from the other op-amps on the PCB,it's a mitsubishi 5201A.
I ask my local surplus store for this but...nothing.He told me that I can order it only from a Marshall dealer.
noticed the mention of the Mitsubishi M5201. This is like a dual op amp with a switch, a DC control voltage on one of the pins (DIP pin 1) selects the output from one of the inputs, and passes it to the output stage.
NJR makes two compatible parts, the NJM2120 and the NJM2121. Search mouser.com for NJM212* to get price and data sheets.
The NJM2120 has 7MHz GBw, the NJM2121 about 14MHz GBw. both of them seem like decent op amps, input offset ain't the greatest at 2 to 6mV typical. Most of the opamps in the Marshall valvestate are low-bandwidth types like the MC1458,TL071, TL072 etc. so the NJM2120 should be fine.
NJR makes two compatible parts, the NJM2120 and the NJM2121. Search mouser.com for NJM212* to get price and data sheets.
The NJM2120 has 7MHz GBw, the NJM2121 about 14MHz GBw. both of them seem like decent op amps, input offset ain't the greatest at 2 to 6mV typical. Most of the opamps in the Marshall valvestate are low-bandwidth types like the MC1458,TL071, TL072 etc. so the NJM2120 should be fine.
hi resident,
I was working on a JCM900 combo amp model 4101, the Marshall marketing literature called the JCM900 their "Valve Series". It is early 90s vintage, maybe this was before they started calling them "Valvestate". The preamp circuit board is marked JMP52, it had 4 of these Mitsubishi switching op amps on the board. The previous owner zorched it pretty badly, every op amp and diode on the preamp board were fried, all the way back to the power supply rectifiers. The other parts are common, the Mitsu op amp was the only one hard to find. I bought some of the NJM2120s and also the NJM2121s just in case, after reading the data sheets I decided the 2120s were OK. With all new semiconductors and ICs in the premap, everything is fine now, it sounds as good as new.
Right, sometimes it is easier to just buy parts locally, the price might be higher but shipping costs less. Marshall might be getting selected or premium parts from Mitsubishi but I doubt it, Marshall probably bought the chip for about 0.3 euro in small quantity, maybe about 0.1 euro in large quantity. Mouser is not a big-volume distributor, in 100 piece quantity they get 0.31USD for the NJM2120, 0.24USD for the NJM2121. If Mitsubishi has discontinued the part (I could not find it on their web site) then that would explain the very high price, if you have stock then you can charge anything you want for discontinued parts.
I was working on a JCM900 combo amp model 4101, the Marshall marketing literature called the JCM900 their "Valve Series". It is early 90s vintage, maybe this was before they started calling them "Valvestate". The preamp circuit board is marked JMP52, it had 4 of these Mitsubishi switching op amps on the board. The previous owner zorched it pretty badly, every op amp and diode on the preamp board were fried, all the way back to the power supply rectifiers. The other parts are common, the Mitsu op amp was the only one hard to find. I bought some of the NJM2120s and also the NJM2121s just in case, after reading the data sheets I decided the 2120s were OK. With all new semiconductors and ICs in the premap, everything is fine now, it sounds as good as new.
Right, sometimes it is easier to just buy parts locally, the price might be higher but shipping costs less. Marshall might be getting selected or premium parts from Mitsubishi but I doubt it, Marshall probably bought the chip for about 0.3 euro in small quantity, maybe about 0.1 euro in large quantity. Mouser is not a big-volume distributor, in 100 piece quantity they get 0.31USD for the NJM2120, 0.24USD for the NJM2121. If Mitsubishi has discontinued the part (I could not find it on their web site) then that would explain the very high price, if you have stock then you can charge anything you want for discontinued parts.
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