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Need a Schematic? Check the Vault *MP-1 Classic Schematics Just Added!!

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Messages - MarshallJMP

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Yep without the ribbon cable the mp-1 won't fire up, that's normal.

Wow Herby, don't give up so easy, this can be fixed, doesn't seem to be so bad.I've seen far worse then this. Maybe we can do a skype session next week so I can help you out finding the problem.Do you have a multimeter?

Discussions / Re: R.I.P Malcome Young
« on: Time Format »
RIP Malcolm, you will be missed. One of my all time favorite rhythm guitar players.

The cap has no polarity, as for the opamp, well many people struggle with it. Even I lift a pad sometimes. Now it's good that nothing has lifted on top, so if it happends on the bottom just run some small thin jumpers.

Say if you have questions, just email me, this will go faster.

Yes you can try it out without the MDRT and SS mod, no problem.

What IC socket?

Sometimes they can get stuck and hard to get out, but I never had one that I couldn't get out. Try to rock it from left to right and see if it comes loose.

How about these?

Hey  Herby if you have any questions just let me know, big or small.

MP1 / Re: MP-1 Ultimate 80's Tones
« on: Time Format »
The AA filter is a 2nd order low pass sallen key filter at 7.3kHz so it can make a "small" difference. But with the older delays the filter freq was much lower and there you can hear a huge difference.

What also makes a difference is that as soon you engage the rate it always starts at the lowest clock freq, so if the depth is set low it will sweep from 30-40kHz vs 50-60kHz that makes quite a difference in sound, so the chorus wil sound much deeper with mp-1's that start on 30kHz vs mp-1's that start at 50kHz.

MP1 / Re: MP-1 Ultimate 80's Tones
« on: Time Format »
The chorus also uses a compander (compressor expander) and some filters (anti aliasing and reconstruction) so that will also have some influence on the sound.

MP1 / Re: MP-1 Ultimate 80's Tones
« on: Time Format »
Well for a clock of 30kHz that would be around 17ms, 50kHz around 10ms.So you see this quite a difference and that's why some MP-1 chorus has a better sound then the other.

Well a BC538 should work if you can find these. If not let me know.

MP1 / Re: MP-1 Ultimate 80's Tones
« on: Time Format »
Well the delay time = N/2.fclk so in case of a MN3007 BBD that's 1024/2.fclk. The clock frequency (fclk) in the mp-1 is (depending on the mp-1) from 30kHz-60kHz to 270kHz-310kHz. (Rate at 0 and depth going from 100 to 0). I have seen all different frequency's but the best sounding ones are the ones with the lowest frequency.
It seems to depend on the CD4046 phase looked loop which can give different frequency's depending on who made it. But the mp-1 was designed to work with 30-270 kHz.
Usually from what I encountered the older mp-1's are more in that area while the newer ones have shifted to a higher clock.

Well there were 7 board revisions, A to G and 5 firmware versions V1.36,V1.37,V1.38,V2.00 and V2.01.Of the midi board there were 2 versions.
Now for a timeline, we could do that if we compare the date codes on the IC's with the revision.

MP1 / Re: MP-1 Ultimate 80's Tones
« on: Time Format »
THAT was some really NICE playing, very Gilbert sounding.

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