MarshallJMP Noise Mod

[Sparker]

You will have to explain that reasoning to me.

[rnolan]

Hey Sparker, thanks for all the good tech help here BTW  :thumb-up: very much appreciated.
So where I'm coming from, first MJMP says (on web site) that MDRT = less noise (and some other beneficial aspects), also he's said the original MP1  tranny wasn't as well designed as the MP2 tranny (partly cos I was agitating/inquiring for a MDRT for MP2).  Also, when electrical widgits work hard they make more noise (typically), it seems that the MDRT is designed to not work as hard and creates less ripple (so filters don't have "as" much to do and the diodes aren't being hit as hard with pulses).  For me, optimum S/N is about getting the gain structure right and all things involved working well within their tolerances (partly why audio files over spec their trannys a bit).
Hope that make sense ?
Cheers R

[robertkoa]

Thanks I needed to hear this

I purchased a 1.38  on Ebay  in  2010  which has  "noise mods"  per the old ADA Site.

I just started playing it again -don't have a way to record it but it's  quiet through headphones and  adding
very little noise to the  POD XT effects.

Less noise than the front end of most tube guitar Amps, excellent Mod, I was lucky  to buy one this way .

[rnolan]

Absolutely, good score  :thumb-up:

[trader144]

I am going to be doing a noise mod in the future and possibly a mdrt later on.

Which of my MP-1s should I mod?
The trusty beat up one which has been with me for 25 years with the blue caps, or my scratch free backup that I got from a guy's studio rack with the gold caps?

What is the difference between the blue and gold caps?

David

[MarshallJMP]

I would mod the oldest one which seems to be a V2.0,the other one is a V2.01.Difference between the 2 is the grounding.

The diff between those caps is the company that made these.The blue ones are normally lelon caps.

[trader144]

Ok old one it is.
Thank you

[trader144]

So I earned my first ADA Depot sticker and completed the noise mod to my stock unit.
thank you to MarshallJMP for all of the support, parts and instructions (and fast shipping).

I had planned on doing a before and after recording to post here, but the pre-mod recording failed and I didn't know it.

Here is what I think I hear:
1. Significantly more and cleaner definition and highs with the new components. My stock board sounded dull compared to this.
2. My Bass EQ has to be set much higher than ever before.
3. Probably less noise...but as I said I cannot make a direct before and after comparison. I'll post a comment once I get a chance to crank it.
4. When pushing V1 to 6.0+, I still need to run a noise gate as I can still hear the tube snow.
5. Is it solid state quiet without a noise gate? No...but that is too much to expect.

Now I know why people send their boards to someone else...lots of tiny soldering and lots of patience required.

[rnolan]

Go David  :thumb-up: >:D , hopefully you didn't burn yourself with the soldering iron LOL, I always seem to.

[MarshallJMP]

Maybe an explanation for the higher bass eq is that if you have a dull sound you have the perception of having enough bass response,but if you get more highs you have to compensate by turning up the bass,I guess.

[El Chiguete]

Here is what I think I hear:
1. Significantly more and cleaner definition and highs with the new components. My stock board sounded dull compared to this.
2. My Bass EQ has to be set much higher than ever before.
3. Probably less noise...but as I said I cannot make a direct before and after comparison. I'll post a comment once I get a chance to crank it.
4. When pushing V1 to 6.0+, I still need to run a noise gate as I can still hear the tube snow.
5. Is it solid state quiet without a noise gate? No...but that is too much to expect.

Has anyone else notice so much change in tone after the mod?

[trader144]

Would the new op amp be a large contributor to the sound change?

The sound is much cleaner and crisper than ever before.
What I am missing is the fat mid-punch I used to have.

[MarshallJMP]

The opamp make the sound a little different but you describe a big change,so normally not.Check if C32 is soldered correctly,the brown 270pF cap near the opamp.

[trader144]

Thank you for the help
I am going to wait until I hear the mdrt

[MarshallJMP]

ok