MB-1 Mods?

[MusicalAlchemy]

Correct me if I'm wrong, but I thought there were MB-1 mods as well on the old site.  Does no one have them, or am I just losing my mind?

[Peter H. Boer]

There are mods done to my 2 MB-1s, however these are not fixed mods like those available for the MP-1 (3.666, Mod4 Mk2, 3-tube, etc).

Only fixed mod is the MDRT (which is a very good one, by the way)

Peter

[MarshallJMP]

Maybe you mean the noise mod for the MB-1?

[Peter H. Boer]

Maybe you mean the noise mod for the MB-1?

Oh, I forgot about that one  ::)

[Andrea86]

do you have a scheme or something else for doin' Noise Mod for MB1?
Thanks :)
Andrea

[rnolan]

Hey Andrea (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm) the MDRT is a "must have" no brainer mod for MB1 (big improvement I'm told) as is the v2.05 EPROM also available from MJMP. When you turn it on it will show the EPROM/firm wear version or you can look under the lid, there will be sticker on the EPROM with the version.
Couldn't find the MB1 noise mod here or on MJMP's site, but he will no doubt get it to you
Cheers Richard

[Andrea86]

I have a 1.19 version. Now i have buied the EPROM 2.05 and when it will arrive i will put it in my ADA.

[rnolan]

Cool let us know how you go... Hopefully you can put in the new RCA tubes while you have the lid off ??
I'd also go for the MDRT when/if you can afford it, from all accounts it will "open up" the MB1 ( "The MDRT is a 24VA transformer which can deliver 12.6V to the heaters.The high voltage has gone up to 240Vdc / 8mA.The original is only a 12VA transformer,only deliver between 8 and 9 V to the heaters and the high voltage is 190Vdc / 4mA.So the MDRT will enhance the sound,better low end,less noise and the sound will sound less compressed.")

[RobbHell]

The Noise Mod and Transformer would be a must if I were you. You could swap out your opamps?  Wjat exactly ate wanting to Mod or not getting out of your MB1?

[Peter H. Boer]

Cool let us know how you go... Hopefully you can put in the new RCA tubes while you have the lid off ??
I'd also go for the MDRT when/if you can afford it, from all accounts it will "open up" the MB1 ( "The MDRT is a 24VA transformer which can deliver 12.6V to the heaters.The high voltage has gone up to 240Vdc / 8mA.The original is only a 12VA transformer,only deliver between 8 and 9 V to the heaters and the high voltage is 190Vdc / 4mA.So the MDRT will enhance the sound,better low end,less noise and the sound will sound less compressed.")

Yup, MDRT really opens up the sound.
As does replacing the opamp with a BurrBrown one  C:-)

[peoriashows]

So, here's what I deciphered from my scribbled down notes for the MB-1 noise mod. MarshallJMP (or anyone) will you confirm this is what it consists of?

Replace C56 with Nichicon P/N: UVZ2W220MHD (22uF, 450V, Radial)
Replace C447 with Nichicon P/N: UVZ2W220MHD (22uF, 450V, Radial)
Replace C446 with Nichicon P/N: UVZ2W220MHD (22uF, 450V, Radial)

Replace C25 with Xicon P/N: 140-LLRL25V2200-RC (2200uF, 25V, Radial)
Replace C26 with Xicon P/N: 140-LLRL25V2200-RC (2200uF, 25V, Radial)

Replace C301 with Xicon P/N: 140-LLRL16V3300-RC (3300uF, 16V, Radial)

Replace U12 with BB OPA2604AP OpAmp

Is this correct? was there more to it, are these the right parts and designators? I remember scribbling my really vague notes from a discussion on the old board.

[MarshallJMP]

See attached pics. I use Panasonic caps. Also if you have an MDRT you can replace the 4700µF with a 10.000µF.

[peoriashows]

thanks. Those values vary quite a bit from what I had above.

[bcklndt]

Really interested in those mods ..
Noise mod
Transformer mod
Opamp to Burrbrown mod

Want my MB-1 taken to another level .. or stratosphere ..

[rnolan]

Hey bcklndt, I have 2 MB1s that MJMP has done for me.  They both have MDRT and whatever else he did.  I've not heard a stock MB1 to compare but both of mine are amazing.  Really (really) quiet and just sound fantastic  :whoohoo!: .@MJMP, do you remember all the things you did to them ?  Anyway, whatever it was, they are both the best bass preamps I've ever heard.