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Let's Get Technical => Schematics & Modifications (mods) => Topic started by: MusicalAlchemy on February 07, 2014, 10:37:33 PM

Title: MB-1 Mods?
Post by: MusicalAlchemy on February 07, 2014, 10:37:33 PM
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?
Title: Re: MB-1 Mods?
Post by: Peter H. Boer on February 08, 2014, 01:27:43 AM
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
Title: Re: MB-1 Mods?
Post by: MarshallJMP on February 08, 2014, 07:21:40 PM
Maybe you mean the noise mod for the MB-1?
Title: Re: MB-1 Mods?
Post by: Peter H. Boer on February 09, 2014, 01:06:25 AM
Maybe you mean the noise mod for the MB-1?
Oh, I forgot about that one  ::)
Title: Re: MB-1 Mods?
Post by: Andrea86 on May 27, 2014, 04:08:09 AM
do you have a scheme or something else for doin' Noise Mod for MB1?
Thanks :)
Andrea
Title: Re: MB-1 Mods?
Post by: rnolan on May 27, 2014, 06:23:14 AM
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

Title: Re: MB-1 Mods?
Post by: Andrea86 on May 27, 2014, 08:24:38 AM
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.
Title: Re: MB-1 Mods?
Post by: rnolan on May 28, 2014, 07:39:10 AM
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.")
Title: Re: MB-1 Mods?
Post by: RobbHell on August 08, 2014, 11:38:13 AM
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?
Title: Re: MB-1 Mods?
Post by: Peter H. Boer on August 09, 2014, 06:51:17 AM
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:-)
Title: Re: MB-1 Mods?
Post by: peoriashows on August 10, 2018, 04:00:02 PM
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.
Title: Re: MB-1 Mods?
Post by: MarshallJMP on August 10, 2018, 04:15:30 PM
See attached pics. I use Panasonic caps. Also if you have an MDRT you can replace the 4700µF with a 10.000µF.
Title: Re: MB-1 Mods?
Post by: peoriashows on August 10, 2018, 04:37:31 PM
thanks. Those values vary quite a bit from what I had above.
Title: Re: MB-1 Mods?
Post by: bcklndt on June 15, 2020, 03:05:09 AM
Really interested in those mods ..
Noise mod
Transformer mod
Opamp to Burrbrown mod

Want my MB-1 taken to another level .. or stratosphere ..
Title: Re: MB-1 Mods?
Post by: rnolan on June 16, 2020, 03:12:09 AM
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!: :thumb-up: .@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.