Dual channel Pultec MB-1 project finished

[vibrolax]

Hey all,

I just finished building a dual channel version of the Pultec MB-1 mic pre. Thanks to rafafreddy for posting the schematic and user manual on his website.

Pictures and build story at http://www.frontiernet.net/~jff/pultec_mb1/DualTubeMicrophonePreamp.html

Here's one pic:

-Jon

 

[SonsOfThunder]

Nice Job!

:thumb: :thumb: :thumb:

Peace!

 

[radiance]

Yes, this is the real deal, with transformers & tubes and stuff...
Very nice.
Where did you find that beautifull lampholder off your's?

I'm about to start on my next DIY project, a solid state Pulteq EQ , sourcing part's....

 

[vibrolax]

I assume what you call lampholders are what we yanks call tube sockets...

Those beautiful shock mount sockets were a gift from my non-building collaborator Arpad, who bought them at a surplus store years ago. He loves DIY and has collected parts for years, but does not have the time to build finished projects. He does my machining jobs, and I lowly turn his parts collection into working gear.

Antique Electronics http://www.tubesandmore.com/
has a bottom-mounted noval socket with shock ring.
The part # is P-ST9-137R US$2.25 each

-Jon

 

[radiance]

No, it's the thing where the lamp (above the on/off switch) fit's in...

 

[MikoKensington]

That is gorgeous! Yummy. Welcome.

 

[electronaut]

Super nice! I like the metal platform things that the tube sockets mount on.

Looks suave.

-E.

 

[vibrolax]

[quote author="radiance"]No, it's the thing where the lamp (above the on/off switch) fit's in...[/quote]

Oh, what you call a lampholder, we call a lampholder....

That is a Drake lampholder from the local surplus store. It was the last one they had that was made for incandescent pilot lamps. The part # is 6102-183. They have hundreds with built-in resistors for neon lamps like the NE-51.

The lamp jewel is a standard screw-in type.

-Jon

 

[vibrolax]

Thank you all for the welcome. I've been an occasional lurker for a while.

The MB-1 was my first tube project that wasn't a guitar amp or preamp. It all started innocently enough when I picked up a UTC A-11 for $1 at a hamfest last summer...then I started looking for something to do with it.

-Jon

 

[maneco]

Excellent work!
And the wiring and point to point comnstruction looks great! :thumb:

 

[rafafredd]

Looks Great!

I´m actually working on another pair of channels of the MB1 right now. This time it´s for a friend...

I must say that I do really recommend the 4:1 or 5:1 output transformer in this circuit... I´ll try the cheap EDCORS on my next clone...

It´s always very nice to see people doing this project. :thumb:

 

[digichild]

[quote author="vibrolax"]Hey all,

I just finished building a dual channel version of the Pultec MB-1 mic pre. Thanks to rafafreddy for posting the schematic and user manual on his website.

Pictures and build story at http://www.frontiernet.net/~jff/pultec_mb1/DualTubeMicrophonePreamp.html

Here's one pic:

-Jon[/quote]

great-thanks also for the pictures and the build story

 

[Kev]

yes
very good

I look forward to seeing the schematic and the layout

WHERE !!! can I get some turret pins ... as Hoffman is out of stock.
someone buy for me and send to Australia .... pLLease
:sad:

 

[nacho459]

Nice, I like the amount or vintage components. keeping it real!

:guinness: :guinness: :guinness: :guinness: :guinness: :guinness:

 

[vibrolax]

[quote author="Kev"]yes
very good

I look forward to seeing the schematic and the layout

WHERE !!! can I get some turret pins ... as Hoffman is out of stock.
someone buy for me and send to Australia .... pLLease
:sad:[/quote]

I prefer using Keystone double level hollow turret pins,
mouser part # 534-1509-4. I'm pretty sure they ship worldwide.
These need 0.112" holes.

US$ 0.09 in quantity 1000, 0.18 in quantity 100. Group buy anyone?

I will finish the documentation before starting the next project.

-Jon

 

[vibrolax]

[quote author="kubi"]Great work, Jon!

How do you like the sound? I built one and simply love the huge bottom end.[/quote]

I haven't had the opportunity to record / listen to anything musical with it yet. I've got a session scheduled at my friend's studio in a couple weeks.

-Jon

 

[vibrolax]

[quote author="rafafredd"]Looks Great!

I´m actually working on another pair of channels of the MB1 right now. This time it´s for a friend...

I must say that I do really recommend the 4:1 or 5:1 output transformer in this circuit... I´ll try the cheap EDCORS on my next clone...

It´s always very nice to see people doing this project. :thumb:[/quote]

Well, it's thanks to you for hosting the schematic and manual. I am hunting for output transformers - I'm thinking about Opamp Labs T610. I'll look into EDCORS and Cinemag, too.

-Jon

 

[rafafredd]

On the opamplabs site they also sell a 422 and 422b that looks right for this...

 

[b3groover]

Just ordered one of those rack chassis from Sescom! Thanks for the heads-up. They seem like a nice, lower-cost alternative to the Par-Metal cases.

 

[vibrolax]

[quote author="b3groover"]Just ordered one of those rack chassis from Sescom! Thanks for the heads-up. They seem like a nice, lower-cost alternative to the Par-Metal cases.[/quote]

The SESCOM enclosures are OK, but are not the most roadworthy. The anodizing isn't the prettiest either. Let us know what you think when you put it together.

-Jon