Mezmerize B1 Buffer Preamp

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myleftear

myleftear

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Joined 2017
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Must the B1 run with 15V+15V?

Hello everyone

I am undertaking the first steps on building a B1 mesmerize, and see big questionmarks on step 2:
Can I run it with a 18V+18V 50MA transformator or does it blow up? Asking because I am trying to source the stuff but couldn't yet find a 2 x 15V 50MA toroidal.

And if it works I'd get a R-Core transformer...
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
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It will not blow up because there are 35V reservoir capacitors in the BOM which will take it but the first in line MOSFETS are going to dissipate 40% more heat than with typical setups. The 7812 regulator will struggle with that high voltage input also and it will need bigger clip-on sinking if to be long term reliable. The space around it is not roomy for such unless you will devise an ingenious solution.
 
nezbleu

nezbleu

Member
Joined 2009
Salas said:
You can, you will have to wire the incoming DC umbilical at the Mez's reservoir capacitors +/0/- area. Those capacitors you will also keep for local charge and decoupling.
Click to expand...



I did something similar when I built a phono preamp powered by a BiB, and I brought the DC from the external chassis to the "AC" inputs of the BiB board, then installed a small-value resistor in place of one of the diodes (leaving the other diode spot empty). I think I had to add one jumper, but can't remember now. My point is that I preferred that to routing directly to the filter caps, it looked nicer and was easier to manage since I still had the terminal blocks.
 
myleftear

myleftear

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Joined 2017
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Variants definition Q

Hi all
I realize I don't understand a lot of things in here...
Just to start with, there are many different variations of the B1:

Nelson's B1 (AC-coupled)
Mezmerize B1 (DC-coupled)
Hypnotize B1 (same but different? Is this the hot-rodded B1?)
hotrodded B1 (different but same, this is a Mez with higher, erm, "values" for better sound and bigger heatsinks?)

Have I got it right so far?

Thanks to all!
david

PS: I highly enjoy just to read along in this thread, everyone is really nice and respectful to everyone, and there are real wizards around! :worship:
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
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Hypnotize was a legacy single input version with double reservoir capacitors and big diodes made to help stronger hot-rod adventures. Most users gravitated towards medium CCS current nonetheless, around 200mA.

The Mezmerize has six inputs and weaker reservoir section. The current "ten years after" board is optimized for 200mA.
 
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