Where to find a Bada PH-12 (Tax return and its all mine, woop!
Apr 17, 2006 at 9:20 PM Post #2 of 6

909

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Check: www.cattylink.com (email Snowy for a price quote to your zip code).

Reviews:
http://www6.head-fi.org/forums/showt...ght=Bada+PH-12
http://www6.head-fi.org/forums/showt...ght=Bada+PH-12

How to buy thread:
http://www6.head-fi.org/forums/showt...ght=Bada+PH-12

EDIT:
Try the Head-Fi search engine because it works very well.
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Apr 18, 2006 at 6:24 AM Post #5 of 6

upstateguy

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Hi Guys

This is an e-mail I got from Snowy Law today, regarding the Bada PH 12:


"KINDLY NOTE THAT THIS MODEL IS AVAILABLE IN 110 V VERSION AND NOT REQUIRING ANY VOLTAGE CONVERTER. HOWEVER, WE HAVE PAUSED THE OFFER OF THIS MODEL OWING TO EASILY DAMAGED MOSFETS BECAUSE OF MALOPERATION (THIS HAS CREATED SERIOUS PROBLEMS TO US REGARDING WARRANTY COST).

THANK YOU FOR YOUR KIND SUPPORT AND YOU CAN CONSIDER ALTERNATIVES SUCH AS MINGDA MC66-AE TRANSFORMER TYPE TUBE HEADPHONE AMPLIFIER.

SINCERELY,

SNOWY LAW"

Regards

USG
 
Apr 18, 2006 at 7:09 AM Post #6 of 6

drarthurwells

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Yes, the PH12 has had some problems with mosfets blowing. I blew a mosfet in using a bad tube. Another owner blew them in tube rolling.

Tube rolling should only be done only with allowing 20 minutes or more power off before replacing tubes and turning the unit on again. I have advised all Bada PH12 owners of this, and it is in the manual (unfortunately in Chinese).
The later model Bada PH12 (with the Electro Harmonix tube) has two 15 V diodes connected negative to negative, where each positve end connects to the two outer wires of the mosfet, to help protect the mosfet. My model did not have this protection, which is why a bad tube blew one of my mosfets, but I have put them in.

Handling and replacing mosfets requres anti-static measures (grounding of your body and the amp) - you can blow one simply by putting it in if static charges it. Handle mosfets with Bounce brand anti-static laundry sheets or static free gloves, while you are grounded, and have the amp gounded, when putting in new mosfets.

Here is what Bada says about Mosfets:

MOSFETS ARE VERY EASILY DAMAGED OUTPUT TRANSISTORS. THEY FAIL FROM MANY CAUSES INCLUDING - NOT FULLY INSERTED HEADPHONE JACKS, RESTART OF POWER WITHIN 5 MINUTES OF POWERING OFF, CHANGE OF TUBES BEFORE THEY COOL DOWN, OR ANY OTHER MINOR OPEARATION FAULT WHICH MAY CAUSE A "SHORT" SITUATION (WHICH WILL PUT STRAIN ON THE MOSFET AND CAUSE THEM TO FAIL).

THE LATER PH12 MODELS HAVE A VERY COMMON 15V STABILIZING DIODE USED TO BETTER PROTECT THE MOSFETS, BUT WILL NOT PROTECT THEM 100%. IF YOU USE THE BADA CAREFULLY THERE WILL BE NO NEED FOR THIS DIODE. IF USED, TWO DIODES ARE CONNECTED -VE TO -VE (NEGATIVE TO NEGATIVE) THEN EACH FREE POSITIVE LEAD IS CONNECTED TO THE TWO OUTER CONNECTIONS OF THE MOSFET (NOT TOUCHING THE CENTER CONECTION) TO BRIDGE THE OUTER CONNECTIONS OF EACH MOSFET. IMPORTANT POINT: MOSFETS ARE EASILY PRONE TO DAMAGE BY "STATIC" AND YOU MUST USE EVERY EFFORT TO PREVENT STATIC WHEN SOLDERING THEM OR DAMAGE WILL OCCUR AGAIN. SO, IN SOLDERING MOSFETS YOU MUST ENSURE STATIC FREE OPERATION. AT LEAST USE STATIC FREE GLOVES AND BE SURE THAT THE SOLDERING PEN IS DISCONNECTED FROM POWER AFTER BEING "HOT ENOUGH" TO SOLDER THE MOSFET AND JUST BEFORE DOING SO.

NEVER CHANGE A TUBE WHEN THEY IT IS STILL HOT - TO PREVENT DAMAGE TO THE MOSFETS AND TO THE INTERNAL STRUCTIURE OF THE TUBE.



I love the Bada PH 12.

The Woo 3 is a great SET OTL design - perhaps as good as any Singlepower at twice the cost of the Woo 3. In many ways it has a more pleasing sound then the Bada, however, the Bada PH12 features better imaging - holographic 3-D well-defined tones surrounded by empty space or air - which I really like in classical music.

I will report on the Woo 4 later - need more time with different tubes to properly evaluate it.
 

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