JP200 Clone - my first audiophile valve project

Based on Jadis JP200 Valve Pre-amp with some modification 

   
Features:

Dual Mono and separate power supply chassis design.

2X EI type power transformers

2X separate tube based regulation circuit boards for B+ high voltage supply involving 2X EL84 and 2X EF86 tubes.

All filament supplies for the main channels are DC regulated and supplied to output and amplification stages separately in each channel.

3X carefully matched and balanced TungSol Gold Pin reissue 12AX7 tubes are used for each channels.

Coupling capacitors are Germany ‘s Mundorf supreme and US made Audio Cap’s RT grade.

All power filtration caps are Nichicon KX grade.

All resistors used in power and preamp sections are audiophile grade Japanese Kiwame 2W carbon film.

Volume is controlled by a ladder type attenuator with all Dale military grade resistors for precise volume control and balance.

Capable of feeding up to 4 sets of stereo signals selected via the professional Takamisawa signal replays

Output signals can be muted by the push switch in the front panel and is about 90 seconds time delayed when the preamp is switched on.

                                                                         

                                         

                                     

                                                                            

                                          

                                     

                                   

                                     

                                         

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With the new dashboard update 14717 or14719, the way used to disable the RGH chip does not work any more. After the update you have to physically disconnect the +3.3V from the the RGH chip to be able to boot oringinal nand. Adding a switch is a simple way but a little messy as you would have to drill a hole on the Xbox360. Some people used a 3.3V relay instead of a switch. But 3.3V relay is not easy to find.

Here we have an electronic solution for the swtich without using a relay or physicall switch. It consists of 2 transistors and 1 resistor as show in picture below:



When the level of pin 2 on Cygnos switch that used to disable RGH chip is Low, its to boot stock nand and High to boot RGH nand. So, when the pin is on High, it turns on Q1 making the base of Q2 low , which in turn switch on Q2. The RGH chip then gets +3.3V power via Q2 that connected to +3.3V rail. The 10K resistor is used to limit the current when Cygnos swith pin2 is on High. it works perfect when tested on a slim Xbox360.

Daul nand with Cygnos360 V2  E on a Slim Xbox360

Cygnos360 V2 E is so far the best device to install dual nand boot for Xbox360 especially for the Slim version. It does not require to cut the tiny CE trace on the motherboard in order to switch between stock nand and hacked nand.

When switching to stock nand, the Glitch chip needs to be disabled. A lot of installs used a replay or toggle switch to interrupt the ground wire. But this can be done by modifying the cpld code without using the a replay or any methods to interrupt the ground wire.

Installation can be viewed at www.consoletronics.com/images/dual_nand.jpg