2016-08-18

Gibson SGJ 2014 inside


This is an investigation of wiring and phasing of the gibson sgj guitar with two humbuckers.


Gibson quickconnect(r) board JL 94V-0


The red compass tip points to the north pole of magnet. the neck coil with screws has a 4.16 kohm dc resistance, neck slug coil - 3.88 kOhm, bridge slug coil - 3.84 kohm, bridge screw coil - 4.02 kohm. this is 1961 alnico v "classic reborn" pickups with more turns in screw coils.



Wiring of bridge and neck sockets on the board are identical. but does not for the tails of the humbuckers.



So that's how it looks about hum cancelling (out of phase for parasite electromagnetic wave) and sound powering (in phase for disturbance of the magnetic field of the magnet by string).



PUs







2016-07-26

Marshall MG15DFX (inside)

Marshall MG15DFX - guitar combo amplifier.


schematic ofmain analog pcb






8"/15 W/4 Ohm speaker 200RFL06-3


2016-01-10

focusrite scarlett 2i4 rmaa test report (wdm vs asio comparison)

The new focusrite scarlett 2i4 usb 3.2.2.292 driver supports 24 bit depth mode by wdm now as like by ASIO driver.
So, let's try to compare...

ASIO: 24-bit @ 96 kHz; 32 samples of asio buffer.
MME: 24-bit @ 96 kHz; 52% of record level by windows mixer.

Balanced 1-st output looped to balanced 1-st input by trs to trs jack cable. rmma mono test. full level monitor output. input with instrument + pad mode. about 10 oclock gain knob. 100% output level by wdm.
Windows 10 x64.

ASIO driver settings


The identical knob settings on the device gets no difference between asio and wdm drivers. about latency - need something better than rmaa to compare - rmaa shows 220 ms with wdm and 200 ms with asio.

Test result


Frequency response


Dynamic range


THD


THD (cropped)


IMD

2016-01-08

grub4dos 4 puppy and windows

puppy frugal install to ntfs/fat (c:\puppy\) 1-st drive 1-st partition hd0,0

menu.lst
===
timeout 1
default 0

title puppy
  root (hd0,0)
  kernel /puppy/vmlinuz psubdir=puppy pmedia=atahd pfix=fsck
  initrd /puppy/initrd.gz

title windows xp
  root(hd0,0)
  chainloader /ntldr
===

http://puppylinux.org/wikka/BootParameters
http://greenflash.su/Grub4Dos/files/boot.htm