GTA02 bass fix - Revision history

PaulFertser: Rework by Hbarosh

2011-02-13T08:06:59Z

Rework by Hbarosh

Adiblol at 12:05, 31 August 2010

2010-08-31T12:05:14Z

Hns: /* Rework offers */

2010-04-28T15:23:13Z

‎Rework offers

Hns at 15:22, 28 April 2010

2010-04-28T15:22:31Z

PaulFertser: Added a big fat warning about the can shorting parts

2009-11-07T20:08:58Z

Added a big fat warning about the can shorting parts

Glenn: catspec Category:Neo FreeRunner reworks and mods

2009-10-18T11:55:26Z

catspec Category:Neo FreeRunner reworks and mods

Andi at 11:36, 10 October 2009

2009-10-10T11:36:25Z

Andi at 11:35, 10 October 2009

2009-10-10T11:35:59Z

PaulFertser: /* Rework performed by Paul Fertser */ bt range unaffected

2009-05-24T09:16:21Z

‎Rework performed by Paul Fertser: bt range unaffected

JOERG: /* Untested Notes and Suggestions */

2009-03-24T03:06:08Z

‎Untested Notes and Suggestions

← Older revision		Revision as of 08:06, 13 February 2011
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	The weak points are that the maximum capacity is limited to 47uF due to the size; again due to the size constraint of being in the can only ceramic caps can be used (which can distort sound because of piezoceramic properties, although for X7R dialectric the effect is minimal).		The weak points are that the maximum capacity is limited to 47uF due to the size; again due to the size constraint of being in the can only ceramic caps can be used (which can distort sound because of piezoceramic properties, although for X7R dialectric the effect is minimal).
		+
		+	=== Rework by Hrabosh ===
		+	Similar to Andy's but he used two caps in parallel per channel covered with heatshrink tubing. Probably the best variant seen so far. See more at http://hnet.endofinternet.net/elektro/Freerunner/Bass_fix/bf.html .

	=== Untested Notes and Suggestions ===		=== Untested Notes and Suggestions ===

← Older revision		Revision as of 12:05, 31 August 2010
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	Nobody has tried to implement it on FreeRunner yet, but this description along with published schematics should be enough: http://www.head-fi.org/forums/f6/apple-diymod-my-take-famous-imod-56k-killer-featuring-3g-4g-5g-nano-1g-269604/		Nobody has tried to implement it on FreeRunner yet, but this description along with published schematics should be enough: http://www.head-fi.org/forums/f6/apple-diymod-my-take-famous-imod-56k-killer-featuring-3g-4g-5g-nano-1g-269604/
		+
		+
		+	Another idea, which doesn't require modifying FreeRunner's hardware, is plugging an external headphone amplifier with high internal input resistance. DIY amplifier built on op-amp should be good. FR's USB can be used for supply (requires host mode). By the way, putting high quality microphone in amplifier case can be useful for audio recording.
		+

	== Rework offers ==		== Rework offers ==

@@ Line 53: / Line 53: @@
 == Rework offers ==
 http://lists.openmoko.org/pipermail/community/2010-April/061171.html
 [[Category:Neo FreeRunner reworks and mods]]

← Older revision		Revision as of 15:22, 28 April 2010
Line 51:		Line 51:

	Nobody has tried to implement it on FreeRunner yet, but this description along with published schematics should be enough: http://www.head-fi.org/forums/f6/apple-diymod-my-take-famous-imod-56k-killer-featuring-3g-4g-5g-nano-1g-269604/		Nobody has tried to implement it on FreeRunner yet, but this description along with published schematics should be enough: http://www.head-fi.org/forums/f6/apple-diymod-my-take-famous-imod-56k-killer-featuring-3g-4g-5g-nano-1g-269604/
		+
		+	== Rework offers ==
		+	http://lists.openmoko.org/pipermail/community/2010-April/061171.html

	[[Category:Neo FreeRunner reworks and mods]]		[[Category:Neo FreeRunner reworks and mods]]

@@ Line 3: / Line 3: @@
 The lack of bass issue has been discussed several times on Community and Hardware lists, including by [[User:jOERG|Joerg Reisenweber]] (e.g. in this mailing list post:
 http://lists.openmoko.org/pipermail/openmoko-kernel/2008-March/001994.html http://lists.openmoko.org/pipermail/hardware/2008-September/000552.html , and Andy Green).
 == The problem description ==

@@ Line 50: / Line 50: @@
 Nobody has tried to implement it on FreeRunner yet, but this description along with published schematics should be enough: http://www.head-fi.org/forums/f6/apple-diymod-my-take-famous-imod-56k-killer-featuring-3g-4g-5g-nano-1g-269604/
+[[Category:Neo FreeRunner reworks and mods]]
-[[Category:Reworks_and_mods]]

← Older revision		Revision as of 11:36, 10 October 2009
Line 51:		Line 51:


−	[[Category:Reworks_and_mods]	+	[[Category:Reworks_and_mods]]

← Older revision		Revision as of 11:35, 10 October 2009
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−	[[Category:~~Neo_FreeRunner_Hardware]~~]	+	[[Category:Reworks_and_mods]

@@ Line 10: / Line 10: @@
 === Rework performed by [[User:PaulFertser|Paul Fertser]] ===
-'''Resulting sound is good with 32Ohm headphones (AKG K-55). With proper shielding GSM interference is very low or non existent. Effect on Bluetooth range is not yet measured!'''  (Due to placement of the caps next to the Bluetooth antenna, it's possible this will reduce performance there).
+'''Resulting sound is good with 32Ohm headphones (AKG K-55). With proper shielding GSM interference is very low or non existent. Effect on Bluetooth range is measured by comparision with another FR and it's confirmed the range wasn't reduced by the rework.'''  (Due to placement of the caps next to the Bluetooth antenna, it's possible this will reduce performance there).
 Here i'll try to describe my take on rework that should radically improve the ability to use FreeRunner as a portable music player.
@@ Line 25: / Line 25: @@
 [[Image:bass_rework_can_closed.jpg|800px]]
 [[Image:bass_rework_whole_picture.jpg|800px]]
 === Rework performed by [[User:warmcat|Andy Green]] ===

@@ Line 40: / Line 40: @@
 === Untested Notes and Suggestions ===
-One possible solution is to place the additional caps outside the can, near the Bluetooth antenna; the other possibility is to build a cap from 20 pieces 4.7uF along a wire grid 4x5 which makes a nice high quality very flat 100uF. This would easily fit anywhere "1.floor" of can interior, just isolate it with a scotch film patch and throw them inside the can.
+One possible solution is to place the additional caps outside the can, near the Bluetooth antenna; another possibility proposed by [[User:jOERG|Joerg]] is >>to build a cap from 20 pieces 4.7uF along a wire grid 4x5 which makes a nice high quality very flat 100uF. This would easily fit anywhere "1.floor" of can interior, just isolate it with a scotch film patch and throw them inside the can<<.
 Also shorting R4407 and R4405 might worth trying (as well as throwing out the useless U4401).
-Another idea proposed by [[User:jOERG|Joerg]] is to perform a modification similar to the popular iPod mod:
+Another idea is to perform a modification similar to the popular iPod mod:
 The purpose of the diyMod is to simplify the signal path from the DAC to the amp. To achieve this goal, the audio signal is taken directly after the DAC and sent to the amp. This path must include the DC blocking, also known as coupling, caps. By necessity, we place DC blocking caps behind the DAC to protect our listening apparatuses. Ensure that nothing lies between your DAC and amp but wires and traces.