for headphones

Prune · 7th September 2003, 07:06 AM

Hey, can this be modified to an X amp???

Nelson Pass · 8th September 2003, 01:39 AM

Anything with a differential pair input stage can be mutated
until it is an X amp. In this case, the mutation is not trivial.

BTW, just becuase a "servo" is not directly in the feedback
loop does not mean that it does not affect the sound.

tschrama · 8th September 2003, 08:44 AM

But Gilmore's amp runs openloop... so it would require some modification of the gain of each stage to alow some global x-feedback .

Or do you would the feedback to stay local? Then the modification would only be around the two input stages ala x-bosoz, wouldn't it?

Regards,
Thijs

Prune · 8th September 2003, 09:29 AM

tschrama,
By openloop do you mean no global feedback? There is global feedback -- in the block diagram under the schematic, showing the bias opamp, the feedback goes into -I through the 10K resistor.
Nelson, he didn't write that the sound is totally unaffected by the servo, just that it's a less significant effect.

Actually I'm more interested in another Gilmore amp that I want to build: this one; could this be easier to mutate into a SUSY design?
(I know I asked this in another post, but there wasn't a complete diagram; also sorry about errors in this one)

jwb · 14th September 2003, 07:41 PM

This amp design is very weird. The "Servo" is very much in the feedback loop. Just because it runs at an extremely low frequency, doesn't mean the amp has no feedback. The author somehow feels that modulating the current on the front-end is somehow better than just modulating the negative input, but doesn't provide any evidence regarding that. You could replace the whole servo setup with a pot, adjust it once, and be done with it.

7th September 2003, 07:06 AM	#1
Prune Account Disabled Join Date: Mar 2003 Location: Vancouver	for headphones Hey, can this be modified to an X amp???

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
ZEN-like headphones amp	tortello	Pass Labs	195	28th January 2012 06:58 PM
Headphones	underwurlde	Solid State	3	23rd August 2009 09:09 PM
My new headphones amp	Sch3mat1c	Solid State	1	25th April 2005 12:13 PM
Which headphones are the best	Bull	Everything Else	11	8th December 2002 09:17 PM
Headphones	JazzFrac	Everything Else	2	26th February 2001 05:13 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

8th September 2003, 01:39 AM	#2
Nelson Pass The one and only Join Date: Mar 2001	Anything with a differential pair input stage can be mutated until it is an X amp. In this case, the mutation is not trivial. BTW, just becuase a "servo" is not directly in the feedback loop does not mean that it does not affect the sound.

8th September 2003, 08:44 AM	#3
tschrama diyAudio Member Join Date: Jul 2001 Location: The Netherlands	But Gilmore's amp runs openloop... so it would require some modification of the gain of each stage to alow some global x-feedback . Or do you would the feedback to stay local? Then the modification would only be around the two input stages ala x-bosoz, wouldn't it? Regards, Thijs

8th September 2003, 09:29 AM	#4
Prune Account Disabled Join Date: Mar 2003 Location: Vancouver	tschrama, By openloop do you mean no global feedback? There is global feedback -- in the block diagram under the schematic, showing the bias opamp, the feedback goes into -I through the 10K resistor. Nelson, he didn't write that the sound is totally unaffected by the servo, just that it's a less significant effect. Actually I'm more interested in another Gilmore amp that I want to build: this one; could this be easier to mutate into a SUSY design? (I know I asked this in another post, but there wasn't a complete diagram; also sorry about errors in this one)

14th September 2003, 07:41 PM	#5
jwb diyAudio Member Join Date: Mar 2002 Location: San Francisco, USA	This amp design is very weird. The "Servo" is very much in the feedback loop. Just because it runs at an extremely low frequency, doesn't mean the amp has no feedback. The author somehow feels that modulating the current on the front-end is somehow better than just modulating the negative input, but doesn't provide any evidence regarding that. You could replace the whole servo setup with a pot, adjust it once, and be done with it.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)