L25D and SILK trafo passive preamp

ZachAttack420 · 30th March 2012, 03:30 AM

I have read that passive preamps are not well suited to the L15/L20/L25D...i was planning on using a transformer based preamp. My understanding was the transformer units are better at this than just a potentiometer? Or not?

Thanks

MrSlim · 02:11 AM

I don't think it's just the LxxD modules that seem to be affected by having a passive(and thus higher in impedance) source.

I found This Post describes the issue. I read up on the silk transformer based passive unit.. It looks very nice, and the output impedance is 10x lower than a regular potentiometer, so it would probably be less likely to cause the downward tilt of the high end frequency response, but the question becomes: Is 10X lower enough.. Measurements would be the only way to verify if it is enough.

Full disclosure: I am in the process of finishing a DCB1 as a source for my L19D's, since the active buffer option is really the best way to get a really low source impedance. I'm also a Bang for the Buck guy, so I would really look at the cost/benefit of both solutions. From what I have seen Transformer based Passive solutions can be a real wallet sucker, whereas a really basic Pass B1 (the original design) can be built for $200 or less..

ZachAttack420 · 31st March 2012, 02:40 AM

I have the passive from my last system....wish I still had the sonic frontiers unit.

Sounds like I will be ok to give it a listen.

30th March 2012, 03:30 AM	#1
ZachAttack420 diyAudio Member Join Date: Dec 2011	L25D and SILK trafo passive preamp I have read that passive preamps are not well suited to the L15/L20/L25D...i was planning on using a transformer based preamp. My understanding was the transformer units are better at this than just a potentiometer? Or not? Thanks

31st March 2012, 02:03 AM	#2
MrSlim diyAudio Member Join Date: Jun 2009 Location: Ottawa, Ontario Blog Entries: 2	I don't think it's just the LxxD modules that seem to be affected by having a passive(and thus higher in impedance) source. I found This Post describes the issue. I read up on the silk transformer based passive unit.. It looks very nice, and the output impedance is 10x lower than a regular potentiometer, so it would probably be less likely to cause the downward tilt of the high end frequency response, but the question becomes: Is 10X lower enough.. Measurements would be the only way to verify if it is enough. Full disclosure: I am in the process of finishing a DCB1 as a source for my L19D's, since the active buffer option is really the best way to get a really low source impedance. I'm also a Bang for the Buck guy, so I would really look at the cost/benefit of both solutions. From what I have seen Transformer based Passive solutions can be a real wallet sucker, whereas a really basic Pass B1 (the original design) can be built for $200 or less.. Last edited by MrSlim; 31st March 2012 at 02:11 AM.

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
L25D	sketchyphish	Class D	4	29th December 2012 01:34 AM
L25D Toroid	sketchyphish	Class D	11	18th March 2012 03:51 PM
L25D, L20D, or L15D	ZachAttack420	Class D	0	16th March 2012 02:36 AM
Why does my oversized preamp trafo gets much too hot?!?!?	Klimon	Tubes / Valves	22	15th November 2005 09:34 PM

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

31st March 2012, 02:40 AM	#3
ZachAttack420 diyAudio Member Join Date: Dec 2011	I have the passive from my last system....wish I still had the sonic frontiers unit. Sounds like I will be ok to give it a listen.