add UL tap for 125ese

jeapel · 17th February 2009, 04:15 PM

hi
anyone see or try something like that on internet
or my idea (no tested) is unique?
thanks

tubelab.com · 17th February 2009, 05:07 PM

Yes, been done before. There was a thread on this topic about a year and a half ago. I had an output stage breadboarded before personal circumstances caused the scaling back of many of my experiments.

Adjustable distributed load discussion

jeapel · 17th February 2009, 07:47 PM

thanks tubelab very good infos on the thread
my english is so so but maybe mosfet input
capacitance delay the screen current maybe
smaller delay with npn but only 300 volt max

if i understand it remains to be proved for
a good solution?

tubelab.com · 17th February 2009, 08:57 PM

We were also looking into seperating the AC and DC components of the signal so that UL can be used on tubes with a low screen grid voltage rating, like some TV sweep tubes. The circuit works but I never had the time to optimize it. There are mosfets that have a low "reverse transfer capacitance" which is the important spec for follower use. Fairchild FQP1N50 is one. An NPN will work too.

17th February 2009, 05:07 PM	#2
tubelab.com diyAudio Member Join Date: Jul 2005 Location: South Florida	Yes, been done before. There was a thread on this topic about a year and a half ago. I had an output stage breadboarded before personal circumstances caused the scaling back of many of my experiments. Adjustable distributed load discussion __________________ Too much power is almost enough! Turn it up till it explodes - then back up just a little.

17th February 2009, 08:57 PM	#4
tubelab.com diyAudio Member Join Date: Jul 2005 Location: South Florida	We were also looking into seperating the AC and DC components of the signal so that UL can be used on tubes with a low screen grid voltage rating, like some TV sweep tubes. The circuit works but I never had the time to optimize it. There are mosfets that have a low "reverse transfer capacitance" which is the important spec for follower use. Fairchild FQP1N50 is one. An NPN will work too. __________________ Too much power is almost enough! Turn it up till it explodes - then back up just a little.

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
HAMMOND 125ESE Transformer WIRING	mrhotmark	Tubes / Valves	2	24th March 2010 09:30 PM
FS: Hammond 125ESE trannies	RockysDad	Swap Meet	0	26th November 2008 03:20 AM
Hammond 125ESE and sections	mpingo	Tubes / Valves	0	10th January 2008 06:41 PM
Cheap Source for Hammond 125ESE	Technotinker	Tubes / Valves	4	1st February 2006 12:01 PM
Hammond 125ese cheap in Europe?	John007	Tubes / Valves	10	4th March 2004 08:18 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

17th February 2009, 07:47 PM	#3
jeapel diyAudio Member Join Date: Sep 2003 Location: quebec	thanks tubelab very good infos on the thread my english is so so but maybe mosfet input capacitance delay the screen current maybe smaller delay with npn but only 300 volt max if i understand it remains to be proved for a good solution?