Pre amp transformer

MikeW · 21st September 2004, 02:08 PM

I found some transformers I want to use for some pre-amps. They will put out 82 volts unloaded and 78 volts into a 150 watt lightbulb. Will they be big enough for a BOZ pre-amp? They are the same size as some 300VA transformers.

kilowattski · 21st September 2004, 02:28 PM

If you go to the PassDIY website and look at the Bride of Zen .pdf file you will see that it calls for an Avel Lindberg D4007. If you go to their website you will find it is only 30VA with two 30v secondaries. I think the voltage of the transformer may be a little high but useable for the BOZ. You will just have to make R1 in the power supply a 1 Watt resistor.

GRollins · 21st September 2004, 03:44 PM

Are those voltages the total or measured from the center tap?
Some combination of caps, inductors, resistors, and/or regulators ought to get you where you want to be. The preamp doesn't really need all that much juice.
Jeez, I wish I had access to stuff like that. About all you can find around here are parts for Chevys and Fords. I'm going to have to devote a brain cell or two to how to use an ignition coil for audio use.

Grey

MikeW · 21st September 2004, 04:33 PM

Those are rectified DC with 11000uf of caps.

eLarson · 21st September 2004, 05:50 PM

I'd say they are plenty big enough. Are you using 100WVDC (or bigger) electrolytics?

If you make the load resistor a little bigger so that the drain sits at 30V, I'd predict you'll get pretty much the same results as in the article.

Kermit · 21st September 2004, 05:54 PM

300VA is overkill, other then that, it will do fine. With 82 volts dc you might want to adjust the resistor feeding the stack of zeners if you want to get exactly the volts specified in the article.

kilowattski · 21st September 2004, 06:09 PM

Gentlemen,

If you read the BOZ article, Nelson states that he gets 86 volts DC out of the rectifier across the filter cap. Mike W's transformer will be perfect without modifying a thing.

21st September 2004, 02:08 PM	#1
MikeW diyAudio Member Join Date: Sep 2002 Location: North of Boston	Pre amp transformer I found some transformers I want to use for some pre-amps. They will put out 82 volts unloaded and 78 volts into a 150 watt lightbulb. Will they be big enough for a BOZ pre-amp? They are the same size as some 300VA transformers. __________________ MikeW

21st September 2004, 02:28 PM	#2
kilowattski diyAudio Member Join Date: Aug 2003 Location: Long Island, New York	If you go to the PassDIY website and look at the Bride of Zen .pdf file you will see that it calls for an Avel Lindberg D4007. If you go to their website you will find it is only 30VA with two 30v secondaries. I think the voltage of the transformer may be a little high but useable for the BOZ. You will just have to make R1 in the power supply a 1 Watt resistor. __________________ ----------------------------------------------- Kilowattski

21st September 2004, 04:33 PM	#4
MikeW diyAudio Member Join Date: Sep 2002 Location: North of Boston	+82 Those are rectified DC with 11000uf of caps. __________________ MikeW

21st September 2004, 05:50 PM	#5
eLarson diyAudio Member Join Date: Aug 2002 Location: Gaithersburg, MD	I'd say they are plenty big enough. Are you using 100WVDC (or bigger) electrolytics? If you make the load resistor a little bigger so that the drain sits at 30V, I'd predict you'll get pretty much the same results as in the article. __________________ Would a woodchuck bother to chuck MDF?

21st September 2004, 05:54 PM	#6
Kermit diyAudio Member Join Date: Jun 2002 Location: Oslo - Norway	300VA is overkill, other then that, it will do fine. With 82 volts dc you might want to adjust the resistor feeding the stack of zeners if you want to get exactly the volts specified in the article. __________________ Sven Sødem


	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

21st September 2004, 03:44 PM	#3
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	Are those voltages the total or measured from the center tap? Some combination of caps, inductors, resistors, and/or regulators ought to get you where you want to be. The preamp doesn't really need all that much juice. Jeez, I wish I had access to stuff like that. About all you can find around here are parts for Chevys and Fords. I'm going to have to devote a brain cell or two to how to use an ignition coil for audio use. Grey

21st September 2004, 06:09 PM	#7
kilowattski diyAudio Member Join Date: Aug 2003 Location: Long Island, New York	Gentlemen, If you read the BOZ article, Nelson states that he gets 86 volts DC out of the rectifier across the filter cap. Mike W's transformer will be perfect without modifying a thing. __________________ ----------------------------------------------- Kilowattski

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

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
Using mains transformer as output transformer	Elias	Tubes / Valves	175	3rd November 2009 08:36 PM
Modulation transformer for a driver transformer?	ironradio	Tubes / Valves	6	28th December 2008 05:05 PM
filament transformer vs plate transformer	contaxchen	Tubes / Valves	10	14th January 2005 10:43 AM
toroid Transformer as power Transformer for tube	tone	Tubes / Valves	7	11th February 2003 08:57 AM
toroid Transformer as output Transformer for tube preamp?	tone	Tubes / Valves	15	2nd February 2003 04:36 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