Need circuit for transformer

avxt · 24th December 2001, 01:38 AM

I have a single rail 0-36V AC 400 watts EI transformer, interested to build a power amplifier any suggestion for reasonable sound quality circuit?

and I also have a 36.8-0-36.8V AC 230VA toroidal transformer and same would like to build a power amplifier and still looking for circuit.

Thanks for help.

AudioFreak · 24th December 2001, 01:47 AM

I dont know about the EI core transformer I dont like them much for audio use ....

As for the toroidal, this should give about +/-40V after rectification allowing for voltage sag.

so you've got a supply capable of +/-40V @ 3A continuous

this might be suitable for some sort of preamp circuit or an amp driving a high resistance load eg. 16ohms

avxt · 24th December 2001, 01:57 AM

any hope for power amp driving 8 ohm speakers
I saw the www.aussieamplifiers.com for the hitachi lateral mosfet power amp but don't know its good or not.

AudioFreak · 24th December 2001, 02:11 AM

using the toroidal @ 8 ohms you would be down to 60-70W for a single channel amp or 15W per channel for a stereo amp

avxt · 24th December 2001, 02:46 AM

you mean for Anthony Holton Hitachi lateral mosfet amp?

but 1 thing I don't understand is I get the transformer from an old Ecleree mosfet amp and they stated 135 watts rms into 8 ohm for stereo channel.

AudioFreak · 24th December 2001, 03:01 AM

I mean for any amp you build with this transformer and use with 8ohm speakers.

thats cause they were overdriving the poor transformer really badly.

avxt · 24th December 2001, 03:03 AM

you mean for Anthony Holton Hitachi lateral mosfet amp?

but 1 thing I don't understand is I get the transformer from an old Ecleree mosfet amp and they stated 135 watts rms into 8 ohm for stereo channel.

AudioFreak · 24th December 2001, 03:11 AM

It doesnt really matter what type of amp if it is driving 8ohm speakers and using that transformer that is all the power it is realistically good for..

They got the 135W into 8ohm stereo by drawing far to much power from the transformer and you should not try to replicate this.

avxt · 24th December 2001, 03:44 AM

OH I see

Actually the second same post I sent was an accidently pressed. sorry for that.

Thanks for your info.

Any one have any advice for the EI single 0-36V AC secondary one?

GRollins · 24th December 2001, 04:25 AM

The 135W amp was very likely class B or lightly biased AB. No big deal.
The EI might make a nice stereo Zen with a choke input filter (instead of cap input) to hold the voltage down.
EI transformers work just fine for audio. Been used since the beginning of time for some very nice sounding circuits. They're somewhat less efficient and can cause hum if they're too close to high gain circuitry, but careful positioning can take care of that.
Have fun.

Grey

24th December 2001, 01:38 AM	#1
avxt diyAudio Member Join Date: Dec 2001	Need circuit for transformer I have a single rail 0-36V AC 400 watts EI transformer, interested to build a power amplifier any suggestion for reasonable sound quality circuit? and I also have a 36.8-0-36.8V AC 230VA toroidal transformer and same would like to build a power amplifier and still looking for circuit. Thanks for help.

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24th December 2001, 01:47 AM	#2
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	I dont know about the EI core transformer I dont like them much for audio use .... As for the toroidal, this should give about +/-40V after rectification allowing for voltage sag. so you've got a supply capable of +/-40V @ 3A continuous this might be suitable for some sort of preamp circuit or an amp driving a high resistance load eg. 16ohms

24th December 2001, 01:57 AM	#3
avxt diyAudio Member Join Date: Dec 2001	any hope for power amp driving 8 ohm speakers I saw the www.aussieamplifiers.com for the hitachi lateral mosfet power amp but don't know its good or not.

24th December 2001, 02:11 AM	#4
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	using the toroidal @ 8 ohms you would be down to 60-70W for a single channel amp or 15W per channel for a stereo amp

24th December 2001, 02:46 AM	#5
avxt diyAudio Member Join Date: Dec 2001	you mean for Anthony Holton Hitachi lateral mosfet amp? but 1 thing I don't understand is I get the transformer from an old Ecleree mosfet amp and they stated 135 watts rms into 8 ohm for stereo channel.

24th December 2001, 03:01 AM	#6
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	I mean for any amp you build with this transformer and use with 8ohm speakers. thats cause they were overdriving the poor transformer really badly.

24th December 2001, 03:03 AM	#7
avxt diyAudio Member Join Date: Dec 2001	you mean for Anthony Holton Hitachi lateral mosfet amp? but 1 thing I don't understand is I get the transformer from an old Ecleree mosfet amp and they stated 135 watts rms into 8 ohm for stereo channel.

24th December 2001, 03:11 AM	#8
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	It doesnt really matter what type of amp if it is driving 8ohm speakers and using that transformer that is all the power it is realistically good for.. They got the 135W into 8ohm stereo by drawing far to much power from the transformer and you should not try to replicate this.

24th December 2001, 03:44 AM	#9
avxt diyAudio Member Join Date: Dec 2001	OH I see Actually the second same post I sent was an accidently pressed. sorry for that. Thanks for your info. Any one have any advice for the EI single 0-36V AC secondary one?

24th December 2001, 04:25 AM	#10
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	The 135W amp was very likely class B or lightly biased AB. No big deal. The EI might make a nice stereo Zen with a choke input filter (instead of cap input) to hold the voltage down. EI transformers work just fine for audio. Been used since the beginning of time for some very nice sounding circuits. They're somewhat less efficient and can cause hum if they're too close to high gain circuitry, but careful positioning can take care of that. Have fun. Grey