Transformerless Tube Amp

Tarzan · 19th May 2009, 07:25 AM

I recently stumbled accross some old magazines from the early sixties.
They had a small article on transformerless power amps.
I did a quick search on the net and found the following pattent extract:

http://www.google.com/patents?id=fo1...BAJ&dq=3092783
E.H. Krohn Power amplifier US Pattent 3.092.783

Here I read that the load is 600 Ohms; a bit unpractical nowadays.
Outout Power is more then adequate.

I keep on searching further and like to know if any one had or has experiance with this kind of amplifiers.

The field of usage is mainly Musical Instrument amplification. No HiFi.
How will this amp behave under the harsh road and stage conditions?

Cheers,
Tarzan

woody · 19th May 2009, 07:45 AM

These transformerless amps are usualy refered to as OTL amplifiers. There are several discused in this tube forum that
can drive an 8 ohm load just fine. Just do a search for OTL and read to your heart's content.

Tarzan · 19th May 2009, 07:55 AM

Yes, OTL, I forgot the abbreviation...
I'll do a search.
Thanks for the so obvious tip.
Cheers,
Tarzan

merlin2069er · 17th June 2009, 08:33 PM

Check out Bruce's amp over at Transcendent.

http://www.transcendentsound.com/T16OTL.htm

I picked up his audio book from the library Audio Reality - it's a good read, with plenty of his projects in it.

http://www.transcendentsound.com/audioreality.htm

Steerpike · 17th June 2009, 11:47 PM

Philips (Holland) has a line of very good OTL amps (AG9014, AG9015, AG9018) and matching 800 Ohm hi-fi speakers (AG5005, AG5040)

19th May 2009, 07:25 AM	#1
Tarzan diyAudio Member Join Date: May 2004 Location: Genk	Transformerless Tube Amp I recently stumbled accross some old magazines from the early sixties. They had a small article on transformerless power amps. I did a quick search on the net and found the following pattent extract: http://www.google.com/patents?id=fo1...BAJ&dq=3092783 E.H. Krohn Power amplifier US Pattent 3.092.783 Here I read that the load is 600 Ohms; a bit unpractical nowadays. Outout Power is more then adequate. I keep on searching further and like to know if any one had or has experiance with this kind of amplifiers. The field of usage is mainly Musical Instrument amplification. No HiFi. How will this amp behave under the harsh road and stage conditions? Cheers, Tarzan

17th June 2009, 11:47 PM	#5
Steerpike diyAudio Member Join Date: Jan 2006 Location: Johannesburg, South Africa	Philips (Holland) has a line of very good OTL amps (AG9014, AG9015, AG9018) and matching 800 Ohm hi-fi speakers (AG5005, AG5040) __________________ Steerpike's Toybox

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19th May 2009, 07:45 AM	#2
woody diyAudio Member Join Date: Jan 2002 Location: Tyrone Ga. U.S.A.	These transformerless amps are usualy refered to as OTL amplifiers. There are several discused in this tube forum that can drive an 8 ohm load just fine. Just do a search for OTL and read to your heart's content.

19th May 2009, 07:55 AM	#3
Tarzan diyAudio Member Join Date: May 2004 Location: Genk	Yes, OTL, I forgot the abbreviation... I'll do a search. Thanks for the so obvious tip. Cheers, Tarzan

17th June 2009, 08:33 PM	#4
merlin2069er diyAudio Member Join Date: Sep 2008 Location: Toronto	Check out Bruce's amp over at Transcendent. http://www.transcendentsound.com/T16OTL.htm I picked up his audio book from the library Audio Reality - it's a good read, with plenty of his projects in it. http://www.transcendentsound.com/audioreality.htm

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