If you were going to build a OTL?

dwhitf · 14th November 2010, 07:49 PM

If you were going to build a OTL (output-transformerless) amplifier and you knew you had to live with it long term which one would it be.

dwhitf · 14th November 2010, 08:42 PM

I made a mistake see other thread with voting, sorry for the Dup. thanks dwhitf

Miles Prower · 14th November 2010, 09:47 PM

Quote:

Originally Posted by dwhitf

If you were going to build a OTL (output-transformerless) amplifier and you knew you had to live with it long term which one would it be.

MOSFET Circlotron final, hollow state front end. The A Number One problem with any hollow state OTL is operating the finals into nearly vertical loadlines. That makes for big time distortion, and it becomes questionable whether that is preferable to just going ahead and using source followers. Just make sure that your source followers stay away from the rails since MOSFET internal capacitances go squirrelly when Vds drops to low voltages.

Besides, a MOSFET Circlotron doesn't need a high current heater transformer, nor does it require knocking a dozen holes in the chassis. There is also the safety question: the MOSFET design won't put bigvolts on the speaker terminals if something poofs.

kevinkr · 14th November 2010, 10:14 PM

Quote:

Originally Posted by dwhitf

If you were going to build a OTL (output-transformerless) amplifier and you knew you had to live with it long term which one would it be.

I'd likely base it on one of Ralph Karsten's Atmosphere OTL amp designs, but more than likely I'd reconsider and probably go for a more conventional PP with an output transformer.

markusA · 15th November 2010, 04:41 AM

A M-60 seems like a likely candidate to me.

Luke · 15th November 2010, 05:46 AM

Quote:

Originally Posted by Miles Prower

MOSFET Circlotron final, hollow state front end.

Hi Miles, do you have a link to this amp?

Miles Prower · 15th November 2010, 08:29 AM

^^

Sure don't. It's a future project for someday. I haven't begun the design work for it.

Luke · 15th November 2010, 08:36 AM

Ah, it sounded interesting so I started googling and came up empty

Brit01 · 15th November 2010, 08:39 AM

I'm working on a OTL, circlotron final, FET source followers, LTP split, and experimenting with different front drivers right now and biasing techniques and protection.

CLS · 15th November 2010, 08:44 AM

MOSFET Circlotron can be found at passdiy

14th November 2010, 07:49 PM	#1
dwhitf diyAudio Member Join Date: May 2008	If you were going to build a OTL? If you were going to build a OTL (output-transformerless) amplifier and you knew you had to live with it long term which one would it be.

15th November 2010, 08:29 AM	#7
Miles Prower diyAudio Member Join Date: May 2005 Location: USA Blog Entries: 6	^^ Sure don't. It's a future project for someday. I haven't begun the design work for it. __________________ There are no foxes in atheistholes www.dolphin-hsl.com

15th November 2010, 08:36 AM	#8
Luke diyAudio Member Join Date: Sep 2001 Location: Wellington NZ	Ah, it sounded interesting so I started googling and came up empty __________________ If you give a man a fish he will eat for a day. But if you teach a man to fish he will buy an ugly hat. And if you talk about fish to a starving man then you are a consultant. Dilbert

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14th November 2010, 08:42 PM	#2
dwhitf diyAudio Member Join Date: May 2008	I made a mistake see other thread with voting, sorry for the Dup. thanks dwhitf

15th November 2010, 04:41 AM	#5
markusA diyAudio Member Join Date: Dec 2009 Blog Entries: 7	A M-60 seems like a likely candidate to me.

15th November 2010, 08:39 AM	#9
Brit01 diyAudio Member Join Date: Jul 2008	I'm working on a OTL, circlotron final, FET source followers, LTP split, and experimenting with different front drivers right now and biasing techniques and protection.

15th November 2010, 08:44 AM	#10
CLS diyAudio Member Join Date: Jun 2005 Location: Taiwan	MOSFET Circlotron can be found at passdiy

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