OTL designed by Glen Orr AudioXpress

desperateaudio · 05:55 PM

I just built this amp. Started listening last night. Very nice sound, nice and clean with nice mids. Although I am not a fan of the 12AX7 overall in this design she is not coming across as bright as the most recent OTL I built which you cab find in this thread:

OTL designed by Tim Mellow with 4 6C33C?

Would love to hear comments if anyone else has built this OTL. This design is a modification of an old OTL design from the 50's I believe and RCA 25 Watt amp.

Thx

D

(attachments removed by moderators)

desperateaudio · 01:36 PM

Here is the last page of the article and my testing rig build up. The power supply in the pic that is at the top center is a regulated PS that is running the 450vdc lines. The 155 plus/neg PS is on the board and from that I am also getting the -70vdc and -225vdc supplies.

SY · 2nd December 2010, 05:57 PM

I've removed the AX article- this is copyrighted material. If you have Ed Dell's written permission to post those scans here, let me know and I'll put them back.

desperateaudio · 2nd December 2010, 06:38 PM

Quote:

Originally Posted by SY

I've removed the AX article- this is copyrighted material. If you have Ed Dell's written permission to post those scans here, let me know and I'll put them back.

No problem Sy sorry about that was not thinking. The schematic in the article is not under copyright so I should be able to post solely that correct? It is from a public schematic for years now as its origin. Thx

SY · 2nd December 2010, 06:40 PM

The 1954 one? That would probably not draw lawyers' attention.

desperateaudio · 2nd December 2010, 07:09 PM

Quote:

Originally Posted by SY

The 1954 one? That would probably not draw lawyers' attention.

Ok I will post that one and then I will let forum members know I have the article if they would like to see it ok?

taj · 07:44 PM

It wouldn't really matter how you distributed the article, it would be a copyright violation if it's done without permission of the owner. All you can legally do is 'refer' to the article and hope people get it from the publisher. Or that the publisher makes it available.

The copyright for the old schematic has probably expired, but you never know without investigating. The Gutenberg Project is currently taking some flack for publishing books they thought were copyright free, but were in fact bound by copyrights that had been renewed.

..Todd

dwhitf · 08:04 PM

desperateaudio

What are the transformers your using? need a simple stereo unit for the office.
dwhitf

sorry miss this
The power supply in the pic that is at the top center is a regulated PS

desperateaudio · 2nd December 2010, 09:53 PM

Here is the original schematic I believe this is not under current copyright otherwise AX would not have been able tp produce the article. Lighten up guys.

Here is a link outside of this forum for those interested.

DigitalJunkie · 2nd December 2010, 10:37 PM

Ooff! Line-powered,and OTL to boot,double whammy! Sometimes it amazes me that they got away with this stuff,even back then.

2nd December 2010, 01:30 PM	#1
desperateaudio diyAudio Member Join Date: Dec 2004 Location: NE USA	OTL designed by Glen Orr AudioXpress I just built this amp. Started listening last night. Very nice sound, nice and clean with nice mids. Although I am not a fan of the 12AX7 overall in this design she is not coming across as bright as the most recent OTL I built which you cab find in this thread: OTL designed by Tim Mellow with 4 6C33C? Would love to hear comments if anyone else has built this OTL. This design is a modification of an old OTL design from the 50's I believe and RCA 25 Watt amp. Thx D (attachments removed by moderators) Last edited by SY; 2nd December 2010 at 05:55 PM. Reason: copyright

2nd December 2010, 05:57 PM	#3
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	I've removed the AX article- this is copyrighted material. If you have Ed Dell's written permission to post those scans here, let me know and I'll put them back. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

2nd December 2010, 06:40 PM	#5
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	The 1954 one? That would probably not draw lawyers' attention. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

2nd December 2010, 07:40 PM	#7
taj diyAudio Member Join Date: Feb 2005	It wouldn't really matter how you distributed the article, it would be a copyright violation if it's done without permission of the owner. All you can legally do is 'refer' to the article and hope people get it from the publisher. Or that the publisher makes it available. The copyright for the old schematic has probably expired, but you never know without investigating. The Gutenberg Project is currently taking some flack for publishing books they thought were copyright free, but were in fact bound by copyrights that had been renewed. ..Todd Last edited by taj; 2nd December 2010 at 07:44 PM.

2nd December 2010, 07:58 PM	#8
dwhitf diyAudio Member Join Date: May 2008	Please list the transformers desperateaudio What are the transformers your using? need a simple stereo unit for the office. dwhitf sorry miss this The power supply in the pic that is at the top center is a regulated PS Last edited by dwhitf; 2nd December 2010 at 08:04 PM. Reason: mis read post

2nd December 2010, 10:37 PM	#10
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	Ooff! Line-powered,and OTL to boot,double whammy! Sometimes it amazes me that they got away with this stuff,even back then.

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