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Old 2nd December 2010, 02:30 PM   #1
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Default 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 06:55 PM. Reason: copyright
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Old 2nd December 2010, 02:33 PM   #2
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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.
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Last edited by desperateaudio; 2nd December 2010 at 02:36 PM.
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Old 2nd December 2010, 06:57 PM   #3
SY is offline SY  United States
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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.
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Old 2nd December 2010, 07:38 PM   #4
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Originally Posted by SY View Post
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
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Old 2nd December 2010, 07:40 PM   #5
SY is offline SY  United States
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The 1954 one? That would probably not draw lawyers' attention.
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And while they may not be as strong as apes, don't lock eyes with 'em, don't do it. Puts 'em on edge. They might go into berzerker mode; come at you like a whirling dervish, all fists and elbows.
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Old 2nd December 2010, 08:09 PM   #6
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Originally Posted by SY View Post
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?
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Old 2nd December 2010, 08:40 PM   #7
taj is offline taj
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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 08:44 PM.
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Old 2nd December 2010, 08:58 PM   #8
dwhitf is offline dwhitf  United States
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Default 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 09:04 PM. Reason: mis read post
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Old 2nd December 2010, 10:53 PM   #9
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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.
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Old 2nd December 2010, 11:37 PM   #10
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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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