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Old 26th April 2009, 10:21 AM   #1
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Question Audio Transformer/Cathode Feedback Info

Hi, tube folks,

I got an opportunity to order a pair of custom-built audio transformers. So my idea is to replicate rare yet highly regarded for its sound quality Sansui AU111 amplifier. Its primary windings have additional section for cathode feedback. Something similar is used in McIntosh tube amplifiers.

Does anyone have (or can just guess) technical data for this transformer? I think its pretty standard for 6L6GC/EL34/6550/KT66 push-pull design.

The question is this additional section for cathode follower - what % of primary winding it should be?

Any other data about material core, winding separation, etc is very welcome.
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Old 26th April 2009, 01:06 PM   #2
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7-8 % from primary coil for 1 tube....
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Old 26th April 2009, 03:40 PM   #3
kevinkr is offline kevinkr  United States
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Check with Hashimoto Japan - they might even have the information on their website. They made the Sansui transformers, and IIRC made this transformer in the recent past. (Maybe for the reissue amp.)
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Old 26th April 2009, 07:46 PM   #4
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Quote:
Originally posted by kevinkr
Check with Hashimoto Japan - they might even have the information on their website. They made the Sansui transformers, and IIRC made this transformer in the recent past. (Maybe for the reissue amp.)
Hi, Kevin! Thanks for suggestion! I know about Hashimoto, checked their reseller www.acoustic-dimension.com and found no transformers with cathode feedback winding. They also sell Tango and Tamura, the same story, only standard generic trafos.

BTW, what is IIRC?
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Old 26th April 2009, 09:13 PM   #5
kevinkr is offline kevinkr  United States
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Quote:
Originally posted by LinuksGuru


Hi, Kevin! Thanks for suggestion! I know about Hashimoto, checked their reseller www.acoustic-dimension.com and found no transformers with cathode feedback winding. They also sell Tango and Tamura, the same story, only standard generic trafos.

BTW, what is IIRC?

In no particular order IIRC - "If I recall correctly..."

AND

Here is another website you might want to check out for Hashimoto (and only Hashimoto) Transformers: http://www.tube-amps.net/index.htm They are directly affiliated with Hashimoto and you can purchase AU-111 output transformers directly from them. This is a link to the OPT-111 which is the AU-111 replacement output transformer, unfortunately it is currently out of stock: http://www.obsinc-products.com/servlet/Detail?no=10 (Note: Obsinc-products.com hosts tube-amps.net) Perhaps someone closer to you can also source this PN..
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