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Electronics => Beginners => Topic started by: stonerbot613 on October 04, 2018, 11:00:42 pm

Title: Obsolete Transformer Help!
Post by: stonerbot613 on October 04, 2018, 11:00:42 pm
I'm currently in the processing of updating a 20-25 year old power amp design and need some help identifying the type of transformer used on it.
The markings on the transformer show either COEV TTI8105 or TRANSFORMER TECHNOLOGIES TTI8105.  After exhaustive Google searching, I can't figure out what it is.  It seems like COEV may have been bought out by TE at some point, but TE's website made no mention of the TTI8105 part number.

Can anybody help me out here?  Information about this transformer (or family of transformers) or old datasheets would be much appreciated.

My apologies if this is the wrong forum for this type of question.

Thanks
Title: Re: Obsolete Transformer Help!
Post by: ArthurDent on October 05, 2018, 12:17:55 am
I think you'll find that the numbers you list are in house part numbers and unless you can find information and parts list from the company that made the amp you may be out of luck.

Is there a problem with the transformer? If not you may be able to measure the winding voltages/ratios and make an educated guess.
Title: Re: Obsolete Transformer Help!
Post by: 6PTsocket on October 05, 2018, 01:09:53 am
More info please. What brand is the amp?  MacIntosh continued to use audio output trasformers for a long time. Is this a power transformer or an output transformer. Take a picture.

Sent from my SM-G900V using Tapatalk

Title: Re: Obsolete Transformer Help!
Post by: stonerbot613 on October 05, 2018, 01:54:58 am
Picture is attached.  I was under the impression that the company was either COEV or TRANSFORMER TECHNOLOGIES.  Maybe I'm wrong.  For scale, they are around 1" in diameter and around 0.5" tall.
Title: Re: Obsolete Transformer Help!
Post by: ArthurDent on October 05, 2018, 02:54:47 am
Those appear to be fairly small ferrite cup-core transformers that are normally not used in audio equipment. A photo of where they were in the circuit would help.

Title: Re: Obsolete Transformer Help!
Post by: floobydust on October 05, 2018, 03:39:37 am
It's surely a custom part. I've only seen JBL, Altec Lansing use interstage transformers in power amplifiers.

Today it's all ferrite materials tailored for SMPS applications. Those cores give high distortion in audio use.
The hard part is finding the pot cores.

Many years ago I searched for "telecom grade" ferrites for a Pultec Eq clone project.
My junk box shows them to be MMG-Neosid P11 material and I thought the B-H curve is fairly linear for low distortion.

Perhaps ask Sowter Transformers (http://www.sowter.co.uk/vintage-audio-transformers.php) as they reverse-engineer and manufacture vintage audio transformers.