honkytonk

v72 repair
« on: February 14, 2020, 03:57:16 AM »
I have two v72 modules with transformer problems. Have understood that these transformers are almost impossible to find, but can it be possible to replace them with other parts?
So I wonder if there are anybody with experience/ knowledge in v72 modules who can share some info about this?

Bjørn Georg
Bjorn Georg


johnheath

Re: v72 repair
« Reply #1 on: February 14, 2020, 08:59:12 AM »
I believe that Sowter makes replacement transformer for these preamps.

So I would recommend to have look at their website.

Best regards

// John
Nothing is impossible - It just takes some more time

Michael Tibes

Re: v72 repair
« Reply #2 on: February 15, 2020, 11:39:49 AM »
Also it would be good to know which transformer is broken? Maybe it is possible to rewind them? There even is a V72 input transformer build sheet somewhere around here, also CJ had a bunch of information on the topic. If all this and the Sowther solution doesn't work I'd look into Lundahl and see if something fits...

Michael

honkytonk

Re: v72 repair
« Reply #3 on: February 16, 2020, 12:50:39 PM »
I believe that Sowter makes replacement transformer for these preamps.

So I would recommend to have look at their website.

Best regards

// John

Hi John
Thanks for replay!
I have been looking at the Sowter. Did you build a diy v72?
Regards
Bjorn
Bjorn Georg

honkytonk

Re: v72 repair
« Reply #4 on: February 16, 2020, 01:00:49 PM »
Also it would be good to know which transformer is broken? Maybe it is possible to rewind them? There even is a V72 input transformer build sheet somewhere around here, also CJ had a bunch of information on the topic. If all this and the Sowther solution doesn't work I'd look into Lundahl and see if something fits...

Michael

Hi Michael,
Thanks for replay. I have read CJ`s info, impressing stuff. I have sent him a message. I bought these v72`s years back, and it looks like "somebody" have switched the original transformers with some other transformers. I just found out when I now was planning to rack them up and use them.
Regards
Bjorn
Bjorn Georg

MatthisD

Re: v72 repair
« Reply #5 on: February 16, 2020, 01:31:03 PM »
If you'd like to post a photo of one of the units maybe we  can identify the transformers and the choke to see what you have at the moment.

Hi Michael,
Thanks for replay. I have read CJ`s info, impressing stuff. I have sent him a message. I bought these v72`s years back, and it looks like "somebody" have switched the original transformers with some other transformers. I just found out when I now was planning to rack them up and use them.
Regards
Bjorn

honkytonk

Re: v72 repair
« Reply #6 on: February 16, 2020, 02:57:25 PM »
If you'd like to post a photo of one of the units maybe we  can identify the transformers and the choke to see what you have at the moment.

Thanks for replay. Yes, I would be grateful for any help about this. Ref. DIY I have no experience on this level.

This is a photo before removing any parts.
Bjorn Georg

honkytonk

Re: v72 repair
« Reply #7 on: February 16, 2020, 03:34:27 PM »
the part to the left on first photo
Bjorn Georg

honkytonk

Re: v72 repair
« Reply #8 on: February 16, 2020, 03:37:53 PM »
the part in the middle of the first photo
Bjorn Georg

honkytonk

Re: v72 repair
« Reply #9 on: February 16, 2020, 03:41:10 PM »
This is the input transformer? The right part of the first photo .....
Bjorn Georg


honkytonk

Re: v72 repair
« Reply #10 on: February 16, 2020, 03:43:22 PM »
Lately I have been told none of these are original V72 parts.
Bjorn Georg

MatthisD

Re: v72 repair
« Reply #11 on: February 16, 2020, 08:17:38 PM »
I would agree.  What about the power transformer,  is it labelled CKV72/N?

Michael Tibes

Re: v72 repair
« Reply #12 on: February 17, 2020, 01:39:12 AM »
Lately I have been told none of these are original V72 parts.
I'm not sure. They all look like they might be from the V-series, but I'd have to check with a real unit to make sure they are the right ones.

Michael

honkytonk

Re: v72 repair
« Reply #13 on: February 17, 2020, 03:57:38 AM »
I would agree.  What about the power transformer,  is it labelled CKV72/N?

I guess this is the power transformer, I find no label on it, maybe hidden under?
Bjorn Georg

honkytonk

Re: v72 repair
« Reply #14 on: February 17, 2020, 04:13:30 AM »
This is one of the v72 units ....
Bjorn Georg

MatthisD

Re: v72 repair
« Reply #15 on: February 17, 2020, 10:27:19 AM »
I guess this is the power transformer, I find no label on it, maybe hidden under?

Maybe, although they could previously have been repaired or rewound without labels. The next obvious question I have is are these functioning preamps?

Re: v72 repair
« Reply #16 on: February 17, 2020, 11:13:18 AM »
Hello Honkytonk,
This tread was brought to our attention...
To confirm from the pic's those are indeed not the original transformers, they appear rewound. Difficult to determine from a picture if the inductor or power transformer meet original specifications, the input transformer definitely does not.  To my knowledge Tab-Funkenwerk founded by Oliver Archut (RIP) is the only company that correctly rewinds and manufactures new V72, V76 input transformers and inductors etc...  (according to original specifications).
Following Oliver's lead TAB continues to provide these products and services (Inputs are very laborious and not cheap) you can email [email protected] for more info.

Disclaimer..... I work at TAB and am not trying to sell or promote our products, just offering information that there are proper solutions available.

-dennis

btw, there are more than a few V-series units working in Norway that use our rewound transformers....

Re: v72 repair
« Reply #17 on: February 17, 2020, 11:46:00 AM »
The original parts list ...

Andreas

honkytonk

Re: v72 repair
« Reply #18 on: February 17, 2020, 04:18:23 PM »
Maybe, although they could previously have been repaired or rewound without labels. The next obvious question I have is are these functioning preamps?

No, they are not working preamps. I bought them some years ago for later racking. Though I got them for a "not working price", I was told they were all original. I was prepared for surprises and here they are ...-.).  However, the v72 preamp is a fantastic preamp when it works, so I would like to go ahead and see if I can make them work oneday.

Thanks to all of you who share info ref the v72. It is not easy to find detailed info about the v72,
Bjorn Georg

honkytonk

Re: v72 repair
« Reply #19 on: February 17, 2020, 04:21:09 PM »
The original parts list ...

Andreas

Thanks so much. I have never seen this before ....
Bjorn Georg


 

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