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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 19th May 2022, 1:40 pm   #1
Western 91
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Default Grundig Tk 46 Reel To Reel

Hi. Would a member of this forum please be able to let me know what the physical size of the output transformers are on Grundig TK46. I will be grateful for your replies.
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Old 20th May 2022, 11:58 am   #2
Edward Huggins
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Default Re: Grundig Tk 46 Reel To Reel

An interesting question. Well they are only rated at 4-5 watts (one half of an ELL80 each) so cannot be very big - 2.5"/3" wide max I would guess.
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Old 20th May 2022, 3:47 pm   #3
Jan Zodiac
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Default Re: Grundig Tk 46 Reel To Reel

Hello.

Hope this will help. I took the bottom cover of mine and did my best to measure the transformers. Grundig really managed to cramp that output stage into a very small corner. Measurements must be seen as approximate, since there is no way to access them properly, without removing the hole amplifier section. Measurements in millimeters.
Btw, the transformers are not identical. One has a terminal strip mounted on top of it.

Kind regards,

Jan
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Old 20th May 2022, 8:29 pm   #4
DMcMahon
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Default Re: Grundig Tk 46 Reel To Reel

What is the reason you need the dimensions for, are your transformers defective ?

It is fairly unusual for output transformers to fail.

One scenario that potentially could lead to transformer failure is if the grid coupling capacitor to the ELL 80 control grid becomes leaky and then pass DC voltage, this potentially will stress the valve and the transformer.

For the TK 46 the capacitors are C129 and C229 respectively for the left and right channels, both being 3.3nF

I have the TK 40 which is the mono version of your TK 46, in mine there are no waxy/paper capacitors of the type that can be problematic with leakage, for your TK 46 it depends upon the capacitor type for C129/C229 as to whether they may be leaky, easily proven by checking the ELL 80 control grids for no positive DC voltage.

On the TK 46 schematic both your transformers are shown as BV 9060-507 so from that appear to be identical transformers, I would guess in this case both transformer wire connections go to the single insulated terminal board.

My transformer is BV 9060-506.01, different from yours as it (mine) only has a single secondary winding. My dimensions are very similar to Jan's dimensions.

David
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Old 20th May 2022, 10:07 pm   #5
Jan Zodiac
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Default Re: Grundig Tk 46 Reel To Reel

Another thing is the cathode capacitor (electrolytic) of the output valve. I had several TK46/47 over time, and I experienced a couple of times that they short out, driving the valve red hot on the plates. They already run hot, so as David wrote, it is important to check for DC on the grids, and also check for correct voltage on the cathode. I would just replace the cathode electrolytic anyway (and grid coupling capacitors), as they sit in a very hot environment.

Jan
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Old 21st May 2022, 10:11 am   #6
DMcMahon
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Default Re: Grundig Tk 46 Reel To Reel

Strangely the TK 46 schematic does not show the cathode capacitor and resistor for the second ELL 80 ?

David
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Old 21st May 2022, 10:21 am   #7
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Default Re: Grundig Tk 46 Reel To Reel

Quote:
Originally Posted by DMcMahon View Post
Strangely the TK 46 schematic does not show the cathode capacitor and resistor for the second ELL 80 ?
Common cathode, B9A.

Lawrence.
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Old 21st May 2022, 10:39 am   #8
DMcMahon
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Default Re: Grundig Tk 46 Reel To Reel

Well done Lawrence, now makes sense, incorrectly thinking it was 2 separate valves.

David
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Old 25th May 2022, 11:50 am   #9
Western 91
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Default Re: Grundig Tk 46 Reel To Reel

Hi all Thank you for your Replies and a special thank you to DMcMahon for the pictures. I have purchased this off Ebay and on receiving the recorder I find that the power amp has been replaced with solid state module. I want to put the valve back same has Grundig made it. I have got to use the ell80 for lack of place. I have checked the machine out and it is clean and no corrosion and there is no wear on the tape guides or the heads and it works fine and sounds very good. The power amp module date is 2001. I am looking for a pair of original Grundig transformers. I have given the transformer specs from the service manual to Majestic Transformer company and he asked for the size. I have used this company for quite a few transformers and found them to be very good. Thank you once a gain for all you help. I will give feed back how the project is going.
Best Regards Western 91
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Old 4th Jun 2022, 7:51 pm   #10
Jan Zodiac
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Default Re: Grundig Tk 46 Reel To Reel

Hello Western,

Did you ever manage to find the transformers? If not, and you still need them, I am scrapping a TK47 (same output amp.), and you can have the complete amp. module (less valves though). It's FOC of course, except for the shipping charges.

Kind regards,

Jan
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Old 28th Jun 2022, 2:48 pm   #11
Western 91
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Default Re: Grundig Tk 46 Reel To Reel

Hi Jan Zodiac. Sorry for late response I don't get messages to let me know that I have any. Yes I would like to have the amp on offer please let me know the cost and sending to UK. Thank You.
Regards Peter.
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