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Old 9th Jun 2021, 7:28 pm   #1
bobhowe
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Default Bush DAC90A Output Transformer

Hi is the Bush DAC90A output transformer more prone to failure than the DAC90 & can they be interchanged ? kind regards Bob
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Old 9th Jun 2021, 7:41 pm   #2
ms660
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Default Re: Bush DAC90A Output Transformer

The transformers are the same so far as I know.

Lawrence.
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Old 9th Jun 2021, 8:50 pm   #3
bobhowe
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Default Re: Bush DAC90A Output Transformer

Hi Lawrence i have seen online DAC90A failures but none for DAC90 wonder if they made with better materials or was the output valve on the DAC90 kinder to the transformer than than DAC90A kind regards Bob
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Old 9th Jun 2021, 9:55 pm   #4
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Default Re: Bush DAC90A Output Transformer

The DAC90 was marginally gentler on the output TX ar 25mA vs 27.5mA. Whether 10% extra current (20% extra Isquared R dissipation) would significant
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Old 9th Jun 2021, 10:09 pm   #5
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Default Re: Bush DAC90A Output Transformer

You can use one from a DAC10, the same apart from the screw terminals for the speaker connections . I have seen a few o/c ones in DAC90A s but I can't remember changing one in a 10. The output valve is the same the only difference is the way they are mounted?
Or maybe I have just been lucky?
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Old 10th Jun 2021, 9:55 am   #6
ms660
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Default Re: Bush DAC90A Output Transformer

Quote:
Originally Posted by bobhowe View Post
Hi Lawrence i have seen online DAC90A failures but none for DAC90 wonder if they made with better materials or was the output valve on the DAC90 kinder to the transformer than than DAC90A kind regards Bob
Same turns ratio, same resistance, same inductance/impedance, same part number, that's all I know.

Lawrence.
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Old 11th Jun 2021, 9:07 am   #7
murphyv310
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Default Re: Bush DAC90A Output Transformer

If it's the same part number then the TX is the same.
Don't forget the UL41 is prone to leaks and a rise in anode current, that's the reason the output TX fails in the DAC90A even though the G1 coupling cap is replaced, the issue doesn't occur in the DAC90.
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Old 11th Jun 2021, 7:18 pm   #8
bobhowe
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Default Re: Bush DAC90A Output Transformer

Hi Trevor that explains a lot kind regards Bob
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