UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Convert Bush DAC90 or AC91 to battery use.

FERNSEH · 10th Jun 2021, 9:55 pm

"The wiring is also far too neat for a "production " set"
Hi Ed,
It's a special prototype model, unlikely to go into production.
Well the news is it works! Very good results on short waves which must be due to the choice of frequency changer valve, the DK40. This valve could be tried in the Zenith Transoceanic sets as replacement for the 1L6.
Plenty audio power, much better than receivers with the usual DL94 etc. Your output transformer is doing a great job.
Not so good is the ex-Ultra TV first IF transformer, it won't peak up properly on 465Kc/s. Intend to fit another IF transformer either the original Bush component or another ex-equipment part.
In terms of sensitivity the set should be as good as the AC91 but will audio output will never be as good as the mains models.

DFWB.

10th Jun 2021, 9:55 pm	#36
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Convert Bush DAC90 or AC91 to battery use. "The wiring is also far too neat for a "production " set" Hi Ed, It's a special prototype model, unlikely to go into production. Well the news is it works! Very good results on short waves which must be due to the choice of frequency changer valve, the DK40. This valve could be tried in the Zenith Transoceanic sets as replacement for the 1L6. Plenty audio power, much better than receivers with the usual DL94 etc. Your output transformer is doing a great job. Not so good is the ex-Ultra TV first IF transformer, it won't peak up properly on 465Kc/s. Intend to fit another IF transformer either the original Bush component or another ex-equipment part. In terms of sensitivity the set should be as good as the AC91 but will audio output will never be as good as the mains models. DFWB.