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Old 1st Jan 2019, 4:28 pm   #88
Jolly 7
Octode
 
Join Date: Feb 2018
Location: Southampton, Hampshire, UK.
Posts: 1,049
Default Re: More Chinese AM radio kits

I suspect poor quality control of the audio driver and output transformers, green B6 and yellow B7 respectively in HX 108-2. For one sample I tested, which worked for a while, B6 had a 230 ohm primary but the second sample only 175 ohm. The secondaries of the two samples I tested were also in wide variation of each other.
In relation to B7, for which I found a defect in one of my samples referred to in an earlier post, the correct reading for the primary would appear to be 12 ohms with a centre tap of approximately 6 ohms. The secondary should be in the region of 2 ohms.

This is a question in relation to the matching of the audio output transformer and the supplied speaker. Is a 2 ohm audio output transformer a good choice for an 8 ohm speaker ?

Last edited by Jolly 7; 1st Jan 2019 at 4:34 pm.
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