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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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17th Feb 2020, 1:18 am | #1 |
Triode
Join Date: Feb 2020
Location: Droitwich, Worcestershire, UK.
Posts: 10
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Philips car radio transistor output
hi i have a philips n4g93vt hybrid car radio. the ouput valve is an ef98.
i have the circuit diagram however what i dont have is the second part of the radio that contains the transistor. the transistor is an oc26 on the circuit diagram it shows 2 transformers i could possible build the final output stage. However how do i work out what transformers i need?? |
17th Feb 2020, 11:03 am | #2 |
Octode
Join Date: Jan 2003
Location: Guildford, Surrey, UK.
Posts: 1,960
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Re: philips car radio transistor output
There is some guidance in "Mullard Manual of Transistor Circuits" detailing a single-ended OC26 output stage for car radio. The section starts on page 137 of the "Class A Output Stages" Chapter.
Ron |
17th Feb 2020, 5:04 pm | #3 |
Triode
Join Date: Feb 2020
Location: Droitwich, Worcestershire, UK.
Posts: 10
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Re: Single-ended Transistor amps.
I am looking for a transformer to run an oc26 off an ef98 valve how ever i don't have much to go on other than 25:1 and 270 ohms
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17th Feb 2020, 8:12 pm | #4 |
Guest
Posts: n/a
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Re: Philips car radio transistor output
If it was mine I would build the external unit using a modern IC amplifier, loading the EF98 to look like what the transformer was, if it hasn't already got an anode resistor.
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18th Feb 2020, 7:13 am | #5 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,195
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Re: Philips car radio transistor output
Winding details for the Mullard transformer are given in the Mullard "reference manual of transistor circuits"
Ed |
19th Feb 2020, 2:17 pm | #6 |
Triode
Join Date: Feb 2020
Location: Droitwich, Worcestershire, UK.
Posts: 10
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Re: Philips car radio transistor output
this is the schematic as you can see with out the transistor side there is no load on the anode. i have attached the circuit for reference.
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21st Feb 2020, 12:55 pm | #7 |
Nonode
Join Date: Jun 2007
Location: Coulsdon, London, UK.
Posts: 2,169
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Re: Philips car radio transistor output
How important is it for you to duplicate the original circuit?
Making a audio amplifier using two unusual transformers could be expensive, bulky and time consuming. You could amplify the output from the EF98 using a readily available audio amplifier chip or possibly a MOSFET source follower. |