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Antique AHUJA Valve Power Amplifier Model A-25 Restored

By on September 6, 2019
valve amplifier repair

 

 

 

 

 

 

 

 

 

 

 

This Amplifier was a gift given by a distant relative, as an appreciation when I restored a rare Russian made tape recorder for him, many years back. After I replaced the electrolytic capacitors and other coupling capacitors, and also a few resistors, the Amp was working very well. There was no cover or bottom plate or legs for this Amp. I had fixed salvaged caps of Mosquito repellent liquids on all the four sides at the bottom as legs, and had provided 3 RC inputs with selection switches on its open sides.

how to repair valve amplifier

I had also replaced the speaker outputs to the standard ones currently in use. It was being used by me in this condition, until I budged to the repeated requests from my friends to sell it off to them. That’s how I took it up again, not only for a re-check, but also for getting a cabinet made.




My searches brought me to a Gulf returned man, running a fabrication workshop about 10Kms away from my house. I took the Amp to him, after removing the Valves and also showed a few pictures of another Ahuja Valve Power Amplifier lying with me. He did a good job and returned the set with cabinet after about a month. He also touched paint on the chassis to the extent possible. I shall continue, after you all view a few pictures now:

valve amplifier fixed

valve amplifier fixed and repair

how to fix valve amplifier

 

I also fixed a cooling fan (230V AC) on top of the cabinet, with a suitable plug and socket. First I had fixed the male to the side that goes to AC 230V mains and female to the fan. But after realizing the danger involved in exposed live pins when doing a service in future, I interchanged it, and made it safer. Drilled holes and provided two nice handles on the sides for easy moving around.




Replaced the potentiometers and changed one input of mic to the standard jack. Also changed one knob, as it broke while trying to remove!

how to repair valve amplifier

The completed Amp was put for continuous testing for a few days and finally disposed of to one of the friends, who came to me first! (This refurbishing and disposing is a part of my ‘load shedding’, about which I have covered in another article!) Now the following picture is that all I have as memory of this wonderful Amp, which was more or less, like a part of my family:

fixing valve amplifier

But, ‘satisfaction’ has no excuse for not jumping into the bag, and it did as usual! (LOL)

This article was prepared for you by Parasuraman Subramanian from India. He is 69 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.




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You may check on his previous repair article below:

https://jestineyong.com/burst-capacitor-and-dry-solder-found-in-zebronics-zeb-450w-smps/

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3 Comments

  1. Albert van Bemmelen

    September 6, 2019 at 8:10 pm

    Nice job Parasuraman. I understand how we grow attached to things we kept and used in our homes for a very long time. I too keep a few old antique but still perfectly working original tube radio's although I never use them. They don't need much space and do not eat bread as they say but if someone gives me a good offer I also gladly would sell them.

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  2. Mark

    September 6, 2019 at 8:15 pm

    Well done Parasuraman,
    There is no doubt you have an eye for detail! 🙂

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  3. Robert Calk Jr.

    September 7, 2019 at 1:04 am

    Good job, Parasuraman!

    Likes(2)Dislikes(0)

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