Stereo Williamson 7591 Amplifier Repair

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Published 2023-05-18

This is a beautiful performing amplifier I would call a "perfect" 15 watts per channel using 7591 and 6SN7 in a Williamson design and running a pair of UTC LS-57 output transformers. I have it run hours per day but a few days back it blew a fuse and smelled something burned. Just wanted to show how I go about repairing the equipment that I build. Hope you enjoy.

All Comments (21)

@luckydubeinrc5165 1 year ago

Never ever stop, its knowledge that are forgotten, i appreciate all your time and effort but more over the knowledge we gain as a audience cant be measured ! thumbs up!
@Dukers2300 1 year ago

Hooray you’re back!!!
@radiojet1429 1 year ago

Thanks for pumping life back into the 7591. It is a wonderful and underrated tube. And don't stop making videos. 😁
@Blaculo 1 year ago

Thanks for taking us along on the journey. I watched this while building a 20 watt tube amp.
@MrMersh-ts7jl 1 year ago

Seriously, you e taught me, and I'm sure countless others knowledge that is disappearing. Between you and Mr Carlson I've learned so so much about vacuum tubes and application. Thank you Sir.
@apexmcboob5161 1 year ago

I have to echo the other comments. I've learned a lot from you and always enjoy your videos, please keep them coming. You have a dedicated set of followers!
@tigerelectronics5966 1 year ago

I am so glad you take us along on your journeys with amplifiers! You have taught me a lot, I am absolutely in love with building my own tube amps. I have now built several with wonderful success :)
@mikemccourt6225 10 months ago

Thanks for sharing the knowledge David - I think I’ve been watching your channel for over ten years now and I always learn something. Be well
@johnnorton6085 1 year ago

David, I always enjoy your videos. Thank you for making them.
@MrBillsmith60 1 year ago

Very enjoyable, hope you stay around+++++
@bob_mosavo 1 year ago

Thank you for sharing your knowledge with us 😁 I'm learning a lot from your videos 👍
@MM0IMC 1 year ago

Please keep making these videos, as they are an inspiration! 👍
@pomonabill220 1 year ago

Great to see you again! You sound well. BOY that cap was SHORTED!!!! Guess the 1.8K resistor acted like a sacrificial fuse and saved everything else. The unloaded voltage sure went above the rated working voltage of those caps too. That was a smart thing to do... changing both of them out for higher voltage caps. Cheap insurance and long life. Take care of yourself and post if you want to and when you want to! It is always good to see you!
@zbaby82 1 year ago

I love repair videos.
@jimcatanzaro7808 1 year ago

Love your videos I just made a few amplifiers by hand with your inspiration
@bob_mosavo 1 year ago

Please keep making videos 🙏
@g0fvt 1 year ago

Well done, an excellent diagnosis. The schematic in the chassis is a great move, always good to open a bit of gear you have built and be impressed how smart the younger you was! In a guitar amp with a similarish situation I used a MOSFET as a series element with a long time constant in the gate circuit so that the HV to the small signal stages ramped up slowly to a predefined level. In this case though I think you have a simple and permanent fix.
@jimibrown1955 1 year ago

Your videos have been a huge inspiration for me. Just got my Tek TM504 and SG505. The AA501 [opt 1] should be here Friday. Also just pulled the trigger on a DM501a for the last slot. Just wanted to let you know, out of the many YouTube video channels, I have enjoyed yours the most.
@daviddahlgren9603 2 months ago

I noticed that on some pl-259's I was using , thanks for the info !
@moodyga40 1 year ago

fixing our home made gear is fun shoebill 300B stereo class A amp i built runs 8 hours every weekend best amp ever