Author Topic: Restoration of Leak 12 Point One mono-blocks  (Read 2701 times)

Offline charles

Restoration of Leak 12 Point One mono-blocks
« on: November 28, 2018, 05:53:09 PM »
In he past I restored some Leak TL12 point one valve amplifiers and some I use on a regular basis.

A couple of weeks ago I obtained two Leak 12 point one mono-blocks.

One must be very careful when restoring these Leaks because its value lies in originality.

These sets are basically original as one can get, with original components such the body, tip spot resistors.

These sets need some restoration because of some small rust spots underneath the chassis, etc.

These are the open frame transformer models (circa 1948 -1953) that are the more sought after models.

One has to replace some electronic components but keep the replaced components.

The Leak 12 point one is probably one of the most collectible vintage valve amplifier.

I just hope I have the time to do this restoration.

I will later post some photographs.

Offline 2wice

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #1 on: November 28, 2018, 06:09:08 PM »
Awesome Charles!
Looking forward to the progress pics.

Thanks for sharing.

Offline peterc

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #2 on: November 28, 2018, 06:21:46 PM »
Great find Charles.

Looking forward to following your project

Peter

Offline Des Miles

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #3 on: November 29, 2018, 08:45:03 AM »
Going to be an awesome project! Looking forward to seeing pics of the restored amps.

Just as an aside, our American friends call those old tip spot resisters, " dog bone resisters " and some restorers actually replicate them using modern resistors.

https://www.radiomuseum.org/forum/replicating_old_dogbone_resistors.html

I saw Sputnik, well... actually the booster rocket that went into orbit with it!!

Offline charles

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #4 on: November 29, 2018, 04:43:57 PM »
Thank all of you for the encouragement regarding the restoration process.

Regarding the body, tip, spot resistors. Most of the time these resistors keep their value.
This is my experience regarding the other Leaks that I restored in the past.

I will test them to see if the values drifted. I try to keep most of the original resistors.

I have a complete and in good cosmetic condition a spare Leak chassis minus the oil capacitor bank,
output-and mains transformers that I am going to use for one of the mono-blocks and to test all the
transformers.   
« Last Edit: November 29, 2018, 05:08:21 PM by charles »

Offline El Sid

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #5 on: November 30, 2018, 11:24:07 AM »
Photos please Charles!  :sd:

Offline afroaudio

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #6 on: December 02, 2018, 01:16:46 PM »
Here we go gents.....

1 by Bregtje Cals, on Flickr

2 by Bregtje Cals, on Flickr

3 by Bregtje Cals, on Flickr

4 by Bregtje Cals, on Flickr

5 by Bregtje Cals, on Flickr

Offline King_Julian_S

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #7 on: December 02, 2018, 01:23:23 PM »
 
Non audiophile music lover...

Offline Family_Dog

  • Administrator
  • Trade Count: (+28)
  • *****
  • Posts: 9,247
  • Total likes: 275
  • STEEL & GLASS - Everlasting Beauty!
    • Repcom 2-way Radios
Re: Restoration of Leak 12 Point One mono-blocks
« Reply #8 on: December 02, 2018, 02:28:18 PM »
It looks like those transformers have cooked, Charles?

-F_D



-Eric

That Guy in South Africa...
*************************************
http://groups.yahoo.com/group/vintage_tube/
*************************************

Offline charles

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #9 on: December 02, 2018, 03:15:16 PM »
Johnathan thank you for the photos.

Eric, these amplifiers stood for many years probably under a carport.

The output transformers look much better.

If necessary, the mains transformers can be rewound.

The coming week I will start measuring the mains transformers.


 
« Last Edit: December 02, 2018, 03:17:44 PM by charles »

Offline marantz123

  • Trade Count: (+2)
  • AVForums Veteran
  • ***
  • Posts: 484
  • Total likes: 60
  • I learnt more from The Internet when it was slower
Re: Restoration of Leak 12 Point One mono-blocks
« Reply #10 on: December 02, 2018, 04:07:50 PM »
Gorgeous !!! ...and in very very capable hands for restoration for future generations to enjoy...on our shores. Good luck Charles, n plenty pics and step-by-step stuff..please.  :thumbs:

Offline Ampdog

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #11 on: December 03, 2018, 05:58:01 AM »
Ach NO!!!

What a way to spend Christmas for a hard-working man! :(  :sweat:

(You will watch that directly heated rectifier?)
Audio must be the only branch of engineering where lack of basics' knowledge is considered a superior form of wisdom. (Anon)

Offline fredeb

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #12 on: December 03, 2018, 11:53:19 PM »
Wow Charles ! Where do you find all these treasures ?

...evolution is the gradual development and stratification of progressive series of wholes, stretching from the inorganic beginnings to the highest level of spiritual creation.
Jan Smuts

Offline charles

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #13 on: December 04, 2018, 12:41:40 PM »
All over the country

Sometimes it takes lots of time and effort to locate a wanted item.

Some good news regarding the Leak 12 point one.

I have put one of the mains transformers in the spare Leak chassis and
started to measure it.

One must first measure the primary resistance, secondary HT winding resistance and others
and also do an insulation test before applying power to it.

Powered it up: All voltages present.

Bear in mind this is without a load.

This is a relief, now for the second mains transformer.

Offline AudioEars

Re: Restoration of Leak 12 Point One mono-blocks
« Reply #14 on: December 04, 2018, 07:16:34 PM »
I am following your endeavour like a favourite mini series
Cant wait  for your next update / "episode"
I wish you luck and may the resoration angels guide you to a smooth path to success
Kind regards
AudioEars