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LEAK st20

F

Fitnessed

pfm Member
An opportunity arisen to buy off Tony at what i consider is a very fair price these days..

Tony has been most helpful and i am very grateful for his advice and help....

Myself and Tony have looked through this amp and are of the agreement it has not been used.

Drop resistor,speaker terminals have no witness marks,plating has no degradation and phonos are not marked up...

Starting point is a few cosmetics,i have the same stance as Tony on cosmetics...

1 open box by Vintage Audioworx, on Flickr

2 black cirlce from lead by Vintage Audioworx, on Flickr

2 cardboard marks by Vintage Audioworx, on

Professional compounds x2 used carefully by hand...
cutting back by Vintage Audioworx, on Flickr
Taking it very easy on the shap edges where historically paint laquer can be thinner.
compounding by Vintage Audioworx, on Flickr
cardboard marks removed by Vintage Audioworx, on Flickr
A bit shiny from the colonite no 476 wax,but it will settle and has a bit of protection for me to handle it,touch up pens on order for minor scratches.
finished by Vintage Audioworx, on Flickr
 
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Excellent stuff, very impressed that the circular marks on top look to have come off.

PS For those unaware of the story I bought this from a local auction many years ago and the octal pre-power lead had been coiled up on the top panel, maybe for a lifetime. It had clearly ‘oozed’ a little, as ancient plastics do, leaving some obvious marking on the top plate. My suspicion is the scratch at the octal plug end of the top-plate was done at the auction as it looked really bright and shiny when I got the amp. Other than that there is nothing I’d not put down to storage marks. It should be a great restoration candidate. Good luck!
 
Nicely done, ST20 can produce nice sound when aged components are replaced.
Some folks ask silly prices though, for a unit that looks cosmetically tatty and needs a lot of work to sound its best.
 
Measured original components and have moved forward with a sympathetic and sensible,reliable build.

Original components are all packaged and saved,should someone want to reform the capacitors etc...

Bit of stripping,no tags broken..


NOS STRIPPED by Vintage Audioworx, on Flickr

Verified Transformer readings with Tonys.....
ST20S by Vintage Audioworx, on Flickr

May help someone,meters do scale slightly differently,hence two meters to verify etc.....,
TRANSFORMER TESTING READS by Vintage Audioworx, on Flickr
The original Terminals are staying,there is no witness marks on them at all from any use.
Utilsed the origional brackets serves as a tray to handle the amp and now has airflow underneath. as its black and shows up finger marks,also now have damping....
IMG_6512 by Vintage Audioworx, on Flickr
These will suffice and some shrink wrap and a bit of trimming on the forks, may sort my ocd out....
Otherwise have the internal deltron ones but really want to keep the original patina etc....
IMG_6503 by Vintage Audioworx, on Flickr
Note plugs not all the way in...
IMG_6506 - Copy by Vintage Audioworx, on Flickr
Origional phonos staying put..
IMG_6508 by Vintage Audioworx, on Flickr
 
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Installed....
kY09 PIO 0.1/0.22
kemet 47uf 63v peg124 installed(rs part no 226-6971)£27.20 for x6
Datasheet -very longlife 27,000hrs at 105/LOW ESL/ESR...
IMG_6602 by vintage audio vintage audio, on Flickr

F&t 50ufs,x2 installed and painted,(amazon) not quite there in direct sunlight,but inside in the house fine,not chasing perfection..
IMG_6607 by vintage audio vintage audio, on Flickr

Not sure on weather to replace the smaller original capacitors,peak esr meter will not read lesser values.....

GREY st20 kyo09 0.22uf reads / bronze st20
0.26/4.9 esr 0.25/5.6 esr
0.26/4.5 esr 0.26/4.9 esr
0.26/4.7 esr 0.26/4.4 esr
0.26/4.5 esr 0.25/5.0 esr

Top tip....if anyone ever has to chuck a dishwasher,save the plastic cutlery organizer for your workshop tools....
 
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You say you're not chasing perfection but it looks pretty close to me. Well done. Hope it sounds as good as it looks. I'll be watching this thread with great interest.
 
Wow, how clean is that chassis? Sparkling. Did you strip it down completely and clean it up? It looks fabulous.
 
chiily said:
Wow, how clean is that chassis? Sparkling. Did you strip it down completely and clean it up? It looks fabulous.
Click to expand...
The underside has not been touched:),just stripped of components,my ocd will kick in in the end with the new grid resistor bending and making sure all wires look right;) etc...
Top has been compounded and carbunara waxed,although it is now full of handling finger marks...
 
Oh nice! So neat.
Out of curiosity what was the reasoning behind going away from tag boards like this? The layout looks much more easy to read and troubleshoot.
Is it sound quality, ground loops, amps getting more complex or cost?
 
DonMarks said:
Oh nice! So neat.
Out of curiosity what was the reasoning behind going away from tag boards like this? The layout looks much more easy to read and troubleshoot.
Is it sound quality, ground loops, amps getting more complex or cost?
Click to expand...
thanks,the resistors dissapate heat,the tag board have airflow holes also.
I use a jewellers round concave long nose forming pliers.
 
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DonMarks said:
Oh nice! So neat.
Out of curiosity what was the reasoning behind going away from tag boards like this? The layout looks much more easy to read and troubleshoot.
Is it sound quality, ground loops, amps getting more complex or cost?
Click to expand...
Manufacturing cost.

You need proper wirepersons and the skills are not there anymore, almost anyone can knock out a passable PCB.
 
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